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Tufts OpenCourseware
Author: Kanchan Ganda, M.D.
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1. Infectious Diseases

Common infectious diseases that must be considered are rheumatic fever, scarlet fever, STDs, infectious mononucleosis, viral hepatitis, and AIDS. All the above-mentioned infections are discussed elsewhere. AIDS and STDs will be discussed in this section.

1.1. "Spectrum Illness"

Asymptomatic Phase Symptomatic Phase
3 - 6 weeks (Most) or 3- 6 months to seroconvert positive ELISA and the Western Blot Tests 1 - 8 years, approximately 8 - 12 years, approximately
0 years -- Onset of HIV Infection Death after 12 - 16 years or longer

1.2. AIDS

AIDS is an infection caused by the human immunodeficiency virus HTLV-III. It is an RNA virus that attacks the CD4 receptors of the T4 lymphocytes. Reverse transcriptase, an enzyme within the virus helps the virus transfer its RNA material into the DNA of the host cell.

The T4 lymphocytes are like the “pilots” of immunity. The T4 cells also govern the quality and quantity of the B-lymphocytes. Thus, with progression of the infection over the years, the patient has defective cell mediated immunity and lymphokine mediated humoral immunity. This is responsible for the increased incidence of opportunistic infections as the patient’s immune system deteriorates.

The HIV virus additionally affects the monocytes, macrophages, and neural cells or glial cells, particularly when the virus crosses the blood brain barrier. This is responsible for the depression and dementia associated with AIDS.

Even though the infection is seen more commonly in certain “high risk” populations like IV drug users swapping needles, prostitutes, men having sex with men, heterosexuals with multiple partners, etc., every patient in the dental clinic should be considered “high risk”, calling for the use of universal precautions during dentistry.

The virus has been isolated from almost all bodily fluids, very particularly from blood and seminal fluid.

The HIV illness is often labeled as a “spectrum illness” which spans for approximately 12-16 years from the start of infection to the time when the patient succumbs to the illness and death occurs. Most patients are asymptomatic at the start of the infection. A small percentage of patients develop an “infectious mononucleosis” type of illness within a week or two after getting infected. The monotype illness simulates an actual mono attack which lasts for 10-14 days. The patient usually recovers from this acute attack and progresses through the spectrum.

In 3-6 weeks, after the start of the infection, most patients develop antibodies against the virus. Occasionally, a patient will convert in 3-6 months. This is the time frame (6 weeks - 6 months) when the patient will test positive for the ELISA (Enzyme Linked Immune Absorbent Assay) test and the Western Blot Test. The ELISA test is 99% sensitive. The Western Blot is 99.5% sensitive. A positive test confirms that the patient has a HIV infection. When the patient gets infected, it is referred to as HIV infection. When the patient comes down with opportunistic infections with or without the CD4 count being below 200 cell/ mm3, it is referred to as AIDS.

From the time of infection to the time when overt symptoms are experienced by the patient, one to eight years may elapse, during which the patient is asymptomatic. If the patient did not have infectious monotype symptoms initially, he/she may never even know till the symptoms occur, that they are infected.

T4 lymphocytes (helper cells) are attacked by the virus causing their number to decrease over time. At the start of the illness, the patient has normal levels of T4 lymphocytes (1000 cells/mm3). Throughout the asymptomatic phase, the T4 count is steadily on the decline. When the T4 count is between 450-500 cells/mm3, the patient begins to get symptomatic. Common symptoms (what the patient experiences) experienced by the patient at the start of the disease are tiredness, weakness, fatigue, anorexia, weight loss, cough with expectoration/bloody sputum, chronic diarrhea, night fevers, night sweats, depression, social withdrawal, forgetfulness, etc.

The common signs (what the clinician elicits on examination) seen are white coating on the tongue, i..e. oral candidiasis (candida infection), OVL (Oral Viral Leukoplakia) caused by EBV, (Epstein-Barr Virus), and very occasionally enlarged lymph glands in the neck, axilla, etc. (generalized lymphadenopathy).

Further deterioration of the immune system occurs as the patient moves through the spectrum of the illness. When the T4 count is < 200 cells/mm3, the patient progresses to full blown AIDS.

1.2.1. Common Infections Seen Are as Follows:

  • Viral infections: Herpes simplex; herpes zoster; CMV (Cytomegalovirus), which can affect the eyes, brain, and adrenal glands; papilloma virus causing warty/cauliflower type lesions on the gums.
  • Fungal infections: Oral and esophageal candidiasis; angular chielitis (soreness and cracking at the angles of the mouth).
  • Bacterial infections: MTB (Mycobacterium tuberculosis); MDRTB (multi drug resistance TB); MAI (Mycobacterium avium intracellulare); and MK (Mycobacterium Kansassi); and PCP (Pneumocystis carinii pneumonia). Both MAI and MK only occur in immunocompromised patients and not in healthy, immunocompetent patients. MTB can occur in the immune competent patient too.
  • Tumors: Lymphomas - Non-Hodgkin’s and Hodgkin’s lymphoma; squamous cell carcinoma; and Kaposis sarcoma . Kaposi’s begins as pink pin head sized lesions, gradually enlarging and changing color from pink to purple to black. Kaposi’s is usually multifocal involving the trunk, upper extremities, head, and neck region in AIDS patients.

One should never ask a patient if they are “high risk” for HIV. That question is inappropriate. It would be better to ask the patient for signs and symptoms associated with HIV/AIDS.

Recently with the use of newer drugs, patients with AIDS are living longer .

1.3. Sexually Transmitted Diseases (STDs)

Sexually transmitted diseases (STDs) will result in pain on urination (dysuria), burning urination, itching, hematuria (blood in the urine), pyuria (pus in urine) and, occasionally, “sores on the bottom.” You can ask the patient if he/she was ever diagnosed and completely treated for gonorrhea or syphilis. If there is a past history of STD, always check with the patient if he/she has been treated with antibiotics and if the treatment was completed.

Questioning the patient about STDs and HIV can be very uncomfortable and embarrassing. Ask for the presence of the symptoms and signs associated with these conditions in a very calm manner. This way, you and the patient do not feel uncomfortable about the questions asked.