Systemic bartonellosis with hepatosplenic granulomas

Systemic bartonellosis is an infection caused by the Gram-negative bacillus Bartonella henselae. The most common form of infection is locoregional. However, in some cases atypical and severe forms develop with visceral involvement that cause hepatosplenic granulomas.^1,2 We present two case reports.

The first case was a 69-year-old woman, with no previous medical history, who developed a fever of up to 39 °C and deterioration in her general condition. On questioning, the patient reported having a cat at home and she had skin lesions from scratches. Physical examination revealed skin lesions caused by scratching, no lymphadenopathy, and a painful abdomen with no organomegaly. Blood tests showed elevated C-reactive protein (CRP) of 60.8 mg/l, in addition to abnormal liver function tests: aspartate aminotransferase (AST) 103 U/l; alanine aminotransferase (ALT) 106 U/l; gamma-glutamyl transpeptidase (GGT) 201 U/l and alkaline phosphatase (AP) 327 U/l. Abdominal ultrasound, followed by a computerised tomography (CT) scan and then magnetic resonance imaging (MRI) revealed a normal-sized spleen with two focal lesions measuring 2.9 cm and 2 cm suggestive of abscesses (Fig. 1). Echocardiogram did not show images suggestive of vegetations. In microbiological tests, the serology was positive for Bartonella henselae IgM and IgG (with titres 1/256). She was started on a six-week course of antibiotic therapy with doxycycline and rifampicin. Three months later, a follow-up abdominal ultrasound showed the focal splenic lesions to have disappeared, which supported the diagnosis.

Figure 1.

a) Case 1: Abdominal computerised tomography (CT), sagittal section. Hypodense splenic lesion; b) Case 1: Abdominal magnetic resonance imaging, T2-weighted sequence. Hyperintense splenic lesions with perilesional oedema; c) Case 2: Abdominal CT, sagittal section. Hypodense and heterogeneous splenic lesions; d) Case 2: Abdominal CT, coronal section. Hypodense and heterogeneous splenic lesions.

The second case was a 34-year-old woman, originally from Paraguay, with a relevant medical history of autoimmune disease involving a combination of rheumatoid arthritis and lupus (Rhupus) on treatment with methotrexate. The patient reported abdominal pain on her left flank for one month, weight loss of 7 kg, asthenia, night-time fever peaks and, in the last week, the addition of left retroauricular lymphadenopathy. She denied recent travel or contact with animals. On examination, left axillary and supraclavicular lymphadenopathy was detected and tenderness in the left hypochondriac region. Blood tests showed CRP 48.2 mg/l with abnormal liver function tests: AST 66 U/l, ALT 64 U/l, GGT 67 U/l and AP 193 U/l. Abdominal ultrasound and a CT scan of the neck-chest-abdomen revealed a 13.2-cm spleen with heterogeneous parenchyma with multiple focal lesions and bilateral periportal and axillary lymphadenopathy (Fig. 1). These were suspected to be splenic abscesses, but without being able to rule out lymphoproliferative syndrome. The imaging study was completed with echocardiogram, which revealed no vegetations. A core needle biopsy of the right axillary lymph node revealed epithelioid granulomatous lymphadenitis with focal necrosis, without evidence of lymphoma. Serology showed positive anti-Bartonella henselae IgM and nonspecific IgG antibodies, and the patient was started on treatment with rifampicin and azithromycin for two weeks. The follow-up CT scan after three months showed a notable decrease in the volume of the axillary lymphadenopathy with radiological improvement of the splenic lesions both in number and size and a decrease in the overall volume of the spleen.

The main reservoir of B. henselae is animals, particularly cats and their fleas.¹ Hepatosplenic involvement is rare, accounting for 5–25% of cases. Persistent fever, abdominal pain and weight loss are some of the main clinical manifestations of visceral involvement.¹ This condition should be considered within the differential diagnosis of fever of unknown origin.^2,3 It is common for blood tests to show abnormal liver function tests and elevated CRP.² In microbiological tests, serology is the technique that offers the best results with high sensitivity and specificity.^2,3 There is a possibility of cross-reactivity between Bartonellaspecies, as well as with other microorganisms (Treponema spp, Chlamydia spp., Mycoplasma spp., Coxiella spp.). Identification would require culture or molecular techniques, which were not performed in the cases presented here, and B. henselae was assumed to be the most likely cause of the condition. Imaging tests show multiple focal lesions,^2,4 which, if biopsied, would correspond to necrotising granulomas.^1,2,5 With regard to treatment, although there is no clear consensus, azithromycin is usually recommended for five days.⁶ However, in a clinical trial comparing azithromycin with placebo, no differences in clinical response were observed in the two groups.⁷ Long courses, aminoglycosides or combinations are reserved for cases of endocarditis or involvement of other organs.^1,3,6

Conflicts of interest

The authors declare that they have no conflicts of interest.