Category Archives: Hydrocephalus

Update: Cryptococcal meningitis

Cryptococcal meningitis

Cryptococcosis is a fungal infection caused by Cryptococcus spp. that enters the body via inhalation, which mainly invades the lungs and central nervous system.

Two types of fungus can cause cryptococcal meningitis (CM). They are called Cryptococcus neoformans (C. neoformans) and Cryptococcus gattii (C.gattii). This disease is rare in healthy people. CM is more common in people who have compromised immune systems, such as people who have AIDS.

Cryptococcal meningitis may have long-term morbidity and requires a permanent cerebrospinal fluid shunt.

see Cryptococcus neoformans ventriculoperitoneal shunt infection.

see Cryptococcal choroid plexitis.

Clinical features

Cryptococcal meningitis are usually subacute or chronic in nature. HIV-infected patients may have minimal or nonspecific symptoms. Common symptoms are as follows:

Headache

Confusion

Lethargy

Obtundation

Coma

Normal or mildly elevated temperature

Nausea and vomiting (with increased intracranial pressure)

Fever and stiff neck (with an aggressive inflammatory response; less common)

Blurred vision, photophobia, and diplopia

Hearing defects, seizures, ataxia, aphasia, and choreoathetoid movements

After lung and CNS infection, the next most commonly involved organs in disseminated cryptococcosis include the skin, the prostate, and the medullary cavity of bones. Cutaneous manifestations (10-15% of cases) are as follows:

Papules, pustules, nodules, ulcers, or draining sinuses

Umbilicated papules in patients with AIDS

Cellulitis with necrotizing vasculitis in organ transplant recipients

Other less common forms of cryptococcosis include the following:

Optic neuritis or endophthalmitis

Myocarditis

Chorioretinitis

Hepatitis

Peritonitis

Renal abscess

Myositis

Adrenal involvement.

Diagnosis

The workup in patients with suspected cryptococcosis includes the following:

Cutaneous lesions: Biopsy with fungal stains and cultures

Blood: Fungal culture, cryptococcal serology, and cryptococcal antigen testing

Cerebrospinal fluid: India ink smear, fungal culture, and cryptococcal antigen testing

Urine and sputum cultures, even if renal or pulmonary disease is not clinically evident

In AIDS patients with cryptococcal pneumonia, culture of bronchoalveolar lavage washings

With possible CNS cryptococcosis, especially in patients who present with focal neurologic deficits or a history compatible with slowly progressive meningitis, consider obtaining a computed tomography or magnetic resonance imaging scan of the brain prior to performing a lumbar puncture. If a mass lesion is identified, do not perform a lumbar puncture to obtain spinal fluid; rather, consult a neurosurgeon for an alternative procedure.

With pulmonary cryptococcosis, radiographic findings in patients who are asymptomatic and immunocompetent may include the following:

Patchy pneumonitis

Granulomas ranging from 2-7 cm

Miliary disease similar to that in tuberculosis.

Treatment

Treatment of cryptococcal meningitis consists of three phases: induction, consolidation, and maintenance. Effective induction therapy requires potent fungicidal drugs (amphotericin B and flucytosine), which are often unavailable in low-resource, high-endemicity settings. As a consequence, mortality is unacceptably high. Wider access to effective treatment is urgently required to improve outcomes. For human immunodeficiency virus-infected patients, judicious management of asymptomatic cryptococcal antigenemia and appropriately timed introduction of antiretroviral therapy are important 1).

Case series

2017

A study aimed to evaluate the risk factors and create a predictive model for permanent shunt treatment in cryptococcal meningitis patients. This was a retrospective analytical study conducted at Khon Kaen University. The study period was from January 2005 to December 2015.

They enrolled all adult patients diagnosed with cryptococcal meningitis. Risk factors predictive for permanent shunting treatment were analyzed by multivariate logistic regression analysis. There were 341 patients diagnosed with cryptococcal meningitis. Of those, 64 patients (18.7%) were treated with permanent shunts. There were three independent factors associated with permanent shunt treatment. The presence of hydrocephalus had the highest adjusted OR at 56.77. The resulting predictive model for permanent shunt treatment (y) is (-3.85) + (4.04 × hydrocephalus) + (2.13 × initial CSF opening pressure (OP) > 25 cm H2O) + (1.87 × non-HIV). In conclusion, non-HIV status, initial CSF OP greater than or equal to 25 cm H2O, and the presence of hydrocephalus are indicators of the future necessity for permanent shunt therapy 2).

2014

In Japan, most cases of cryptococcosis are caused by Cryptococcus neoformans(C. neoformans). Until now, only three cases which the infectious agent was Cryptococcus neoformans var. gattii(C. gattii)have been reported. As compared with cryptococcosis caused by C. neoformans, which is often observed in immunocompromised hosts, cryptococcosis caused by C. gattii occurs predominantly in immunocompetent hosts and is resistant to antifungal drugs. Here, we report a case of refractory cerebral cryptococcoma that was successfully treated by surgical resection of the lesions. A 33-year-old man with no medical history complained of headache, hearing disturbance, and irritability. Pulmonary CT showed a nodular lesion in the left lung. Cerebrospinal fluid examination with Indian ink indicated cryptococcal meningitis, and PCR confirmed infection with C. gattii. C. gattii is usually seen in the tropics and subtropics. Since this patient imported trees and soils from abroad to feed stag beetles, parasite or fungal infection was, as such, suspected. Although he received 2 years of intravenous and intraventricular antifungal treatment, brain cryptococcomas were formed and gradually increased. Because of the refractory clinical course, the patient underwent surgical resection of the cerebral lesions. With continuation of antifungal drugs for 6 months after the surgeries, Cryptococcus could not be cultured from cerebrospinal fluid, and no lesions were seen on MR images. If cerebral cryptococcosis responds poorly to antifungal agents, surgical treatment of the cerebral lesion should be considered. 3).

1)

Sloan DJ, Parris V. Cryptococcal meningitis: epidemiology and therapeutic options. Clin Epidemiol. 2014 May 13;6:169-82. doi: 10.2147/CLEP.S38850. eCollection 2014. Review. PubMed PMID: 24872723; PubMed Central PMCID: PMC4026566.

2)

Phusoongnern W, Anunnatsiri S, Sawanyawisuth K, Kitkhuandee A. Predictive Model for Permanent Shunting in Cryptococcal meningitis. Am J Trop Med Hyg. 2017 Aug 14. doi: 10.4269/ajtmh.17-0177. [Epub ahead of print] PubMed PMID: 28820702.

3)

Inada T, Imamura H, Kawamoto M, Sekiya H, Imai Y, Tani S, Adachi H, Ishikawa T, Mineharu Y, Asai K, Ikeda H, Ogura T, Shibata T, Beppu M, Agawa Y, Shimizu K, Sakai N, Kikuchi H. [Cryptococcus Neoformans Var. Gattii meningoencephalitis with cryptococcoma in an immunocompetent patient successfully treated by surgical resection]. No Shinkei Geka. 2014 Feb;42(2):123-7. Japanese. PubMed PMID: 24501185.

Update: Cerebrospinal fluid shunt complication

see Lumboperitoneal shunt complication.

see Ventriculoperitoneal shunt complication.

Ventricular shunts for pediatric hydrocephalus continue to be plagued with high failure rates. Reported risk factors for shunt failure are inconsistent and controversial. The raw or global shunt revision rate has been the foundation of several proposed quality metrics.

