Vol. 16, No. 36
THE JOHNS HOPKINS MICROBIOLOGY NEWSLETTER
Monday, September 22, 1997
A. Provided by Carmela Groves, R.N., M.S., Chief, Division of Outbreak Investigation, Maryland Department of Health and Mental Hygiene
11 outbreaks were reported between August 29 and September 22, 1997.
B. The Johns Hopkins Hospital: Information provided by David Taylor, M.D., Pathology
Clinical Information: The patient is a 32 yr. old male HIV positive male with a CD4 count of 66 cells/mm who developed several red/purple nodular lesions on the face, scalp and posterior pharynx. Biopsies of the skin and the pharyngeal lesions were consistent with Bacillary Angiomatosis (BA). Warthin-Starry silver stain demonstrated clusters of bacilli consistent with BA. The patient was started on erythromycin 500 mg q.i.d. A CT scan of the abdomen revealed numerous small (< 1cm) low density liver lesions consistent with peliosis hepatitis. After four months of antibiotics, repeat CT scan of the abdomen showed resolution of the liver lesions.
Bacillary Angiomatosis
Bacillary Angiomatosis is a reactive vascular proliferation caused by bacilli of the genus Bartonella (formerly Rochalimaea ), specifically B. henselae and B. quintana. Bartonella spp. are small gram-negative rods that are often slightly curved. BA was initially described in the skin, but can occur in a variety of organs or as septicemia. First reports were in patients infected with HIV; infections were subsequently identified in other immunocompromised hosts and later in some apparently immunocompetent patients as well.
Epidemiology: The geographic distribution of BA largely parallels that of HIV infection. BA is at least in part a zoonosis because one of its agents, B. henselae is harbored by both cats and their fleas. Immunocompromised patients who own cats and have been licked, bitten or scratched by a cat seem to have an increased incidence of BA. Although some BA is caused by B. quintana, the louse, Pediculus humanus, which transmits the same agent as trench fever, does not seem to play a role in BA.
Clinical Features: Bacillary angiomatosis has now been reported to affect almost every organ system, but cutaneous lesions are most common. These lesions can be few or many, small or large, and occur with or without systemic disease. Papules and nodules of BA range from skin colored to pink to deep red or purple, with intact, smooth or ulcerated surfaces.
The number and distribution of lesions of cutaneous BA appear to reflect the degree of immunosupression and the route of infection. Patients with less compromised immunity and a clear history of traumatic inoculation often have only a few lesions, or a single one at the site of entry. Patients with overwhelming infection can be covered with myriad lesions, which show a propensity to involve mucocutaneous junctions. Endobronchial, tracheal, and esophageal lesions can be life threatening.
BA can present as a subcutaneous mass, mimicking a soft tissue neoplasm when cutaneous lesions are absent. Erosion of underlying bone can occur, as can osteolytic bone lesions.
Lymph nodes involved by BA are often markedly enlarged and can be affected in the absence of other lesions, or can accompany visceral peliosis. In bacillary peliosis, the affected tissue contains numerous blood filled, partially endothelial-cell-lined cystic structures often separated from surrounding parenchymal cells by fibromyxoid stroma containing a mixture of inflammatory cell, dilated capillaries and clumps of bacilli identified by Warthin-Starry silver staining. In addition to abdominal fullness, bacillary peliosis hepatis can cause elevated transaminase levels with a normal or slightly elevated bilirubin. Splenic and hepatic peliosis may cause catastrophic inter-abdominal hemorrhage if a vascular space ruptures. Splenic peliosis often causes pancytopenia.
Ophthalmic involvement is a newly recognized complication of BA. The diagnosis can be difficult if cutaneous lesions are absent. Many of the patients with ophthalmic BA are immunocompetent, suggesting that intraoccular inoculation of organisms does not require an immune deficit.
Systemic symptoms caused by BA may be difficult to distinguish from other causes of immune deficiencies. Most patients with BA and HIV infection have fewer than 100 CD4 cells/mm. Septicemia, fever, malaise, visual impairment, bone pain, stridor, dysphagia and other signs can be the result of widespread infection. Bacteremia with B. henselae can develop in the absence of tissue infiltrates of BA.
Diagnosis: The diagnosis of BA can be confirmed by conventional histopathologic examination supplemented by special stains or electron microscopy. Cutaneous lesions are well-circumscribed rounded areas of vascular proliferation, situated in the superficial or deep dermis, or both. Pyogenic granuloma, epitheliod hemangioma and Kaposi's sarcoma can resemble BA clinically. A PCR assay from blood for Bartonella is currently under development.
Treatment: The initial therapy of choice is oral doxycycline 100 mg twice daily or oral erythromycin 500-1000 mg four times daily. Other oral agents with clinical utility include tetracycline, minocycline, chloramphenicol, azithromycin and clarithromycin.
For BA only involving the skin, oral therapy of 8-12 weeks is recommended. Lesions often begin to resolve in one week, but usually take considerably longer to involute completely and may leave residual hyperpigmentation. If not resolved by 12 weeks, therapy should be extended. Bacillary peliosis or osseous or parenchymal involvement with BA may resolve with oral therapy alone, but the possibility of relapse may be less if initial therapy is paternal, followed by many months of oral therapy.
References
1. LeBoit PE. Bacillary Angiomatosis in Conner DH, Chandler FW eds. Pathology of Infectious Disease. Stamford, Connecticut, Appelton and Lange; 1997:407-415.
2. Slater LN, Welch DF. Rochalimaea Species in Mandel GL, Bennett JE and Dolin R eds. Principles and Practice of Infectious Disease, 4th edition, vol. 2. New York City, Churchill Livingstone; 1995:1742-1744.
3. Perocha LA, Geaghan SM, Yen TS, et al. Clinical and pathological features of bacillary peliosis hepatis in association with human immunodeficiency virus infection. N Engl J Med. 1990;323:1581-1586.
Special Seminars: RoomW2030, 12:00 P.M., School of Public Health
September 23rd - "Tuberculosis in a London Borough: Old Problems Need New Solutions"
September 25th - "Can We Move Beyond the Broad Street Pump: Applications of GIS"
Special Seminar: Hurd Hall, 1:00 P.M. - 3:30 P.M. - RSVP: 955-8384
September 25th - "Vancomycin-Resistant Enterococci (VRE): Control of an Emerging Pathogen" - live interactive continung education- accredited satellite videoconference