Hydrocephalus

Question 1

Definition

Answer 1

• Excessive accumulation of CSF with enlargement of cerebral ventricles with or without increase of the intra cranial pressure; ICP
• Hydrocephalus is not a specific disease; it represents a diverse group of conditions that result mainly from impaired circulation and/or absorption of CSF .

Question 2

Normal CSF circulation:

Answer 2

CSF amount in infant = 50 ml (150 in adult)

Question 3

Normal circulation of csf

Answer 3

1. CSF is formed by active secretion by choroids plexus mainly in the lateral ventricles
2. CSF passes via foramen of Monro to the 3 rd ventricle
3. Then via aqueduct of Sylvius to the 4 th ventricle
4. Then via foramena of Lnuscka & Magendi to the subarachnoid space
5. CSF in subarachnoid space is absorbed by arachnoid villi to dural venous sinuses

Question 4

Causes of hydrocephalus

I. Relative hydrocephalus: Normotensive hydrocephalus

Answer 4

• Apparent increase in CSF due to brain atrophy

- Not associated with raised ICP

Question 5

Causes of A. Obstructive hydrocephalus

Answer 5

Obstructed CSF flow within the ventricular system (Non-communicating)

1. 💔Obstruction of aqueduct of Silvius:
   * Congenital atresia:
   - May be sex linked recessive.
   - May be associated with spina bifida occulta * Obstruction from outside by:
   - Brain tumors.

• Malformation of vein of Galen (‘listen for A cranial bruit).
• Obstruction from inside:
• Post hemorrhagic (especially in premature).
• Post meningitis (T.B., pneumocci, mumps)
  2. Congenital atresia of:
• Foramen of Monro.
• Foramina of Luscka & Magendi: Cystic dilatation of 4 th ventricle usually with cerebellar vermis agenesis (Dandy Walker malformation)
  3. Arnold Chiari malformation:

Congenital downward displacement of cerebellum, pons & medulla

4. Congenital infection especially toxoplasmosis
5. Brain tumors

Question 6

Causes of Non obstructive hydrocephalus (Communicating) due to either:

Answer 6

1. Defective CSF absorption * Subarachnoid space adhesions: - Post hemorrhagic or post meningitic * Leukemic infiltration.
   * Dural sinus thrombosis
2. Excessive CSF secretion (Rare) due to:
   - Choroid plexus papilloma
   - Choriod plexus congestion as in meningitis

Question 7

Head signs

Answer 7

• Accelerated rate of enlargement of the head is the most prominent sign. (increasing head circumference on serial measurements)
• Fontanels are widely opened & bulging.
• Sutures are widely separated.
• Dilated scalp veins.
• Eyes deviated downwards p Sunset appearance
• Skull percussion p Cracked pot sound (Macewen sign).
• Craniotabes in all bones
• A foreshortened occiput suggests Chiari malformation, and a prominent occiput suggests the Dandy-Walker malformation.

In older child

Marked neurologic manifestations as the sutures are not easily separated with subsequent marked increase ICP

• Bursting headache; severe in the morning
• Blur of vision
• Projectile vomiting (unrelated to meals, not preceded by nausea)
• Bradycardia & hypertension (Cushing response)

Question 8

Diagnosis Diagnosis

Answer 8

1- clinical picture
2- cranial X-ray
3- head ct & MRI
4-Trans fontanel cranial us
5- CSF examination
6-Fundus examination

Question 9

TX

Answer 9

1- medical → Carbonic anhydrase inhibitors; acetazolamide
2- surgical → Choroid plexectomy or diathermy for choroid papilloma

2. Extra cranial shunt operation

Question 10

Complications of the shunt

Answer 10

• Shunt nephritis
• Obstruction
• Infection commonly with staph epidermidis (fever, headache, meningismus)
• Relative shortening as the child grow