The most common problems related to cerebrospinal fluid shunt are shunt obstruction, shunt infection and shunt overdrainage. The incidence of shunt complications is higher when less time has elapsed since the previous shunt surgery. Nearly all shunt patients end up with one or multiple reoperations. Thorough history, head scan (ultrasound, CT or MRI) and plain x-ray (shunt series) are the corner stones when reviewing shunt problems.

Wong et al. performed a PubMed search using search terms “cerebral shunt,” “cerebrospinal fluid shunt,” “CSF shunt,” “ventriculoperitoneal shunt,” “cerebral shunt AND complications,” “cerebrospinal fluid shunt AND complications,” “CSF shunt AND complications,” and “ventriculoperitoneal shunt AND complications.” Only papers that specifically discussed the relevant complication rates were included. Papers were chosen to be included to maximize the range of rates of occurrence for the adverse events reported. RESULTS: In this review of the neurosurgery literature, the reported rate of mechanical malfunction ranged from 8% to 64%. The use of programmable valves has increased but remains of unproven benefit even in randomized trials. Infection was the second most common complication, with the rate ranging from 3% to 12% of shunt operations. A meta-analysis that included 17 randomized controlled trials of perioperative antibiotic prophylaxis demonstrated a decrease in shunt infection by half (OR 0.51, 95% CI 0.36-0.73). Similarly, use of detailed protocols including perioperative antibiotics, skin preparation, and limitation of OR personnel and operative time, among other steps, were shown in uncontrolled studies to decrease shunt infection by more than half. Other adverse events included intraabdominal complications, with a reported incidence of 1% to 24%, intracerebral hemorrhage, reported to occur in 4% of cases, and perioperative epilepsy, with a reported association with shunt procedures ranging from 20% to 32%. Potential management strategies are reported but are largely without formal evaluation.

Surgery for CSF shunt placement or revision is associated with a high complication risk due primarily to mechanical issues and infection. Concerted efforts aimed at large-scale monitoring of neurosurgical complications and consistent quality improvement within these highlighted realms may significantly improve patient outcomes 1).

Infection

Shunt dysfunction

Shunt overdrainage

see Shunt overdrainage.

Solid noninfectious growing mass

Shunt-related craniocerebral disproportion.

Slit ventricle syndrome and secondary craniosynostosis are late-onset complications after shunt placement these 2 conditions occasionally occur together.

see Tension pneumocephalus after shunt insertion.

The results of shunt testing are helpful in many circumstances, such as the initial choice of shunt and the evaluation of the shunt when its dysfunction is suspected 2).

Shunting procedures for syringomyelia have been criticized due to the inconsistent long-term outcomes.

This is largely the result of small volume flow at a very low-pressure profile leading to occlusion or malfunction of the shunts.

 Noises

Patients have reported anecdotally on noises associated with their shunts 4).

Diagnosis

Radionuclide shuntogram is important in the evaluation of cerebrospinal fluid shunt complications such as mechanical failure, malpositioning, pseudocyst, or overdrainage. Bermo et al present a case of congenital hydrocephalus and posterior fossa cyst with multiple shunt procedures and revisions with breakage of the proximal tube of the ventriculoperitoneal shunt but preserved CSF drainage through the patent fibrous tract. Careful correlation with SPECT/CT images helped confirm the breakage and exclude CSF leak outside of the tract, which was suspected on planar images 3).

Books

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Case series

2017

Kaestner et al. from the Department of Neurosurgery, Klinikum Kassel, Germany, identified all patients who had been treated or followed in our neurosurgical department within a 15-year period from January 2000 up to the end of 2014. After approval of the local ethics committee all patients who were cognitively intact were explored by a questionnaire and by personal interview about acoustic phenomena related to their shunts.

Three hundred forty-seven patients were eligible for the survey, and 260 patients completed the questionnaire. Twenty-nine patients (11.2%) reported on noises raised by their shunts. All of them experienced short-lasting noises while changing body posture, mainly from a horizontal to an upright position, or while reclining the head. Most of the patients reported on soft sounds, but loud and even very loud noises occurred in some patients. Seventy-six percent of the patients were not bothered by these noises as they considered it as a normal part of the therapy or as proof that the shunt device was functioning. Modern valves with gravitational units are prone to produce noises in young adults, but nearly all valve types can evoke noises.

Noises caused by a shunt do occur in a considerable number of patients with shunts. One should be aware of this phenomenon, and these patients must be taken seriously 5).

2016

Rossi et al undertook a study to determine risk factors for shunt revision within their own patient population.

In this single-center retrospective cohort study, a database was created of all ventricular shunt operations performed at the authors’ institution from January 1, 2010, through December 2013. For each index shunt surgery, demographic, clinical, and procedural variables were assembled. An “index surgery” was defined as implantation of a new shunt or the revision or augmentation of an existing shunt system. Bivariate analyses were first performed to evaluate individual effects of each independent variable on shunt failure at 90 days and at 180 days. A final multivariate model was chosen for each outcome by using a backward model selection approach.

There were 466 patients in the study accounting for 739 unique (“index”) operations, for an average of 1.59 procedures per patient. The median age for the cohort at the time of the first shunt surgery was 5 years (range 0-35.7 years), with 53.9% males. The 90- and 180-day shunt failure rates were 24.1% and 29.9%, respectively. The authors found no variable-demographic, clinical, or procedural-that predicted shunt failure within 90 or 180 days.

In this study, none of the risk factors that were examined were statistically significant in determining shunt failure within 90 or 180 days. Given the negative findings and the fact that all other risk factors for shunt failure that have been proposed in the literature thus far are beyond the control of the surgeon (i.e., nonmodifiable), the use of an institution’s or individual’s global shunt revision rate remains questionable and needs further evaluation before being accepted as a quality metric 6).

2015

A study aims to review the imaging findings of distal (thoracic and abdominal) complications related to ventriculo-peritoneal (VP), ventriculo-pleural (VPL), and ventriculo-atrial (VA) cerebrospinal fluid (CSF) shunt catheter placement. Institution review board-approved single-center study of patients with thoracic and abdominal CSF catheter-related complications on cross-sectional imaging examinations over a 14-year period was performed. Clinical presentation, patient demographics, prior medical history, and subsequent surgical treatment were recorded. The presence or absence of CSF catheter-related infection and/or acute hydrocephalus on cross-sectional imaging was also recorded. There were 81 distal CSF catheter-related complications identified on 47 thoracic or abdominal imaging examinations in 30 patients (age 5-80 years, mean 39.3 years), most often on CT (CT = 42, MRI = 1, US = 4). Complications included 38 intraperitoneal and 11 extraperitoneal fluid collections. Extraperitoneal collections included nine abdominal wall subcutaneous (SC) pseudocysts associated with shunt migration and obesity, an intrapleural pseudocyst, and a breast pseudocyst. There were also two large VPL-related pleural effusions, a fractured catheter in the SC tissues, and a large VA shunt thrombus within the right atrium. Ten patients (33.3 %) had culture-positive infection from CSF or shunt catheter samples. Ten patients (33.3 %) had features of temporally related acute or worsening hydrocephalus on neuroimaging. In four of these patients, the detection of thoracic and abdominal complications on CT preceded and predicted the findings of acute hydrocephalus on cranial imaging. Thoracic and abdominal complications of CSF shunts, as can be identified on CT, include shunt infection and/or obstruction, may be both multiple and recurrent, and may be predictive of concurrent acute intracranial problems 7).

2011

From January 1999 to December 2006, Korinek et al., conducted a prospective surveillance program for all neurosurgical procedures including reoperations and infections. Patients undergoing CSF shunt placement were retrospectively identified among patients labeled in the database as having a shunt as a primary or secondary intervention. Revisions of shunts implanted in another hospital or before the study period were excluded, as well as lumbo- or cyst-peritoneal shunts. Shunt complications were classified as mechanical dysfunction or infection. Follow-up was at least 2 years. Potential risk factors were evaluated using log-rank tests and stepwise Cox regression models.

