A 46-year-old man is brought to the emergency department due to a generalized tonic-clonic seizure. The patient has no chronic medical problems and, prior to today, had never had a seizure. He does not use tobacco, alcohol, or illicit drugs. The patient is a Christian missionary and recently spent 3 months with rural Bolivian pig farmers. Temperature is 36.8 C (98.2 F), blood pressure is 120/70 mm Hg, and pulse is 86/min. The patient is drowsy and postictal. Electroencephalogram shows epileptiform activity. MRI of the brain demonstrates several intraparenchymal, 5- to 10-mm cystic lesions with surrounding edema. There is no mass effect or midline shift. A rapid HIV test is negative. Which of the following is the most likely cause of this patient's current condition?

Question

A 46-year-old man is brought to the emergency department due to a generalized tonic-clonic seizure.  The patient has no chronic medical problems and, prior to today, had never had a seizure.  He does not use tobacco, alcohol, or illicit drugs.  The patient is a Christian missionary and recently spent 3 months with rural Bolivian pig farmers.  Temperature is 36.8 C (98.2 F), blood pressure is 120/70 mm Hg, and pulse is 86/min.  The patient is drowsy and postictal.  Electroencephalogram shows epileptiform activity.  MRI of the brain demonstrates several intraparenchymal, 5- to 10-mm cystic lesions with surrounding edema.  There is no mass effect or midline shift.  A rapid HIV test is negative.  Which of the following is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

11ec25c8_d463_cdde_bc81_f73410a7029e_MD0003_00 Taenia solium is a tapeworm transmitted to humans by the ingestion of undercooked, contaminated pork. Tapeworms typically remain localized in the gastrointestinal tract, but shed eggs may pass to other individuals via the fecal-oral route. Ingested eggs hatch in the small intestine, invade the bowel wall, and spread hematogenously (brain, muscle, liver), causing cysticercosis. Most patients are initially asymptomatic, but cysts may degenerate over months or years causing inflammation, edema, and clinical illness. Neurocysticercosis typically manifests as an adult-onset seizure. Less commonly, patients develop signs of increased intracranial pressure (eg, vomiting, headache, papilledema) due to obstruction of cerebral spinal fluid outflow. Systemic symptoms are usually absent, and laboratory studies are typically normal. Brain imaging (CT, MRI) usually reveals >1 cystic lesion with surrounding contrast enhancement and edema (without displacement of adjacent tissue). Cysts at various stages of development (hypodense lesions without enhancement, calcified nodules) are also sometimes found. Diagnosis is typically made based on clinical and radiologic findings; brain biopsy is rarely needed. Patients are treated with antiepileptics (eg, phenytoin), antiparasitics (eg, albendazole), and corticosteroids (for brain inflammation). > cystic lesion (Choice A) Creutzfeldt-Jakob disease is a prion disease that causes personality change, dementia, and (often) myoclonus. Seizures and MRI findings of cystic, enhancing lesions are not common. (Choice B) Toxoplasma encephalitis typically manifests in patients with advanced HIV (CD4 count <100/mm³). Symptoms include headache, confusion, fever, focal neurologic deficits, and seizures. Multiple ring-enhancing lesions are usually present on MRI. This patient with a seizure without other symptoms, no known history of HIV, and recent travel to a T solium endemic region (developing world near pig-farming) is more likely to have neurocysticercosis. (Choice C) Rabies usually manifests with prodromal symptoms (eg, fever, chills, malaise, headache) followed by hydrophobia, pharyngeal spasms, hyperactivity, coma, and death. (Choice E) Cerebral malaria usually manifests with fever, altered mental status, delirium, and seizures. This patient with an isolated seizure and cystic lesions on MRI is more likely to have neurocysticercosis. (Choice F) Naegleria fowleri is a fresh-water amoeba that may cause acute meningoencephalitis (fever, headache, vomiting, altered mental status, seizures) with a mortality rate of approximately 99%. Several cystic lesions would be atypical. Educational objective: Taenia solium is a pork tapeworm whose eggs cause neurocysticercosis. Most infections are asymptomatic, but patients can develop seizure (without other symptoms) or signs of increased intracranial pressure (vomiting, headaches, papilledema) months or years after inoculation. Diagnosis is made largely by clinical and radiographic findings (>1 cyst often with enhancement/edema on brain MRI). >

A 46-Year-Old Man Is Brought to the Emergency Department Due