Infectious Diseases

A 42-year-old woman is brought to the emergency department by her husband due to a 24-hour history of severe headache, high fever, and worsening confusion. Her medical history is significant for a recent kidney transplant, for which she takes immunosuppressive medications. Her temperature is 39.2°C (102.6°F). Physical examination demonstrates marked nuchal rigidity and a new left lower extremity weakness. Arrange the following diagnostic and therapeutic steps in the most appropriate chronological sequence for managing this patient.

Match each patient scenario describing the initiation of a specific targeted biologic or immunomodulatory therapy with the most appropriate infectious disease screening or prophylactic management step.

A $74$-year-old man is admitted to the hospital with a four-week history of low-grade fevers, progressive fatigue, and an unintentional weight loss of $4\text{ kg}$ ($8.8\text{ lbs}$). His medical history is significant for ischemic cardiomyopathy, type 2 diabetes mellitus, and a surgical aortic valve replacement with a bioprosthetic valve three years ago. His temperature is $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), blood pressure is $122/76\text{ mmHg}$, and pulse is $92/\text{min}$. Physical examination reveals a grade 3/6 diastolic murmur at the right upper sternal border. Inspection of the hands reveals small, painless, erythematous macules on the palms. A transesophageal echocardiogram shows an oscillating $1.1\text{ cm}$ mass on the bioprosthetic aortic valve. Three sets of blood cultures grow gram-positive cocci in pairs and short chains that are catalase-negative and capable of growing in $6.5\%$ sodium chloride broth. Susceptibility testing indicates that the organism is susceptible to ampicillin, vancomycin, and daptomycin, but it exhibits high-level resistance to gentamicin and streptomycin. His serum creatinine is $1.9\text{ mg/dL}$. Which of the following is the most appropriate targeted intravenous antibiotic regimen for this patient?

During morning rounds on the general medical floor, a resident evaluates a newly admitted patient who presented overnight with chronic cough, progressive fatigue, and hemoptysis. The patient recently emigrated from a country with a high incidence of endemic respiratory pathogens. Vital signs reveal a temperature of $38.3^\circ\text{C}$ ($100.9^\circ\text{F}$). Review of a portable chest radiograph obtained in the emergency department demonstrates a prominent cavitary opacity in the right upper lobe with surrounding consolidation. The clinical team strongly suspects active pulmonary tuberculosis.

Arrange the following clinical and infection control interventions in the most appropriate chronological sequence for this patient.

Match each patient's clinical presentation with the most likely causative pneumonia pathogen.

A group of patients presents to the emergency department with signs and symptoms of lower respiratory tract infection. Based on the unique clinical features described for each patient, match the clinical presentation with the most likely causative pathogen.

A 54-year-old man is brought to the emergency department by his husband due to severe headache, high fever, and new-onset confusion that began 24 hours ago. His medical history is notable for a deceased-donor renal allograft three years ago, and he currently takes tacrolimus and mycophenolate mofetil. This morning, he developed right-sided weakness and difficulty speaking. His temperature is $39.4^\circ\text{C}$ ($102.9^\circ\text{F}$), blood pressure is $112/68\text{ mmHg}$, pulse is $118/\text{min}$, and respiratory rate is $20/\text{min}$. Physical examination reveals marked nuchal rigidity, expressive aphasia, and a mild right-sided hemiparesis. Arrange the following interventions in the most appropriate sequential order for the acute management of this patient.

A 62-year-old man is admitted to the hospital with a 2-day history of fever, chills, and severe right flank pain. He has a history of benign prostatic hyperplasia and recurrent urinary tract infections. His temperature is $39.1^{\circ}\text{C}$ ($102.4^{\circ}\text{F}$), blood pressure is $92/60\text{ mmHg}$, heart rate is $118/\text{min}$, and respiratory rate is $20/\text{min}$. Physical examination reveals marked right costovertebral angle tenderness.

Laboratory studies show a leukocyte count of $16,500/\text{mm}^3$. Intravenous fluids are administered, and he is started empirically on intravenous vancomycin and piperacillin-tazobactam.

On hospital day 3, the patient's clinical status has significantly improved. He is afebrile with a blood pressure of $118/76\text{ mmHg}$. Blood and urine cultures obtained on admission both grow *Enterobacter cloacae*.

The antimicrobial susceptibility report for the *Enterobacter cloacae* isolate is as follows:

Which of the following is the most appropriate next step in this patient's pharmacologic management?

An emergency department physician is evaluating a college student brought in by roommates for a severe headache, high fever, and altered mental status. On physical examination, the patient is lethargic, has pronounced nuchal rigidity, and exhibits a new right-sided hemiparesis. Acute bacterial meningitis is highly suspected. Arrange the following interventions in the most appropriate sequential order for the immediate management of this patient.

A public health clinic evaluates four patients presenting with different types of genital lesions. Match each patient's clinical presentation (left) with the most appropriate first-line pharmacotherapy (right) according to current infectious disease guidelines.

