A 47-year-old man comes to the office due to 2 weeks of a mildly pruritic, diffuse skin rash.  Medical history is significant for hypertension, chronic kidney disease, and HIV infection.  The patient takes no medications.  Temperature is 37.2 C (99 F), blood pressure is 136/82 mm Hg, pulse is 80/min, and respirations are 14/min.  BMI is 17 kg/m².  Physical examination shows oropharyngeal thrush.  There are scattered lung crackles, and heart sounds are normal.  The abdomen is soft and nontender.  The liver is palpable 3 cm below the right costal margin, and mild splenomegaly is present.  There are no focal neurologic deficits or signs of meningeal irritation.  Skin examination reveals multiple umbilicated papules on his face, neck, trunk, and upper thighs.  Some of the lesions have central necrosis and are covered with a hemorrhagic crust.

Item 1 of 2

Which of the following is the most likely cause of this patient’s skin lesions?

Item 2 of 2

Chest x-ray reveals bilateral nodular infiltrate and mediastinal adenopathy.  Serum cryptococcal antigen testing is positive.  Which of the following additional diagnostic tests is most appropriate in this patient?

A 54-year-old man comes to the office for a routine follow-up visit.  He feels well and has had no ongoing symptoms but has noticed a slow increase in his weight over the past year.  He says, “When the nurse weighed me around this time last year I was 74.8 kg (165 lb) and now I am 82.5 kg (182 lb).  I don’t know what’s causing that; my diet hasn’t changed.”  The patient was diagnosed with HIV a year ago and initiated on antiretroviral therapy, which improved his CD4 count and viral load.  He has no other chronic medical problems and has tested negative for hepatitis B and C viruses.  His father had coronary artery disease and died of a myocardial infarction at age 55.  The patient has a 28-pack-year smoking history and continues to smoke a pack of cigarettes daily.  He used intravenous drugs in the past but is currently not using alcohol or illicit drugs.  Temperature is 36.5 C (97.7 F), blood pressure is 112/72 mm Hg, pulse is 76/min, and respirations are 16/min.  BMI is 26.9 kg/m².  There is adipose tissue deposition on the back of the neck.  Abdominal examination reveals increased girth without a substantial increase in subcutaneous fat and palpable hepatomegaly with a soft, nontender liver edge.  No striae, bruising, or skin atrophy are present.

Item 1 of 2

Which of the following is most likely to be associated with this patient’s condition?

Item 2 of 2

Laboratory studies reveal a normal complete blood count, basic chemistry, hepatic function panel, hemoglobin A1c, and TSH level.  Lipid profile is as follows:

Liver ultrasound reveals increased parenchymal echogenicity, consistent with steatosis.  Besides recommending lifestyle modifications, including regular exercise, tobacco cessation, and a heart-healthy diet, what is the best next step in management of this patient?

A 25-year-old man comes to the employee health center for a physical examination prior to starting work as a patient care technician in a community hospital.  The patient’s family immigrated to the United States from Eastern Europe when he was a toddler.  He received a medical evaluation prior to immigrating, but the records are not available.  The patient has had no fevers, chills, night sweats, weight loss, cough, or fatigue.  He has no chronic medical problems and takes no medications.  He consumes alcohol occasionally but does not use tobacco or recreational drugs.  The patient went on a 2-month backpacking trip through Central and South America a year ago.  His immunization records are up to date.  He has a small scar in the right deltoid area and notes that he received a bacillus Calmette-Guérin vaccination as an infant.  The patient has no other abnormalities on physical examination.

Item 1 of 2

Regarding pre-employment evaluation for tuberculosis, which of the following is the most appropriate next step in management of this patient?

Item 2 of 2

The patient’s interferon-gamma release assay (IGRA) is positive.  He is asymptomatic and feels well.  Chest x-ray reveals no abnormalities.  Which of the following is the next most appropriate step in management of this patient?

A 35-year-old woman comes to the office due to anorexia and unintentional weight loss of 10 kg (22 lb) over the past 3 months.  She has also had occasional cough, subjective fevers, and night sweats.  The patient has no prior medical problems and takes no medications.  She was previously homeless and used injection drugs but has not done so for 4 years and now has stable housing and employment.  The patient does not use tobacco or alcohol.  Temperature is 37 C (98.6 F), pulse is 90/min, blood pressure is 120/70 mm Hg, and respiratory rate is 16/min.  Physical examination reveals inspiratory crackles over the right upper lung field.  Chest x-ray reveals an infiltrate with small cavitation in the apical-posterior segment of the right upper lobe.  Rapid HIV testing is negative.

