Preface: Introduction to blog

This blog would be dedicated to NP Medical Biochemistry project, and we would be working on Blood-borne disease: HIV infection. Hope you enjoy^^


What is HIV? [1]

HIV or the Human Immunodeficiency Virus targets vital cells (helper T-cells, specifically CD4+ T-cells, macrophages and dendritic cells) in the human immune system thereby compromising one's ability to fight off infection. While someone may be HIV-positive (infected with HIV), the signs and syntomns of the infection may not be obvious or it may not even present any syntomns of unwell; which in the words of a virologist - HIV is a very good (elusive) virus or rather it presents an interesting set of problems. While there are therapies and drugs (High Active Antiviral Therapy HAART) that can specifically target the proliferating virus, a lot of times it just ends in empty hope; as that small window of being "cured" of the virus is but a brief respite, or a guise for the virus latency as it awaits safely within the host for another chance to start propagating. So while being infected may not affect a person in one or two day's time, it sure as hell would do a lot of damage as the AIDS becomes fully-blown, as the immune system give way to your daily interaction with a cocktail of diseases. (Perfect condition in which opportunistic infections and cancer thrives)




Signs & Syntomns of HIV infection [2]

As the HIV come out of it latency and it can start infecting the healthy cells that carry the protein CD4 (e.g macrophage , dendritic cells and CD4+ T cells). As the CD4+ T cells population dwindles due to HIV infection, the body's capability to recognize pathogens and target them also starts to fail; which enables these opportunistic pathogens that would normally elicit an immune response from the helper T-cell to bypass the screening process completely. This then increase the likelihood for opportunistic infections:

Opportunistic Infections: Brain

Cryptoccoccal Menigitis — This is a yeast-like fungus infection that usually involves the brain and lungs, although it can affect almost any organ. The fungus that causes this condition is found in soil throughout the world. It is most common in soil contaminated by bird droppings. This disease most often occurs when a person's CD4+ T cell count falls below 100 cells per cubic millimeter of blood.

HIV-related Encephalopathy — Encephalopathy is a term for diseases that alter brain function or structure, leading to problems with cognitive function, or mental processes, and memory. In people with HIV and AIDS, encephalopathy is usually caused by an infectious agent, such as a bacteria, virus or prion.

Encephalopathy most often occurs when a person's CD4+T cell count falls below 50 cells per cubic millimeter of blood. Toxoplasma-seropositive patients who have a CD4+T cell count of less than 100 cells per cubic millimeter of blood should be treated with prophylaxis to prevent developing encephalopathy.

Progressive Multifocal Leukoencephalopathy (PML) — Progressive multifocal leukoencephalopathy is a rare disorder of the nervous system caused by a common human polyomavirus, JC virus. It leads to the destruction of the myelin sheath that covers nerve cells. The myelin sheath is the fatty covering that acts as an insulator on nerve fibers in the brain. Symptoms include mental deterioration, vision loss, speech disturbances, inability to coordinate movements, paralysis and ultimately coma. In rare cases, seizures may occur.

This disease can occur when the CD4+T cell count falls below 200 cells per cubic millimeter of blood.

Toxoplasmosis — This condition occurs when a parasite infects the brain. Symptoms include confusion or delusional behavior, severe headaches, fever, seizures and coma. It can affect the eye, causing eye pain and reduced vision.

Toxoplasmosis most likely occurs when the CD4+ T cell count falls below 100 cells per cubic millimeter of blood. Preventative treatment — usually with trimethoprim-sulfamethoxazole, also called Septra and Bactrim — may be administered when the CD4+ T cell count falls below 100 cells per cubic millimeter of blood.

Opportunistic Infections: Eyes

Cytomegalovirus (CMV) — Although this virus can affect the entire body, it commonly affects the eye's retina, causing blurry vision and in severe cases, blindness. Other common symptoms include chronic diarrhea and nerve problems. It is most likely to occur when a person’s CD4+ T cell count falls below 100 cells per cubic millimeter of blood.

Opportunistic Infections: Gastrointestinal Tract

Cryptosporidiosis — This is a parasite that can cause chronic diarrhea. Other symptoms include stomach cramps, nausea, fatigue, weight loss, appetite loss, vomiting and dehydration.

This infection is difficult to treat and there is no definitive effective treatment. Symptom control and treatment of HIV are necessary.

Cytomegalovirus — Although this virus can affect the entire body, it commonly occurs in the stomach, causing fever, diarrhea and stomach pain. It most likely occurs when the CD4+ T cell count falls below 50 cells per cubic millimeter of blood.

Mycobacterium Avium Complex — This is a bacterial infection that can cause persistent fever, night sweats, fatigue, weight loss, anemia, abdominal pain, dizziness, diarrhea and weakness. The bacteria that cause this infection is found in water, dust, soil and bird droppings.

