Posttraumatic Hydrocephalus

Updated: Feb 03, 2021
Author: John J Danko, DO, FAAPMR; Chief Editor: Elizabeth A Moberg-Wolff, MD 

Overview

Practice Essentials

Posttraumatic hydrocephalus (PTH) is a frequent and serious complication that follows a traumatic brain injury (TBI).[1, 2, 3, 4] Its incidence varies greatly from study to study, largely based on different criteria for its diagnosis. However, PTH could greatly impact morbidity following a TBI and could result in increased mortality if it is not recognized and treated.

PTH may result from one or a combination of pathophysiologic factors. It can be caused by the overproduction of cerebrospinal fluid (CSF), the blockage of normal CSF flow, or insufficient absorption that results in excessive accumulation of CSF around the brain. Ultimately, PTH is caused by an imbalance that occurs between CSF production and absorption.[5]

PTH may present similarly to normal pressure hydrocephalus (NPH) or as a syndrome of increased intracranial pressure.[6] Because of differences in prognosis and treatment, PTH needs to be distinguished from other disease processes that can elevate intracranial pressure (ICP), such as hemorrhage, tumor, edema, venous sinus thrombus, and meningitis. Additionally, overproduction of CSF may be due to choroid plexus tumor. If PTH goes unrecognized or untreated, increased morbidity or mortality following a TBI is more likely.[7, 8, 9]

In addition to incontinence, gait deterioration, and cognitive decline, which are symptoms classically present in NPH, early symptoms of PTH may include headache, nausea, and vomiting and acute mental status changes such as confusion or lethargy.[9, 10] Arrival at a functional plateau or regression in a patient's rehabilitation course may also be a symptom of PTH.

Classification of hydrocephalus

Dandy and Blackfan introduced the classification of hydrocephalus as either noncommunicating or communicating.[11]  In noncommunicating, or obstructive, hydrocephalus, normal CSF flow is blocked. As a result, CSF can accumulate in the ventricles, leading to ventriculomegaly and hemispheric displacement. The following sites are prone to the obstruction of CSF flow, which can stem from a variety of causes, including the presence of a stricture, mass, or hemorrhage[9] :

  • Foramen of Monro
  • Third ventricle
  • Aqueduct of Sylvius
  • Fourth ventricle
  • Foramen of Luschka
  • Foramen of Magendie

In addition, overproduction of CSF, as a result of, perhaps, a tumor of the choroid villi, may lead to relative ventriculomegaly, which could result in mass effect and, eventually, obstructive hydrocephalus.

In communicating hydrocephalus (also referred to as nonobstructive hydrocephalus), full communication between the ventricles and subarachnoid space exists. Impaired CSF absorption at the arachnoid villi, perhaps due to the presence of blood and other inflammatory mediators, may cause communicating hydrocephalus. Severe skull fractures, hemorrhage, and meningitis may predispose patients to this type of PTH.[9]

Portnoy proposed that PTH can develop as a result of increased dural sinus pressure, causing decreased CSF outflow.[12]

Normal pressure hydrocephalus (NPH), a form of communicating hydrocephalus, may result from subarachnoid hemorrhage caused by an aneurysm rupture or a TBI, encephalopathy, or Alzheimer disease. NPH often presents as the classic triad of a progressive gait disorder, impairment of mental function, and urinary incontinence.[9] In NPH, ventricles enlarge despite normal or even slightly reduced intracranial pressure and they continue to press against brain parenchyma.

Signs and symptoms of posttraumatic hydrocephalus

If PTH is acute, patients may present with coma and other focal neurologic deficits. If the condition is chronic, individuals may demonstrate a gradual decline in functional status or may show a failure to improve.[6]

Workup in posttraumatic hydrocephalus

Pertinent laboratory studies include the following:

  • Urine analysis and culture - Evaluate for urinary tract infections
  • Complete blood count (CBC) with differential - Evaluate for infection and anemia
  • Metabolic profile - Evaluate for electrolyte abnormalities
  • Thyroid-stimulating hormone (TSH), free thyroxine (free T4) - Evaluate for hypothyroidism or hyperthyroidism
  • Arterial blood gas level - Assess oxygenation and acid/base balance
  • Serum medication levels - Measure medication levels if toxicity suspected
  • CSF analysis - Evaluate for infectious etiologies, autoimmune disease, and certain cancers

