A 17-year-old boy is brought to the emergency department after his mother heard a loud crash and found him unconscious at the bottom of the stairs in their house. Vital signs are normal. Examination shows a confused adolescent with a 2-cm contusion on the forehead. Foot examination is shown in exhibit 1, and CT scan of the head is shown in exhibit 2. This patient most likely has which of the following underlying conditions?

Question

A 17-year-old boy is brought to the emergency department after his mother heard a loud crash and found him unconscious at the bottom of the stairs in their house.  Vital signs are normal.  Examination shows a confused adolescent with a 2-cm contusion on the forehead.  Foot examination is shown in exhibit 1, and CT scan of the head is shown in exhibit 2.  This patient most likely has which of the following underlying conditions?

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11ec25c8_d5e0_f751_bc81_0f78f82049c0_MD0003_00 This patient has subependymal nodules, periungual fibromas, and an unwitnessed fall suggestive of a seizure. These findings are concerning for tuberous sclerosis complex (TSC), an autosomal dominant neurocutaneous disorder in which a TSC gene mutation leads to benign hamartomas in various organs (eg, brain, eye, skin, heart, kidney). subependymal nodules Epilepsy is present in most TSC patients; although onset is more common in infancy, a first-time seizure can occur at any age, as seen in this adolescent patient. Seizures often prompt neuroimaging, and characteristic subependymal nodules are seen on CT scan as small, calcified lesions along the ventricles. Although benign, the nodules may grow into subependymal giant cell tumors and cause obstructive hydrocephalus, necessitating surgical resection. Cortical glioneural hamartomas (tubers) are also commonly found in the CNS but are better appreciated on brain MRI (yellow circles). brain MRI Classic dermatologic manifestations of TSC include multiple periungual fibromas (fibrous growths arising from the nail fold), which may develop in adolescence or adulthood. Other common skin findings include ash-leaf spots (hypopigmented macules), malar angiofibromas, and shagreen patches (orange peel-like plaque on lower back). A constellation of clinical findings and/or genetic testing confirms the diagnosis of TSC. (Choice A) Ataxia-telangiectasia is an autosomal recessive disorder that typically manifests in childhood with unstable gait, uncoordinated eye movements, and telangiectasias, none of which are seen in this patient. (Choice B) Typical findings of bacterial endocarditis include fever, shortness of breath, and a cardiac murmur. Splinter hemorrhages can occur under the nails, but not ungual fibromas. Splinter hemorrhages (Choice C) Neurofibromatosis type 1 is an autosomal dominant neurocutaneous disorder that can cause seizures, CNS lesions (most commonly optic gliomas), and cutaneous neurofibromas that are typically on the trunk. This patient's toenail lesion and subependymal nodules make TSC more likely. cutaneous neurofibromas (Choice E) Von Hippel-Lindau syndrome is an autosomal dominant disorder associated with multiple CNS tumors, most commonly cerebellar and retinal hemangioblastomas. Subependymal nodules and ungual fibromas do not occur. Educational objective: Tuberous sclerosis complex is an inherited neurocutaneous disorder characterized by benign hamartomas of various organs. Epilepsy is a frequent finding that often begins in infancy but can manifest later in life. Other characteristic features include periungual fibromas and subependymal nodules. References: Tuberous sclerosis complex: a review. (http://www.ncbi.nlm.nih.gov/pubmed/28414398)

A 17-Year-Old Boy Is Brought to the Emergency Department After