What is the diagnosis and treatment for microcephaly (small head size)?

From the Guidelines

Microcephaly is a complex condition that requires a comprehensive diagnostic work-up, including accurate perinatal history-taking, brain scans, and genetic testing, to identify the underlying cause and provide appropriate management and supportive care. The aetiology of microcephaly is heterogeneous, including both genetic and non-genetic factors, such as intrauterine teratogen exposure, congenital infections, and perinatal and postnatal brain injuries 1. The severity of symptoms varies widely, ranging from mild developmental delays to severe intellectual disability, seizures, vision and hearing problems, and motor function impairments.

Key Considerations

• Microcephaly can be caused by genetic factors, infections during pregnancy, exposure to certain drugs or toxins during pregnancy, severe malnutrition, or decreased oxygen to the fetal brain 1.
• The clinical outcome cannot be predicted by head size alone and largely depends on the underlying cause and the appearance of the brain on MRI 1.
• A detailed eye examination should be routinely performed in every individual with microcephaly to identify ophthalmological abnormalities, which are found in up to 48% of patients with microcephaly 1.
• Management focuses on addressing specific symptoms and providing supportive care, including early intervention services like speech, occupational, and physical therapies to maximize a child's abilities and development.

Diagnostic Approach

• Accurate perinatal history-taking aids the identification of teratogen exposure and infections 1.
• Brain scans should be scrutinized for signs of fetal injury, including gliosis, cysts, and calcifications 1.
• Genetic testing, including trio-based whole-genome sequencing and RNA sequencing, may be necessary to identify the underlying cause of microcephaly 1.
• The diagnostic work-up should also include an assessment of the child's growth, development, and health complications to ensure they receive appropriate interventions and support 1.

From the Research

Definition and Diagnosis of Microcephaly

• Microcephaly is defined as a head circumference more than two standard deviations below the mean for gender and age 2.
• It is an important neurological sign and predictor of future disability.
• The diagnosis of microcephaly can be challenging due to the need for a reliable head circumference reference.
• The World Health Organization (WHO) has developed growth curves that can be used universally, but there may be discrepancies.

Etiology and Evaluation of Microcephaly

• The etiology of microcephaly can be classified into congenital and postnatal causes 2.
• Genetic causes, prenatal infections, and other factors can contribute to the development of microcephaly.
• The evaluation of a child with microcephaly requires a thorough analysis of their history, clinical examination, and complementary studies such as MRI and genetic testing 2.

Complications and Management of Microcephaly

• Children with microcephaly may experience various complications, including intellectual disabilities, developmental retardation, epilepsy, cerebral palsy, and vision and hearing disorders 2.
• The management of microcephaly requires a multidisciplinary approach, including initial assessment and post-program monitoring.
• There is no direct evidence in the provided studies on the management of microcephaly, but studies on epilepsy and antiepileptic drugs may be relevant for some cases 3, 4, 5, 6.