PANCE (Physician Assistant National Certifying Exam) — All Questions

A 72-year-old woman develops 6 watery stools a day during a course of clindamycin. Stool testing is positive for Clostridioides difficile toxin. Her white count is 11,000/µL and creatinine is normal. Which is an appropriate first-line treatment for this initial episode?

• a.IV vancomycin
• b.Oral vancomycin or fidaxomicin✓
• c.Oral metronidazole as the preferred agent
• d.Loperamide and oral rehydration only

For an initial episode of C. difficile infection in adults, oral fidaxomicin or oral vancomycin is first-line (IDSA/SHEA 2021 focused update); metronidazole is no longer recommended as first-line and is reserved for when those agents are unavailable. IV vancomycin does not reach the colon lumen. Antimotility agents alone do not treat the infection and can worsen toxin-mediated colitis.

A 30-year-old hiker from Connecticut has an expanding 9-cm red patch with central clearing on her thigh, fatigue and myalgias 10 days after a camping trip. She recalls no tick bite. What is the most appropriate management?

• a.Start topical clotrimazole for tinea corporis
• b.Reassure her; the rash will clear without treatment
• c.Doxycycline now, without waiting for serology✓
• d.Lyme serology first, and treat only if positive

An expanding annular rash after exposure in an endemic area is erythema migrans, which is diagnosed clinically and treated with an antibiotic such as doxycycline; serology is often negative this early because the rash appears before antibodies develop. Waiting for serology delays therapy, and although the rash fades, untreated infection can disseminate. Tinea corporis is scaly and does not cause systemic symptoms.

A 6-year-old from North Carolina has fever, severe headache and myalgias for 4 days after a tick bite, followed by a rash that started on the wrists and ankles and spread to the palms, soles and trunk. What is the most appropriate treatment?

• a.Azithromycin
• b.Supportive care only
• c.Doxycycline✓
• d.Amoxicillin

Fever, headache and a rash beginning on the wrists and ankles and spreading centrally after a tick bite suggest Rocky Mountain spotted fever. Doxycycline is first-line for all patients, including young children, and should be started on clinical suspicion because delay increases mortality; short courses have not been shown to stain teeth. Amoxicillin and azithromycin are not effective against Rickettsia rickettsii, and supportive care alone risks death.

A 27-year-old man has a single painless, clean-based ulcer with indurated edges on the penis and nontender inguinal lymphadenopathy. Treponemal and nontreponemal tests are positive. He has no drug allergies. What is the treatment of choice?

• a.Oral acyclovir for 7 days
• b.Benzathine penicillin G intramuscularly✓
• c.Oral azithromycin single dose
• d.Ceftriaxone 500 mg intramuscularly

A painless indurated chancre with positive serology is primary syphilis, and benzathine penicillin G given intramuscularly is the treatment of choice; sex partners should also be evaluated. Acyclovir treats herpes simplex, which causes painful vesicles and ulcers. Azithromycin has widespread treponemal resistance, and ceftriaxone is the treatment for gonorrhea.

A 60-year-old with pneumonia has a blood pressure of 78/40 mm Hg that persists after 30 mL/kg of IV crystalloid. Norepinephrine is started. Serum lactate is 4.2 mmol/L. What is the usual initial mean arterial pressure target?

• a.65 mm Hg✓
• b.50 mm Hg
• c.100 mm Hg
• d.85 mm Hg

In septic shock, vasopressors are titrated to an initial mean arterial pressure of 65 mm Hg (Surviving Sepsis Campaign 2021), and septic shock is defined as sepsis requiring vasopressors to keep MAP at or above 65 mm Hg with a lactate above 2 mmol/L despite adequate fluid resuscitation. A target of 50 mm Hg risks organ hypoperfusion, and higher targets such as 85 or 100 mm Hg have not improved outcomes and add vasopressor exposure.

A 34-year-old man with HIV started antiretroviral therapy a year ago for a CD4 count of 90 cells/µL and has taken trimethoprim-sulfamethoxazole since. His viral load is now suppressed and his CD4 count has stayed above 200 cells/µL for 4 months. What is appropriate regarding Pneumocystis prophylaxis?

• a.It must continue for life
• b.Switch it to inhaled pentamidine
• c.Double the trimethoprim-sulfamethoxazole dose
• d.It can be discontinued✓

Pneumocystis prophylaxis can be stopped once antiretroviral therapy raises the CD4 count to 200 cells/µL or more for at least 3 months. Lifelong prophylaxis is not required after immune recovery. Switching to pentamidine is for intolerance of trimethoprim-sulfamethoxazole, and increasing the dose has no role in prophylaxis.

An unvaccinated 5-year-old has 3 days of high fever, cough, runny nose and red eyes, followed by a red maculopapular rash that began at the hairline and spread downward. Small white spots are seen on the buccal mucosa. Which infection-control precaution is required in the clinic?

• a.Standard precautions only
• b.Contact precautions only
• c.Droplet precautions only
• d.Airborne precautions✓

Fever, cough, coryza, conjunctivitis, Koplik spots and a rash spreading from head to trunk indicate measles. Measles spreads by aerosols that can remain in the air for up to 2 hours, so airborne precautions with a negative-pressure room and N95-level respirators are required. Contact, droplet or standard precautions alone do not stop airborne transmission.