You are in: eMedicine Specialties > Neurosurgery > MEDICAL TOPICS HydrocephalusArticle Last Updated: Dec 19, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Herbert H Engelhard III, MD, PhD, Director, UIC Neuro-Oncology Program, Chief, Division of Neuro-Oncology, Associate Professor, Department of Neurosurgery, University of Illinois at Chicago Herbert H Engelhard, III, is a member of the following medical societies: American Association for Cancer Research, American Association of Neurological Surgeons, American College of Surgeons, American Medical Association, American Society for Cell Biology, American Society of Clinical Oncology, Chicago Medical Society, Congress of Neurological Surgeons, Illinois State Medical Society, Society for Neuro-Oncology, and Society for Neuroscience Coauthor(s): Kamran Sahrakar, MD, Clinical Professor, Department of Neurosurgery, University of California-Davis; Dachling Pang, MD, FRCS(C), FACS, Clinical Professor of Neurosurgery, Chief of Pediatric Neurosurgery, University of California Davis School of Medicine; Chief, Regional Center for Pediatric Neurosurgery, Kaiser Permanente Hospitals of Northern California Editors: Duc Hoang Duong, MD, Associate Professor, Director of Neuroscience Physician Assistant Program, Departments of Neurological Surgery and Neuroscience, Epilepsy Center, Charles R Drew University; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Ryszard M Pluta, MD, PhD, Associate Professor, Neurosurgical Department Medical Research Center, Polish Academy of Sciences at Warsaw, Poland; Senior Researcher, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH; Herbert H Engelhard III, MD, PhD, Director, UIC Neuro-Oncology Program, Chief, Division of Neuro-Oncology, Associate Professor, Department of Neurosurgery, University of Illinois at Chicago; Allen R Wyler, MD, Medical Director, Northstar Neuroscience, Inc Author and Editor Disclosure Synonyms and related keywords: hydrocephalus, abnormal rise in cerebrospinal fluid volume, abnormal rise in cerebrospinal fluid pressure, CSF, imbalance of cerebrospinal fluid production and absorption, spinal bifida, congenital hydrocephalus, acquired hydrocephalus, aqueductal stenosis, intracranial tumor obstruction, intracranial trauma, intracranial hemorrhage, intracranial infection, disorders of cerebrospinal fluid production, disorders of cerebrospinal fluid circulation, disorders of cerebrospinal fluid absorption, cerebrospinal fluid diversion, third ventriculostomy, normal pressure hydrocephalus INTRODUCTIONSection 2 of 12
  History of the ProcedureHydrocephalus was first described by Hippocrates. Hydrocephalus was not treated effectively until the mid 20th century, when the development of appropriate shunting materials and techniques occurred. Interestingly, at the beginning of the 20th century, doctors (including urologists) attempted to introduce scopes into the ventricular system. Attempts were also made to remove the choroid plexus, which generates much of the cerebrospinal fluid (CSF), in an attempt to treat hydrocephalus. Today, the focus of hydrocephalus research is on pathophysiology, valve design in shunting, and minimally invasive techniques of treatment. ProblemHydrocephalus is the abnormal rise in CSF volume and, usually, pressure, that results from an imbalance of CSF production and absorption. FrequencyThe overall incidence of hydrocephalus is unknown. When cases of spina bifida are included, congenital hydrocephalus occurs in 2-5 births per 1000 births. Incidence of acquired types of hydrocephalus is unknown. EtiologyThe etiology of hydrocephalus in congenital cases is unknown. Very few cases (<2%) are inherited (X-linked hydrocephalus). The most common causes of hydrocephalus in acquired cases are tumor obstruction, trauma, intracranial hemorrhage, and infection. PathophysiologyHydrocephalus can be subdivided into the following 3 forms:
ClinicalThe various types of hydrocephalus can present differently in different age groups. Acute hydrocephalus typically presents with headache, gait disturbance, vomiting, and visual changes. In infants, irritability or poor head control can be early signs of hydrocephalus. When the third ventricle dilates, the patient can present with Parinaud syndrome (upgaze palsy with a normal vertical Doll response) or the setting sun sign (Parinaud syndrome with lid retraction and increased tonic downgaze). Occasionally, a focal deficit, such as sixth nerve palsy, can be the presenting sign. Papilledema is often present, although it may lag behind symptomatology. Infants present with bulging fontanelles, dilated scalp veins, and an increasing head circumference. When advanced, hydrocephalus presents with brainstem signs, coma, and hemodynamic instability. Normal pressure hydrocephalus has a very distinct symptomatology. The patient is older and presents with progressive gait apraxia, incontinence, and dementia. This triad of symptoms defines normal pressure hydrocephalus. INDICATIONSSection 3 of 12
Most cases of symptomatic hydrocephalus need to be treated before permanent neurologic deficits result or neurologic deficits progress. When an etiologic factor is known, hydrocephalus can be treated with temporary measures while the underlying condition is treated. Examples of temporary treatment measures are ventriculostomy until a posterior fossa tumor is resected or lumbar punctures in a neonate with intraventricular hemorrhage until the blood is absorbed and normal cerebrospinal fluid (CSF) absorption resumes. RELEVANT ANATOMYSection 4 of 12
See Intraoperative details for a discussion of relevant anatomy. CONTRAINDICATIONSSection 5 of 12
Few cases of hydrocephalus should not be treated. Cases in which treatment should not be implemented include the following:
WORKUPSection 6 of 12
Imaging Studies
Diagnostic Procedures
TREATMENTSection 7 of 12
Medical therapyMedical therapy is usually a temporizing measure. In transient conditions, such as sinus occlusion, meningitis, or neonatal intraventricular hemorrhage, medical therapy can be effective.
