HIV Infection: Clinical Basics

Department of the Navy
Bureau of Medicine and Surgery

Almost 20 years into the epidemic, HIV disease has unquestionably moved out of the domain of the generalist, and become the nearly exclusive province of the HIV specialist. The latter are generally, although not always, infectious disease specialists. In spite of this, military primary care physicians, including GMOs, will provide some care to patients with established HIV infection. Perhaps more importantly, primary care providers will serve as the initial (and often only) point of contact with the health care system for infected individuals in the process of seroconverting.

Detection of patients in the process of seroconverting (i.e. with acute HIV illness) is woefully inadequate in all settings, military and civilian; however, it is a potentially very valuable contribution to the care of these individuals when it occurs. Up to two-thirds of patients newly infected with HIV will have manifestations of acute infection, generally referred to as seroconverting illness. Oftentimes this takes the form of an infectious mono-like illness or "flu." Common symptoms include fever, sore throat, a maculopapular rash, generalized lymphadenopathy, fatigue, malaise, myalgias, oral ulcerations, and less commonly an aseptic meningitis. Occasionally, more impressive manifestations such as thrush, shingles, or even full-blown opportunistic infections may occur; although these are certainly the exception rather than the rule. While the first group of symptoms is admittedly nonspecific, any combination of them should suggest the possibility of HIV seroconversion. This is particularly true if symptoms last for a week or longer, as illness associated with acute HIV infection generally lasts from one to several weeks. Current thought is that detection of illness at this stage followed by aggressive treatment will likely, favorably alter the course of the disease, by lowering the viral "setpoint" that develops over the first 6 months or so of infection.

As already mentioned, detection of infection at this early stage is highly desirable. Unfortunately, the majority of the time serology for HIV will still be negative during this period, and so testing with a surrogate is important. Historically, testing has been done by checking a p24 antigen and this has now been largely supplanted by an HIV viral load evaluation. The latter is a highly sensitive and specific test, as viremia is generally very high during acute infection. If one of these tests cannot be obtained (i.e. deployment), it is important to check HIV serology shortly after the acute infection, along with a viral load if possible. A patient found to be seroconverting should be discussed urgently with an infectious disease specialist, and if possible referred acutely.

Although disease may progress unchecked in a subset of patients (perhaps 10 percent) after HIV infection, the large majority of individuals will enjoy a period of "latent" infection. During this time they will generally be free of symptoms related to the disease, even though the virus continues to replicate at an astounding rate, and slowly chops away at the immune system. On average, a loss of about 50 – 100 CD4+ lymphocytes will occur annually, in the absence of therapy. Particularly since the advent of the protease inhibitors in 1995, the standard of care is to treat individuals aggressively in early and middle stages of disease, in the hope of delaying or preventing progression to advanced disease. This has clearly been successful, with AIDS deaths down 47 percent in 1997 alone.

Therapy of HIV disease has changed dramatically over the last several years, and will continue to do so for the foreseeable future. As of late 1998, there are 13 antiretrovirals on the market, with another 3 pending approval. Use of these drugs in appropriate combinations and sequences is critically important in achieving and sustaining a good response, and once again should always be done in conjunction with an HIV specialist.

As the disease progresses to somewhat more advanced stage, a variety of clinical manifestations may occur. As these often begin to appear when the CD4+ count drops below 350 or 300, they may been seen with some regularity in patients who remain on active duty. Some of these conditions include generalized lymphadenopathy, zoster (shingles), thrush, oral hairy leukoplakia, oral ulcers, and recurrent herpetic infections. While none of these conditions are AIDS-defining or grounds for a medical board by themselves, they are an indicator of disease progression. By the time a patient meets criteria for a diagnosis of AIDS (including a CD4+ count of < 200), a medical board should be initiated.

Known or Suspected HIV Exposure

An area of some controversy has been how best to address the individual with definite or possible exposure to HIV. Examples can include a health care provider who sustains a needle stick injury with a sharp from an HIV+ patient or an individual who presents after a sexual exposure to an infected or possibly infected partner. Without going into excessive detail, it may be safely stated that an individual who sustains a moderate or high-risk exposure in the health care setting should be emergently counseled and offered antiretroviral treatment. This should ideally be discussed with an HIV specialist or at least a general internist, but if this is not possible, strong consideration should be given to beginning a 3-drug combination (e.g. AZT, 3TC, and a protease inhibitor such as Indinavir or Nelfinavir). Ideally, this should be done within 2 - 3 hours of the exposure. The decision to give medications after a sexual exposure is more problematic, and should be handled on a case-by-case basis. Prophylactic medication should certainly not be given, unless the contact is known to be HIV+.

Web Resources

Revised by CDR James C. Pile, MC, USNR, Infectious Disease Department, National Naval Medical Center, Bethesda, MD (1999).