This document discusses approaches to macrocephaly and microcephaly. Macrocephaly is defined as a head circumference over 2 standard deviations above the mean, while microcephaly is under 3 standard deviations below the mean. Causes of macrocephaly include genetic factors, hydrocephalus, tumors, and metabolic disorders. Hydrocephalus results from abnormal CSF accumulation and can be obstructive or communicating. Microcephaly can be primary/genetic due to syndromes or secondary from infections, drugs, or hypoxia that impact brain development prenatally or in the first two years. Evaluation and treatment depends on the underlying cause.

1. Approach to Macro and
Microcephaly
Dr. Kalpana Malla
MD Pediatrics
Manipal Teaching Hospital
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2. MACROCEPHALY
• Head circumference ( occipito frontal ) > 2
standard deviation above the mean for age
and sex
MICROCEPHALY
Head circumference > 3 standard deviations
below the mean for age and sex

3. Take 50 centile as base
line
1 SD = 1.25 CM
Macrocephaly > 2 SD i.e.
2.5 cm
Microcephaly < 3 SD
i.e 3.75 cm

4. CAUSES OF LARGE HEAD
• Familial
• Congenital : Achondroplasia, Cranioskeletal
dysplasia, Hydrocephalus, Porencephaly.
• Degenerative : white matter degeneration
• Infectious : Hydrocephalus, sudural
effusion/empyema

5. CAUSES OF LARGE HEAD
• Metabolic : GM1 gangiosidosis,
mucopolysaccharidosis, hypoparathyroid.
• Space occupying : tumors, hematoma
• Neurocutaneous defects : tuberous sclerosis,
neurofibroma
• Thickened Skull: Rickets, hemolytic anaemia,
fibrous dysplasia of bone

6. Head circumference
• Normal head circumference growth velocity:
• Birth-35cm
• 0-3 months : +2 cm/mon(41cm)
• 3-6 months :+ 1 cm/mon(44cm)
• 6-12 months :+ 0.5cm/mon
• 1-3 year : 0.25 cm/ mon
• 3-6 year : 1 cm/year

7. HYDROCEPHALUS
• Pathological increase in ventricular
volume due to abnormal CSF
accumulation
• Imbalance between CSF production and
flow leading to ventricular enlargement

8. Physiology of CSF
• CSF secreted @ 500ml/day
@ 20 ml/hr
• Total CSF volume in infant = 50 ml
in adult = 150ml.
• 80% CSF – produced from choroid plexus of
lateral, 3rd and 4th ventricle.
• 20% CSF – from cerebrum and spinal cord

9. CSF DRAINAGE
CSF Lateral Ventricles
Interventricular
Foramen of MONRO
3rd VENTRICLE
AQUEDUCT
OF SYLVIUS
4th VENTRICLE
Paired Lateral MEDIAN
FORAMEN OF LUSCHKA FORAMEN
OF MAGENDIE

10. 80 % Enters into 20 % Enters
CISTERNAL SYSTEM Subarachnoid
Space OF SPINAL
CORD
Then flows into VENOUS SINUSES
Due to increased HYDROSTATIC
PRESSURE Through ARACHNOID
VILLI AND GRANULATIONS

11. Pathophysiology:
1. Obstruction to flow
2. Decreased absorbtion
3. Increased production- rarely by choroid
plexus papilloma

12. CLASSIFICATION OF HYDROCEPHALUS
• Obstructive/ Non Communicating/ Internal:
• Obstruction is within ventricular system upto
and including outlet foramina of 4th
ventricle.
• SAS is compressed - ventricles can’t
communicate with subarachnoid space

13. OBSTRUCTIVE/ NON COMMUNICATING - causes
• Aqueductal stenosis:
- 70% of congenital
- 2% are inherited, mostly secondary to IVH,
meningitis.
• Arnold chiari malformation esp. type 2
• Dandy walker syndrome
• Chromosomal anomalies

14. OBSTRUCTIVE/ NON COMMUNICATING/
INTERNAL:
• Intra uterine infections
• Midline brain tumors - Cerebellar tumors
• Vein of Galen malformation
• Posterior fossa subdural hematoma
• Congenital septa or membrane block at outlet of
4th ventricle

