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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