A 26-year-old man is brought to the emergency department by his roommate, who found him lethargic in his apartment an hour ago. Earlier that day, the patient complained of headache and asked for aspirin. He also has felt weak and "exhausted" for the last 10 days. His past history is notable for intravenous heroin abuse, but periodic HIV screening has been negative. His temperature is 38.3 C (101 F), blood pressure is 112/70 mm Hg, and pulse is 102/min. The patient appears somnolent but follows simple commands. Needle tracks are seen on both arms. Pupils are symmetric and reactive. There are a few palatal petechiae on oral examination. The patient's neck is stiff. A 3/6 holosystolic murmur is heard at the apex. Lungs are clear to auscultation and the abdomen is nontender. He moves all extremities, and deep-tendon reflexes are symmetric. Which of the following is the most likely diagnosis in this patient?

Question

A 26-year-old man is brought to the emergency department by his roommate, who found him lethargic in his apartment an hour ago.  Earlier that day, the patient complained of headache and asked for aspirin.  He also has felt weak and "exhausted" for the last 10 days.  His past history is notable for intravenous heroin abuse, but periodic HIV screening has been negative.  His temperature is 38.3 C (101 F), blood pressure is 112/70 mm Hg, and pulse is 102/min.  The patient appears somnolent but follows simple commands.  Needle tracks are seen on both arms.  Pupils are symmetric and reactive.  There are a few palatal petechiae on oral examination.  The patient's neck is stiff.  A 3/6 holosystolic murmur is heard at the apex.  Lungs are clear to auscultation and the abdomen is nontender.  He moves all extremities, and deep-tendon reflexes are symmetric.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bf8b_9946_8f63_b3657d6ed98f_MD0005_00 This patient's clinical presentation, with fever, petechiae, history of intravenous drug abuse, and holosystolic murmur at the apex, is suggestive of infective endocarditis (IE) involving the mitral valve. The headache, lethargy, and neck stiffness suggest subarachnoid hemorrhage secondary to rupture of a mycotic aneurysm. Mycotic or infected arterial aneurysms can develop due to metastatic infection from IE, with septic embolization and localized vessel wall destruction in the cerebral (or systemic) circulation. Intracerebral mycotic aneurysms can present as an expanding mass with focal neurologic findings or may not be apparent until aneurysm rupture with stroke or subarachnoid hemorrhage. The diagnosis of mycotic cerebral aneurysm can usually be confirmed with computed tomography angiography. Management includes broad-spectrum antibiotics (tailored to blood culture results) and surgical intervention (open or endovascular). (Choice A) Patients with basilar artery occlusion present with motor weakness, ataxia or incoordination, altered level of consciousness, facial weakness, dysphagia and/or dysarthria, and unilateral or bilateral gaze paralysis. The presence of neck stiffness is more suggestive of subarachnoid hemorrhage. (Choice B) Herpes simplex encephalitis is characterized by acute-onset (<1 week) fever, headaches, seizures, altered mental status, and focal neurologic findings such as hemiparesis or cranial nerve deficits. This patient's weakness/fatigue for >1 week, heart murmur, history of drug abuse, and absence of focal neurologic deficits make endocarditis with mycotic aneurysm more likely than herpes encephalitis. (Choice C) Progressive multifocal leukoencephalopathy is a demyelinating illness of the central nervous system that typically occurs in immunosuppressed patients, especially those with AIDS. It is caused by reactivation of the polyomavirus JC (JC virus) and presents with neurologic deficits including hemiparesis, gait ataxia, visual symptoms, and altered mental status. It is not seen in non-immunosuppressed patients, and fever is not typical. (Choice E) Valvular insufficiency in IE is due primarily to destruction of valve leaflets; papillary muscle rupture is rare. Papillary muscle rupture leads to acute and severe mitral regurgitation with sudden onset of hypotension, pulmonary edema, and cardiogenic shock. Educational objective: Mycotic aneurysms can occur in the cerebral or systemic circulation due to septic embolization and localized vessel wall destruction as a complication of infective endocarditis. Intracerebral mycotic aneurysms can present as an expanding mass with focal neurologic findings or with aneurysm rupture and subarachnoid hemorrhage. References: Mycotic aneurysm: a rare and dreaded complication of infective endocarditis. (http://www.ncbi.nlm.nih.gov/pubmed/23814229) Infectious endocarditis: diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/22612050)

A 26-Year-Old Man Is Brought to the Emergency Department by His