Surgical therapyAs performance of cerebrospinal fluid (CSF) diversion (most often ventriculoperitoneal shunting) has increased in frequency, so has awareness of the pitfalls of the procedure. Recently, a resurgence of interest in third ventriculostomies has occurred. Preoperative detailsMake every effort to identify the cause of hydrocephalus prior to considering a diversion procedure. Do not consider an indwelling distal catheter in patients with active infection or high cerebrospinal fluid protein (>150 mg/dL). Obtain some idea of brain compliance in order to select the optimum valve pressure and decide if the pressure-programmable valve should be used. Use one dose of preoperative prophylactic antibiotics. Intraoperative details
Postoperative detailsICU observation after third ventriculostomy is advised. In patients with high brain compliance, gradual assumption of the upright position and slow mobilization may reduce the incidence of early subdural hematoma formation. Plain radiographs of the entire hardware system confirm good position and serve as excellent baseline studies for the future. Postoperative CT scan is used to document ventricular size (see Follow-up section). Wounds should remain dry for at least 3 days postoperatively, until epithelialization has occurred. In patients with pleural shunts, perform an early postoperative chest radiograph to ensure adequate absorption of fluid. Large effusions can occur in short periods, and respiratory problems can ensue. Follow-up
COMPLICATIONSSection 8 of 12
The most common complications differ depending on the type of shunt and the underlying pathophysiology. Infection is the most feared complication in the young age group. The overwhelming majority of infections occur within 6 months of the original procedure. Common infections are staphylococcal and propionibacterial. Early infections occur more frequently in neonates and are associated with more virulent bacteria such as Escherichia coli. Infected shunts need to be removed, the cerebrospinal fluid (CSF) needs to be sterilized, and a new shunt needs to be placed. Treatment of infected shunts with antibiotics alone is not recommended because bacteria can be suppressed for extended periods and resurface when antibiotics are stopped. Subdural hematomas occur almost exclusively in adults and children with completed head growth. Incidence of subdural hematomas can be reduced by slow postoperative mobilization and perhaps by avoiding rapid intraoperative ventricular decompression. This allows for brain compliance reduction. The treatment is drainage and may require temporary occlusion of the shunt. Shunt failure is mostly due to suboptimal proximal catheter placement. Occasionally, distal catheters fail. Suspect infection if the distal catheter is obstructed with debris. Abdominal pseudocysts are synonymous with low-grade shunt infection. Overdrainage is more common in lumboperitoneal shunts and manifests with headaches in the upright position. In most cases, overdrainage is a self-limiting process. However, revision to a higher-pressure valve or a different shunt system occasionally may be necessary. A positional valve that closes when the patient is upright is also available. Slit ventricle syndrome is an extremely rare condition in which brain compliance is unusually low. It mostly occurs in the setting of prior ventriculitis or shunt infection. The patient may develop high pressures without ventricular dilatation. The slit ventricle syndrome does not imply overdrainage, and the symptoms usually are those of high pressure rather than low pressure. Most experts also agree that slit ventricles predispose the patient to a higher incidence of ventricular catheter failure. Repeated ventricular blockage by the coapted ventricular wall may be helped by performing a subtemporal decompression that creates an artificial pressure reservoir and induces slight reenlargement of the slit ventricle. OUTCOME AND PROGNOSISSection 9 of 12
In general, outcome is good. A typical patient should return to baseline after shunting, unless prolonged elevated intracranial pressure or brain herniation has occurred. The neurologic function of children is optimized with shunting. Infection, especially if repeated, may affect cognitive status. The best long-term results in the most carefully selected patients are no better than 60% in normal pressure hydrocephalus. Few complete recoveries occur. Often, gait and incontinence respond to shunting, but dementia responds less frequently. Often, various other neurologic abnormalities associated with hydrocephalus are the limiting factor in patient recovery. Examples are migrational abnormalities and postinfectious hydrocephalus. FUTURE AND CONTROVERSIESSection 10 of 12
Hydrocephalus research and treatment have advanced tremendously in the last 20 years. Examples are the development of new shunt materials and, more recently, programmable valve technology. Current research categories include the following:
ACKNOWLEDGMENTSSection 11 of 12
The author would like to thank Dr. Yoon Hahn and Dr. David McLone for their guidance in treating patients with hydrocephalus. REFERENCESSection 12 of 12
Article Last Updated: Dec 19, 2007 |
