From the Guidelines
Solid masses within the spleen associated with Bartonella infection typically require antibiotic treatment with azithromycin, doxycycline, or a combination therapy. For immunocompetent patients, doxycycline 100mg twice daily for 2-4 weeks is often effective, as supported by the guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents 1. Immunocompromised patients may need longer treatment courses of 3-4 months, potentially with combination therapy such as doxycycline plus rifampin 300mg twice daily. These splenic lesions, known as splenic abscesses or granulomas, develop when Bartonella bacteria (commonly B. henselae) infect the spleen, often following cat scratches or bites. Diagnosis typically involves:
- Serology
- PCR testing
- Imaging studies like ultrasound or CT scan to visualize the splenic masses. Most splenic lesions resolve with appropriate antibiotic therapy, though larger abscesses may occasionally require percutaneous drainage or splenectomy if medical management fails, as discussed in the guidelines for the management of patients with valvular heart disease 1. Patients should be monitored with follow-up imaging to ensure resolution of the lesions. Prevention includes avoiding cat scratches and practicing good hand hygiene after handling cats. It is also important to note that asplenic or hyposplenic patients are at increased risk of overwhelming post-splenectomy infections (OPSI) and should receive immunization against encapsulated bacteria, as well as annual influenza vaccination, and be aware of the need for prompt medical attention in case of fever or other symptoms, as recommended in the guidelines for splenic trauma 1.
From the Research
Solid Masses within the Spleen and Bartonella
- Solid masses within the spleen can be associated with various conditions, including infections such as bartonellosis 2.
- Bartonellosis is caused by the Gram-negative intracellular bacterium Bartonella, which can lead to a range of clinical manifestations, from benign to life-threatening illnesses 3, 4.
- The severity of Bartonella infection correlates with the patient's immune status, and clinical conditions associated with Bartonella spp. include local lymphadenopathy, bacteraemia, endocarditis, and tissue colonisation resulting in bacillary angiomatosis and peliosis hepatis 4.
Diagnosis and Treatment of Bartonella Infections
- Diagnosis of Bartonella infections can be challenging, and treatment decisions are often based on case reports and limited patient data 4.
- Antibiotics such as azithromycin, doxycycline, gentamicin, and ciprofloxacin are commonly used to treat Bartonella infections, but treatment of chronic infection remains problematic 3, 4, 5.
- Recent studies have identified FDA-approved drugs with activity against stationary phase Bartonella henselae, including pyrvinium pamoate, daptomycin, and gentamicin, which may facilitate the development of more effective treatments for persistent Bartonella infections 6.
Bartonella Infection in the Spleen
- Systemic Bartonella henselae infections are unusual in immunocompetent adults, but can occur and present with fever and multinodular splenomegaly 2.
- Real-time quantitative PCR and sequencing of amplified products can be used to identify Bartonella henselae in the spleen, preventing misdiagnosis and unnecessary splenectomy 2.
- The use of antibiotics such as gentamicin and doxycycline may be effective in treating Bartonella infections in the spleen, but further research is needed to determine the best treatment approach 4, 5.