During the 8-year surveillance period, a total of 14 275 patients underwent neurosurgical procedures, including 839 who underwent shunt placement. One hundred nineteen patients were excluded, leaving 720 study patients. Mechanical dysfunction occurred in 124 patients (17.2%) and shunt infection in 44 patients (6.1%). These 168 patients required 375 reoperations. Risk factors for mechanical dysfunction were atrial shunt, greater number of previous external ventriculostomies, and male sex; risk factors for shunt infection were previous CSF leak, previous revisions for dysfunction, surgical incision after 10 am, and longer operating time.

Shunt surgery still carries a high morbidity rate, with a mean of 2.2 reoperations per patient in 23.3% of patients. Our risk-factor data suggest methods for decreasing shunt-related morbidity, including peritoneal routing whenever possible and special attention to preventing CSF leaks after craniotomy or external ventriculostomy 8).

Case reports

James et al. describe 3 children who presented with progressively enlarging skin-covered solid masses over the shunt catheter in the neck/clavicular region. The authors reviewed the clinical, laboratory, pathological, radiographic, and follow-up data for all 3 patients and reviewed the literature on the subject. The patients had no clinical evidence of an infectious process. Surgical exploration revealed that masses were surrounding and encasing the shunt tubing to which they were strongly attached. Pathological studies of the tissues demonstrated varying degrees of exuberant chronically inflamed granulation tissues, interstitial fibrosis, and dystrophic calcification. One patient had associated thinning of the skin overlying the mass and subsequently developed ulceration. No infectious organisms were observed. The cerebrospinal fluid aspirates from the shunts did not yield any organisms. There has been no recurrence of the masses. The presence of a growing mass over the shunt tube in the neck or the chest region without clinical evidence of infection does not indicate that the mass should be treated with antibiotics and complete shunt removal. Rather, the mass can be cured by extirpation and with “bypass” new shunt tubing locally 9).

1)

Wong JM, Ziewacz JE, Ho AL, Panchmatia JR, Bader AM, Garton HJ, Laws ER, Gawande AA. Patterns in neurosurgical adverse events: cerebrospinal fluid shunt surgery. Neurosurg Focus. 2012 Nov;33(5):E13. doi: 10.3171/2012.7.FOCUS12179. Review. PubMed PMID: 23116093.

2)

Chari A, Czosnyka M, Richards HK, Pickard JD, Czosnyka ZH. Hydrocephalus shunt technology: 20 years of experience from the Cambridge Shunt Evaluation Laboratory. J Neurosurg. 2014 Jan 3. [Epub ahead of print] PubMed PMID: 24405071.

3)

Bermo M, Leung AS, Matesan M. A Case of Discontinued Proximal Limb of a Ventriculoperitoneal Shunt With Patent Fibrous Tract. Clin Nucl Med. 2016 Feb 24. [Epub ahead of print] PubMed PMID: 26914568.

4)

Kaestner S, Fraij A, Deinsberger W, Roth C. I can hear my shunt-audible noises associated with CSF shunts in hydrocephalic patients. Acta Neurochir (Wien). 2017 Apr 14. doi: 10.1007/s00701-017-3179-z. [Epub ahead of print] PubMed PMID: 28411322.

5)

Kaestner S, Fraij A, Deinsberger W, Roth C. I can hear my shunt-audible noises associated with CSF shunts in hydrocephalic patients. Acta Neurochir (Wien). 2017 Jun;159(6):981-986. doi: 10.1007/s00701-017-3179-z. Epub 2017 Apr 14. PubMed PMID: 28411322.

6)

Rossi NB, Khan NR, Jones TL, Lepard J, McAbee JH, Klimo P Jr. Predicting shunt failure in children: should the global shunt revision rate be a quality measure? J Neurosurg Pediatr. 2016 Mar;17(3):249-59. doi: 10.3171/2015.5.PEDS15118. Epub 2015 Nov 6. PubMed PMID: 26544083.

7)

Bolster F, Fardanesh R, Morgan T, Katz DS, Daly B. Cross-sectional imaging of thoracic and abdominal complications of cerebrospinal fluid shunt catheters. Emerg Radiol. 2015 Nov 26. [Epub ahead of print] PubMed PMID: 26610766.

8)

Korinek AM, Fulla-Oller L, Boch AL, Golmard JL, Hadiji B, Puybasset L. Morbidity of ventricular cerebrospinal fluid shunt surgery in adults: an 8-year study. Neurosurgery. 2011 Apr;68(4):985-94; discussion 994-5. doi: 10.1227/NEU.0b013e318208f360. PubMed PMID: 21221037.

9)

James HE, Postlethwait RA, Sandler ED. Solid noninfectious growing masses over cerebrospinal fluid shunts: report of 3 cases. J Neurosurg Pediatr. 2015 Jan 30:1-4. [Epub ahead of print] PubMed PMID: 25634820.

Callosal Angle

Ideally the angle should be measured on a coronal image perpendicular to the anterior commissureposterior commissure (AC-PC) plane at the level of the posterior commissure 1) 2).

Indications

The shapes of the ventricles, the ventricular index and a callosal angle of 110 degrees or less provided supporting evidence of obstruction in a study. Recognition of an obstructive element in ventricular dilatation following head injury is important, since in a small carefully selected group of patients a ventricular shunting operation may favourably affect recovery 3).

Measuring the Callosal angle (CA) helps in differentiating INPH patients from Alzheimer’s disease (AD) and normally aged subjects4).

In iNPH, Evans’ index, which indicates external enlargement, is not appropriate for evaluating ventricular enlargement; alternatively, the size of cerebral ventricles estimated by coronal sections can be used 5).

The callosal angle has been proposed as a useful marker of patients with idiopathic normal pressure hydrocephalus (iNPH) 6).

It is helpful in distinguishing these patients from those with ex-vacuo ventriculomegaly.

A small callosal angle, wide temporal horns, and occurrence of disproportionately enlarged subarachnoid space hydrocephalus are common in patients with idiopathic normal pressure hydrocephalus and were significant predictors of a positive shunt outcome. These noninvasive and easily assessed radiologic markers could aid in the selection of candidates for shunt surgery 7).

Values

In general patients with iNPH have smaller angles than those with ventriculomegaly from atrophy or normal controls.

A normal value is typically between 100-120°. In patients with iNPH that value is lower, between 50-80°.

In one study, symptomatic iNPH patients who responded to shunting had a significantly smaller mean preoperative callosal angle (59° (95% CI 56°-63°)) compared with those who did not respond (68° (95% CI 61°-75°)).

CA and Evans Index (EI) may serve as a screening tool to help the radiologist differentiate patients with NPH from patients without NPH, which would allow for designation of patients for further volumetric assessment 8).

Simple linear regression analyses demonstrated that presurgical high-convexity tightness, callosal angle, and Sylvian fissure dilation were significantly associated with the 1-year changes in the clinical symptoms. A multiple linear regression analysis demonstrated that presurgical high-convexity tightness alone predicted the improvement of the clinical symptoms 1 year after surgery 9).

In a retrospective cohort study, Kojoukhova et al evaluated brain CT or MRI scans of 390 patients with suspected iNPH. Based on a 24-h intraventricular pressure monitoring session, patients were classified into a non-NPH (n = 161) or probable iNPH (n = 229) group. Volumes of cerebrospinal fluid compartments (lateral ventricles, sylvian and suprasylvian subarachnoid spaces and basal cisterns) were visually assessed. Disproportionally enlarged subarachnoid spaces, flow void, white matter changes, medial temporal lobe atrophy and focally dilated sulci were evaluated. Moreover, we measured quantitative markers: Evans’ index (EI), the modified cella media index, mean width of the temporal horns and callosal angle.