15. • Non Obstructive/ Communicating/
External:
• Obstruction is distal to 4th ventriclular outlet
- foramina in cisterns, subarachnoid space or
arachnoid villi
• Patent ventricular system - SAS space is
enlarged

16. NON OBSTRUCTIVE/ COMMUNICATING – causes
• Post infectious - Meningitis ( TB COMMONEST,
also pnemococcal), Intra uterine infections –
toxoplasma, CMV,
• Sub arachnoid hemorrhage
• Meningeal leukemic infiltrates
• Secondary to excessive CSF production-papilloma
of choroid plexus
• Mucopolysacchridosis, achondroplasia
• Craniosynostosis

17. CLASSIFICATION
• Congenital : • Acquired :
Eg. IUI, Eg . TBM,
IVH meningitis,
AV-malformations Post. fossa tumor,
Cong. tumors

18. Clinical Features
• 50% may be asymptomatic
Symptoms
• Vomiting, headache
• Drowsiness
• Failure to thrive, poor appetite
• Shrill cry, irritability, lethargy
• Delayed motor milestones – mainly motor
• Progressive enlargement of head
• Abnormal shape of head – inverted triangle
• Slow mental deterioration

19. Signs
• Progressive increase in OFC (>1cm/wk )
• Head shape abnormal, forehead is broad,
frontal bossing
• Ant fontanel: wide open and bulging, non
pulsatile
• Open squamo parietal suture

20. Signs
• Macrocephaly
• Skin of skull –
shiny, tense, dilated veins
• Transillumination test:
• MacEwen Sign: percussion
of the skull produces a
“cracked pot” sound

21. Trans illumination of head
When Translucency extends beyond 2 CM in frontal area and over
1 CM in occipital area is abnormal and S/O – sub dural effusion
Hematoma, hydrocephalus , Hydranencephaly
ENTIRE SKULL IS LIT UP -
HYDRANENCEPHALY.
SOME PART OF SKULL LIGHTED
- HYDROCEPHALUS

22. MACEWEN’S SIGN
Aka. Crack pot sign
Elicited by percussion of
skull
Amplified sound can be
heard from Steth from other
end - Indicative of separated
sutures due to raised intra
cranial tension
Physiologically present if AF is
open

23. Eyes signs
• Ocular signs: eyes deviated downward “sun
setting sign”- due to pressure of 3rd ventricle
supra pineal recess on mesencephalic tectum
, causing impairment of upward gaze
• Squint - 6th n. palsy
• Nystagmus, ptosis, Optic atrophy
• Chorioretinitis (I.U. infec)
• Papilledema

24. Signs
• Pyramidal signs: spasticity, brisk tendon
reflexes, clonus, Babinski sign due to
compression & stretching of myelienated para
central corticospinal fibers arising from leg
area of motor cortex
• Others: mental retardation, gait anomaly,
epilepsy

25. Pseudo bulbar palsy
• Presents as difficulty in
feeding, sucking, drooling, aspiration
• Due to -
- Disruption of B/L cortico bulbar fibers
- Can be due to arnold chiari malformation

26. Look for
• Multiple café au- lait spots – NF
• Cranial bruit – Vein of Galen malformation
• NTD – Arnold chiari
• DANDY WALKER - prominent occiput

27. Investigation:
• USG: when ant fontanelle is open. Assesses
ventricular size, detects IVH
• Plain skull films- shows sign of ICP:
- separation of sutures
- erosion of the post. Clinoid process
- increased convolutional markings (beaten
silver appearance)
-Flat enlarged sella tursica

28. Investigation:
• CT: helps to identify the cause
• MRI: better visualization of post fossa
pathologies
• Opthalmological evaluation
• Psychomotor assessment: using different dev
scales

29. TREATMENT
• Medical :aims to decrease ICP&CSF formation
1.MANNITOL 20% - 5ML/KG stat followed by
2ml/kg 6th hourly for 2 days.
2.ACETAZOLAMIDE 50-100mg/kg/day to reduce
CSF production
3.ORAL GLYCEROL
4.FRUSEMIDE

30. SURGICAL
VENTRICULO PERITONEAL SHUNT
• SILASTIC one way low pressure valve shunt –
Upadhya shunt
• Indications for surgery:
Papilledema/ periventricular ooze on
fundoscopy/CT.
Cortical mantle < 2.5cm on initial neuroimaging
Progressive thinning of mantle despite medical
treatment.

