Overview Hydrocephalus is excessive accumulation of CSF in the cerebral ventricles. In children, look for increasing head circumference, increased intracranial pressure, a bulging fontanelle, scalp vein engorgement, and paralysis of upward gaze. The most common causes include:

  • Congenital malformations
  • Tumors
  • Inflammation (i.e hemorrhage, meningitis).

Treat the underlying cause, if possible; otherwise a surgical shunt is created to decompress the ventricles.


Anatomy and Physiology of CSF

  • CSF is produced primarily by the choroid plexus, which is responsible for 60 to 80 percent of CSF production.
  • The choroid plexus tissue is located in each cerebral ventricle and consists of villous folds lined by epithelium with a central core of highly vascularized connective tissue.
  • CSF supplies brain tissue with nutrients and flows through the ventricles before being absorbed back into circulation from the venous sinus.

Production or CSF

Anatomy and physiology

CSF flow around brain occurs via ventricles

  • CSF production rates are constant in physiological conditions unless extremely high levels of intracranial pressure are reached.
  • Thus, absorption of CSF generally matches the rate of production to accommodate the volume of CSF being formed each day.
  • CSF returns to circulation via the venous sinus.


Types of Hydrocephalus

Hydrocephalus can be divided up into congenital and acquired

Congenital Hydrocephalus are picked up on ultrasound

  • In uterus infections
  • Aquedcut stenosis
  • Dandy walker malformation
  • Chiari malformation (associated spina bifida)

Acquired Hydrocephalus - usually occur later in life due to some sort of "event"

  • Meningitis
  • Haemorrhage (bleeding)
  • Tumours

Hydrocephalus can be communicating or non-communicating

  • Communicating - ventricles are connect without obstruction
  • Non-communicating - ventricles are not connected because of an obstruction
Side note Hydrocephalus ex vacuo describes increases in CSF volume without increased CSF pressure, which is seen in conditions of reduced cerebral tissue (i.e malformation, atrophy).

Risk Factors

Infantile Risk Factors
Birth weight <1500 g
Prematurity (gestational age ≤30 weeks)
Maternal diabetes
Low socioeconomic status
Male sex
Race/ethnicity (the risk is decreased in Asians)

Signs and Symptoms

Signs and symptoms

Clinical Presentation between acquired and congenital

Infant Older Child
Increasing head circumference, Macrocephaly Headache (morning worse)
Delayed closure of the fontanel Nausea and vomiting
Suture separation Personality and mood changes
Bulging fontanel Lethargy
Failure to thrive Anorexia
Paresis of upward gaze (known as setting-sun sign) Diplopia as a result of sixth-nerve palsy or third-nerve palsy with uncal herniation
Shrill cry Papilledema

Differential Diagnosis

  • Neurofibromatosis
  • Pituitary gigantism
  • Sotos syndrome
  • Achondroplasia


Hydrocephalus should be suspected in an infant whose head circumference is enlarged at birth or in whom serial measurements cross percentiles in standard growth curves, indicating excessive head growth. Hydrocephalus should be considered in children with severe headache and other features suggesting increased intracranial pressure (ICP).

  • Serial Head circumference
  • Head ultrasound
  • CT
  • MRI
  • Pressure flow studies
Side note
In a newborn, ultrasonography is the preferred technique for the initial examination because it is portable and avoids ionizing radiation. As the anterior fontanelle closes, the ultrasound is no longer a useful diagnostic modality.
In older infants and children with suspected hydrocephalus, CT or MRI should be performed. These imaging studies will also detect associated central nervous system (CNS) malformations or tumors.Brain imaging can help to distinguish obstructive (non-communicating) from absorptive (communicating) hydrocephalus.


  • Head circumference increases at an abnormal rate, passing 2 deviation
  • The diagnosis of hydrocephalus is confirmed by neuroimaging.


Excessive accumulation of cerebrospinal fluid in the brain that can be due to:

  • Increased production of CSF (rare)
  • CSF flow obstruction (most common) also known as non-communicating
  • Decreased absorption of CSF also known as communicating

Many cases of hydrocephalus have both obstructive and absorptive components



  • Transfer as an emergency -> neurosurgery clinic for review
  • Ventricular tap
  • Shunt
    • Ventricuoatrial
    • Ventriculoperitoneal
Remember Assume patients who present to emergency with headaches associated with a ventricular shunt, has infection/blockage. Refer as an emergency. Associated drowsiness is a particular pointer to blockage


Shunt Complication

  • Infection
  • Blockage
  • Disconnection
  • Pulmonary hypertension


Royal Children's Hospital Melbourne


Video: Hydrocephalus