A 2-month-old boy is brought to the emergency department by ambulance after a seizure. His mother says that he rolled off the bed last night while his older sister was changing his clothes and that he cried for a few minutes but fed well last night. Today, the patient had a tonic-clonic seizure that lasted 4 minutes after his morning feeding. He has been otherwise healthy. The patient was born at 31 weeks gestation, and his postnatal course was complicated by respiratory distress and hypoxia requiring intubation for several days. Height and weight are at the 50th percentile; head circumference is at the 98th percentile. Temperature is 36.7 C (98 F), blood pressure is 90/50 mm Hg, and pulse is 144/min. Physical examination shows a limp infant who withdraws from painful stimuli. The anterior fontanelle is full and tense. Funduscopy reveals bilateral papilledema and retinal hemorrhages. The abdomen is soft with no hepatosplenomegaly. Which of the following is the most likely etiology of this patient's seizure?
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This patient's seizure, disproportionately large head circumference, full fontanelle, papilledema, and retinal hemorrhages are alarming for abusive head trauma (ie, shaken baby syndrome). Infants are particularly susceptible because they have a relatively large, heavy head; weak neck musculature; immature brain myelination; and a soft brain with high water content. Nonaccidental injury to the head or brain is the most common cause of death from child abuse, and babies born prematurely or with congenital defects are at higher risk of abuse.
The most common mechanism of inflicted injury in infants involves violent shaking. Repetitive acceleration-deceleration forces cause subdural bleeding due to shearing of the bridging veins and coup-contrecoup injury as the brain impacts the skull. Subdural hemorrhage can manifest as seizures, increasing head circumference, bulging/tense anterior fontanelle, papilledema, and altered mental status. Shaking also causes vitreoretinal traction and retinal hemorrhages, a virtually pathognomonic finding for abusive head trauma.
Child abuse should be suspected when the mechanism of injury is inconsistent with the patient's developmental stage. For instance, this patient reportedly fell after rolling; however, rolling is typically achieved at age 4-6 months. The patient should undergo a noncontrast CT scan of the head to evaluate for intracranial injury and a skeletal survey to identify occult fractures. Hospitalization and contacting child protective services are required to ensure the patient's safety.
(Choice A) Severe intraventricular hemorrhage (IVH) can obstruct cerebrospinal fluid flow, leading to signs of hydrocephalus (eg, seizures, bulging fontanelle). However, IVH generally presents in premature infants within the first few days of life.
(Choice B) Electrolyte abnormalities (eg, hyponatremia, hypocalcemia) can lead to seizures but do not cause retinal hemorrhages.
(Choice C) Premature infants with perinatal hypoxia can experience hypoxic encephalopathy but typically have seizures and lethargy shortly after birth, unlike this patient with an acute change in mental status at age 2 months.
(Choice D) Meningeal inflammation from meningitis can cause seizure and altered mental status in an infant but is unlikely in the absence of fever and the presence of retinal hemorrhages.
(Choice F) Thromboembolic stroke is rare in previously healthy children without congenital heart disease, hematologic abnormalities, or indwelling central venous catheters. In addition, thromboembolism would not cause retinal hemorrhages.
Educational objective:
Abusive head trauma is the most common cause of death from child abuse. Repetitive acceleration-deceleration forces cause shearing of the subdural bridging veins and vitreoretinal traction, resulting in subdural and retinal hemorrhages.