1)

Virhammar J, Laurell K, Cesarini KG et-al. The callosal angle measured on MRI as a predictor of outcome in idiopathic normal-pressure hydrocephalus. J. Neurosurg. 2014;120 (1): 178-84. doi:10.3171/2013.8.JNS13575
2)

Ishii K, Kanda T, Harada A et-al. Clinical impact of the callosal angle in the diagnosis of idiopathic normal pressure hydrocephalus. Eur Radiol. 2008;18 (11): 2678-83. doi:10.1007/s00330-008-1044-4
3)

Hawkins TD, Lloyd AD, Fletcher GI, Hanka R. Ventricular size following head injury: a clinico-radiological study. Clin Radiol. 1976 Jul;27(3):279-89. PubMed PMID: 1086181.
4)

Ishii K, Kanda T, Harada A, Miyamoto N, Kawaguchi T, Shimada K, Ohkawa S, Uemura T, Yoshikawa T, Mori E. Clinical impact of the callosal angle in the diagnosis of idiopathic normal pressure hydrocephalus. Eur Radiol. 2008 Nov;18(11):2678-83. doi: 10.1007/s00330-008-1044-4. Epub 2008 May 24. PubMed PMID: 18500524.
5)

Naruse H, Matsuoka Y. [Post-operative improvement of 14 cases who were considered iNPH despite Evans’ index of 0.3 or less]. No Shinkei Geka. 2013 Jan;41(1):25-30. Japanese. PubMed PMID: 23269252.
6)

Cagnin A, Simioni M, Tagliapietra M, Citton V, Pompanin S, Della Puppa A, Ermani M, Manara R. A Simplified Callosal Angle Measure Best Differentiates Idiopathic-Normal Pressure Hydrocephalus from Neurodegenerative Dementia. J Alzheimers Dis. 2015;46(4):1033-8. doi: 10.3233/JAD-150107. PubMed PMID: 26402630.
7)

Virhammar J, Laurell K, Cesarini KG, Larsson EM. Preoperative prognostic value of MRI findings in 108 patients with idiopathic normal pressure hydrocephalus. AJNR Am J Neuroradiol. 2014 Dec;35(12):2311-8. doi: 10.3174/ajnr.A4046. Epub 2014 Jul 10. PubMed PMID: 25012669.
8)

Miskin N, Patel H, Franceschi AM, Ades-Aron B, Le A, Damadian BE, Stanton C, Serulle Y, Golomb J, Gonen O, Rusinek H, George AE; Alzheimer’s Disease Neuroimaging Initiative.. Diagnosis of Normal-Pressure Hydrocephalus: Use of Traditional Measures in the Era of Volumetric MR Imaging. Radiology. 2017 May 10:161216. doi: 10.1148/radiol.2017161216. [Epub ahead of print] PubMed PMID: 28498794.
9)

Narita W, Nishio Y, Baba T, Iizuka O, Ishihara T, Matsuda M, Iwasaki M, Tominaga T, Mori E. High-Convexity Tightness Predicts the Shunt Response in Idiopathic Normal Pressure Hydrocephalus. AJNR Am J Neuroradiol. 2016 Jun 30. [Epub ahead of print] PubMed PMID: 27365329.

Update: Idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a progressive neurodegenerative disease in the elderly with enlarged ventricles and normal or slightly elevated cerebrospinal fluid pressure, clinically characterized by an insidious onset and gradual progression of impairments of gait, balance, cognition, with urinary incontinence 1).

History

Normal Pressure Hydrocephalus first became recognized on March 10, 1964 as a distinct medical syndrome by Salomón Hakim, M.D., Ph.D.

The classic triad of magnetic apraxia, urinary incontinence, and dementia remain relevant into the 21(st) century as being the basis for symptomatic diagnosis and predicting potential benefit from ventriculoperitoneal shunting, though they have been greatly augmented by the addition of modern neuroimaging, particularly MRI.

Modern criteria recognize a wider range of diagnostic criteria, and new positive and negative prognostic indicators for treatment benefit have been discovered, though the mainstay remains initial drainage of a large volume of cerebrospinal fluid and monitoring for clinical improvement. Even with our advances in understanding both primary and secondary normal pressure hydrocephalus, diagnosis, management, and counseling remain challenging in this disorder 2).

Epidemiology

In people over 65 years old, pooled prevalence obtained from specific population studies was 1.3%, almost 50-fold higher than that inferred from door-to-door surveys of dementia or Parkinsonism. Prevalence may be even higher in assisted-living and extended-care residents, with up to 11.6% of patients fulfilling the criteria for suspected iNPH and 2.0% of patients showing permanent improvement after cerebrospinal fluid (CSF) diversion. The only prospective population-based survey that reported iNPH incidence estimated 1.20 cases/1000 inhabitants/year, 15-fold higher than estimates obtained from studies based on hospital catchment areas. The incidence of shunt surgery for iNPH and SRiNPH obtained from incident cases of hospital catchment areas appears to be fewer than two cases and one case/100,000 inhabitants/year, respectively. Unfortunately, there is no population-based study reporting the real values for these two parameters.

iNPH appears to be extremely under-diagnosed. Properly designed and adequately powered population based studies are required to accurately characterize this disease’s epidemiology 3).

The prevalence of iNPH is high—for example, in Japan among people older than 65, the prevalence is between 0.5% and 2.9% 4)and the syndrome is both underdiagnosed and undertreated.

Classification

It is recommended that INPH be classified into probable, possible, and unlikely categories. It is hope that these criteria will be widely applied in clinical practice and will promote greater consistency in patient selection in future clinical investigations involving INPH 5).

Etiology

Unknown.

All patients with idiopathic normal pressure hydrocephalus (INPH) who underwent shunting in Sweden in 2008-2010 were compared to age- and sex-matched population-based controls. Inclusion criteria were age 60-85 years and no dementia. The 10 most important vascular risk factor (VRFs) and cerebrovascular and peripheral vascular disease were prospectively assessed using blood samples, clinical examinations, and standardized questionnaires. Assessed VRFs were hypertension, hyperlipidemia, diabetes, obesity, psychosocial factors, smoking habits, diet, alcohol intake, cardiac disease, and physical activity.

In total, 176 patients with INPH and 368 controls participated. Multivariable logistic regression analysis indicated that hyperlipidemia (odds ratio [OR] 2.380; 95% confidence interval [CI] 1.434-3.950), diabetes (OR 2.169; 95% CI 1.195-3.938), obesity (OR 5.428; 95% CI 2.502-11.772), and psychosocial factors (OR 5.343; 95% CI 3.219-8.868) were independently associated with INPH. Hypertension, physical inactivity, and cerebrovascular and peripheral vascular disease were also overrepresented in INPH. Moderate alcohol intake and physical activity were overrepresented among the controls. The population-attributable risk percentage was 24%.

The findings confirm that patients with INPH have more VRFs and lack the protective factors present in the general population. Almost 25% of cases of INPH may be explained by VRFs. This suggests that INPH may be a subtype of vascular dementia. Targeted interventions against modifiable VRFs are likely to have beneficial effects on INPH 6).


Although the exact pathogenesis of NPH is unknown, many possible causes have been postulated, including cerebrovascular ischemia. Studies have demonstrated that periventricular blood flow and cerebrovascular autoregulation are reduced.

