6-day history of fever • groin pain and swelling • recent hiking trip in Colorado • Dx?

THE CASE

A 33-year-old Caucasian woman presented to the emergency department with a 6-day history of fever (103°-104°F) and right groin pain and swelling. Associated symptoms included headache, diarrhea, malaise, weakness, nausea, cough, and anorexia. Upon presentation, she admitted to a recent hike on a bubonic plague–endemic trail in Colorado.

Her vital signs were unremarkable, and the physical examination demonstrated normal findings except for tender, erythematous, nonfluctuant right inguinal lymphadenopathy. The patient was admitted for intractable pain and fever and started on intravenous cefoxitin 2 g IV every 8 hours and oral doxycycline 100 mg every 12 hours for pelvic inflammatory disease vs tick- or flea-borne illness. Due to the patient’s recent trip to a plague-infested area, our suspicion for Yersinia pestis infection was high.

The patient’s work-up included a negative pregnancy test and urinalysis. A complete blood count demonstrated a white blood cell count of 8.6 (4.3-10.5) × 10³/UL with a 3+ left shift and a platelet count of 112 (180-500) × 10³/UL. A complete metabolic panel showed hypokalemia and hyponatremia (potassium 2.8 [3.5-5.1] mmol/L and sodium 134 [137-145] mmol/L). Blood cultures were negative for any bacterial or fungal growth after 48 hours; stool cultures were negative for Salmonella, Shigella, Campylobacter, Giardia, generalized Yersinia, and Escherichia coli O157:H7. Swabs for Gardnerella vaginalis, Trichomonas vaginalis, Candida, Chlamydia trachomatis, and Neisseria gonorrhea also were negative. Lyme, Bartonella henselae, and heterophile antibodies were also negative. Francisella tularensis was not cultured due to low suspicion.

Imaging included a normal chest x-ray and a computed tomography scan of the abdomen and pelvis that showed enlarged right inguinal lymph nodes with fatty stranding, a thicker distal right iliopsoas, hepatosplenomegaly, and an enlarged right adnexa (FIGURE 1). Initial ultrasound of the bubo showed 2 enlarged suprapubic lymph nodes, the largest measuring 3.5 × 1.4 × 2.4 cm³ (FIGURE 2), and 8 enlarged inguinal nodes.

The patient continued to have a low-grade fever, diarrhea, and inguinal lymphadenopathy throughout her first 2 hospitalized days. The cefoxitin was discontinued by Day 3, and the consulting infectious disease physician started oral metronidazole 500 mg every 12 hours due to the patient’s failure to improve. Later that night, the patient experienced increasing erythema and pain in her right inguinal region. A repeat ultrasound showed increased inguinal lymphadenopathy with the largest nodes measuring 2.9 × 1.5 × 2.5 cm³ and 2.7 × 1.3 × 2 cm³ (FIGURE 3).

Although doxycycline is considered an acceptable regimen for Y pestis infection, the infectious disease physician added oral ciprofloxacin 750 mg every 12 hours the following morning, as the patient had not improved.

THE DIAGNOSIS

Although the initial gram stain was negative for Yersinia, clinical suspicion pointed to a diagnosis of bubonic plague. Serology was considered; however, it was not available through the hospital. A definitive diagnosis required bubo aspiration and culture, which was performed but required 48 hours before results would be available.

Continue to: By Day 5, the patient was clinically improved and...