43-Large and Small Head

Question 1

NORMAL HEAD GROWTH

Answer 1

The head circumference is determined by measuring the greatest occipitofrontal circumference (from the occipital prominence to the frontal prominence – taking the biggest measurement of three).

Question 2

CEREBRO SPINAL FLUID (CSF)

Answer 2

Part of extracellular fluid (ECF)
 Rate of formation is about 0.3 ml/
min and normally 500ml of CSF is
formed everyday and equal amount
is absorbed .
FUNCTIONS • Protects & lubricates the brain • Provides nutrients ,remove waste • Modulates pressure changes • serves as a chemical buffer to maintain constant ionic
environment • Serves as a transport medium for nutrients and metabolites,
endocrine substances and even neurotransmitters

Question 3

CSF PRODUCTION

Answer 3

CSF PRODUCTION
• Choroid plexuses are the main
site of  CSF production. • Then.. The passage of the
plasma ultra  filtrate through
the endothelium, facilitated
by hydrostatic pressure. • Then.. Passes into the
ventricles • An active metabolic process
which  transforms the ultra
filtrate into  secretion CSF.

Question 4

MACROCEPHALY

Answer 4

Definition: Head circumference ( occipito frontal ) > 2 standard
deviation(SD) above the mean for age and sex.

Question 5

1 SD = 1.25 CM

Answer 5

Macrocephaly > 2 SD (i.e. 2.5 cm)

Microcephaly < 3 SD (i.e 3.75 cm)

Question 6

CAUSES OF MACROCEPHALY

Answer 6

CAUSES OF MACROCEPHALY
1. Megalencephaly
• Benign Familial
• Neurocutaneous syndromes: Neurofibromatosis, tuberous sclerosis
• Fragile X
syndrome
• Leucodystrophies & Lysosomal storage disease 2. Increased Cerebrospinal fluid
• Hydrocephalous
• Benign enlargement of subarachnoid space 3. Enlarged Vascular compartment
• Arteriovenous malformation
• Subdural, epidural, subarachnoid or intraventricular hemorrhage
CAUSES OF MACROCEPHALY
4. Increase in bony compartment
• Bone disease : Achondroplasia, osteogenesis imperfecta, osteopetrosis
• Bone marrow expansion: Thalassemia major 5. Miscellaneous causes
• Intracranial mass lesions: Cyst, abscess or tumor
• Raised intracranial pressure: Idiopathic pseudotumor cerebri, lead
poisoning, galactosemia

Question 7

CAUSES OF HYDROCEPHALUS

1) CONGENITAL HYDROCEPHALUS

Answer 7

CAUSES OF HYDROCEPHALUS
1) CONGENITAL HYDROCEPHALUS • Intrauterine infections: Rubella, Cytomegalovirus, Toxoplasmosis. • Congenital malformations:
• Dandy-walker syndrome.
• Aqueduct stenosis: it accounts for 33% of hydrocephalus cases. Stenosis of
aqueduct of sylvius causes dilation of lateral and 3rd ventricles. In 2% of cases this could be familial with X linked recessive inheritance.
• Arnold-Chiari syndrome- Portions of cerebellum & brainstem herniating into
cervical spinal canal, blocking the flow of CSF to the posterior fossa.

Question 8

Dandy-walker syndrome

Answer 8

Block of 4th ventricle agnesis of cerebellar vermis

Congenital obstructive hydrocephalus

Question 9

CAUSES OF HYDROCEPHALUS

2) ACQUIRED HYDROCEPHALUS

Answer 9

CAUSES OF HYDROCEPHALUS

2) ACQUIRED HYDROCEPHALUS • Meningitis. • Post-intraventricular hemorrhage. • Posterior fossa tumors: medulloblastoma, astrocytoma,
ependymoma. • Arteriovenous malformation • intracranial hemorrhage • ruptured aneurysm.

Question 10

TYPES OF HYDROCEPHALUS

Answer 10

Communicating (extraventricular) hydrocephalus- • there is normal communication between the
ventricles & the spinal subarachnoid space. • There is an interference with the absorption of
CSF caused by an occlusion of the subarachnoid
cisterns around the brain stem. • Communicating hydrocephalus may be due to
subarachnoid hemorrhage or meningitis,
toxoplasmosis or cytomegalovirus infection,
in which there is an obliteration of the
subarachnoid spaces by fibrous tissue
reaction, or to diseases of connective tissue.

