Head Circumference

Aka: Head Circumference, Microcephaly, Microcephalic Infant, Macrocephaly, Macrocephalic Infant

1. See Also
   1. Newborn Head and Neck Exam
   2. Newborn Neurologic Exam
   3. Craniosynostosis
   4. Fontanelle
2. Head Size Measurement
   1. Normal term newborn Head Circumference: 33 to 38 cm
   2. Technique
      1. Measuring tape around frontal forehead and occiput
      2. Take largest of several measurements
3. Macrocephaly causes
   1. Familial with autosomal dominant inheritance
   2. Hydrocephalus
   3. Other conditions
      1. Achondroplasia (skeletal dysplasia)
      2. Sotos' Syndrome (Cerebral Gigantism)
      3. Alexander's Disease
      4. Canavan's Disease
      5. Gangliosidoses
      6. Glutaric aciduria Type I
      7. Neurofibromatosis Type I
4. Microcephaly cause
   1. Familial
   2. Trisomy 13
   3. Trisomy 18 (Edward Syndrome)
   4. Trisomy 21 (Down Syndrome)
   5. Cornelia de Lange
   6. Rubinstein-Taybi
   7. Smith-Lemli-Opitz
   8. Prader-Willi
   9. Teratogen Exposure
      1. Fetal Alcohol Syndrome
      2. Radiation exposure in utero (<15 weeks gestation)
      3. Fetal Hydantoin
   10. TORCH Virus congenital infection
       1. Cytomegalovirus
       2. Rubella
       3. Toxoplasmosis
   11. Other causes
       1. Meningitis or Encephalitis
       2. Gestational Diabetes
       3. Maternal hyperphenylalaninemia
       4. Hypoxic-ischemic encephalopathy
5. Diagnostic evaluation for Microcephaly
   1. Maternal phenylalanine level
   2. Karyotype of child for suspected congenital abnormality
   3. Head imaging (Head Ultrasound, Head CT, Head MRI)
   4. Amino acid analysis (fasting plasma and urine)
   5. Serum ammonium
   6. TORCH Virus serum titers (mother and child)
   7. Urine Culture for Cytomegalovirus
6. References
   1. Behrman (2000) Nelson Pediatrics, Saunders, p. 1809
   2. Goetz (1999) Clinical Neurology, Saunders, p. 512
   3. Fuloria (2002) Am Fam Physician 65(1):61-8