A 43-year-old man comes to the emergency department due to 5 days of slowly worsening fever, cough, and malaise. He has a history of HIV infection, and his last known CD4 count 3 months ago was 210/mm³. He also has a distant history of seizures. The patient drinks alcohol daily and was hospitalized for alcohol withdrawal a year ago.
Temperature is 38.3 C (100.9 F) , blood pressure is 98/62 mm Hg, pulse is 111/min and regular, and respirations are 20/min. The patient has poor dentition. Small, mobile lymph nodes are palpable in the submandibular area. Scattered rhonchi are heard bilaterally. Heart sounds are normal with no murmur. The tip of the spleen is not palpable, and the liver span is normal.
Laboratory results are as follows:
CT scan of the chest reveals several bilateral cavitating lesions. Blood cultures grow Staphylococcus aureus in 2 of 2 bottles.
Which of the following is most often associated with this patient's condition?

Question

A 43-year-old man comes to the emergency department due to 5 days of slowly worsening fever, cough, and malaise. He has a history of HIV infection, and his last known CD4 count 3 months ago was 210/mm³. He also has a distant history of seizures. The patient drinks alcohol daily and was hospitalized for alcohol withdrawal a year ago.
Temperature is 38.3 C (100.9 F) , blood pressure is 98/62 mm Hg, pulse is 111/min and regular, and respirations are 20/min. The patient has poor dentition. Small, mobile lymph nodes are palpable in the submandibular area. Scattered rhonchi are heard bilaterally. Heart sounds are normal with no murmur. The tip of the spleen is not palpable, and the liver span is normal.
Laboratory results are as follows:

CT scan of the chest reveals several bilateral cavitating lesions. Blood cultures grow Staphylococcus aureus in 2 of 2 bottles.
Which of the following is most often associated with this patient's condition?

Quizplus · Accepted Answer

This patient with Staphylococcus aureus bacteremia has several bilateral cavitating pulmonary lesions raising suspicion for septic emboli due to right-sided infective endocarditis (IE). Most cases of right-sided IE are due to injection drug use and are associated with the following clinical features: The tricuspid valve is most commonly affectedHeart murmurs are often absent on examinationS aureus is the most common pathogenUp to 75% of patients develop septic emboli and pneumoniaSeptic emboli can also affect other organs (eg, kidney, brain, spine)Heart failure is rarePatients commonly have coinfection with HIV, hepatitis B, and/or hepatitis C The tricuspid valve is most commonly affected Heart murmurs are often absent on examination S aureus is the most common pathogen Up to 75% of patients develop septic emboli and pneumonia Septic emboli can also affect other organs (eg, kidney, brain, spine) Heart failure is rare Patients commonly have coinfection with HIV, hepatitis B, and/or hepatitis C (Choice A) Aspiration pneumonia usually affects the dependent pulmonary zones (eg, lower lobes, posterior segments of the upper lobes), and anaerobic bacteria are most commonly involved. (Choice C) Latent tuberculosis (TB) is a dormant TB infection that can reactivate, causing symptomatic disease. Manifestations of active disease usually include indolent symptoms (eg, cough, weight loss, fevers) and focal infiltration/cavitation of the upper lobes of the lung. This patient with S aureus bacteremia is more likely to have IE. (Choice D) Poor dentition and periodontal infection/abscess increase the risk of developing IE with oral pathogens (eg, streptococcus). S aureus IE is not typically associated with poor dentition; injection drug use is more likely to be the underlying cause. (Choice E) S aureus pneumonia is a life-threatening complication of influenza infection. Most cases are marked by an initial improvement of influenza symptoms (eg, rhinorrhea, cough, fever) prior to developing worsened fever, respiratory symptoms, and a multilobar pneumonia. This patient with 5 days of progressive symptoms, no history of influenza-like upper respiratory symptoms, and cavitations with no lobar infiltrate is more likely to have septic emboli from right-sided IE. Educational objective: Injection drug users are at increased risk for infective endocarditis (IE) involving the right-sided heart valves. Staphylococcus aureus is the most common organism. Patients often present due to septic pulmonary emboli (eg, multiple bilateral cavitary lesions). Cardiac examination is usually normal (eg, no heart murmurs). __________ References: Tricuspid endocarditis and septic pulmonary embolism in an intravenous drug user with advanced HIV Infection. (http://www.ncbi.nlm.nih.gov/pubmed/22125735) Human immunodeficiency virus infection and infective endocarditis among injecting drug users. (http://www.ncbi.nlm.nih.gov/pubmed/8899380)

A 43-Year-Old Man Comes to the Emergency Department Due to 5