A 16-month-old girl is brought to the clinic by her father due to behavior concerns. For the past 6 weeks, the patient has been less interactive with family members and increasingly irritable. Her last checkup was at age 12 months, when she met all developmental milestones and was noted to be growing appropriately. Since then, the patient has not attained new milestones in speech, gross motor, or fine motor development, which her father attributes to recent social stressors because the parents are undergoing a divorce. Temperature is 37.3 C (99.1 F), blood pressure is 140/90 mm Hg, and pulse is 70/min. The patient has poor eye contact. The anterior fontanelle is closed. Cardiopulmonary examination is unremarkable. The skin is pink and well perfused. The remainder of the examination is normal. Growth charts for head circumference as well as for height and weight are shown in the exhibits. Which of the following is the most likely cause of this patient's presentation?
Hydrocephalus in children | |
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*May not be present if the anterior fontanelle is open. CSF = cerebrospinal fluid; ICP = intracranial pressure. | |
This child has irritability, hypertension, and a rapidly enlarging head circumference (HC), as evidenced by serial head measurements that have crossed over two major growth percentiles (eg, 25th, 50th). These findings are concerning for increased intracranial pressure due to hydrocephalus, or excessive cerebrospinal fluid (CSF).
CSF is produced by the choroid plexus, flows through the ventricular system, and is absorbed into the venous circulation. Any disruption in this process results in abnormal CSF accumulation. The most common cause is obstructive (ie, noncommunicating) hydrocephalus, in which there is an anatomic blockage (eg, aqueductal stenosis, tumor, infection) of CSF flow. Obstruction results in ventricular dilation and increased intracranial pressure, eventually leading to white matter atrophy.
While the cranial sutures are still open during infancy, hydrocephalus typically results in a rapidly enlarging HC and a full or bulging fontanelle. Once the anterior fontanelle closes, which likely occurred between age 12 and 15 months in this patient, children who develop hydrocephalus are more likely to present with signs/symptoms of increased intracranial pressure. These may include behavior changes (eg, irritability), vomiting, hypertension/bradycardia, and papilledema. Developmental delay, as seen in this patient, is common and related to axonal damage, and pressure on the midbrain may cause impairment of upward gaze, which could explain this patient's poor eye contact.
(Choice A) Adjustment disorder is characterized by functional impairment or behavioral symptoms due to an identifiable stressor (eg, divorce). It does not explain a rapidly enlarging HC.
(Choice B) Holoprosencephaly is characterized by abnormal development of the forebrain in utero and is associated with microcephaly, not an enlarging HC. In addition, most patients have associated craniofacial anomalies (eg, cleft lip, hypotelorism), not seen here, and developmental delay is present from birth, not after a year of normal development.
(Choice D) Hypothyroidism often causes delayed linear growth velocity, constipation, and lethargy. It would not lead to a rapidly enlarging HC.
(Choice E) Rett syndrome most commonly presents in female toddlers with developmental regression after a period of normal development. In contrast to this case, Rett syndrome is associated with declining HC percentiles and microcephaly, and most patients have stereotypical hand movements (eg, wringing).
Educational objective:
Hydrocephalus should be suspected in an infant or young child with a rapidly enlarging head circumference crossing multiple growth percentiles. Signs/symptoms of increased intracranial pressure are more commonly seen once the anterior fontanelle closes and include irritability, developmental delay, hypertension/bradycardia, and papilledema.