It is also thought that biomechanical changes, such as the combination of tissue distortion caused by ventricular dilation, CSF and interstitial fluid stasis, and impaired autoregulation may result in failure of drainage of neurotoxic compounds such as amyloid-b.

Increased CSF stroke volume through the aqueduct has also been demonstrated in the NPH population despite normal CSF pressures. The reaction of the cerebral mantle to all or some of these processes is poorly understood. It is thought that white matter tract connections serving the cortex could be disrupted in a variety of ways, including disconnection, swelling, stretching, and compression. Therefore, it is possible that some types of disruption may be more tolerable (i.e., more reversible) than others.

Only a few studies have seized the opportunity to reevaluate the theories of pathogenesis of NPH using developments in imaging techniques.


The disorders of Alzheimer disease, vascular dementia and normal pressure hydrocephalus are all causes of dementia in the elderly population. It is often the case that it is clinically very difficult to tell these diseases apart. All three forms of dementia share the same risk factors, which for the most part are vascular risk factors. Bateman proposes that there is an underlying vascular pathophysiology behind these conditions, which is related to the strength of the pulse waves induced in the craniospinal cavity by the arterial vascular tree. It is proposed the manifestation of the dementia in any one patient is dependant on the way that the pulsations interact with the brain and its venous and perivascular drainage. This interaction is predominately dependant on the compliance of the craniospinal cavity and the chronicity of the increased pulse wave stress 7).


Experimental animal model

Kaolin was injected bilaterally into the subarachnoid space overlying the cranial convexities in 20 adult rats. Magnetic resonance imaging (MRI) was obtained by using an 11.7 T scanner at 14, 60, 90, and 120 days after kaolin injection. Locomotor, gait, and cognitive evaluations were performed independently. Kaolin distribution and the associated inflammatory and fibrotic responses were histologically analyzed.

Evans index of ventriculomegaly showed significant progressive growth in ventricular size over all time points examined. The greatest enlargement occurred within the first 2 months. Evans index also correlated with the extent of kaolin distribution by MRI and by pathological examination at all time points. First gait changes occurred at 69 days, anxiety at 80, cognitive impairment at 81, and locomotor difficulties after 120 days. Only locomotor deterioration was associated with Evans index or the radiological evaluation of kaolin extension. Inflammatory/fibrotic response was histologically confirmed over the cranial convexities in all rats, and its extension was associated with ventricular size and with the rate of ventricular enlargement.

Kaolin injected into the subarachnoid space over the cerebral hemispheres of adult rats produces an inflammatory/fibrotic response leading in a slow-onset communicating hydrocephalus that is initially asymptomatic. Increased ventricular size eventually leads to gait, memory, and locomotor impairment closely resembling the course of human adult chronic hydrocephalus 8).

Pathophysiology

Disturbed cerebrospinal fluid (CSF) dynamics are part of the pathophysiology of normal pressure hydrocephalus (NPH).

A study investigated the contribution of established CSF dynamic parameters to mean pulse amplitude (AMP), a prognostic variable defined as mean amplitude of cardiac-related intracranial pressure pulsations during 10 min of lumbar infusion test, with the aim of clarifying the physiological interpretation of the variable. AMP(mean) and CSF dynamic parameters were determined from infusion tests performed on 18 patients with suspected NPH. Using a mathematical model of CSF dynamics, an expression for AMP(mean) was derived and the influence of the different parameters was assessed. There was high correlation between modelled and measured AMP(mean) (r = 0.98, p < 0.01). Outflow resistance and three parameters relating to compliance were identified from the model. Correlation analysis of patient data confirmed the effect of the parameters on AMP(mean) (Spearman’s ρ = 0.58-0.88, p < 0.05). Simulated variations of ±1 standard deviation (SD) of the parameters resulted in AMP(mean) changes of 0.6-2.9 SD, with the elastance coefficient showing the strongest influence. Parameters relating to compliance showed the largest contribution to AMP(mean), which supports the importance of the compliance aspect of CSF dynamics for the understanding of the pathophysiology of NPH 9).

Clinical Features

Elderly presenting with gait abnormality, cognitive decline, and urinary incontinence, with enlarged ventricles of the brain but normal or slightly elevated cerebrospinal fluid (CSF) pressure 10) 11).

Postural stability in NPH is predominantly affected by deficient vestibular functions, which did not improve after spinal tap test. Conditions which improved best were mainly independent from visual control and are based on proprioceptive functions 12).

The natural course of iNPH is symptom progression over time, with worsening in gait, balance and cognitive symptoms. This deterioration is only partially reversible.

Currently there is no pathological hallmark for iNPH 13).

It is frequently present with cerebral vasculopathy; significantly increased prevalence of cardiovascular disease iNPH patients, which provide evidence that cardiovascular disease is involved as an exposure in the development of iNPH 14).

Idiopathic normal pressure hydrocephalus (iNPH) may present, besides the classic triad of symptoms, extrapiramidal parkinsonian like movement disorders.

Scales

Diagnosis

There is no accurate test for diagnosing normal pressure hydrocephalus or for screening for patients who will benefit from shunt surgery.

Shunting is possibly effective in iNPH (96% chance subjective improvement, 83% chance improvement on timed walk test at 6 months) (3 Class III). Serious adverse event risk was 11% (1 Class III). Predictors of success included elevated Ro (1 Class I, multiple Class II), impaired cerebral blood flow reactivity to acetazolamide (by SPECT) (1 Class I), and positive response to either external lumbar drainage (1 Class III) or repeated lumbar punctures. Age may not be a prognostic factor (1 Class II). Data are insufficient to judge efficacy of radionuclide cisternography or aqueductal flow measurement by MRI.


There is limited Class I evidence that impaired cerebral blood flow (CBF) reactivity to acetazolamide is a predictor of successful CSF shunting, but single photon emission computed tomography (SPECT) is not a practical screening tool for NPH.

Imaging

There remains a lack of consensus about the role of individual imaging modalities in characterizing specific features of the condition and predicting the success of CSF shunting. Variability of clinical presentation and imperfect responsiveness to shunting are obstacles to the application of novel imaging techniques. Few studies have sought to interpret imaging findings in the context of theories of NPH pathogenesis 15).

Although attempts at predictive methodology, such as highvelocity aqueductal flow rate measurement on MRI, have achieved widespread acceptance in clinical practice, there is no Class I evidence (only 1 Class II study and 2 Class III studies) available to support this 16).

MRI

NPH is characterized by an ongoing periventricular neuronal dysfunction seen on MRI as periventricular hyperintensity (PVH). Clinical improvement after shunt surgery is associated with CSF changes indicating a restitution of axonal function. Other biochemical effects of shunting may include increased monoaminergic and peptidergic neurotransmission, breakdown of blood brain barrier function, and gliosis 17).

An MRI-based diagnostic scheme used in a multicenter prospective study (Study of Idiopathic Normal Pressure Hydrocephalus on Neurological Improvement [SINPHONI]) appears to suggest that features of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) are meaningful in the evaluation of NPH 18).

