A 13-year-old girl is brought to the emergency department due to a head injury. The patient was climbing a tree when she fell and injured the right side of her head. She briefly lost consciousness after the injury. On arrival, the patient is awake and reports pain over the right frontal area but has no focal neurologic deficits. CT scan of the head reveals a right frontotemporal epidural hematoma. Neurosurgery is consulted for craniotomy. While waiting for the surgery, the patient becomes somnolent and develops left lower extremity weakness. Bilateral pupillary responses are normal. Which of the following best explains this patient's worsening neurologic status?

Question

A 13-year-old girl is brought to the emergency department due to a head injury.  The patient was climbing a tree when she fell and injured the right side of her head.  She briefly lost consciousness after the injury.  On arrival, the patient is awake and reports pain over the right frontal area but has no focal neurologic deficits.  CT scan of the head reveals a right frontotemporal epidural hematoma.  Neurosurgery is consulted for craniotomy.  While waiting for the surgery, the patient becomes somnolent and develops left lower extremity weakness.  Bilateral pupillary responses are normal.  Which of the following best explains this patient's worsening neurologic status?

Quizplus · Accepted Answer

11ec25c8_d585_b878_bc81_e76c43923e6b_MD0003_00 This patient with a traumatic epidural hematoma developed somnolence and left lower extremity weakness while awaiting surgery. Her acute deterioration is concerning for brain herniation, a potentially fatal condition that can occur when hemorrhage expansion (ie, mass effect) causes a portion of the brain to protrude through an opening in the dural folds. Subfalcine herniation occurs when the cingulate gyrus (a medial gyrus of the cerebral cortex just above the corpus callosum) is pushed beneath the falx cerebri, usually due to a unilateral frontal, parietal, or temporal lobe lesion (eg, frontotemporal epidural hematoma). Because the brainstem and associated cranial nerves are not compressed as they are in other herniation syndromes (eg, uncal, tonsillar), subfalcine herniation typically does not cause pupillary involvement (ie, oculomotor nerve compression), irregular respirations (ie, respiratory center compression), or coma (ie, reticular activating system compression). As subfalcine herniation progresses, however, ipsilateral anterior cerebral artery compression can lead to contralateral leg weakness. brainstem and associated cranial nerves contralateral leg weakness Diagnosis is typically made via a CT scan, and treatment focuses on lowering intracranial pressure and correcting the cause of mass effect (eg, hematoma evacuation) to prevent further herniation progression. (Choice A) Head trauma with sudden acceleration-deceleration can cause diffuse axonal injury (DAI). However, DAI typically causes severe neurologic impairment (eg, Glasgow coma scale score <8) rather than focal findings (eg, left leg weakness). Major neuroimaging findings (eg, epidural hematoma) are typically absent, although minute white matter punctate hemorrhages with blurring of the gray-white interface are sometimes seen. (Choice B) Subarachnoid hemorrhage from trauma can cause headache and somnolence. However, it also commonly causes symptoms of meningeal irritation (eg, vomiting, photophobia, neck stiffness). A CT scan often reveals blood within the basilar cisterns and the cerebral sulci. (Choices D and E) Intracranial hemorrhage expansion can cause other forms of brain herniation (eg, tonsillar, uncal). However, these typically present with signs of brainstem compression (eg, irregular respirations, unconsciousness) and pupillary changes. Tonsillar herniation usually causes fixed, midposition pupils due to disruption of both sympathetic and parasympathetic innervation. Uncal herniation usually causes an ipsilateral fixed and dilated pupil due to compression of the ipsilateral oculomotor nerve and accompanying parasympathetic fibers. Educational objective: Subfalcine herniation, a type of brain herniation, occurs when the cingulate gyrus is displaced under the falx cerebri. This typically does not cause pupillary involvement but may cause ipsilateral anterior cerebral artery compression that leads to contralateral leg weakness. References: Brain herniations in patients with intracerebral hemorrhage. (http://www.ncbi.nlm.nih.gov/pubmed/19053952)

A 13-Year-Old Girl Is Brought to the Emergency Department Due