Review Question - QID 107422

This patient has cat-scratch disease, caused by an infection with Bartonella henselae. Any child with unilateral lymphadenopathy and history of interacting with cats should be worked up for cat-scratch disease.

Patients infected with B. henselae, following a cat bite or scratch, develop a papule at the site of injury. One to two weeks later patients start to develop lymphadenopathy, fever, and malaise. There is typically one erythematous and tender lymph node involved, ipsilateral to the scratch or bite, which may suppurate. Treatment of cat-scratch disease is supportive, unless more serious sequelae develop.

Klotz et al. discuss diagnosis and other less common manifestations of cat-scratch disease. In any patient with fever of unknown origin or lymphadenopathy, include cat-scratch fever in the differential. Children are most commonly affected and diagnosis is made by serologic testing as culturing B. henselae is difficult. If patients show signs of systemic disease (hepatosplenomegaly, meningoencephalitis) or immunodeficiency (bacillary angiomatosis) treatment should include azithromycin.

Meier et al. review the differential diagnosis of neck masses in children. When working-up a neck mass in a child, separate the differential into: developmental (i.e. branchial cyst or hemangioma), inflammatory/infectious or neoplastic. If infectious causes are suspected, outside of cat-scratch disease, consider antibiotics. If the patient does not respond to antibiotics perform a more comprehensive workup, which includes viral titers (and toxoplasmosis) and imaging. Further management may involve incision and drainage of the mass or biopsy.

Figure A depicts a child with posterior cervical lymphadenopathy. Illustration A depicts bacillary angiomatosis, most likely in an immunocompromised patient

Incorrect answers:
Answer 1: Persistent lymph nodes greater than two cm along with B symptoms (fever, night sweats, weight loss) would be more indicative of ALL.
Answer 2: Tuberculosis is unlikely in this scenario as the patient has had no foreign travel.
Answer 3: Although toxoplasmosis is transmitted through cat feces, lymphadenopathy from T. gondii is typically diffuse.
Answer 5: S. aureus infection can also present with a tender erythematous lymph node. However, the patient's history of interacting with cats is more suggestive of cat-scratch disease.