A 58-year-old man is brought to the emergency department after a witnessed tonic-clonic seizure. The patient was at work when he suddenly collapsed and convulsed for approximately a minute. His coworker says that the patient was confused immediately afterward; however, he is now awake and cooperative. He has been having headaches for the past several weeks and has never before had a seizure. He has no prior medical problems and takes no medications. The patient is a former smoker with a 45-pack-year history. He occasionally drinks alcohol but does not use illicit drugs. The patient has lived most of his life in Texas and has never traveled outside of the country. Temperature is 36.7 C (98.1 F), blood pressure is 122/70 mm Hg, and pulse is 77/min. Cardiopulmonary auscultation is normal, and no masses are present on abdominal examination. Cranial nerves are intact, and there is no muscle weakness or sensory loss. MRI of the brain reveals several discrete, circumscribed lesions at the junction of the gray and white matter with surrounding edema. Rapid HIV testing is negative. Which of the following is the most likely cause of this patient's seizure?

Question

A 58-year-old man is brought to the emergency department after a witnessed tonic-clonic seizure.  The patient was at work when he suddenly collapsed and convulsed for approximately a minute.  His coworker says that the patient was confused immediately afterward; however, he is now awake and cooperative.  He has been having headaches for the past several weeks and has never before had a seizure.  He has no prior medical problems and takes no medications.  The patient is a former smoker with a 45-pack-year history.  He occasionally drinks alcohol but does not use illicit drugs.  The patient has lived most of his life in Texas and has never traveled outside of the country.  Temperature is 36.7 C (98.1 F), blood pressure is 122/70 mm Hg, and pulse is 77/min.  Cardiopulmonary auscultation is normal, and no masses are present on abdominal examination.  Cranial nerves are intact, and there is no muscle weakness or sensory loss.  MRI of the brain reveals several discrete, circumscribed lesions at the junction of the gray and white matter with surrounding edema.  Rapid HIV testing is negative.  Which of the following is the most likely cause of this patient's seizure?

Quizplus · Accepted Answer

11ec25c8_d595_21e0_bc81_ed378c082596_MD0003_00 This patient with a history of tobacco abuse has multiple brain lesions suggesting metastatic lung cancer, the most common malignancy to spread to the brain. Neoplastic cells travel through the vasculature and lodge in the small-caliber vessels at the gray and white matter junction. Multiple lesions typically form and may cause mass effect from tumor growth and edema. Although pulmonary symptoms arise in the majority of patients with lung cancer, up to 30% of cases present with manifestations of metastatic brain disease, including headaches, focal deficits, cognitive changes, and seizures. MRI of the brain with contrast usually reveals multiple well-circumscribed lesions with vasogenic edema at the gray and white matter junction. Glucocorticoids are often prescribed to reduce swelling and palliate symptoms, but the primary tumor site must be identified (usually with chest x-ray and/or CT scans) and biopsied for definitive diagnosis. (Choice A) Cerebral toxoplasmosis is most common in patients with advanced HIV (CD4 count <100/mm³). Manifestations include fever, headache, altered mental status, and/or seizures, and imaging typically reveals multiple ring-enhancing lesions. This patient has a negative HIV test and no fever or ring-enhancing lesions. (Choice B) Glioblastoma multiforme commonly causes headache and seizure; however, single (not multiple) lesions are the norm. Metastatic lesions to the brain are far more common. (Choice C) Lacunar infarctions are mostly seen in patients with systemic hypertension and typically manifest with hemiparesis or sensory/sensorimotor stroke (not headache and seizures). Imaging usually reveals deep brain lesions (not lesions at the gray and white matter junction). (Choice E) Multiple sclerosis often causes sensory symptoms, unilateral vision loss, and/or motor weakness (not seizures). Imaging typically reveals inflammatory white matter lesions (not well-circumscribed lesions at the gray and white matter junction). (Choice F) Neurocysticercosis is caused by the pork tapeworm Taenia solium and often presents with new-onset seizure; however, imaging typically reveals cysts at various stages of development (eg, nonenhancing/hypodense lesions, calcified granulomas). (Choice G) Primary central nervous system lymphoma is an uncommon form of non-Hodgkin lymphoma seen primarily in patients with HIV or other forms of immunocompromise. Imaging typically reveals a periventricular (not gray and white matter junction) lesion. Educational objective: Lung cancer is the most common neoplasm to metastasize to the brain and may present with headache, focal neurologic dysfunction, cognitive change, or seizure. An MRI of the brain typically reveals multiple, well-circumscribed lesions with vasogenic edema at the gray and white matter junction. References: Diagnostic evaluation of patients with a brain mass as the presenting manifestation of cancer. (http://www.ncbi.nlm.nih.gov/pubmed/16186533)

A 58-Year-Old Man Is Brought to the Emergency Department After