The progressive enlargement of the ventricular system shown on repeat computed tomography (CT) scans is the key to the diagnosis of PTH. [7] Magnetic resonance imaging (MRI) is useful in the evaluation of injury to structures in the posterior fossa, including cerebral aqueduct stenosis and cerebellar tonsil herniation. [12]

Another exam, the CSF tap test, is a lumbar puncture (LP) with manometry and CSF removal. Cognitive and physical functions are assessed before and after the removal of 50 mL of CSF. Improvement suggests that shunting may be beneficial.

Management of posttraumatic hydrocephalus

Shunting is the most common treatment for hydrocephalus. The outcome is typically favorable. A shunt is usually placed from the right ventricle to the peritoneal space. The right side is normally used to avoid injury to the language centers on the left side of the brain. Shunts are most often equipped with reservoirs that are used for transiently increasing output and for testing the patency of flow.

The resumption of rehabilitation is usually prompt after the placement of a ventriculoperitoneal (VP) shunt. [13, 14] Patients are typically observed for 2-3 days postoperatively. They then return to rehabilitation services to complete their brain-injury rehabilitation program. Successful shunting is usually related to more obvious and rapid improvements during rehabilitation efforts. [15]

See also the following related resource in Medscape:

Resource center: Trauma

See also the following related topics in Medscape Drugs & Diseases:

Hydrocephalus [Neurology]

Hydrocephalus [Neurosurgery]

Classification and Complications of Traumatic Brain Injury

Normal Pressure Hydrocephalus [Neurology]

Normal Pressure Hydrocephalus [Radiology]

Pathophysiology

Normal anatomy and physiology

CSF is produced, primarily in the lateral ventricles by the choroid plexuses, with smaller contributions from the third and fourth ventricles, at a rate of 500 mL/d. The CSF flows down toward the third ventricle through the foramen of Monro and into the fourth ventricle through the cerebral aqueducts. The CSF then exits the ventricular system through the foramen of Magendie (medially) and the foramen of Luschka (laterally) and flows into the perimedullary and perispinal subarachnoid spaces. The CSF continues around the brainstem to the basal and ambient cisterns. It then flows to the lateral and superior surfaces of the cerebral hemispheres, where it is largely absorbed through the arachnoid villi. The total volume of CSF is replaced several times daily.[9]  Primary functions of the CSF include cushioning of the brain and spinal cord and removal of neuronal metabolic waste products.

In normal adults, the following measurements have been observed[9] :

  • Normal intracranial pressure (ICP) is approximately 8 mm Hg.
  • The average intracranial volume is about 1700 mL.
  • The average CSF volume is about 104 mL.

By volume, the intracranial contents include the following[13] :

  • Brain parenchyma - About 80%
  • CSF - About 10%
  • Blood - About 10%

Epidemiology

Frequency

United States

The onset of PTH may vary from 2 weeks to years after TBI. Studies cite a wide range of incidence (0.7-50%); part of this variation results from underdiagnosis and atypical presentation, as well as from the fact that different sets of clinical criteria are used to diagnose PTH.[6, 7, 8, 14]

Mazzini and colleagues found that 50% of patients with postacute phase severe TBI had PTH but that only 11% required surgery.[8]

International

In a multi-year study, Kim and colleagues followed 789 patients who had suffered a TBI, diagnosing PTH in 129 (16.3%) of them.[15] Sixty-four patients with PTH required shunting.

Mortality/Morbidity

If PTH goes unrecognized or untreated, increased morbidity or mortality following a TBI is more likely.[7, 8]

Race

Race does not appear to be a factor in the development of PTH.

Sex

Sex does not appear to be a risk factor in the development of PTH.

Age

Increased age appears to increase the risk of developing PTH.[8]

 

Presentation

History

Posttraumatic hydrocephalus (PTH) often has an atypical or nonspecific presentation and therefore may be easily missed. A high level of clinical suspicion is important for diagnosis.[16, 17]

  • If acute, patients may present with coma and other focal neurologic deficits.