During morning rounds, a physician evaluates a patient admitted two days ago for a severe lower respiratory tract infection. The patient, a 52-year-old non-smoker, initially presented with a high fever, productive cough, and lobar consolidation on chest radiography. At admission, he was empirically started on intravenous ceftriaxone and oral azithromycin. Today, he is completely afebrile, his respiratory rate is 16/min, his oxygen saturation is 97% on ambient air, and he is eager to go home. The microbiology laboratory reports that the admission sputum culture is growing *Streptococcus pneumoniae*. Susceptibility testing indicates the isolate is susceptible to penicillin, amoxicillin, ceftriaxone, levofloxacin, and vancomycin. Blood cultures remain sterile. The physician is writing discharge orders to complete a total 5-day course of therapy. Which of the following is the most appropriate oral antibiotic regimen for discharge?

A 45-year-old man is brought to the emergency department by his wife due to a 24-hour history of high fever, severe headache, and progressively worsening confusion. On physical examination, his temperature is 39.2°C (102.6°F), blood pressure is 130/80 mm Hg, and heart rate is 110/min. He has marked nuchal rigidity. Neurologic examination reveals a lethargic patient who only opens his eyes to painful stimuli. He demonstrates mild left-sided hemiparesis. Arrange the following steps in the most appropriate chronological sequence for the initial management of this patient.

A $19$-year-old male college student presents to the student health clinic complaining of a severely painful throat, subjective fevers, and profound exhaustion that has progressively worsened over the past $7$ days. He notes that he has been too tired to attend his classes. He has no chronic medical conditions and takes no daily medications. Vital signs show a temperature of $38.4^\circ\text{C}$ ($101.1^\circ\text{F}$), blood pressure of $115/72\text{ mm Hg}$, pulse of $92/\text{min}$, and respirations of $14/\text{min}$. Physical examination demonstrates marked bilateral posterior cervical lymphadenopathy, erythematous tonsils with grayish-white exudates, and mild splenomegaly. A point-of-care heterophile antibody test yields a positive result. Which of the following is the most appropriate management for this patient?

A 62-year-old man is evaluated in the hospital on hospital day 3. He was initially admitted for fever, chills, and a warm, swollen right calf. On admission, his temperature was 39.1 C (102.4 F), blood pressure was 105/65 mm Hg, and pulse was 110/min. He was started on empiric intravenous vancomycin and piperacillin-tazobactam. Today, his temperature is 37.4 C (99.3 F), blood pressure is 120/75 mm Hg, and pulse is 82/min. The erythema on his right calf has significantly decreased. Blood cultures drawn on admission are positive for Staphylococcus aureus in 2 of 2 bottles. Susceptibility testing shows the isolate is resistant to penicillin but susceptible to oxacillin, cefazolin, and vancomycin. The patient has no history of medication allergies. Which of the following is the most appropriate next step in management?

Match each classic clinical presentation of an infectious disease with its most appropriate first-line pharmacotherapy.

Match each highly specific clinical scenario to the most appropriate guideline-directed pharmacotherapy, taking into account patient-specific contraindications.

A 34-year-old man with advanced, untreated HIV infection is evaluated in the emergency department for a two-week history of constant, severe headaches, low-grade fevers, and intermittent nausea. He appears lethargic. Vital signs show a temperature of 38.1°C (100.6°F), blood pressure of 118/76 mmHg, and a heart rate of 92/min. Neurologic examination shows mild nuchal rigidity but no focal deficits. Laboratory studies confirm a CD4 count of 18 cells/mm³. A lumbar puncture is performed, demonstrating an elevated opening pressure of 290 mm H2O. Cerebrospinal fluid (CSF) analysis reveals 45 leukocytes/mm³ (90% lymphocytes), a glucose level of 32 mg/dL, and a protein level of 88 mg/dL. A CSF India ink stain displays encapsulated budding yeast, and the cryptococcal antigen assay is profoundly positive.

Arrange the following therapeutic interventions in the most appropriate chronological order of their initiation for the optimal management of this patient.

A 71-year-old man with a history of a cerebrovascular accident and neurogenic bladder managed with a chronic indwelling urethral catheter is evaluated during a routine home health visit. He reports feeling well and denies fever, chills, flank pain, suprapubic discomfort, or increased spasticity. His temperature is $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure is $130/80\text{ mmHg}$, heart rate is $76/\text{min}$, and respiratory rate is $14/\text{min}$. Physical examination reveals a soft, non-tender abdomen and no costovertebral angle tenderness. The urine in his collection bag appears cloudy. A urinalysis reveals positive leukocyte esterase and $30$ white blood cells per high-power field. A urine culture obtained 48 hours ago grows $>100,000\text{ CFU/mL}$ of *Pseudomonas aeruginosa*. Which of the following is the most appropriate next step in management?

A clinical guideline committee is creating a quick-reference protocol for managing specific infectious disease exposures. Match each patient scenario with the single most appropriate pharmacological management plan.

Match each clinical exposure scenario with the most appropriate definitive post-exposure prophylaxis (PEP) or management regimen based on current clinical guidelines.