Head growth

Question 1

What is…

1. obstructive hydrocephaly
2. communicating hydrocephaly
3. external hydrocephaly?

Answer 1

Hydrocephalus is obstruction of the ceerebrospinal fluid leading to dilatation of ventricular system proximal to the site of obstruction

Obstructive hydrocephaly__: obstruction within ventricular system or aqueduct.

• Causes:
  
  • congenital malformations
    
    • aqueduct stenosis, Dandy-Walker (4th ventricle outflow malformation), chiari malformation
  • posterior fossa neoplasm
  • vascular malformation
  • IVH in preterm infant

Communicating hydrocephaly: obstruction at the arachnoid villi, the site of absorption of CSF

• Causes: subarachnoid haemorrhage, meningitis (TB, pneumococcal)

External hydrocephaly: rapidly enlarging heads are found to have a CT scan that shows widening of the subarachnoid space with mild or no ventricular dilation

• Cause: delayed development or delayed function of the arachnoid villi at the sagittal sinus

Question 2

Common causes of macrocephaly

Answer 2

• Definition: head circumference above the 98th centile
• Causes- most are normal children, parents have large heads! Worry when rapidly increasing
  
  • ​hydrocephalus- progressive or arrested
  • tall stature
  • familial macrocephaly
  • raised ICP
  • chronic subdural haematoma
  • cerebral tumour
  • NFM
  • cerebral gigantism (Sotos syndrome)
  • CNS storage disorders (Hurler syndrome)

Question 3

Common causes of microcephaly

Answer 3

• Definition: head circumference below the 2nd centile
• Causes:
  
  • ​familial- presentation at birth and development normal
  • autosomal recessive condition (+developmental delay)
  • congenital infection
  • perinatal hypoxia, hypoglycaemia or meningitis
    
    • +/- CP and seizures

Question 4

How does craniosynostosis occur and how may they present?

Answer 4

• Define: preamture fusing of one or more of the sutures which may lead to distortion of the head shape
  
  • ​GENERAL: multiple sutures resulting in microcephaly and developmental delay. Genetic syndroms (Apert, Crouzon).
  • LOCALISED:
    
    • sagittal suture affected most therefore result: narrow long skull
    • rarely affects lamboid suture causing skull flattening
    • coronal suture: asymmetrical skull
  • PLAGIOCEPHALY: is asymmetric flattening of one side of the skull from positional moulding
• If likely to cause raised intracranial pressure/ cosmetic reasons: craniofacial reconstructive surgery