Item 1 of 2

Which of the following is the most appropriate for establishing the diagnosis in this patient?

Item 2 of 2

Three sputum smears are negative for acid-fast bacilli but tuberculin skin testing shows a 15-mm induration.  Which of the following is the most accurate statement about the patient’s current condition?

A 65-year-old man comes to the office due to a foot ulcer.  The ulcer began 2 weeks ago, a few days after he scrubbed a callus off the bottom of his left foot.  The patient tried over-the-counter antibiotic creams, but the ulcer gradually enlarged and started draining a foul discharge.  The foot is not painful and he has had no fever.  The patient has a history of hypertension, hyperlipidemia, and type 2 diabetes mellitus.  His diabetes has been poorly controlled by oral medications, and he has refused to take insulin.  The patient is a retired veteran and does not use tobacco, alcohol, or illicit drugs.  Temperature is 37.2 C (99 F), blood pressure is 130/86 mm Hg, and pulse is 80/min.  BMI is 32 kg/m².  Examination of the left foot shows a 2×2 cm plantar ulcer with a necrotic base.  No surrounding erythema or induration is present, and metal probing does not contact bone.  Lower extremity pulses are diminished but palpable.  Sensation to light touch and vibration is reduced, and ankle reflexes are absent bilaterally.  Leukocyte count is 13,000 cells/mm³ and erythrocyte sedimentation rate is 95 mm/hr.  Blood cultures and wound swab cultures are obtained.

Item 1 of 2

Which of the following is most helpful for ruling out bone infection in this patient?

Item 2 of 2

Imaging reveals soft tissue inflammation and cortical destruction.  Blood cultures are negative, but the wound swab culture grows Staphylococcus epidermidis, Proteus mirabilis, and Bacteroides susceptible to all tested antibiotics.  Debridement of the necrotic tissue and wound care is planned.  Which of the following is the best approach for antibiotic selection in this patient?

A 45-year-old man comes to the office due to a rash on his right upper extremity.  He first noticed a small red papule on his right hand 7 days ago.  The lesion grew and then ulcerated.  It is now draining clear fluid.  The patient has several more new red bumps on his forearm.  He has not traveled recently; he works for a tree and brush removal service.  Temperature is 36.7 C (98 F), blood pressure is 120/80 mm Hg, pulse is 84/min, and respirations are 14/min.  Several indurated, nontender, erythematous nodules measuring 2-4 cm are noted on the right hand and forearm with central shallow ulceration, as shown in the image below.

Several smaller nodules are ulcerating along the right forearm proximally.  There is no hepatosplenomegaly.  No epitrochlear, axillary, or cervical adenopathy is present.  Which of the following is the best next step in management of this patient?

A 21-year-old woman comes to the office due to weakness and fever for 9 days.  She has also developed headaches, myalgia, and a sore throat.  The patient’s symptoms have worsened since their onset, causing her to be unable to go to work.  Despite remaining in bed for most of the day, she feels “exhausted.”  She has lost 2 kg (4.4 lb) over the past week.  The patient has no significant medical history and takes no medications.  She drinks alcohol occasionally and has smoked a pack of cigarettes a day for the past 7 years.  She is sexually active and uses condoms “most of the time.”  Temperature is 38.3 C (100.9 F), blood pressure is 120/70 mm Hg, pulse is 82/min, and respirations are 16/min.  Physical examination shows an awake but tired woman.  There is no rhinorrhea or erythema of tympanic membranes; she has enlarged tonsils with white exudates.  Large cervical and axillary lymph nodes are palpable bilaterally.  S1 and S2 are normal without murmurs.  Lungs are clear to auscultation bilaterally.  The abdomen is soft and nontender with normal bowel sounds; the liver edge extends 2 cm below the right costal margin and there is palpable splenomegaly.  There are no rashes or lesions.

Item 1 of 3

What is the most appropriate next step in this patient’s workup?

Item 2 of 3

The appropriate workup is completed and the correct diagnosis is made.  Which of the following is the most appropriate management?

Item 3 of 3

The appropriate treatment was started and the patient was discharged and scheduled for follow-up.  Two days later, she comes to the emergency department due to difficulty breathing.  The patient states that she has developed shortness of breath when lying down.  She has also had increased difficulty swallowing.  On examination, she appears agitated.  Her tonsils have increased erythema and swelling and now meet at the midline; there is copious white exudate.  Multiple enlarged anterior and posterior cervical lymph nodes are present.  What is the most appropriate next step in management of this patient’s condition?

