HIV/AIDS

Opportunistic Infections in Patients with HIV/AIDS

  • In patients with Acquired Immunodeficiency Syndrome (AIDS), impaired cell-mediated immunity causes various infections and malignancies to behave more aggressively than in immunocompetent individuals.

  • Common clinical observations for these aggressive behaviors include:

    • Rapid progression of disease.

    • Diffuse pulmonary infiltrates visible on chest imaging.

    • Disseminated (widespread) disease involving multiple organ systems.

Specific Bacterial and Fungal Opportunistic Infections

  • Tuberculosis (TB):

    • Patients with AIDS are highly susceptible to developing tuberculosis due to impaired immune function.

    • Active tuberculosis in these patients typically results from the reactivation of a previous latent infection.

  • Candidiasis:

    • This is an opportunistic fungal infection common in AIDS patients.

    • Oral Thrush: Presents as white plaques on the buccal mucosa or the tongue. The presence of oral thrush in an HIV-infected patient is an indicator of progression to AIDS.

    • Esophagitis: Involvement of the esophagus causes significant difficulty swallowing (dysphagia), along with pain and a burning sensation that intensifies during swallowing.

    • Vaginal Candidiasis: In women with AIDS, vaginal yeast infections occur frequently and are often recurrent.

  • Mycobacterium avium complex (MAC):

    • Typically occurs late in the disease course when CD4 cell counts fall below 50 mm−350\,mm^{-3}.

    • MAC is more common in women than in men.

    • The infection is caused by organisms found in food, water, and soil.

    • It is a primary cause of wasting syndrome.

    • Nearly every organ can be infected; most patients with MAC develop disseminated disease.

    • Manifestations: Chills, fever, weakness, night sweats, abdominal pain, diarrhea, and significant weight loss.

Viral Infections in AIDS

  • Herpesvirus Infections:

    • These are common and frequently severe in patients with AIDS.

  • Cytomegalovirus (CMV):

    • CMV infection can affect multiple sites:

      • Retina: Leads to retinitis and permanent vision loss.

      • Gastrointestinal (GI) Tract: Leads to esophagitis and colitis.

      • Lungs: Leads to pneumonitis.

  • Herpes Simplex Virus (HSV):

    • Characterized by severe mucocutaneous lesions.

    • Disseminated infection can also occur.

  • Herpes Zoster:

    • May become disseminated throughout the body in AIDS patients.

Central Nervous System (CNS) and Gastrointestinal (GI) Infections

  • Toxoplasmosis:

    • Presentation: Encephalitis (inflammation and swelling of the brain) and intracerebral mass lesions.

    • Symptoms: Mental status changes, focal neurologic deficits, and seizures.

  • Cryptococcosis:

    • A fungal infection caused by the fungus Cryptococcus.

    • Presentation: Meningitis and disseminated disease.

    • Common Organ Involved: The lungs are frequently affected.

  • Cryptosporidiosis:

    • Caused by protozoan parasites.

    • This infection is a major cause of prolonged, severe diarrhea in AIDS patients.

  • Salmonella Infection (Salmonellosis):

    • A common bacterial cause of diarrhea in this population.

Gynecologic Infections and Management

  • Pelvic Inflammatory Disease (PID):

    • Women with AIDS experience a higher incidence of PID.

    • While caused by the same pathogens as HIV-negative women, the disease course is significantly more severe.

    • Management: Often requires hospitalization; intravenous (IV) antibiotics are frequently necessary.

Secondary Cancers and Malignancies

  • As cell-mediated immune function declines, the risk of malignancy increases.

  • Kaposi Sarcoma (KS):

    • The most common cancer associated with HIV/AIDS, appearing in the late stages.

    • Can progress slowly or rapidly with an average survival time of approximately 18 months18\,\text{months}.

    • Cause: Associated with Kaposi Sarcoma-Associated Herpesvirus, also known as Human Herpesvirus 8 (HHV-8).

    • Transmission: Mainly through sexual contact; also reported among injection drug users.