CT or MRI

In a retrospective cohort study, Kojoukhova et al evaluated brain CT or MRI scans of 390 patients with suspected iNPH. Based on a 24-h intraventricular pressure monitoring session, patients were classified into a non-NPH (n = 161) or probable iNPH (n = 229) group. Volumes of cerebrospinal fluid compartments (lateral ventricles, sylvian and suprasylvian subarachnoid spaces and basal cisterns) were visually assessed. Disproportionally enlarged subarachnoid spaces, flow void, white matter changes, medial temporal lobe atrophy and focally dilated sulci were evaluated. Moreover, we measured quantitative markers: Evans’ index (EI), the modified cella media index, mean width of the temporal horns and callosal angle.

iNPH was more likely in patients with severe volumetric disproportion between the suprasylvian and sylvian subarachnoid spaces than in those without disproportion (OR 7.5, CI 95 % 4.0-14.1, P < 0.0001). Mild disproportion (OR 2.6, CI 95 % 1.4-4.6, P = 0.001) and narrow temporal horns (OR per 1 mm 0.91, CI 95 % 0.84-0.98, P = 0.014) were also associated with an iNPH diagnosis. Other radiological markers had little association with the iNPH diagnosis in the final combined multivariate model. Interestingly, EI was higher in non-NPH than iNPH patients (0.40 vs. 0.38, P = 0.039). Preoperative radiological markers were not associated with shunt response.

Visually evaluated disproportion was the most useful radiological marker in iNPH diagnostics. Narrower temporal horns also supported an iNPH diagnosis, possibly since atrophy was more pronounced in the non-NPH than iNPH group 19).


The Evans index is useful as a marker of ventricular volume and thus has been proposed as a helpful biomarker in the diagnosis of normal pressure hydrocephalus (NPH)

Unfortunately it is a very rough marker of ventriculomegaly, and varies greatly depending on the location and angle of the slice.

As such Evans’ index has little role to play in day-to-day reporting.

Phase contrast magnetic resonance imaging

Psychomotor Tasks

Although gait is the primary indicator for treatment candidacy and outcome, additional monitoring tools are needed. Line Tracing Test (LTT) and Serial Dotting Test (SDT), two psychomotor tasks, have been introduced as potential outcome measures20).

Lumbar infusion test

Cerebrospinal fluid tap test

Cerebrospinal fluid tap test (CSF-TT), are often used in practice to provide further predictive value in detecting suitable patients for shunting.

Pressure recording

see Idiopathic normal pressure hydrocephalus intracranial pressure monitoring

—-

Alzheimer disease (AD)-related pathology was assessed in cortical biopsy samples of 111 patients with idiopathic normal-pressure hydrocephalus. Alzheimer disease hallmark lesions amyloid beta (Aβ) and hyperphosphorylated tau protein (HPtau)-were observed in 47% of subjects, a percentage consistent with that for whole-brain assessment reported postmortem in unselected cohorts. Higher-immunostained area fraction of AD pathology corresponded with lower preoperative mini mental state examination scores. Concomitant Aβ and HPtau pathology, reminiscent of that observed in patients with AD, was observed in 22% of study subjects. There was a significant correlation between Aβ-immunostained area fraction in tissue and Aβ42 (42-amino-acid form of Aβ) in cerebrospinal fluid (CSF). Levels of Aβ42 were significantly lower in CSF in subjects with concomitant Aβ and HPtau pathology compared with subjects lacking pathology. Moreover, a significant correlation between HPtau-immunostained area fraction and HPtau in CSF was noted. Both HPtau and total tau were significantly higher in CSF in subjects with concomitant Aβ and HPtau pathology compared with subjects lacking pathology. The 42-amino-acid form of Aβ (Aβ42) and HPtau in CSF were the most significant predictors of the presence of AD pathology in cortical biopsies. Long-term follow-up studies are warranted to assess whether all patients with idiopathic normal-pressure hydrocephalus with AD pathology progress to AD and to determine the pathologic substrate of idiopathic normal-pressure hydrocephalus 21).

Differential diagnosis

Secondary normal pressure hydrocephalus (NPH) does indeed exist and should be differentiated from iNPH based on outcome as well as clinical, pathophysiological, and epidemiological characteristics but should not be considered as a separate entity. Evaluation of patients with NPH to identify a known cause is recommended because the response to treatment varies considerably. Although clinical presentation is often the same, a multitude of primary etiologies can lead to the development of sNPH. The most common etiologies of sNPH include SAH, traumatic brain injury, intracranial malignancies, meningitis, and stroke. Further studies are required to investigate differences in management and outcome among the diverse etiologies of sNPH 22).


In Alzheimer’s disease (AD) patients, diffuse aggregates of amyloid-β (Aβ) and neurofibrillary hyperphosphorylated tau are detected in the neocortex of the brain, while similar accumulation of Aβ is also detected in iNPH.

Apolipoprotein E (APOE4) affects the Aβ deposition in the brain of iNPH and AD patients in a similar manner 23).

APOE4 is not a risk factor for iNPH and does not predict the response to shunt. Data further support the view that the iNPH syndrome is a distinct dementing disease 24).

Treatment

Shunt surgery has been established as the only durable and effective treatment for idiopathic normal pressure hydrocephalus

To maximise the benefits of shunt treatment, surgery should be performed soon after diagnosis 25).

The results of a prospective multicentre study on patients with iNPH diagnosed solely on clinical and radiological criteria support shunt surgery in patients presenting with symptoms and signs and MRI findings suggestive of iNPH 26).

Shunt

Endoscopic third ventriculostomy

The only randomized trial of endoscopic third ventriculostomy (ETV) for idiopathic normal pressure hydrocephalus (iNPH) compares it to an intervention which is not a standard practice (VP shunting using a non-programmable valve). The evidence from this study is inconclusive and of very low quality. Clinicians should be aware of the limitations of the evidence. There is a need for more robust research on this topic to be able to determine the effectiveness of ETV in patients with iNPH 27).

Outcome

Complications

Subdural collections, shunt malfunction, and postoperative seizures constituted the most frequent complications 28).

see Shunt overdrainage in idiopathic normal pressure hydrocephalus.

Case series

2016

Twelve of 56 patients with NPH-like symptoms presented with morphological aqueductal stenosis (AS) (21.4 %). Patent aqueduct and non-patent aqueduct groups had similar values of mean opening lumbar pressure (8.2 vs. 8.1 mmHg), and mean opening pulse amplitude (3.1 vs. 2.9 mmHg). Mean pressure in the plateau stage (28.6 vs. 23.2 mmHg), and mean pulse amplitude in the plateau stage (12.5 vs. 10.6 mmHg) were higher in the patent aqueduct group. These differences were not statistically significant. Only Rout was significantly higher in the patent aqueduct group (13.6 vs. 10.1 mmHg/ml/min). One-third of NPH patients with AS presented Rout >12 mmHg/ml/min.

No differences in mean pressure or pulse amplitude during basal and plateau epochs of the lumbar infusion test in NPH patients were detected, regardless of aqueductal patency. However, Rout was significantly higher in patients with patent aqueduct 29).


Bir et al., retrospectively reviewed the clinical notes of 2001 patients with adult-onset hydrocephalus who presented to Louisiana State University Health Sciences Center within a 25-year span. Significant differences between the groups were analyzed by a chi-square test; p < 0.05 was considered significant.

The overall mean (± SEM) incidence of adult hydrocephalus in this population was 77 ± 30 per year, with a significant increase in incidence in the past decade (55 ± 3 [1990-2003] vs 102 ± 6 [2004-2015]; p < 0.0001). Hydrocephalus in a majority of the patients had a vascular etiology (45.5%) or was a result of a tumor (30.2%). The incidence of hydrocephalus in different age groups varied according to various pathologies. The incidence was significantly higher in males with normal-pressure hydrocephalus (p = 0.03) or head injury (p = 0.01) and higher in females with pseudotumor cerebri (p < 0.0001). In addition, the overall incidence of hydrocephalus was significantly higher in Caucasian patients (p = 0.0002) than in those of any other race.

Knowledge of the demographic variations in adult-onset hydrocephalus is helpful in achieving better risk stratification and better managing the disease in patients. For general applicability, these results should be validated in a large-scale meta-analysis based on a national population database 30).