A 4-year-old girl is brought to the emergency department due to fever and lethargy.  Her parents say she has been withdrawn and less playful over the last 2 weeks.  She has also had several days of low-grade fever and headaches.  Since yesterday morning, the patient has mostly slept and seems to be increasingly confused.  She has no significant prior medical problems and is up to date with recommended vaccinations.  Her grandfather, who is visiting the family from South Asia, is being evaluated for cough; otherwise, the patient has no sick contacts.  The family has a pet cat.  Temperature is 38 C (100.4 F).  The patient is somnolent and responds to painful stimuli.  There is resistance to passive neck flexion.  Her right eye is deviated medially, and funduscopic examination reveals several ill-defined, raised, yellow-white nodules near the bilateral optic discs.  CT scan of the head reveals basilar meningeal enhancement.  Lumbar puncture is performed, and cerebrospinal fluid analysis results are as follows:

Item 1 of 2

Which of the following is most likely to yield the diagnosis in this patient?

Item 2 of 2

The patient’s cerebrospinal fluid samples are sent for acid-fast bacilli staining and culture.  The parents note that her grandfather’s evaluation for cough revealed acid-fast bacilli in sputum samples.  Which of the following is most accurate about the management of this child?

A 19-year-old woman comes to the office due to intermittent nausea, abdominal discomfort, and diarrhea.  She has also had a diminished appetite and feels that her abdomen is swollen.  Her parents immigrated to the United States from Guatemala when she was an infant, and she recently went there for 3 weeks to meet her cousins.  The patient had a mild cough for a few days during the trip but no diarrhea or abdominal pain.  She is a college freshman and does not use tobacco, alcohol, or illicit drugs.  She does not take any medications.  Vital signs are within normal limits.  The lungs are clear to auscultation and heart sounds are normal.  The abdomen is soft, mildly distended, and nontender with increased bowel sounds.  There is no rebound tenderness or hepatosplenomegaly.  Fecal occult blood is positive.  Laboratory results are as follows:

This patient is most likely to improve with which of the following medications?

A 34-year-old woman comes to the office to discuss a recent diagnosis of HIV infection.  The patient recently donated blood and later received a letter indicating a positive HIV test.  She has no symptoms besides feeling anxious about the diagnosis.  The patient had an episode of chlamydia cervicitis 5 years ago, and HIV testing was negative at that time.  She has had several sexual partners in her lifetime but has been in a monogamous relationship for the past year.  She drinks 1-2 glasses of wine at social events and does not use tobacco or illicit drugs.  Vital signs are within normal limits.  Physical examination findings are normal.  Laboratory results are as follows:

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

A 74-year-old woman is brought to the emergency department from a skilled nursing facility due to a positive stool PCR test for Clostridioides difficile.  The patient was discharged from the hospital to the nursing facility 10 days ago after treatment for urinary tract infection and septic shock.  She developed C difficile–associated diarrhea during the hospitalization and completed a course of oral fidaxomicin therapy 3 days ago.  This treatment resolved the diarrhea, nausea, and abdominal pain; yesterday, the patient had an episode of bloating, nausea, and loose stool after a meal at the nursing facility, prompting repeat stool testing.  Since then, she has had no additional abdominal pain, nausea, vomiting, or diarrhea.  Other medical conditions include hypertension, hyperlipidemia, ischemic stroke with residual left hemiparesis, and gastroesophageal reflux.  Temperature is 37 C (98.6 F), blood pressure is 130/68 mm Hg, and pulse is 84/min.  The abdomen is soft, nondistended, and nontender, with normoactive bowel sounds in all quadrants.  Rectal examination shows soft, brown stool negative for occult blood.  Leukocyte count is 7,100/mm³.

Item 1 of 2
Which of the following is the most appropriate course of action in management of this patient’s symptoms?

Item 2 of 2
The patient has no diarrhea or other gastrointestinal symptoms while in the emergency department.  Prior to discharge, she asks if there is any way to prevent Clostridioides difficile–associated diarrhea in the future.  In addition to minimizing antibiotic use, which of the following is most likely to prevent recurrent episodes of the disease in this patient?

