MACROCEPHALY

Dr. D. Gunasekaran, Consultant Paediatrician,MGMC & RI, Pondicherry

Macrocephaly - Definition > 2 S.D above the mean for the age & sex OR > 97th percentile for the age & sex OR> 2.5 cms above the mean for age & sex

Macrocephaly How to find out the expected HC for a particular

child?

Only by comparing the standardized charts which shows HC for a particular age & sex

Normal HC at birth At birth 33-35cm

<3 months 2 cm / month

3-6 months 1cm / month

6 months – 1 year 0.5 cm / month

1-3 years 1cm / 6 months

3-5 years 1cm / year

Macrocephaly - causes

Big skull

Big brain

More CSF in ventricles

Abnormal accumulation

Familial

Chronic anemia, O.I, Rickets

Megalencephaly (Tay-sach), Cerebral gigantism

Hydrocephalus

Subdural effusion

Commonest (at the community level)

Hydrocephalus

Greek word – “water in head”

Definition: Excessive accumulation of CSF in the ventricular system

Normal CSF

Normal Volume of CSF:

Normal CSF

Normal Volume of CSF:

Newborn: total of 24 ml at any time Adult: total of 150 ml, at any time 1 hour : 24 ml production

Normal CSF Pressure

Normal ICP: Newborn: 10-20 cm H2O Infants: 20-80 Older child: 40-100

Hydrocephalus – Normal CSF

Where is CSF formed? Choroid Plexus in Lateral Ventricles (75%) Choroid Plexus in 3rd & 4th Ventricles Capillary endothelium

It is actually an ultra filtrate of Plasma

Hydrocephalus – Normal CSF

How CSF Circulates in side the skull and Spinal cord?

Pathways of CSF

CSF PATHWAY

CSF IS FORMED IN THE LATERAL VENTRICLE

3RD VENTRICLE THROUGH FORAMEN OF MONRO

4TH VENTRICLE THROUGH AQUEDUCT OF SYLVIUS

INTO SUBARACHANOID SPACE of spinal cord THROUGH FORAMEN OF LUSCHKA & MAGENDIE

Hydrocephalus – Normal CSF

Where CSF is absorbed?

Arachnoid villi, lymphatic channels

3 types of mechanisms predisposing for developing Hydrocephalus

1. Increased production (Communicating H)

2. Decreased absorption (Communicating H)

3. Obstruction (aqueduct – 3 mm long & 2 mm wide) (Obstructive H / Non-Communicating H)

1. Increased production of CSF

Tumours in the choroid plexus - rare

2. Decreased absorption of CSF

Obliteration of Arachnoid villi & cisterns:

Congenital: TORCH Acquired: Meningitis Blood Leukemia

3. Obstruction of CSF Congenital:-Aque ductal stenosis: TORCH, malformations of aqueduct, Aneurysmal dilatation of vein of Galen, X-linked

Arnold- Chiari malformation II: Dandy-Walker syndrome:

Hydrocephalus - Obstructive

AcquiredAque ductal gl iosis Meningitis, Bleeding (intraventricular - in

preterms), Mumps encephalitisPosterior fossa tumours:

Medulloblastoma obstructing aqueduct

Clinical features – Before AF close

Clinical features – Before AF close

Big headBig fontanalle (Normal at birth: 2.5 cms)Widely placed sutures (>5 mm)Broad foreheadProminent subcutaneous veinsSun-set eyes (dilated suprapineal recess impinges on the tectum,

midbrain, which controls eye movements)

Weakness of lower limbs (stretching and disruption of CS fibres originating from the leg region of the motor cortex, while crossing over the dilated ventricles)

Prominent subcutaneous veins

Clinical features – after AF closure - ICT

Headache, vomiting Blurring of vision -stooping and bending Bradycardia, increase in BP (Cushing’s triad –

ICT disturbs the vasomotor centre in Medulla)

6th CN palsy (often unilateral)PapilloedemaTransillumination (2.5cm & 1cm)- (when there

is massive dilatation of the ventricles or in Dandy-Walker syndrome)

Clinical features – after AF closure - ICT

Macewan sign (crack pot sound - significant only after the AF & sutures

close)

Small occiput – Arnold Chiari

Prominent occiput – Dandy-walker

Diagnosis 1. History:- Familial: X linked or AR Aqueductal stenosis Prematurity Intra uterine infection Intracranial hemorrhage Meningitis Mumps Encephalitis (leads to aqueductal stenosis) 2. 0/E: Café-au-lait patches (NC markers) Spinal dysraphism (tufts of hair, lipoma, angioma) Wide AF, wide sutures, sun set eye sign, LL weakness Cranial bruit (AV Malformation of Galen) Transillumination +: massive dilatation of ventricles; D. W. syndrome Eye: Papillodema, chorioretinits

Diagnosis -Investigations

1. X-Ray skull:-

Infant:

Older child:

In long standing cases:

Diagnosis -Investigations

1. X-Ray skull:-

Infant: Calcification (IU infection) Separated sutures

Older child: Thinning of the floor of the sella Erosion of the posterior clinoids

In long standing cases: Silver-beaten appearance (an increase in convolution markings)

Diagnosis - Investigations

2. USG (through AF), CT scan & MRI:-

Dilatation of all ventricles: communicating type

3rd ventricle dilatation & 4th ventricle normal: Aqueductal stenosis

Treatment – Supportive- Control of ICP

1. Head elevated to 30 deg & in neutral2. Control of temperature3. Control of seizures4. Maintain blood pressure5. Analgesia & sedation

Treatment – Supportive- Control of ICP

Hypertonic solutions:- Mannitol or Oral glycerol

Passive hyperventilation:- Decline of PCO2 Mild constriction of blood vessels in brain Mild (10-30%) reduction of ICT

Treatment

For decreasing the production:- Acetazolamide – temporary

For Obstruction and decreased absorption:- Ventriculo Peritoneal shunt Complication: Infection (Staph. Epid) Obstruction

Prognosis

Depends on:- the cause for ICT the rate of increase in ICT the presence of other developmental abnormalities of brain the time at which the treatment was initiated

(early or late)

Prognosis

Abnormalities observed in long term follow-up are:

Developmental disabilitiesMemory disturbancesVisual problems – strabismus, field defects, optic

atrophy

Accelerated pubertal development Increased Gonadotrophin levels

To Sum UpTo Sum Up

THE END