A detailed screening process included neurological, neurosurgical and neuropsychological evaluations, followed by cerebrospinal fluid (CSF) tap test (TT) and resistance outflow (Ro) measurement. Outcome was evaluated through the Japanese NPH grading scale-revised (JNPHGSR) and the motor (third) section of the Unified Parkinson’s Disease Rating Scale (UPDRS-m). Friedman’s analysis of variance with Wilcoxon post-hoc test was used to evaluate the difference in JNPHGSR and UPDRS-m scores between pre-treatment and follow-up (12 months) in the two groups, while Kruskal-Wallis statistic and post-hoc Mann-Whitney test was used to compare the change in JNPHGSR and UPDRS-m scores between the two groups.

32/54 (59%) patients (mean age 73.2) screened in 36 months met the inclusion criteria, but only 30 were enrolled (two refused surgery), 15 in each group. Preoperative 123I-Ioflupane-cerebral SPECT (DaTSCAN) revealed striatal dopaminergic deficit in 14/30 patients (46.5%). At the final 12 months follow-up, both groups improved JNPHGSR and UPRDS-m scores. The UPDRS-m score improvement was significant in both groups, but greater in group A (p0.003); JNPHGSR score improvement was similar in the two groups.

iNPH associated with parkinsonism may be a frequent finding. In these cases, patients may benefit from VP shunt plus dopamine oral therapy 31).


From 2008 to 2013, consecutive patients diagnosed with INPH based on clinical and radiological criteria were included in a single-centre study. All patients received programmable-valve ventriculoperitoneal shunts. Outcome measures were assessed at baseline, 3, 6 and 12months post-operatively. Outcomes included gait time and scores on the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III), the Addenbrooke’s Cognitive Examination Revised (ACE-R) and the Mini-Mental State Examination (MMSE). Thresholds for improvements were set a priori as ⩾20% decrease in gait time, ⩾10point decrease in UPDRS-III score, ⩾5point increase in ACE-R score and ⩾2point increase in MMSE score at last follow-up. The proportion of patients improving varied between measures, being gait time (60%), UPDRS-III (69%), MMSE (63%), and ACE-R (56%). Overall, improvement in at least one outcome measure was observed in 85% of patients and 38% improved in gait time, UPDRS-III score and cognitive scores. Only 15% of patients experienced no improvement on any measure. This study demonstrates that the majority of INPH patients can sustain improvements in multiple symptoms up to 12months after shunting 32).

2015

A study included 29 patients with a mean age of 73.9 years; 62.1% were male and 65.5% had hypertension. Clinical improvement (complete or partial) was observed in 58% after one year and in 48% by the end of the follow-up period (mean follow-up time was 37.8 months). Older age, presence of hypertension, and surgery-related complications were more prevalent in the group responding poorly to treatment. One patient died, 20.7% experienced severe complications, and 69% were dependent (mRS ≥ 3) by the end of the follow-up period. Age at diagnosis was independently associated with poorer clinical response at one year and a higher degree of dependency by the end of follow-up.

Symptomatic benefits offered by VPS were partial and transient; treatment was associated with a high complication rate and poor functional outcomes in the long term, especially in the oldest patients 33).

2010

Fifty-one patients were included after confirmation of the diagnosis by extensive clinical and diagnostic investigations. Surgery included ventriculoatrial or ventriculoperitoneal shunting with differential pressure valves in the majority of patients. For each of the cardinal symptoms, postoperative outcome was assessed separately with the Krauss Improvement Index, yielding a value between 0 (no benefit) and 1 (optimal benefit) for the overall outcome.

Mean age at surgery was 70.2 years (range, 50-87 years). Thirty patients were women, and 21 were men. Short-term (18.8 +/- 16.6 months) follow-up was available for 50 patients. The Krauss Improvement Index was 0.66 +/- 0.28. Long-term (80.9 +/- 51.6 months) follow-up was available for 34 patients. The Krauss Improvement Index was 0.64 +/-0.33. Twenty-nine patients died during the long-term follow-up at a mean age of 75.8 years (range, 55-95 years). The major causes of death were cardiovascular disorders: cardiac failure (n = 7) and cerebral ischemia (n = 12). Other causes were pneumonia (n = 2), acute respiratory distress syndrome (n = 1), pulmonary embolism (n = 1), cancer (n = 2), renal failure (n = 1), and unknown (n = 3). There was no shunt-related mortality.

Idiopathic normal pressure hydrocephalus patients may benefit from shunting over the long term when rigorous selection criteria are applied. Shunt-related mortality is negligible. The main cause of death is vascular comorbidity 34).


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Update: Transient obstructive hydrocephalus

Epidemiology

While obstructive hydrocephalus is a relatively common and potentially life-threatening condition, transient obstructive hydrocephalus is a rare condition in adults.

Etiology

Transient obstruction of cerebrospinal fluid (CSF) flow through the ventricular system has been reported to result from systemic causes such as lead and carbon monoxide poisoning as well as CNS infections and meningitis 1).

Previous case reports have also described spontaneous resolution of obstructive hydrocephalus after intraventricular hemorrhage (IVH) in neonates and adults.

Transient acute hydrocephalus after spontaneous intracranial bleeding in adults 2).

Obstructive hydrocephalus with deterioration of consciousness from a ruptured arteriovenous malformation (AVM) requires urgent decompression, but also vigilance during the preoperative stage in case of rare spontaneous resolution 3).


The acute phase in a cerebellar infarction may become complicated with transient obstructive hydrocephalus, subsequent intracranial hypertension, and the need for surgical management. Although many patients respond well to medical treatment, clinical findings and neuroimaging methods must be considered to determine whether the hydrocephalus can be surgically treated in a timely fashion.

In fourteen patients, six required surgery for hydrocephalus management. Three of the cases had an endoscopic third ventriculostomy without complications, the rest were managed conservatively. As an average, patency was re-established in the aqueduct three months post ictus.

Management of obstructive hydrocephalus in the acute phase of a cerebellar stroke must be individualized. In cases with transient obstructive hydrocephalus, endoscopic third ventriculostomy is a good surgical treatment option that avoids the risks of a long-term ventricular shunt 4).

Case reports

2016

Two cases of transient obstructive hydrocephalus caused by obstruction of mesencephalic duct in patients that presented with altered consciousness which resolved spontaneously in a few hours5).


A 66-year-old male was admitted with sudden onset right-sided hemiparesia. CT demonstrated a hematoma on the left basal ganglia with extension to all ventricles. The following day, the patient’s neurological status progressed to coma and developed bilateral pyramidal signs. MRI demonstrated obstructive hydrocephalus and acute diffuse infarction accompanied by elevation of the CC. On the same day there was improvement in his neurological status with significant decrease in ventricular size and complete resolution of the clot in the third ventricle. The mechanism of signal abnormalities is probably related with the neural compression of the CC against the falx. Presumably, the clot causing obstruction in the third ventricle dissolved or decayed by the help of fibrinolytic activity of CSF, which was raised after IVH and caused spontaneous improvement of hydrocephalus. Bilateral neurological symptoms suggest diffuse axonal damage and normalization of the intracranial pressure should be performed on the early onset of clinical detorioration in order to prevent axonal injury 6).

2013

A 33-year-old man with a previously diagnosed Spetzler-Martin Grade 5 arteriovenous malformation presented with severe headache, which was found to be due to IVH. Forty hours after presentation he developed significant obstructive hydrocephalus due to the thrombus migrating to the cerebral aqueduct, and a ventriculostomy placement was planned. However, shortly thereafter his headache began to improve spontaneously. Within 4 hours after onset the headache had completely resolved, and an interval head CT scan revealed resolution of hydrocephalus.

