Diagnosis

Hydrocephalus

Etiology

Cause [abz]

• Obstruction in the CSF-flow (non-communicating): brain tumor

• Reduced absorption into the venous system:

  • Post hemorrhagic: Subarachnoid hemorrhage, trauma

  • Post-inflammatory: Meningitis

• Hypersecretory: excessive production of CSF (plexus papilloma or rarely a carcinoma)

• Normal-pressure hydrocephalus (NPH): increased incidence in older age, not fully understood pathogenesis

Clinical classification

• Congenital: Aqueduct stenosis, Dandy-Walker syndrome, Chiari malformation

• Acquired: Subarachnoid hemorrhage (meningeal adhesions), infectious/inflammatory (meningeal adhesions), obstructing masses, postoperative neurosurgery

• Communicating (normal-pressure): Flow remains between all the ventricles (defective absorption by arachnoid granulations)

• Noncommunicating (obstructive): Increased pressure within the ventricular system due to disruption of CSF flow between the ventricles (aqueductal stenosis, tumor, cyst)

• Ex vacuo: Atrophic parenchymal tissue loss resulting in dilated ventricles (Huntingtons disease)

Pathophysiology [abz]

1. CSF is produced by the choroid plexus (located in the third and fourth ventricles)

2. Travels through the ventricular system (CSF volume 150ml)

3. CSF absorption takes place in arachnoid granulations

4. CSF is absorbed into the venous sinuses and enters systemic circulation

5. The total volume of the brain, CSF, and blood within the skull is constant

   • An increase in one compartment must accompany a decrease in volume in another compartment; otherwise, the pressure within the head will be increased

6. Hydrocephalus --> Increased ICP --> brain damage and pressure-induced atrophy

7. Congenital hydrocephalus: present at birth

   • An unusually large head

   • Tense and bulge fontanelle

   • “The setting sun” pupils

   • Failure to thrive

   • Macewen sign

8. Acute hydrocephalus is a life-threatening (risk of brain herniation:

   • Dilated and nonreactive ipsilateral pupil

   • Autonomic dysfunction

   • Loss of brain stem reflexes

   • Coma

9. Acquired hydrocephalus can occur at any age

   • Headache, neck pain, nausea, explosive vomiting, drowsiness, lethargy, irritability, seizures, confusion, disorientation, blurred vision, diplopia, urinary and bowel incontinence, gait instability, balance problems, lack of appetite, personality changes, and memory problems

Epidemiology

Prevalence per 100.000 [ikr][abz]

Incidence per 100.000 [ikr][abz]

Approach

• Ophtalmoscopy

• CT caput

• MR caput

• Lumbar puncture

• Xanthochromia

Treatment

1. Treat underlying cause: [abz][7vd]

   • Surgical evacuation of intraparenchymal hemorrhage or tumors

2. Ventricular shunt placement

   • Emergency situation in infants: anterior fontanelle ventricular tap

   • Lumbar puncture in posthemorrhagic and postmeningitic hydrocephalus

3. Endoscopic third ventriculostomy (ETV)

4. Choroid plexus cauterization

Differential diagnoses

Arteriovenous malformation, Brain tumor, Cerebral aneurysm, Dementia, Elevated intracranial pressure, Epidural hematoma, Epilepsy, HIV, Intracerebral hemorrhage, Lymphoma, Migraine, Multiple sclerosis, Pituitary adenoma, Stroke, Subarachnoid hemorrhage, Subdural empyema, Subdural hematoma, Temporal arteritis, Toxoplasmosis