    • Higher-Risk Groups: Men who have sex with men (MSM), women who have sex with infected men, and organ transplant recipients.

    • Pathophysiology: Arises from cells lining the lymph vessels and small blood vessels.

    • Manifestations:

      • Skin lesions are common; in early disease, they are usually painless.

      • In progressive disease, lesions may become painful.

      • Visceral involvement occurs in the GI tract, lungs, and lymphatic system.

      • Tumors may obstruct organ function or cause bleeding.

      • Pulmonary Involvement: If the lungs are affected, there is severe impairment of gas exchange and a risk of pulmonary hemorrhage.

  • Lymphomas:

    • Two specific types are common: Non-Hodgkin lymphoma (including Burkitt lymphoma) and primary lymphoma of the CNS (starting in the brain and spinal cord).

    • Hodgkin lymphoma occurs five times more frequently in HIV-infected individuals.

    • Common sites for lymphoma include the CNS, bone marrow, GI tract, liver, skin, and mucous membranes.

    • Characterized by rapid growth and spread.

    • Early Symptoms: Headache and changes in mental status.

  • Cervical Cancer:

    • Cervical dysplasia is common and tends to be aggressive in women with HIV.

    • Many women with HIV and cervical cancer die from the cancer itself rather than from AIDS.

    • Recommendations: Papanicolaou (PAP) test every 6 months6\,\text{months}; aggressive treatment of dysplasia and colposcopy are required.

Diagnostic and Monitoring Tests

  • Rapid Screening Tests:

    • Assess oral secretions or urine for HIV antibodies using an ELISA technique.

    • Administered to women in labor with unknown HIV status and little to no prenatal care.

  • Non-Rapid Screening Tests:

    • Uses a blood sample to detect HIV antibodies; used to confirm positive results from rapid screening.

  • HIV Viral Load Test:

    • Measures the amount of actively replicating HIV in the blood.

    • Used to monitor disease progression and response to antiretroviral therapy (ART).

    • A viral load greater than 5,000−10,000 copies/mL5,000-10,000\,copies/mL may indicate a need for initiating or changing treatment.

  • CD4 Cell Count:

    • The most widely used test to monitor HIV progression and guide treatment.

    • Reflects the degree of immunodeficiency.

    • AIDS Definition: Diagnosed when CD4 count is $< 200\,cells/mm^{3}$ or when the CD4 percentage is $< 14\%$.

    • Monitoring Frequency: Recommended every 3−6 months3-6\,\text{months}.

  • Antiretroviral Resistance Testing:

    • Used to choose the most effective drugs and achieve maximum viral suppression.

    • Genotypic Assay (Preferred): Faster, lower cost, and more sensitive for detecting resistance mutations.

    • Phenotypic Assay: Measures how well drugs inhibit HIV replication outside the body.

  • Additional Diagnostic Tests:

    • Complete Blood Count (CBC): Used to detect anemia, leukopenia, lymphopenia, and thrombocytopenia.

    • Tuberculin Skin Test: Screens for possible tuberculosis.

    • MRI of the Brain: Used specifically to identify CNS lymphomas.

    • Cultures and Serologic Tests: Used for diagnosing infections like Pneumocystis Pneumonia (PJP) and Toxoplasmosis.

    • Pap Test Guidelines: Begin within 1 year1\,\text{year} of sexual activity or by age 2121. Women aged 21−2921-29 should be screened at HIV diagnosis and then every 6−12 months6-12\,\text{months} if normal. After three normal tests, screening can occur every 3 years3\,\text{years}, continuing throughout life.

HIV and Pregnancy

  • Vertical Transmission: Infants can acquire HIV from the mother via the placenta, smoking, drug use, STIs, sexual intercourse with multiple partners during pregnancy, and exposure to blood and amniotic fluid.

  • Management during Pregnancy:

    • Pregnancy does not accelerate the course of HIV/AIDS in asymptomatic women.

    • Most HIV medications are safe during pregnancy.

    • Contraindications: Teratogenic drugs like Efavirenz should be avoided.