A 25-year-old man is brought to the emergency department due to high fever, chills, myalgia, and a rash that started this morning.  The patient also has had nausea and 3 episodes of profuse watery diarrhea and is now feeling light-headed.  Two days ago, he underwent corrective surgery for a deviated nasal septum but otherwise has no significant medical history.  The patient has not traveled recently and has had no sick contacts.  He does not use tobacco, alcohol, or recreational drugs.  Temperature is 39.4 C (102.9 F), blood pressure is 85/50 mm Hg, and pulse is 116/min.  Oxygen saturation is 98% on room air.  The patient is lethargic but has no focal weakness or nuchal rigidity.  Examination shows clear lungs and tachycardia with normal S1 and S2.  The abdomen is soft and nontender.  There is nasal packing in both nostrils.  Skin examination shows a diffuse, red, macular rash that includes the palms and soles.

Item 1 of 2
Which of the following is the most likely underlying cause of this patient’s symptoms?

Item 2 of 2
Blood cultures are obtained.  Intravenous fluids and empiric antibiotics are begun.  Which of the following additional interventions is most appropriate at present?

A 43-year-old man comes to the emergency department due to 2 days of persistent fever, headache, malaise, and severe muscle and joint pain.  He has been taking ibuprofen, which provides mild relief.  The patient frequently travels internationally for business and returned from India a week ago.  He received appropriate vaccinations prior to travel, took all advised prophylactic medications, and consumed bottled water during the trip.  Temperature is 38.9 C (102 F), blood pressure is 110/70 mm Hg, and pulse is 98/min.  After a few minutes with an inflated sphygmomanometer cuff on the patient’s arm, petechiae develop in that area; no other rash is present.  There is mild cervical lymphadenopathy.  The lungs are clear to auscultation, and no heart murmurs are present.  The abdomen is nontender, and the liver is palpated 3 cm below the costal margin.  Laboratory results are as follows:

This patient is at greatest risk for which of the following complications?

A 31-year-old woman comes to the emergency department due to 2 days of fever, chills, and cough productive of brown-tinged sputum.  She has also had shortness of breath, and her chest hurts when she inhales deeply.  She has not had any sick contacts.  The patient has a history of HIV, hypertension, and generalized anxiety disorder.  She is on antiretroviral therapy, and 2 months ago her CD4 cell count was 325 cells/mm³.  The patient smokes a pack of cigarettes daily but does not drink alcohol or use illicit drugs.  Temperature is 38.8 C (101.8 F), pulse is 90/min, blood pressure is 120/65 mm Hg, and respirations are 18/min.  The patient is in no apparent distress.  Mucous membranes are moist.  Cardiopulmonary auscultation reveals decreased breath sounds over the right middle lung field and regular heart rate with no murmurs.  The remainder of the examination is normal.  Laboratory results are as follows:

Chest x-ray is shown in the image.  The most likely cause of the patient’s symptoms is infection with which of the following?

A 26-year-old man comes to the office due to several months of dysuria and increased urinary frequency.  He also has blood in his urine at the end of urination.  A month ago, he finished 7 days of oral antibiotics for urinary tract infection, but his symptoms did not improve.  The patient has no other medical issues and takes no medications.  He emigrated from Ghana 2 years ago and works in a chemical fertilizer factory.  The patient smokes a pack of cigarettes daily and occasionally drinks alcohol.  He is married and has no children.  Temperature is 37.2 C (99 F), blood pressure is 130/80 mm Hg, and pulse is 76/min.  No abdominal mass or suprapubic or costovertebral angle tenderness is present.  Genital examination is normal.  Laboratory results are as follows:

A dipstick urinalysis shows 1+ blood but is otherwise negative.  Which of the following is the best next step to establish the diagnosis in this patient?

A 32-year-old woman at 12 weeks gestation is brought to the emergency department due to fever, chills, headache, and confusion.  The patient is a teacher and returned from East Africa 2 days ago after participating in a monthlong teacher exchange program.  She did not take antimalarial prophylaxis.  Fever and chills started just prior to her return.  Today, the patient also had a worsening headache and became confused.  Temperature is 38.9 C (102 F), blood pressure is 110/68 mm Hg, pulse is 112/min, and respirations are 20/min.  Pulse oximetry shows 92% on room air.  On physical examination, the patient is lethargic and disoriented.  The lungs are clear on auscultation, and heart sounds are normal.  The abdomen is soft and nontender.  There is no extremity edema or rash.  Neurologic examination is nonfocal with no signs of meningeal irritation.  Laboratory results are as follows:

Chest x-ray reveals scattered, fluffy infiltrates.  Blood smear examination shows intraerythrocytic Plasmodium falciparum with a high parasite load.  The patient experiences a brief seizure while being evaluated.  Which of the following pathogen-related effects most likely led to severe disease manifestation in this patient?