Learning objectives

• Define hydrocephalus
• Describe the age-related signs and symptoms of hydrocephalus
• Anesthetic management of a patient with hydrocephalus

Definition and mechanisms

• Hydrocephalus is the excess accumulation of cerebrospinal fluid (CSF) in the ventricular system of the brain, resulting in increased intracranial pressure (ICP) 
• It is caused by obstruction to CSF flow in the ventricles or subarachnoid space, or by excess CSF production from a congenital malformation blocking normal drainage or from complications of head injuries or infections
• Hydrocephalus can happen at any age but occurs more frequently among infants and older adults (>60 years)

Signs and symptoms

The signs and symptoms vary by the age of onset

Infants

• Changes in the head
  • Unusually large head
  • Rapid increase in the size of the head
  • Bulging or tense soft spot (fontanel) on the top of the head
• Physical signs and symptoms
  • Nausea and vomiting
  • Sleepiness or lethargy
  • Irritability
  • Poor eating
  • Seizures
  • Reduced upward gaze (Parinaud’s syndrome)
  • Problems with muscle tone and strength

Toddlers and older children

• Physical signs and symptoms
  • Headache
  • Blurred or double vision
  • Abnormal eye movements
  • Abnormal enlargement of the head
  • Sleepiness or lethargy
  • Nausea or vomiting
  • Unstable balance
  • Poor coordination
  • Poor appetite
  • Loss of bladder control or frequent urination
• Behavioral and cognitive changes
  • Irritability
  • Change in personality
  • Decline in school performance
  • Delays or problems with previously acquired skills (e.g., walking, talking)

Young and middle-aged adults

• Headache
• Lethargy
• Loss of coordination or balance
• Loss of bladder control or frequent urination
• Vision problems
• Decline in memory, concentration, and other thinking skills

Older adults (>60 years)

• Loss of bladder control or frequent urination
• Memory loss
• Progressive loss of other thinking or reasoning skills
• Gait disturbance
• Poor coordination or balance

Causes

Noncommunicating hydrocephalus: Obstruction of CSF outflow 

• Space-occupying lesion
• Subarachnoid or intraventricular hemorrhage 
• Spina bifida
• Arnold-Chiari malformation
• Dandy-Walker malformation
• Head injury
• Aqueductal stenosis
• Tumors

Communicating hydrocephalus: Failure of absorption of CSF by the arachnoid villi 

• Subarachnoid or intraventricular hemorrhage
• Meningitis
• Head injury
• Achondroplasia
• Craniofacial syndromes
• Other skull base deformities
• Choroid plexus papilloma or carcinoma

Risk factors

Newborns 

• Abnormal development of the central nervous system that obstructs the CSF flow
• Bleeding within the ventricles (i.e., intraventricular hemorrhage), a possible complication of premature birth
• Infection in the uterus (e.g., rubella or syphilis) during pregnancy may cause inflammation in the fetal brain tissues

Other contributing factors

• Lesions or tumors of the brain or spinal cord
• Central nervous system infections (e.g., bacterial meningitis or mumps)
• Bleeding in the brain from a stroke or head injury
• Other traumatic injury to the brain

Treatment

• Short-term (acute and emergency situations): External ventricular drain or ventriculostomy
  • Inserted into the frontal horn of the lateral ventricle
  • Drain reduces the ICP and allows to measure ICP
  • Only short-term management due to the risk of infection
• Long-term: Cerebral shunt
  • Allows drainage of CSF to distal sites
  • Placement of a ventricular catheter into the cerebral ventricles to bypass the flow obstruction/malfunctioning arachnoid villi and drain the excess CSF into other body cavities from where it can be resorbed
  • Most shunts drain fluid into the peritoneal cavity (ventriculoperitoneal shunt), alternative sites include the right atrium (ventriculoatrial shunt), pleural cavity (ventriculopleural shunt), and gallbladder
  • The shunt can also be placed in the lumbar space of the spine to redirect the CSF to the peritoneal cavity (lumboperitoneal shunt)

Management

Suggested reading

• Krovvidi H, Flint G, Williams AV. Perioperative management of hydrocephalus. BJA Educ. 2018;18(5):140-146.
• Pollard BJ, Kitchen G. Handbook of Clinical Anaesthesia. 4th ed. Taylor & Francis group; 2018. Chapter 14 Neurosurgery, Chapman E.