    • If not already on treatment, doctors test for antiviral drug resistance to choose the best regimen.

    • Monitoring: Assessments for STIs, TB, cervical dysplasia, pneumonia, and influenza. Vaccines for Hepatitis B, pneumonia, and influenza are recommended.

    • Fetal Surveillance: Weekly nonstress tests starting at 32 weeks32\,\text{weeks}, regular ultrasounds for intrauterine growth restriction, and biophysical profiles.

    • Safety: Invasive procedures (e.g., amniocentesis) should be avoided to prevent transmission.

  • Labor and Delivery:

    • Delivery by Cesarean section (C-section) reduces transmission risk.

    • Scheduled C-section: Recommended at 38 weeks38\,\text{weeks} for women with high viral loads, performed before the rupture of membranes.

    • Zidovudine (AZT): Given via IV during labor to all HIV-positive pregnant women to reduce newborn transmission risk.

  • Newborn Considerations:

    • Babies may test positive for HIV antibodies at birth due to passive immunity from the mother; this does not confirm infection.

    • Post-birth treatment: Infants receive antiretroviral medication immediately to prevent the virus from taking hold.

    • Breastfeeding: In developed countries, the CDC recommends HIV-positive mothers SHOULD NOT breastfeed to reduce transmission risk.

  • Postpartum Care:

    • Closely monitor for hemorrhage, infection, poor wound healing, and reproductive tract infections.

    • Follow-up care with an HIV specialist is essential.

Pediatric HIV and AIDS

  • Neonatal Care:

    • Infants exposed to HIV receive antiretroviral (ART) medicine for 6 weeks6\,\text{weeks}.

    • Low-risk infants: Receive AZT (Zidovudine) alone.

    • High-risk infants: Receive a two-drug regimen or full HIV treatment.

    • If the infant tests HIV-positive, AZT is stopped and multidrug therapy is initiated.

    • PJP Prevention: Starts at 4−6 weeks4-6\,\text{weeks} of age.

  • Testing in Infants:

    • Standard antibody tests (ELISA/Western blot) are ineffective for infants under 18 months18\,\text{months} due to maternal antibodies.

    • Preferred Tests: HIV DNA PCR or HIV RNA tests.

  • Disease Progression in Children:

    • Congenital infection typically progresses faster; symptoms often appear within the first year.

    • Early Signs: Enlarged liver/spleen, swollen lymph nodes, frequent respiratory infections, runny nose, pneumonia, diarrhea, weight loss, urinary infections, oral thrush (candida), and delayed development.

    • Chronic Issues: Wasting syndrome, eczema/dermatitis, heart and kidney problems, and frequent ear/sinus infections.

    • Neurological Impact: Encephalopathy (brain damage), loss of motor skills, and intellectual disabilities.

  • Vaccination Guidelines:

    • Safe (Inactivated): DTaP, Polio, Hib, Hepatitis B, Pneumococcal, and seasonal Flu shot.

    • Live Vaccines (MMR & Varicella): MMR is given at 12 months12\,\text{months} unless severely immunocompromised. Varicella can be given if symptoms are mild.

    • Precautions: Do NOT use the MMRV combination vaccine. If exposed to chickenpox, the child may need immune globulin within 96 hours96\,\text{hours}; if exposed to measles, they may need a vaccine within 72 hours72\,\text{hours}.

Pediatric HIV Categories

  • Category N (No symptoms): HIV positive but feels healthy; no HIV-related illness; growth is normal.

  • Category A (Mild symptoms): Minor frequent health problems such as swollen lymph nodes, enlarged liver/spleen, skin rashes, recurrent upper respiratory infections, or ear/sinus infections.

  • Category B (Moderate symptoms): Increased illness including thrush, pneumonia, persistent fever, blood problems (anemia), and heart or kidney issues.

  • Category C (Severe symptoms/AIDS-defining): Severely damaged immune system characterized by repeated serious infections, encephalopathy, cancers (lymphoma/KS), and severe wasting syndrome.