In patients with IVH, acute obstructive hydrocephalus can develop at any time after the ictus. Though a delayed presentation of acute but transient obstructive hydrocephalus is unusual, it is important to be aware of this scenario and ensure that deterioration secondary to thrombus migration and subsequent obstructive hydrocephalus do not occur 7).


Transient obstructive hydrocephalus following traumatic brain injury 8).

2012

Transient obstructive hydrocephalus by intraventricular fat migration after surgery of the posterior fossa 9).

2011

A 86-year-old man with right frontal stroke developed obstructive hydrocephalus caused by blood in the cerebral aqueduct. The patient had sudden and immediate clinical improvement and a repeated head computed tomography (CT) scan showing spontaneous resolution of hydrocephalus. Spontaneous resolution of obstructive hydrocephalus is possible when the cause is minimal blood in the cerebral aqueduct without any blood in the fourth ventricle 10).

2001

Spontaneous resolution of acute hydrocephalus without aspiration of cerebral fluid is rare. In a neonate born at full term this has only been reported once before. Abubacker et al., report on one further case that was caused by intraventricular haemorrhage (IVH). The probable mechanism is resolution of the acute haemorrhage in the region of the aqueduct, resulting in resolution of the hydrocephalus itself. The importance of considering conservative management of acute hydrocephalus in the clinically stable neonate is emphasised 11).

1997

A 64-year-old woman presented with headache. Computerized tomography (CT) scan revealed hydrocephalus with tiny blood clots in the left foramen of Monro and in the aqueduct. Six hours after the onset, the signs and symptoms disappeared spontaneously. The second CT showed improvement of the hydrocephalus with migration of the clot into the i.v. ventricle. Aqueductal trapping and releasing of the clot formed by bleeding from the choroid plexus located in the left foramen of Monro was suspected for the origin of the transient hydrocephalus 12).

1993

Acute transient hydrocephalus in carbon monoxide poisoning: a case report 13).

1990

In the Sultanate of Oman acute lead encephalopathy in neonates is common. Brain oedema in acute lead encephalopathy occurs predominantly in the cerebellar vermis and may act as a midline posterior fossa mass, occluding the fourth ventricle. The resultant transient obstructive hydrocephalus may need emergency drainage of cerebro-spinal fluid. The hydrocephalus is transient as vermis oedema subsides with medical treatment. Two such cases are reported and discussed 14).

1982

Spontaneous resolution of acute hydrocephalus. A case report 15).

1981

One and a half years old boy was admitted with vomiting and somnolence four days after head injury. The first CT scans taken on admission showed high density areas in the prepontine and ambient cisterns and in the aqueduct. The lateral and third ventricles were dilated, while the fourth ventricle was normal. On the 2nd hospital day he was nearly asymptomatic. The second CT scans done seven days after injury no longer revealed the high density areas and the ventricular dilatation. Vomiting is one of the most important signs for intracranial mass lesions after head injury. But children often vomit even without having mass lesions, and CT scan is useful for evaluation of such cases. In our case, vomiting was probably due to aqueductal obstruction by a small clot resulting acute hydrocephalus, as revealed by CT scans. This case suggested that transient obstructive hydrocephalus must be taken into consideration as one of causes for posttraumatic vomiting 16).


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Impact of timing of cranioplasty on hydrocephalus after decompressive hemicraniectomy in malignant middle cerebral artery infarction

There is an increasing body of evidence in the recent literature, which demonstrates that cranioplasty may also accelerate and improve neurological recovery. Although the exact pathophysiological mechanisms for this improvement remain essentially unknown, there are a rapidly growing number of neurosurgeons adopting this concept.


Communicating hydrocephalus is an almost universal finding in patients after hemicraniectomy. Delayed time to cranioplasty is linked with the development of persistent hydrocephalus, necessitating permanent CSF diversion in some patients.

Waziri et al., propose that early cranioplasty, when possible, may restore normal intracranial pressuredynamics and prevent the need for permanent CSF diversion in patients after hemicraniectomy 1).

Factors

One modifiable factor that may alter the risk of cranioplasty is the timing of cranioplasty after craniectomy. Case series suggest that early cranioplasty is associated with higher rates of infection while delaying cranioplasty may be associated with higher rates of bone resorption.

When considering ideal timing for cranioplasty, predominant issues include residual brain edema, brain retraction into the cranial vault, risk of infection, and development of delayed post-traumatic hydrocephalus.


Waiting to perform cranioplasty is important to prevent the development of devitalized autograft or allograft infections.

It is generally accepted to wait 3 to 6 months before reconstructive surgery. If there is an infected area, this waiting period can be as long as one year.

Cranioplasty is performed after craniectomy when intracranial pressure is under control for functional and aesthetic restorations and for protection, but it may also lead to some neurological improvement after the bone flap placement 2) 3) 4).

Timing of cranioplasty after decompressive craniectomy for trauma

The optimal timing of cranioplasty after decompressive craniectomy for trauma is unknown.

After decompressive craniectomy for trauma, early (<12 weeks) cranioplasty does not alter the incidence of complication rates. In patients <18 years of age, early (<12 weeks) cranioplasty increases the risk of bone resorption. Delaying cranioplasty (≥12 weeks) results in longer operative times and may increase costs 5).

Timing of cranioplasty after decompressive craniectomy for malignant middle cerebral artery infarction

Patients with malignant middle cerebral artery infarction frequently develop hydrocephalus after decompressive hemicraniectomy. Hydrocephalus itself and known shunt related complications after ventriculoperitoneal shunt implantation may negatively impact patients outcome.

A later time point of cranioplasty might lead to a lower incidence of required shunting procedures in general 6).


1) Waziri A, Fusco D, Mayer SA, McKhann GM 2nd, Connolly ES Jr. Postoperative hydrocephalus in patients undergoing decompressive hemicraniectomy for ischemic or hemorrhagic stroke. Neurosurgery. 2007 Sep;61(3):489-93; discussion 493-4. PubMed PMID: 17881960.
2) Honeybul S, Janzen C, Kruger K, Ho KM. The impact of cranioplasty on neurological function. Br J Neurosurg. 2013;27:636–641. doi: 10.3109/02688697.2013.817532.
3) Jelcic N, De Pellegrin S, Cecchin D, Della Puppa A, Cagnin A. Cognitive improvement after cranioplasty: a possible volume transmission-related effect. Acta Neurochir (Wien) 2013;155:1597–1599. doi: 10.1007/s00701-012-1519-6.
4) Di Stefano C, Sturiale C, Trentini P, Bonora R, Rossi D, Cervigni G, et al. Unexpected neuropsychological improvement after cranioplasty: a case series study. Br J Neurosurg. 2012;26:827–831. doi: 10.3109/02688697.2012.692838.
5) Piedra MP, Nemecek AN, Ragel BT. Timing of cranioplasty after decompressive craniectomy for trauma. Surg Neurol Int. 2014 Feb 25;5:25. doi: 10.4103/2152-7806.127762. PubMed PMID: 24778913; PubMed Central PMCID: PMC3994696.
6) Finger T, Prinz V, Schreck E, Pinczolits A, Bayerl S, Liman T, Woitzik J, Vajkoczy P. Impact of timing of cranioplasty on hydrocephalus after decompressive hemicraniectomy in malignant middle cerebral artery infarction. Clin Neurol Neurosurg. 2016 Dec 9;153:27-34. doi: 10.1016/j.clineuro.2016.12.001. [Epub ahead of print] PubMed PMID: 28012353.