From the Guidelines
A head circumference of 19cm in a 12-month-old child is a critical indication of severe microcephaly, necessitating immediate medical evaluation by a pediatric neurologist. This measurement falls significantly below the normal range for this age, typically between 43-47cm, suggesting abnormal brain development 1. The child should undergo a comprehensive neurological assessment, including brain imaging (with MRI preferred over CT due to its higher resolution and safety), genetic testing, and developmental screening. Parents should be connected with early intervention services immediately, as microcephaly often leads to developmental delays, intellectual disability, seizures, and motor function problems.
Key Considerations
- The severity of microcephaly can be classified based on the degree of reduction in head circumference, with measurements 2-3 standard deviations below the mean indicating microcephaly 1.
- Microcephaly can result from various causes, including genetic disorders, intrauterine infections (such as Zika, cytomegalovirus), maternal substance exposure, or severe malnutrition 1.
- An extremely small head size indicates the brain has not grown properly, which typically results in reduced brain volume and potentially significant neurological impairment.
- Early intervention is crucial to optimize developmental outcomes, though the prognosis depends on the underlying cause and severity of the microcephaly.
Diagnostic Approach
- A detailed eye examination should be routinely performed in every individual with microcephaly, as ophthalmological abnormalities are found in up to 48% of patients, including conditions such as chorioretinal lacunae, microphthalmia, and cataract 1.
- Accurate perinatal history-taking aids in the identification of teratogen exposure and infections, although a negative history cannot reliably rule out these causes.
- Brain scans should be scrutinized for signs of fetal injury, including gliosis, cysts, and calcifications, which can indicate the underlying cause of microcephaly.
Management and Support
- Treatment focuses on managing symptoms and maximizing development through physical, occupational, and speech therapies.
- Connecting parents with support services and early intervention programs is essential to address the developmental needs of the child and provide family support.
- The child's care should be managed by a multidisciplinary team, including pediatric neurologists, geneticists, therapists, and support services, to ensure comprehensive care and optimize outcomes.
From the Research
Implications of Microcephaly
A head circumference of 19cm in a 12-month-old child is significantly below the average, indicating microcephaly. According to 2, microcephaly is defined as a head circumference more than 2 standard deviations below the mean for age and sex.
Associated Conditions
Children with microcephaly are at a higher risk of associated conditions, including:
- Intellectual delay
- Epilepsy
- Cerebral palsy
- Language delay
- Strabismus
- Ophthalmologic disorders
- Cardiac, renal, urinary tract, and skeletal anomalies 2, 3
- Vision and hearing disorders 4
Evaluation and Diagnosis
The evaluation of a child with microcephaly requires a thorough analysis of their history, clinical examination, and complementary studies, including MRI and genetic testing 4.
Prognosis and Management
The prognosis for children with microcephaly varies depending on the severity and underlying cause. Early identification and intervention can help improve outcomes, and a multidisciplinary approach to management is recommended 2, 4.
Classification and Severity
Microcephaly can be classified as congenital or postnatal, and the severity can range from mild to severe 4. The classification and severity of microcephaly can impact the associated conditions and prognosis.
Importance of Accurate Diagnosis
Accurate diagnosis and distinction between microcephaly and other conditions, such as "small head," are important to avoid unnecessary distress for parents and caregivers 5.
Clinical Profile
Children with microcephaly and developmental delay often have a distinct clinical profile, including lower developmental quotient, higher comorbidities, and associated conditions such as epilepsy and cerebral palsy 6.