A 77-year-old woman with chronic obstructive pulmonary disease is brought from her skilled nursing facility to the emergency room with fever and mixed hypoxemic-hypercarbic respiratory failure. She was last hospitalized 4 months ago for a hip fracture and last received antibiotics during that hospitalization. She has no known history of multidrug resistant infections, and no risk factors for methicillin-resistant Staphylococcus aureus infection. Chest X-ray demonstrates a right middle lobe infiltrate, and she is admitted to the intensive care unit for hypoxemia.
What is the MOST appropriate antibiotic choice and duration for her pneumonia?
Correct Answer: D
In 2016, the category of healthcare-associated pneumonia was eliminated from the American Thoracic Society and Infectious Diseases Society of America guidelines, as it was thought to be overly sensitive and lead to increased, inappropriately broad, antibiotic use. The 2016 guidelines include the categories of community-acquired pneumonia (CAP), hospitalacquired pneumonia (HAP), and ventilator-associated pneumonia. The HAP category is reserved for patients who develop pneumonia at least 48 hours into hospitalization. Antibiotic choices for answers A, B, and C above are appropriate selections for HAP, although the recommended duration is generally 7 to 8 days, if the patient demonstrates sufficient clinical improvement on therapy. The patient in this scenario does not meet criteria for HAP and should be treated in a similar fashion to a patient with CAP admitted to the intensive care unit, accounting for additional risk factors. Residing in a skilled nursing facility is a risk factor for Pseudomonas pneumonia, and two antipseudomonal antibiotics are recommended as initial therapy. The duration of therapy can be tailored to clinical course, but no less than 5 days’ and no more than 10 days’ therapy is generally recommended.
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A 66-year-old man is admitted to the intensive care unit in respiratory distress. He was attending a conference in a local hotel when he developed fevers and shortness of breath, followed by mild confusion. He also has end-stage renal disease managed with thriceweekly hemodialysis and is anuric. Chest X-ray demonstrates a patchy infiltrate in the left upper lobe. As you admit him to the intensive care unit, you are called by the emergency department for a second admission—this time for a 52-year-old woman with chronic obstructive pulmonary disease who also attended the same conference. In addition to fever and tachypnea, the second patient has a serum sodium of 119 mEq/L, diarrhea, and vomiting. Her chest X-ray demonstrates diffuse bilateral patchy infiltrates.
What is the MOST sensitive test to diagnose the organism causing these patients’ symptoms?
Correct Answer: B
These two patients present with Legionnaire’s disease, pneumonia due to the intracellular pathogen Legionella pneumophilia. The scenario portrayed here likely represents an outbreak because both patients were attending the same conference. Although certain features such as gastrointestinal symptoms and hyponatremia increase suspicion of Legionella pneumonia, the presentation can also closely mimic other types of CAP. PCR testing of lower respiratory tract specimens is the most sensitive diagnostic assay, although exact sensitivity and specificity are difficult to determine owing to lack of a perfect reference standard. Urinary antigen testing appears to be 70% to 80% sensitive and nearly 100% specific for Legionella disease, and it is a reasonable alternative when PCR is not available or a lower respiratory tract specimen cannot be obtained. Culture performed on lower respiratory tract specimens is nearly 100% specific for Legionella, but sensitivity varies widely from <10% up to 80% and is thought to be significantly lower than PCR. Because Legionella is an intracellular pathogen, Gram stain plays no role in diagnosis of Legionnaire disease.
You admit a 28-year-old man to the intensive care unit in July for a generalized tonic-clinic seizure in the setting of 2 days of fevers, headache, and myalgias. The patient’s girlfriend tells you that they were backpacking in Tennessee’s Great Smoky Mountains National Park the week before the patient became ill, and 3 weeks before he became ill they went for a hike in the woods on Massachusetts’ Cape Cod. Chest X-ray is clear, and his white blood cell count is normal. Platelet count on presentation is 139,000/µL, and hemoglobin and hematocrit are normal. Two days after admission, he develops worsening thrombocytopenia and a rash.
What is the MOST likely diagnosis?
RMSF (Answer B) is the most common tick-borne illness in the United States, with a broad distribution across most of the lower 48 states. Symptoms on presentation are often nonspecific. The classic rash (which often eventually involves palms and soles) is rarely present when the patient becomes ill and commonly develops 3 to 5 days into the course of illness. RMSF has an incubation period of 2 to 14 days after being bitten by an infected tick, and many patients do not recall any tick bite. Although Lyme disease (Answer D) can cause thrombocytopenia, confusion and seizures are not common with central nervous system Lyme disease; nor is late presentation of rash. Mumps (Answer C) often begins as a nonspecific illness of fever and malaise, but rarely presents with fever or seizures, and usually involved salivary gland swelling within 2 days of developing symptoms. Babesiosis (Answer A) is also a tick-borne disease that can be contracted on Massachusetts’ Cape Cod, but usually presents with anemia and does not cause seizures. Coinfections should always be considered when evaluating a patient with suspected tick-borne illness, as it is not uncommon for a single tick bite to transmit multiple infectious pathogens.
Which of the following patients should receive antiviral medication for seasonal influenza infection?
People at risk of severe seasonal influenza disease and poor outcomes include pregnant women and women up to 2 weeks postpartum; immunosuppressed patients and immunodeficient patients including people living with HIV and a CD4 T-cell count <200 cells/mL, adults over the age of 65 years, people with active malignancy, chronic liver, kidney, lung, or cardiovascular disease (except isolated hypertension), among others. When seasonal influenza is suspected or confirmed in any of these groups, prompt initiation of antiviral therapy is recommended.
A 47-year-old woman with poorly controlled insulin-dependent diabetes mellitus presents to the emergency room with diabetic ketoacidosis. She reports severe pain in her paranasal sinuses with purulent discharge from the bilateral nares for 1 day. On examination, you notice swelling of the paranasal soft tissues and a dark eschar over the left nasal mucosa.
What is the BEST management strategy?
Correct Answer: A
This patient has rhino-orbital mucormycosis, which is best managed with a combination of surgical debridement and broad-spectrum antifungal therapy. Voriconazole are not effective against the Mucorales species causing mucormycosis, nor are antibacterial agents. Treating diabetic ketoacidosis, metabolic acidosis, and reducing immune suppression are helpful adjunctive therapies, when possible. Almost all patients presenting with this disease have an underlying predisposing comorbidity, including diabetes mellitus (often with diabetic ketoacidosis), hematologic malignancy, hematopoetic stem cell transplantation, trauma, glucocorticoid treatment, solid organ transplant, AIDS, or malnutrition.
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