Excerpt from Bacillary Angiomatosis

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Background

Bacillary angiomatosis (BA) is a systemic disease first described by Stoler and associates in 1983.¹ They reported a 32-year-old patient with presumed acquired immunodeficiency syndrome (AIDS) who developed multiple subcutaneous nodules characterized histologically by a vascular proliferation. Bacillary forms were demonstrated, and the patient responded to erythromycin with an apparent cure.

In 1987, Cockerell and associates² called widespread attention to BA, describing 6 patients with AIDS and unusual cutaneous papules and nodules distinct from Kaposi sarcoma. Being unaware of its infectious origin, they called it epithelioid angiomatosis. This name was selected because the deeper dermis has alterations similar to those of epithelioid hemangiomas, with endothelial cells adherent to one another in an epithelioid pattern. Its bacterial origin was later confirmed, and the name bacillary angiomatosis was proposed by LeBoit et al^{3, 4}, originally as a transitional term pending proper identification of the causative agent(s).

Its systemic nature became evident when postmortem examinations showed nodules in the larynx, gastrointestinal tract, peritoneum, and diaphragm. Others observed additional patients with BA and postulated a likely bacterial origin. The organism was found to have some features in common with the etiologic agent of cat scratch disease and some in common with that of bartonellosis. Originally proposed as a new species, Rochalimaea henselae and Rochalimaea quintana, the 2 agents of BA have been reclassified as Bartonella species rather than Rochalimaea species.

BA often responds to therapy with oral erythromycin, although other oral antibiotics and antituberculosis medications, including tetracycline, trimethoprim-sulfamethoxazole, and rifampin, may also be effective. While BA is treatable and curable, it may be life threatening if untreated.

The eMedicine article Bacillary Angiomatosis (infectious diseases focus) may be helpful. Additionally, visit the Medscape HIV Pathogenesis Resource Center and the HIV Transmission and Prevention Resource Center.

Pathophysiology

The etiologic agents of BA are 2 Bartonella species, Bartonella henselae and Bartonella quintana. BA can occur in immunocompetent persons, although it has been linked most commonly with AIDS. DNA hybridization, 16S rRNA sequence homology, cellular fatty acid profiles, and cytosine and guanine content studies have shown these Bartonella species are closely related to Bartonella bacilliformis. Epidemiologic evidence has suggested that B henselae–induced BA is also associated with exposure to cats. Speculation about nonhuman reservoirs and vectors of transmission is reasonable because both trench fever and bartonellosis are arthropod borne.

BA has been suggested to be caused with equal frequency by B henselae and B quintana. Infection with these tiny gram-negative bacilli that are difficult to culture results from exposure to flea-infested cats in B henselae infection and the human body louse in B quintana infection. B quintana can also cause bacteremia, urban trench fever, and endocarditis in immunocompetent persons. It is associated with lytic bone lesions. Peliosis hepatis and lymph node involvement are linked with B henselae.

Age

A wide age range exists, with infants to elderly people affected. The age range was 26-52 years in one early series of patients with AIDS.

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