Sean K. Verma et al report on a 28-year-old man with no past medical history presented with fevers, chills, abdominal pain, night sweats, 3 weeks of weight loss, and cramping abdominal pain not associated with eating. He denied alcohol or drug use. He reported cats at home, with scratches but no bites. He travelled to Ecuador 2 weeks before his symptoms appeared. When his symptoms developed, he was given ciprofloxacin but did not improve.
The patient had no palpable lymphadenopathy or cutaneous lesions, and his laboratory test results, including liver function tests, were normal. However, computed tomography of his abdomen and pelvis revealed several hepatic and splenic masses with central necrosis (see picture).
The authors were not sure if the patients had a malignancy (lymphoma) or metastasis; granulomatous disease, such as sarcoidosis; or infections such as endocarditis, amebiasis, schistosomiasis, brucellosis, or bartonellosis. Liver biopsy analysis revealed an abscess with numerous neutrophils, histiocytes, and lymphocytes, with surrounding fibroblast proliferation, lymphocytes, histiocytes, and eosinophils.
Given his close contact with cats, occasional scratches, and hepatosplenic lesions not otherwise explained, he was treated for atypical cat scratch disease with rifampin and azithromycin while he underwent further testing.
A test for Bartonella henselae antibody confirmed his recent infection. Following a 2-week course of antibiotics, his symptoms recurred after 1 week. He was then given doxycycline and rifampin, and had complete resolution of symptoms 4 weeks later. He completed an additional 4 months of therapy and follow-up computed tomography demonstrated near complete resolution. The patient remained asymptomatic 1 year later.
Cat scratch disease is caused by a bacterium called Bartonella henselae. The disease spreads when an infected cat licks a person’s open wound, or bites or scratches a person hard enough to break the surface of the skin.
Verma et al explain that although typical cat scratch disease usually produces cutaneous nodules at the inoculation site with regional lymphadenitis, some patients have hepatosplenic involvement, neuroretinitis, endocarditis, and fever of unknown origin. Disseminated atypical cat scratch disease with hepatic involvement is more common in immune suppressed patients.
Hepatosplenic involvement without regional lymphadenopathy is a rare presentation that can cause a delay in diagnosis.
Verma et al state that it has been difficult to determine if any single antibiotic regimen is superior for treatment of hepatosplenic disease. Prolonged combination therapy might benefit patients with significant hepatosplenic burden. Choice of antibiotic, combination treatment, and treatment duration for atypical cat scratch disease require further study.