  • If chronic, patients may demonstrate a gradual decline in functional status or may show a failure to improve.[6] The decline in performance or functioning may be initially observed by therapists.

Physical

A complete neurologic examination should be performed and repeated as necessary to assess for changes over time.

PTH may present as a syndrome of increased intracranial pressure with symptoms of papilledema, focal neurologic deficits, or coma.[6]

Most commonly, PTH presents as noncommunicating hydrocephalus with the following findings[5] :

  • Papilledema resulting from increased intracranial pressure and transmission through the subarachnoid space
  • Cognitive changes, including decreased memory, decreased attention, and irritability

Causes

PTH results from TBI, with or without intracerebral hemorrhage. Hemorrhage may be seen in the subdural, subarachnoid, or intraventricular spaces or may arise within brain parenchyma.[18]  Additional, non–trauma-related causes of acquired hydrocephalus include aneurysm rupture, arteriovenous malformation, and hemorrhagic stroke.[19]

A study by Kammersgaard et al indicated that older age and low consciousness level are independent risk factors for the development of PTH during rehabilitation in patients with severe TBI. The study involved 444 patients with severe TBI, 14.2% of whom developed PTH, with 75% of the hydrocephalus cases arising during rehabilitation.[20]

Age may further affect risk factors in that, as indicated in a retrospective study by Ved et al, pediatric patients who have suffered a TBI may have a greater likelihood of PTH in the presence of intraventricular and/or subarachnoid hemorrhages, subdural hematomas, or severe TBI. Previous research has found that risk factors for PTH in adults with TBI include severe TBI, subdural hematomas, and the need for surgery.[21]

A retrospective study by Su et al indicated that in patients who have suffered TBI, independent risk factors for the development of PTH in association with unilateral decompressive craniectomy include age and contralateral subdural hygroma. The investigators noted a 3.6% rise in the PTH development rate for every 1-year increase in age. Subdural hygroma existed in 58.1% of patients with PTH, versus 27% of patients without PTH.[22]

A retrospective study by Di et al reported that other risk factors for the development of PTH in TBI patients who undergo decompressive craniectomy include a Glasgow Coma Scale score of less than 6 on admission, a finding of intraventricular hemorrhage on initial head CT scan, and a requirement for bilateral decompressive craniectomy.[23]

Another study, by Vedantam et al, indicated that in cases of severe TBI treated with decompressive craniectomy, patients with interhemispheric subdural hygromas and of younger age are at greater risk for the development of shunt-dependent PTH.[24]

A retrospective study by Fotakopoulos et al reported that in patients with severe TBI who undergo decompressive craniectomy, craniectomy size, but, in contrast to the Su and Vedantam studies, not patient age, correlates with the incidence of PTH.[25]

 

DDx

Diagnostic Considerations

These include the following:

  • Intracranial bleeding

  • Electrolyte imbalance

  • Adverse effects of medications

  • Hypoxia

  • Infection

  • Tumors

  • Stroke

  • Seizures

  • Uremia

  • Encephalopathy

  • Dementia

Differential Diagnoses

 

Workup

Laboratory Studies

Laboratory studies in the assessment of posttraumatic hydrocephalus (PTH) include the following:

  • Urine analysis and culture - Evaluate for urinary tract infections
  • Complete blood count (CBC) with differential - Evaluate for infection and anemia
  • Metabolic profile - Evaluate for electrolyte abnormalities, including syndrome of inappropriate secretion of antidiuretic hormone (SIADH), cerebral salt wasting, calcium deficiency, hypoglycemia, hyperglycemia, and encephalopathy (uremic or hepatic)
  • Thyroid-stimulating hormone (TSH), free T4 - Evaluate for hypothyroidism or hyperthyroidism
  • Arterial blood gas level - Assess oxygenation and acid/base balance
  • Serum medication levels - Measure medication levels if toxicity suspected
  • CSF analysis - Evaluate for infectious etiologies, autoimmune disease, and certain cancers

Imaging Studies

See the list below:

  • Noncontrast CT scan of the brain is one of the most commonly used diagnostic modalities.