This disease most likely occurs when the CD4+T cell count falls below 50 cells per cubic millimeter of blood. Preventive treatment, usually with azithromycin, is administered when CD4+ T cells are less than 50 cells per cubic millimeter of blood.

Opportunistic Infections: Genitals

Candidiasis — Candidiasis is an infection caused by the candida fungi. Also known as a yeast infection, it's the most common HIV-related fungus infection. It can affect the entire body, but most commonly occurs in the mouth, called thrush, or vagina. An overgrowth of yeast in the vagina can cause irritation, itching, burning and thick white discharge.

Herpes Simplex — This virus causes genital herpes, which are painful blisters in the genital area, or cold sores. Severe conditions are more common in the advanced stage of AIDS.

Human Papilloma Virus (HPV) — This condition is considered the most common sexually transmitted disease (STD) in the United States. It can cause warts on the anus, cervix, esophagus, penis, urethra, vagina and vulva. Studies have shown that certain types of HPV can contribute to the development of cervical and anal cancer. Individuals with HIV and AIDS are at increased risk for developing precancerous and cancerous lesions.

Opportunistic Infections: Liver

Liver Disease — Liver disease is one of the leading causes of death among AIDS patients, especially liver disease caused by the hepatitis B and hepatitis C virus. Many drugs used in the treatment of HIV and AIDS can cause liver disease or hepatitis. It is important that patients infected with hepatitis receive treatment and follow-up care.

Opportunistic Infections: Lungs

Coccidiomycosis — This infection is caused by inhaling an infective fungus called Coccidioides immitis, found mainly in contaminated soil in the southwestern United States, Mexico, Central America and parts of South America. The lungs are most commonly affected by this infection. In severe cases, it can involve the kidneys, lymph system, brain and spleen. Symptoms include cough, weight loss and fatigue. Meningitis is a common complication when left untreated.

Histoplasmosis — This infection almost always involves the lungs, although other organs may be affected. The fungus that causes this condition is found in southern parts of the United States and South America. It is usually found in soil contaminated with bird droppings and must be inhaled to cause infection.

Signs and symptoms include high fever; weight loss; respiratory complaints; an enlarged liver, spleen, or lymph nodes; depressed production of white cells, red blood cells and platelets from the bone marrow; and life-threatening, unstable, low blood pressure.

Pneumocystis Carinii — This condition occurs when a fungus infects the lungs. Symptoms may include fever, cough, difficulty breathing, weight loss, night sweats and fatigue.

It is most likely to occur when the CD4+ T cell count falls below 200 cells per cubic millimeter of blood. Preventative treatment may be administered when the CD4+ T cell count falls below 200 cells per cubic millimeter of blood. Treatment is usually trimethoprim-sulfamethoxazole, also called Septra or Bactrim, dapsone or atovoquone.

Recurrent Pneumonia — People with AIDS are at risk for recurrent bacterial pneumonia. Bacteria can infect the lungs, which may lead to problems ranging from a mild cough to severe pneumonia. Recurrent pneumonia is most likely to occur when the CD4+ T cell count falls below 200 cells per cubic millimeter of blood.

Tuberculosis (TB) — This is a serious, and often deadly, bacterial infection that primarily infects the lungs. TB is transmitted when a person with active TB coughs or sneezes, releasing microscopic particles into the air. If inhaled, these particles may transmit the condition.

Once infected by TB, most people remain healthy and develop only latent infection. People with latent infection are neither sick nor infectious. However, they do have the potential to become sick and infectious with active TB. It can occur at any CD4+ T cell level but especially when the CD4+ T cell count falls below 350 cells per cubic millimeter of blood.

Opportunistic Infections: Lymphatic System

Non-Hodgkin's Lymphoma — Non-Hodgkin's lymphoma is a disease in which tumors develop from white blood cells in the lymphatic system. It is another common disease associated with AIDS.

Opportunistic Infections: Mouth and Throat

Candidiasis — This is the most common HIV-related fungus infection. It can affect the entire body, but most commonly occurs in the mouth (thrush) or vagina. An overgrowth of yeast causes white patches on gums, tongue or lining of the mouth, pain, difficulty in swallowing and loss of appetite. Candida in the esophagus, trachea, bronchi or lungs is AIDS defining.

Opportunistic Infections: Skin

Herpes Simplex — This virus causes cold sores or genital herpes, which are painful blisters in the genital area. Chronic herpes simplex virus (HSV) lesions and severe mucocutaneous HSV disease are common in the advanced stages of AIDS.

Kaposi's Sarcoma — This is the most common AIDS-related cancer. It causes reddish-purple lesions that usually appear on the skin. They also can appear on the lymph nodes, mouth, gastrointestinal tract and lungs.

Shingles — Shingles are caused by a reactivation of the chicken pox virus. It may cause a painful rash or blisters that follow the path of nerves.

References
[1] http://en.wikipedia.org/wiki/HIV
[2] http://www.ucsfhealth.org/conditions/aids/signs_and_symptoms.html