A 34-year-old woman comes to the office due to 3 days of discomfort and swelling in the right axilla. The patient has no known medical problems. She is the local community veterinarian and volunteers as a swim coach at her children's school. She owns a parrot and a hamster. Temperature is 36.9 C (98.4 F). On physical examination, there is an enlarged, tender axillary lymph node on the right, measuring about 3 cm and with slight surrounding erythema but no skin breakdown. There is no other area of lymphadenopathy present. Several scratch marks are seen on the right arm. The organism responsible for the lymphadenopathy is also associated with which of the following conditions?

Question

A 34-year-old woman comes to the office due to 3 days of discomfort and swelling in the right axilla.  The patient has no known medical problems.  She is the local community veterinarian and volunteers as a swim coach at her children's school.  She owns a parrot and a hamster.  Temperature is 36.9 C (98.4 F).  On physical examination, there is an enlarged, tender axillary lymph node on the right, measuring about 3 cm and with slight surrounding erythema but no skin breakdown.  There is no other area of lymphadenopathy present.  Several scratch marks are seen on the right arm.  The organism responsible for the lymphadenopathy is also associated with which of the following conditions?

Quizplus · Accepted Answer

This patient with extensive animal exposure and scratch marks on her arm likely has cat-scratch disease (cat-scratch fever), a condition caused by Bartonella henselae. This organism resides in the oral cavity of cats and is transmitted to humans by cat scratches and bites. Typically, a primary inoculation lesion evolves from vesicular to erythematous to papular, followed by the development of tender regional lymphadenopathy (often involving a single lymph node) proximal to the lesion. Axillary lymphadenopathy is extremely common. B henselae can also cause bacillary angiomatosis (BA) in immunocompromised patients. BA presents with red-purple papular skin lesions. These vascular proliferations may also be found within the viscera. BA can be fatal if left untreated. (Choice B) Schistosomia haematobium, which can present acutely as swimmer's itch (organism penetration into skin) or Katayama fever (fever, urticaria, angioedema, eosinophilia), can affect the bladder (causing terminal hematuria, fibrosis); chronic infection is a risk factor for bladder cancer. (Choice C) Condylomata acuminata (genital warts) are caused by Human papillomavirus 6 and 11. They present as soft, tan, cauliflowerlike masses on the penis, vulva, and perianal areas. (Choice D) Hemolytic uremic syndrome is the triad of microangiopathic hemolytic anemia, thrombocytopenia, and renal insufficiency caused by Escherichia coli strain O157:H7. (Choice E) Pseudomonas aeruginosa can cause malignant otitis externa in individuals using contaminated swimming pools and hot tubs. Pseudomonal hot tub folliculitis typically manifests as a rash rather than lymphadenopathy. (Choice F) Toxic shock syndrome (TSS) is caused by Staphylococcus aureus. TSS presents with fever, vomiting, diarrhea, desquamation, and hypotension. Educational objective: Bartonella henselae causes cat-scratch disease, bacillary angiomatosis, and culture-negative endocarditis. Cat-scratch disease is characterized by low fever, lymphadenopathy, and a self-limited course.

A 34-Year-Old Woman Comes to the Office Due to 3