Hydrocephalus Flashcards

1
Q

Definition

A
  • 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 .
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2
Q

Normal CSF circulation:

A

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

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3
Q

Normal circulation of csf

A
  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
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4
Q

Causes of hydrocephalus

I. Relative hydrocephalus: Normotensive hydrocephalus

A
  • Apparent increase in CSF due to brain atrophy

- Not associated with raised ICP

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5
Q

Causes of A. Obstructive hydrocephalus

A

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

  1. Congenital infection especially toxoplasmosis
  2. Brain tumors
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6
Q

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

A
  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
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7
Q

Head signs

A
  • 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)
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8
Q

Diagnosis Diagnosis

A
1- clinical picture
2- cranial X-ray
3- head ct & MRI
4-Trans fontanel cranial us
5- CSF examination
6-Fundus examination
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9
Q

TX

A

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

  1. Extra cranial shunt operation
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10
Q

Complications of the shunt

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