    • The progressive enlargement of the ventricular system shown on repeat computed tomography (CT) scans is the key to the diagnosis of PTH.[7]

    • CT scans may show enlarged lateral ventricles, effaced cerebral sulci, and dilation on ventricles proximal to an obstruction.[5]

    • Periventricular edema may occur in white matter, particularly around the frontal horns.[5]

    • Sulcal enlargement with ventricular enlargement suggests atrophy and hydrocephalus ex vacuo rather than hydrocephalus.[5]

    • Large cisterns and focal regions of encephalomalacia suggest atrophy.[6]

  • Magnetic resonance imaging (MRI) is another method of diagnostic evaluation.[26]

  • MRI is more useful in the evaluation of injury to structures in the posterior fossa, including cerebral aqueduct stenosis and cerebellar tonsil herniation.[27]

  • It is the neuroimaging study of choice in patients with NPH.[27]

  • MRI may be more useful than CT scanning in the identification of other neurologic disorders, especially cerebrovascular disease.[28]

Mazzini studied another imaging technique, single-photon emission CT (SPECT).[8] Mazzini found that SPECT had higher sensitivity than MRI or CT scanning in the demonstration of temporal lobe abnormality secondary to PTH.

Other Tests

See the list below:

  • Radionuclide cisternography:[5]

    • Radioiodinated serum albumin (RISA) injected into the subarachnoid space by way of lumbar puncture (LP) can normally be detected in the cisterna magna, basal cisterns, and subtentorial subarachnoid space within 6 hours, with little accumulation in the ventricular system. In NPH, RISA accumulates in the ventricular system with delayed pericerebral diffusion.

    • Cisternography is usually normal in hydrocephalus ex vacuo.

  • Although debate exists, cisternography may be a useful adjunct to CT scanning of the brain.

Procedures

See the list below:

  • CSF tap test

    • This test is an LP with manometry and CSF removal.

    • Imaging of the brain should be performed before initiating the LP. The risk of cerebral herniation associated with the LP is increased in patients with greatly elevated ICP.

    • The CSF tap test may be a useful predictor of the potential benefits of shunting. Kim (2005) found that symptomatic improvement after lumbar drainage has a significant role in predicting the result of shunting.

    • CSF pressure is normally 110 mm water. Shunting may help if the pressure is 135-275 mm water, and it does help if the pressure is greater than 275 mm water.

    • Cognitive and physical functions are assessed before and after the removal of 50 mL of CSF. Improvement suggests that shunting may be beneficial.

 

Treatment

Rehabilitation Program

Physical Therapy

The resumption of rehabilitation is usually prompt after the placement of a ventriculoperitoneal (VP) shunt.[29, 30] Patients are typically observed for 2-3 days postoperatively. They then return to rehabilitation services to complete their brain-injury rehabilitation program. Successful shunting is usually related to more obvious and rapid improvements during rehabilitation efforts.[31]

A study by Weintraub et al indicated that earlier shunting in posttraumatic hydrocephalus (PTH) is associated with improved rehabilitation outcomes. The study involved 52 PTH patients who had a VP shunt placed, with the period from injury to placement ranging from 9 to 366 days (median time, 69 days).[32]

Surgical Intervention

See the list below:

  • Before treatment, conditions such as infection, anemia, hypoxia, seizure disorder, uremia, and encephalopathy must be ruled out or addressed. If PTH is suspected, prompt neurosurgical evaluation is highly recommended.

  • Shunting is the most common treatment for hydrocephalus. The outcome is usually favorable.

  • A shunt is usually placed from the right ventricle to the peritoneal space. The right side is normally used to avoid injury to the language centers on the left side of the brain. Shunts are usually equipped with reservoirs that are used for transiently increasing output and for testing the patency of flow.

