1. HYDROCEPHALUS

2.  Definition:
Increase the amount of CSF in the cranial cavity, with or without increase in its tension.

3.  Circulation of CSF:
1- CSF is formed by active secretion by the
choroid plexus in the lateral ventricles.
2- Passage of CSF: Lat. V.  foramen of Monro
 3rd V.  Aqueduct of Sylvius  4th V.  Foramena of Luscka and Magendi  Subarachnoid space.
3- CSF is absorbed from arachnoid villi  dural
sinuses  venous circulation  Heart.

4.  Types and causes of hydrocephalus:
I- Relative hydrocephalus:
2ry to brain atrophy, so  the amount of CSF relative to the small sized brain. It is not associated with  in CSF tension (normotensive hydrocephalus).
II- Absolute hydrocephalus:
 the amount and tension of CSF (hypertensive hydrocephalus), it will be classified into obstructive or non-obstructive hydrocephalus.

5. OBSTRUCTIVE (NON-COMMUNICATING)
1- Foramina of Monro:
 Congenital atresia.
 Brain tumours (3rd ventricle T.).
2- Aqueduct of Sylvius
 Congenital atresia. “Common”
 Brain tumours (4th ventricle T.).

6. 3- Foramina of Luscka and Magendi 
 Congenital atresia (Dandy-Walker malformation).
 Congenital downword displacement of
cerebellum, medulla and pons
(Arnold-Chiaria malformation).
 Brain tumours (posterior fossa. T.).
 Post meningitic adhesions.

7. NON OBSTRUCTIVE (COMMUNICATING)
1- Excessive CSF production: 
 Tumours of choroid plexus (Papilloma).
 Congestion of choroid plexus (Meningitis).
2- Decrease CSF absorption 
 Adhesions in subarachnoid space

8.  C/P: 1- Head signs: Marked (as the sutures are still opened).
 Large head with progressive increase in size.
 Wide fontanelles + delayed closure of ant. fontanelle.
 Widely separated sutures.
 Scalp veins dilatation.
 Sun set eyes (forward and downward displacement).
 Cracked pot sound on skull percussion (Macwen sign).
 Craniotabes (in all skull bones).

9. 2- Neurological signs: Mild (as skull enlargement protects against development of marked  ICT).
 Mild vomiting, squint  papilloedema.
 Delayed motor milestones of development (cortical compression).
 In chronic untreated cases  M.R. and optic atrophy.

10. B- IN OLDER CHILDREN
1- Head signs: Mild as the sutures are not easily separated.
2- Neurological signs: Manifestations of  ICT:
 Severe headache esp. in the morning relieved by vomiting.
 Projectile vomiting, not related to meal, not preceded by nausea.
 Blurring of vision and papilloedema.
 Cushing response (Bradycardia & Hypertension).

11.  Diagnosis of hydrocephalus: I- Is it hydrocephalus or not
 Diagnosis of hydrocephalus: I- Is it hydrocephalus or not? Hydrocephalus must be differentiated from other causes of large head (Macrocephaly) which are.
1- Skull causesFamilial ,Achondroplasia, .Rickets ,Mucopolysaccaridosis,Cretinism.Ch. hemolytic anemia.
2- Intracranial causesHydrocephalus,Hydranencephaly ( fluid + brain atrophy)Subdural hematoma or effusionSpace occupying lesions (Brain tumours, cyst or abscess).

12.  Hydrocephalus can be differentiated from other causes of macrocephaly by:
a- Clinical examination: (see before) esp. progressive enlargement of the head by serial measurements of head circumference
b- Plain X-ray skull:
 Before closure of sutures  wide fontanelles and widely separated sutures.
 After closure of sutures  picture of  ICT (silver-beaten, wide sella turcica).

13. c- Transillumination: +ve in hydranencephaly (may be +ve in marked vent. dilat.)
d- Cranial ultrasound: If the fontanelle is still opened.
e- C.T. or MRI: Showing hydrocephalus + Identify the cause.

14. II- Is it obstructive or communicating?
a- Simultaneous lumbar and ventricular manometry:
If obstructive ventricular pressure will be higher than spinal pressure.
b- Lumbar pneumoencephalography:
Injecting air through lumbar puncture will appear in X-ray skull in
communicating (not in obstructive) hydrocephalus.
c - CT or MRI:
The most accurate non invasive method.

15.  Management of hydrocephalus:
I- Medical treatment Limited value
Dehydrating measures (mainly used in communicating(
 Restriction of salt intake.
 Carbonic anhydrase inhibitors e.g. Diamox.

16. II- Surgical treatment
1- Choroid plexectomy: In cases of excess of secretion.
2- Bypass (shunt) operations:
 Types:
 Ventriculo-peritoneal shunt.
 Ventriculo-pleural shunt.
 Ventriculo-atrial shunt (to Rt. atrium).

17.  Complications:
 Re-obstruction.  Infection and sepsis.
 Nephritis.`  Shortening of the tube

18.  Contra-indications for surgery:
 Associated lethal extracranial anomalies.
 Blindness.
 Cortical thickness less than 1cm.
 Severe motor or mental Disability.