Question 11

CLINICAL MANIFESTATIONS

HYDROCEPHALUS

Answer 11

CLINICAL MANIFESTATIONS
 Head grows at abnormal rate.  Anterior fontanel is tense, often bulging, &
non pulsatile.  Scalp veins are dilated & markedly so when
infant cries.  Frontal bossing with depressed eyes.  Setting-sun sign- eyes rotated downward, in
which sclera may be visible above iris.

Question 12

DIAGNOSTIC EVALUATION

hydrocephalus

Answer 12

Routine daily head (occipitofrontal) circumference measurements.
• A head CT scan is one of the best tests for identifying hydrocephalus. • Cranial ultrasound • Lumbar puncture and examination of the cerebrospinal fluid.

Question 13

MANAGEMENT OF HYDROCEPHALUS

Answer 13

MANAGEMENT OF HYDROCEPHALUS
• MEDICAL MANAGEMENT
• This can be tried in mild cases of hydrocephalus.
• Acetozolamide: dose of 50mg/kg/day • SURGICAL MANAGEMENT
• The removal of the obstruction (tumor, hemorrhage or cyst) to the flow
of CSF.
• Shunting of CSF from the ventricle to another site in the normal
circulatory passageway of this fluid. • Shunting of CSF from the ventricle to an area outside the CNS, an
extracranial body compartment.
Ventriculoperitonial(VP) shunt-

Question 14

APPROACH ON MACROCEPHALY

APPROACH

Answer 14

History • Examination including auscultation of the skull for bruit • Developmental history • Rate of head growth – serial measurements
Investigations : 1. Urea/electrolytes 2. Thyroid function test 3. Plasma amino acids 4. Urine amino acids and organic acids, glycosaminoglycans 5. CT head / MRI head preferably 6. Bone profile

Question 15

APPROACH ON MACROCEPHALY

Answer 15

APPROACH ON MACROCEPHALY
• History
• 50% may be asymptomatic Symptoms
• Vomiting, headache,Drowsiness
• Failure to thrive
• Irritability, lethargy
• Delayed motor milestones – mainly motor
• Progressive enlargement of head
• Abnormal shape of head – inverted triangle
• Slow mental deterioration
APPROACH ON MACROCEPHALY
• Examination
• General observation
• Measure head circumference of parents and Request percentile
• Dysmorphic features and Skeletal anomalies
• Looking for Movement
• Symmetry and Upper limb versus lower limb
• Café-au-lait patches (NC markers)

Question 16

APPROACH ON MACROCEPHALY

• Head Palpate

Answer 16

APPROACH ON MACROCEPHALY
• Head Palpate (With child sitting up; interact with child and observe
responsiveness)
• Craniotabes • Split sutures • Bulging fontanelle • Absent fontanelle pulsation • Shunts—trace shunt tubing, look for chest (VA) and abdomen (VP) scars

Question 17

APPROACH ON MACROCEPHALY

Answer 17

APPROACH ON MACROCEPHALY
• Eyes and pupil
• eyes deviated downward “sun setting sign”
(due to pressure of 3rd ventricle) • Ptosis • proptosis • Nystagmus and Squint • Corneal clouding
• External ocular movements and Fundus examination

Question 18

MICROCEPHALY

Answer 18

MICROCEPHALY
• Definition: - head circumference
more than 3 standard deviations
below the mean for age and sex. Types :
• Primary (Genetic) • Secondary (non-genetic)

Question 19

SECONDARY ( non genetic) MICROCEPHALY
• Radiation • Congenital infections – rubella, CMV, toxoplasmosis, HIV, Syphilis • Drugs – fetal alcohol, fetal hydantoin • Meningitis/encephalitis • Metabolic – maternal diabetes • Hypoxic ischemic encephalopathy • Malnutrition • Hyperthermia

Question 20

APPROACH ON MICROCEPHALY

Answer 20

HISTORY • Family history- to r/o primary • h/o prenatal,perinatal and postnatal insults • Exposure of radiation during pregnancy • Maternal drug history • Infections/DM/PKU • Difficult delivery/MSAF/low apgars • Significant fever in neonatal period • h/o high-pitched cry/ poor feeding/ seizures/ increased movement of the arms and legs (spasticity)

Question 21

CRANIOSYNOSTOSIS

Answer 21

Definition: premature fusion of
one or more cranial sutures, either major(e.g metopic, coronal, sagittal, and lambdoid) or minor( frontnasal, temporosquamosal, and frontosphenoidal).

Question 22

CRANIOSYNOSTOSIS

Answer 22

CRANIOSYNOSTOSIS

1. Plagiocephaly 2. Scaphocephaly 3. Trigonocephaly 4. Turencephaly 5. Brachycephaly