  • Patients with acute presentations and clear signs of high-pressure hydrocephalus benefit from a shunting procedure. Patients with chronic presentations can be observed with frequent CT scanning of the brain to monitor for progression of hydrocephalus.[6]

  • In a study by Tribl and Oder, 52% of patients with PTH had significant improvement within 3 months of shunting.[33]

  • Patients with NPH also may benefit from a shunting procedure. In patients with a TBI and communicating hydrocephalus, Groswasser found that shunting promoted a recovery of consciousness and motor capacity but not a return of neurobehavioral function.[7]

  • Complications and shunt malfunctions are common.[33, 29] Complications of shunts include the following:

    • Infection - Wound infection or contamination during placement

    • Shunt failure - Displacement and leakage

    • Occlusion - Kinking and tube clotting

    • Overshunting - More fluid is shunted than necessary

    • Placement errors

  • Assessing the efficacy of surgical intervention can be problematic because of the heterogeneity of TBI severity, TBI location, nonuniform diagnostic criteria used across studies, variants of PTH, the severity of PTH, and the length of time between the occurrence of a TBI and the development of PTH. Further research is needed to control for confounding factors, elucidate criteria for surgical intervention, and assess the outcome of surgery.[17]

Consultations

When hydrocephalus is confirmed, consultation with a neurosurgeon should be expedited. Additionally, consultation with a physical medicine and rehabilitation specialist to evaluate for functional impairments and design a patient-centered rehabilitation program is recommended.

 

Medication

Medication Summary

The management of hydrocephalus centers on the reduction of intracranial pressure and on the correction of factors that lead to increased ICP. Elevation of the head may help to reduce pressure, as well as to maintain normotensive blood pressure. Medications with osmotic effects (such as mannitol) or that reduce CSF production (such as acetazolamide) may have limited value. Hence, medications likely do not play a major role in the treatment of posttraumatic hydrocephalus (PTH).

The discontinuation of medications that may contribute to the impairment of cognitive or physical functioning should be considered.

 

Follow-up

Further Outpatient Care

Routine follow-up with the patient's primary care physician, neurosurgeon, and rehabilitation specialist, as well as with skilled therapists, is crucial to continued community reintegration and maximization of patient outcomes. Patients or caregivers should seek immediate medical evaluation and attention if the signs and symptoms of posttraumatic hydrocephalus (PTH) return.

Further Inpatient Care

Patients typically make rapid gains in the first 1-2 weeks following shunt placement for PTH; therefore, inpatient rehabilitation may be beneficial as PTH resolves.

Because shunts may malfunction, physicians should monitor patients for the signs and symptoms of PTH.

Complications

The possible complications of PTH include the following:

  • Cerebral herniation
  • Risk of aspiration as a result of dysphagia
  • Increased risk of falls
  • Cognitive decline
  • Loss of independence
  • Inability to benefit from rehabilitation [34]

Prognosis

Groswasser found that in patients who developed communicating hydrocephalus following a TBI, the duration of coma was longer and the incidence and severity of behavioral problems was greater.[7] Furthermore, in patients with a TBI and communicating hydrocephalus, the rate at which these individuals returned to their previous occupation was lower than it was in patients with a TBI but no PTH.

Patients typically do well after the placement of a shunt for PTH. Tribl and Oder's study indicated that the best predictor of outcome following shunting is the patient's pre-operative status. The authors' results also indicated that age at time of injury does not influence outcome.[33]

Similarly, Kim and colleagues found evidence that symptomatic improvement after pre-operative lumbar drainage provides a strong indication of the results of shunt placement and that age and sex seems to have no impact on outcome.[15]

Shunts may malfunction and require revision or replacement;[35] therefore, careful monitoring for the signs and symptoms of functional decline is important for the physiatrist and for caretakers.

A study from Denmark indicated that in patients undergoing inpatient rehabilitation for TBI, the occurrence of PTH does not affect rehabilitation outcome or the extent of disability at discharge but does prolong the patient’s stay. The study involved 417 patients with severe TBI, with multiple regression analysis used to evaluate the effects of PTH on rehabilitation. PTH was found to increase patients’ rehabilitation stay by nearly 3 weeks.[36]

Patient Education

See the list below:

  • Patients and caregivers need to be educated about symptoms that might suggest shunt failure and should be instructed as to when medical evaluation should be sought.

  • For excellent patient education resources, visit eMedicineHealth's Brain and Nervous System Center. Also, see eMedicineHealth's patient education article Normal Pressure Hydrocephalus.