Clinical Pearls & Morning Reports
In many disease conditions, the concept of Occam’s razor applies, whereby one unifying diagnosis explains most, if not all, of the presenting symptoms. However, in patients with advanced human immunodeficiency virus (HIV) infection, Occam’s razor does not apply; rather, advanced HIV infection is more consistent with Hickam’s dictum, which states that a patient may have several diseases that are causing the presenting symptoms. Read the latest Case Records of the Massachusetts General Hospital here.
Q: What is the cause of Kaposi’s sarcoma and how is it transmitted?
A: Kaposi’s sarcoma, which is caused by human herpesvirus 8 (HHV-8, also known as Kaposi’s sarcoma–associated herpesvirus), is known to be transmitted sexually but also is believed to be transmitted from mother to child and potentially among siblings through excretion in saliva.
Q: Can the violaceous skin lesions of Kaposi’s sarcoma be confused with those of any other condition?
A: Bacillary angiomatosis is a condition characterized by skin lesions resulting from disseminated bartonella infection from either Bartonella henselae or B. quintana. The skin lesions, which appear as numerous pinpoint purplish-to-bright red raised spots or nodules, are often indistinguishable from those associated with Kaposi’s sarcoma.
A: Among patients with HIV infection, Kaposi’s sarcoma is characterized by painless violaceous macules or nodules on the feet, legs, trunk, or face. There is typically no fever, the skin lesions usually have irregular borders, and silent lesions can be present in the gut or lungs, even when no skin lesions are present. As the disease advances, it can spread to regional lymph nodes, sometimes resulting in profound lymphedema of dependent areas, or it can progress to disseminated involvement of the oropharynx, lungs, gut, genitals, or visceral organs. Visceral involvement is often accompanied by Kaposi’s sarcoma lesions in the mouth, usually on the hard or soft palate, gums, or buccal mucosa. These lesions are often subtle and may not be easily identified on physical examination.
A: Combination antiretroviral therapy (ART), which is the backbone of the systemic treatment of newly diagnosed AIDS-related Kaposi’s sarcoma, can lead to prolonged disease control and can induce slow clinical regression of Kaposi’s sarcoma lesions. Although chemotherapy is associated with a relatively high response rate in patients with Kaposi’s sarcoma and has been reported to reduce symptoms, studies showing a survival advantage over ART alone are lacking. Disease and patient factors that support the initiation of chemotherapy could include widely disseminated or rapidly progressing disease, organ dysfunction (e.g., pulmonary involvement), progression despite the use of ART, Kaposi’s sarcoma–immune restoration inflammatory syndrome, and symptoms (e.g., edema, pain, and bleeding). Therefore, the challenge is to identify the patients who will derive the most benefit from chemotherapy, since many patients can do well with the use of ART alone.