32. EVALUATION OF SHUNT
• Pump the reservoir by finger pressure
• Normally shunt empties and refills on release
• IF FAILS TO REFILL = Proximal block = Due to
choroid plexus tissue
• IF RESISTANCE TO EMPTYING= Distal block =
Omental block

33. • SHUNT FAILURE CAN OCCUR DUE TO:
Shunt infection, calcifications, malposition.
• Shunt infection - mostly due to staph
epidermis, staph aureus.

34. Prognosis
• “arrested hydrocephalus” - may undergo spontaneous arrest
• Untreated : 50% mortality
• These children are at an increased risk of:
– Dev. Disabilities with less IQ
– Visual problems: visual field
defects, strabismus, optic atrophy
– Behavioral problems:
– Accelerated pubertal dev- due to increased
gonadotropin secretion in response to raised ICP

35. Post Meningitis with enlarging head
CT, CSF EXAM, FUNDOSCOPY
LOOK FOR CSF CELLS PROTEINS, INTRA CRANIAL PRESSURE
PERIVENTRICULAR OOZE
Significant
RAISED ICT Mild hydro, hydroc.
LOW CELLS ICT NOT RAISED High cells Ooze +, high
LOW PROTEIN High cells,
proteins protein
SHUNT MEDICAL
Try to avoid
Shunts.
Treat External
medically drainage

36. POST TBM HYDROCEPHALUS
IN Acute Stage not indicated as high PROTEINS -
GREATER SHUNT BLOCK also it responds well to ATT AND
STEROIDS.
INDICATION FOR SURGERY BEING – Persistent
decerebration no improvement in sensorium in 10days

37. Follow up
• 1,3,6 months then yearly.
• Check – HC, neurological signs, Fundus, shunt
function, IQ testing.

38. Hydranencephaly
• The cerebral hemispheres are replaced by a thin-
walled, fluid-filled cyst
• The aqueduct is usually atretic, and increased
fluid pressure causes the cyst to enlarge
• The empty cranial cavity transilluminates

39. MICROCEPHALY
Is defined as head circumference > 3
standard deviations below the mean for
age and sex

40. PRIMARY ( Genetic ) MICROCEPHALY
Refers to group - associated with
specific genetic syndromes.
USUALLY have slanting forehead.
Identified at birth itself

41. Causes for primary
• Familial - AR
• Autosomal dominant
• Syndromes : Down, Cri du
chat, Edward, Cornelia de
Lange, Rubinstein
Tyabi, Smith Lemli Opitz.

42. Secondary ( non genetic) Microcephaly
• Results from noxious agents that may
affect a fetus in utero or an infant during
periods of rapid brain growth,
particularly the first 2 years of life

43. Causes for secondary microcepahaly
• Radiation
• Congenital infections – rubella, CMV, toxo
• Drugs – fetal alcohol, fetal hydantoin
• Meningitis/encephalitis

44. Causes for secondary microcepahaly
• Metabolic – maternal diabetes
• Hypoxic ischemic encephalopathy
• Malnutrition
• Hyperthermia

45. Microcephaly Craniosynostosis
• Shape of skull • Shape of skull -
usually normal abnormal
• Suture line - • Suture line –
normal ridged.

46. Evaluation of microcephaly
• Familial microcephaly needs exclusion
• Detail birth history
• OFC of siblings and parents should be
recorded
• Examine for associated dysmorphism
Developmental assessment
• Detailed neurological evaluation - seizures,
spasticity

47. Investigations
• X ray skull -determine suture
patency, overriding, fusion and calcification
• TORCH serology-
• KARYOTYPE- if dysmorphism
• Metabolic screening

48. • CT Head- for evidence of HIE sequelae,
and intracranial calcifications
• MRI- in cases of familial microcephaly
and suspected migrational disorders

49. Treatment and Prognosis
• Usually supportive
• Treat neurological & sensory deficits
• Treat seizures
• If MR present, special schools may be
needed
• Genetic councelling

50. Thank you
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