II. Exam: Head Size Measurement
- Normal term newborn Head Circumference: 33 to 38 cm
- Technique
- Measuring tape around frontal forehead and occiput
- Take largest of several measurements
III. Causes: Macrocephaly
- Familial with Autosomal Dominant inheritance
- Hydrocephalus
- Other conditions
- Achondroplasia (skeletal dysplasia)
- Sotos' Syndrome (Cerebral Gigantism)
- Alexander's Disease
- Canavan's Disease
- Gangliosidoses
- Glutaric aciduria Type I
- Neurofibromatosis Type I
IV. Causes: Microcephaly
- Familial
- Trisomy 13
- Trisomy 18 (Edward Syndrome)
- Trisomy 21 (Down Syndrome)
- Cornelia de Lange
- Rubinstein-Taybi
- Smith-Lemli-Opitz
- Prader-Willi
-
Teratogen Exposure
- Fetal Alcohol Syndrome
- Radiation exposure in utero (<15 weeks gestation)
- Fetal Hydantoin
- TORCH Virus congenital infection
- Other causes
- Meningitis or Encephalitis
- Gestational Diabetes
- Maternal hyperphenylalaninemia
- Hypoxic-ischemic encephalopathy
V. Diagnostic evaluation for Microcephaly
- Maternal Phenylalanine level
- Karyotype of child for suspected Congenital Abnormality
- Head imaging (Head Ultrasound, Head CT, Head MRI)
- Amino Acid analysis (Fasting plasma and urine)
- Serum ammonium
- TORCH Virus serum titers (mother and child)
- Urine Culture for Cytomegalovirus
VI. References
- Behrman (2000) Nelson Pediatrics, Saunders, p. 1809
- Goetz (1999) Clinical Neurology, Saunders, p. 512
- Fuloria (2002) Am Fam Physician 65(1):61-8 [PubMed]