September 3, 2002

     A few weeks ago, it was discussed how HIV/AIDS is still a huge and growing problem worldwide, and that the Philippines is now beginning to see its fair share of victims. Since this epidemic will eventually catch up with us, it may be worthwhile to discuss a little bit about it.

     There have been numerous disease entities that have been labeled as “disease mimickers”. After man discovered the world of microbes, syphilis was found to be able to infect nearly every organ of the body & imitate different syndromes. After knowing how to stain these spirochetes, the acid-fast smear revealed another group of organisms; and then tuberculosis became the next mimicker. With the advances in immunology, autoantibodies brought with it Systemic Lupus Erythematosus (SLE) and other autoimmune disorders, adding SLE to the list. Now, a retrovirus which scientists believe to have originated from African monkeys has wrecked havoc in human immune systems, virtually opening a Pandora’s box for other microbes and anaplasia to imitate nearly all diseases known to man.

     The main mechanism of HIV disease is the destruction of CD4 cells that constitutes the bulwark of Cell Mediated Immunity (CMI). The major role of CMI is defense against mycobacteria, fungi, and tumors. Of course, late in the spectrum of AIDS, even Humoral immunity is adversely affected. Knowing this basic principle would help in the recognition of opportunistic infections and malignancies that herald AIDS. The big problem is, in a poor tropical country like the Philippines, infections are all over the place in the first hand. This is the challenge.

     First, anyone who has risk factors is a candidate. High-risk behavior includes unprotected sex, being in the sex trade business and people who have multiple partners. Overseas Contract Workers (OCW) and their spouses (or mistresses) and gay or lesbians should be considered at risk. The list includes drug addicts especially mainliners and skin-poppers and anyone who received blood transfusion and other blood products. Often-neglected routes are tattoos, body piercing and barbershops where the instruments or needles may have been reused or not properly sterilized before using on another customer. Babies and children of these individuals are also at risk, so a careful family history is essential for pediatric patients. No one is exempt, no matter how immaculate a person’s image is.

     Second, anyone who seems to be so sickly or too sick of an otherwise nuisance illness may have an underlying immunodeficiency. It must be remembered that the most common cause of low immunity are diabetes, alcoholism, malnutrition and renal insufficiency, so these must be sought for and ruled out. Patients who have malignancies and undergoing chemotherapy or transplant recipients can of course get infected with pretty much anything. There are also congenital and acquired immunodeficient states that we need to be aware of. Most of these affect predominantly neutrophil function and therefore manifest differently than AIDS but there are also combined immunodeficiency states. These are easy to spot by their presentation, because the patients are often young, have congenital abnormalities and have no HIV risk factors.

     Third, think of CMI related illnesses. The top five general groups are: fungi, latent viruses, mycobacteria, parasites and lymphomas. The most common opportunistic infection in HIV is thrush due to Candida species. Recurrent thrush and any candidal esophagi is are considered AIDS defining illnesses. It may even herald Acute HIV infection together with FUO (fever of unknown origin), sweats, chills, rashes and lymphadenopathy. Surprisingly, other yeasts and molds are not significantly associated with HIV. Among latent viruses, Herpes, Varicella-Zoster virus (VZV) and Cytomegalovirus (CMV) are the topnotchers. Anyone with severe, recurrent, or disseminated Herpes (both Type 1 and 2), recurrent Shingles, or Shingles involving more than one dermatome should raise suspicion of immunodeficiency. CMV is the most common infectious cause of blindness in HIV and it can also cause encephalitis, colitis, hepatitis, pancreatitis, neuropathy and myelitis.

     Bacterial infections are more common in AIDS. Recurrent pneumonia (3 or more per year) is AIDS defining, as well as miliary or extrapulmonary tuberculosis (TB). TB is so prevalent in the Philippines however, so risk factors should be looked for. AIDS patients also tend to get the multiply-resistant strains. There are other mycobacteria besides TB; the most common one is Mycobacterium-avium intracellulare (MAI/MAC) that causes disseminated or local infections in AIDS. The treatment is different (clarithromycin+ethambutol) so this must be kept in mind. Just like TB, parasites can be picked up anywhere you step in the Philippines. The protozoal ones are more of the problem however, not the helminths. The former include Pneumocystis carinii (PCP) that causes interstitial pneumonia, Toxoplasma gondii (brain abscess and chorioretinitis), and Giardia, Crytosporidium and Microsporidium that cause chronic diarrhea. Anyone with the runs not responding to the typical Amoeba-bacterial diarrhea regimen must be tested for the latter three.

     A person presenting with a swollen lymph node or enlarged spleen may have a lymphoma. Unlike infections, which correspond to the CD4 count level, these lymphomas appear no matter what the CD4 count is. Lymphomas are also the most common malignancy in HIV and often presents as FUO or painless lump. Other cancers are also more frequent and severe. Another physical sign to alert a clinician of HIV is chronic wasting, which may be confused with malnutrition or severe substance abuse.

     Lastly, as we have all been taught in medical diagnosis, when you hear hooves, think of horses before you think of zebras. But as the species of horses are eventually ruled out, think of the rarer disease entities, the “zebras.” So that when you eventually see AIDS, you will recognize it when you see it.

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     The author's e-mail address is at docdan1@pol.net.

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