In late-stage HIV infection, the virus would have spread through the body and attacked the immune system for many years without treatment. On blood tests, the number of viral copies, or viral load (VL), will be very high, while the CD4 cells of the immune system would be very low.
When the immune system is in this weakened state, it is much easier for certain pathogens (bacterial, viral, fungal etc.) to invade and cause an infection – these types of infections are called Opportunistic Infections (OI’s). Sometimes, these infections can cause certain types of cells to become cancerous, and these are also classified as Opportunistic Infections.
What is an Opportunistic Infection?
In a healthy and normal functioning immune system, these pathogens do not usually cause infection, or they may cause very mild disease. Apart from advanced HIV infection, Opportunistic Infections may affect people who are on chemotherapy for cancer, immunosuppression for autoimmune diseases or post-organ transplant, among other conditions.
In HIV, many of these Opportunistic Infections are what we also term as “AIDS-defining illnesses” – that is, if these infections are found in someone who has HIV, we would classify them as having AIDS (Acquired Immunodeficiency Syndrome). Many of the symptoms and signs of late-stage HIV infection are due to these Opportunistic Infections rather than directly from the virus itself.
What is HIV Treatment?
HIV treatment and management consists of taking a set of correct HIV medicines to delay the control HIV, monitoring for and treating any opportunistic infections, and taking care of the patient’s general health and well being.
What are the most common Opportunistic Infections?
This is a list of some of the most common HIV-related opportunistic infections:
1) Candidiasis (Esophageal, Tracheal, Bronchial)
Also known as thrush, candida is a very common fungal organism that is found almost everywhere in the environment and can be isolated from around 30-50% of healthy people. Most of the time, it does not cause any symptoms of infection; however, in people with HIV, there can be invasive candida overgrowth in the esophagus and airways. It is often the first sign of a weakened immune system in previously undiagnosed individuals.
Caused by the fungus cryptococcus neoformans, this can infect any part of the body, but most commonly will invade the lungs (pneumonia) or the brain (abscesses).
3) Cytomegalovirus (CMV)
Caused by an intracellular virus, this infection can cause inflammation of the brain, lungs, intestines, and eyes. CMV retinitis of the eye is sight-threatening and should be treated as a medical emergency.
4) Herpes Simplex Virus (HSV)
Another common virus, Herpes Simplex Virus (HSV) can cause symptoms in people with a normal immune system as well – usually cold sores or blisters around the mouth, genital region or anus.
However, in people with a weak immune system, outbreaks tend to be more frequent, severe, and prolonged in duration, and can also invade the lungs and esophagus.
5) Mycobacterium Tuberculosis (TB) & other Mycobacterial infection
Tuberculosis (TB) would most commonly affect the lungs, but may also spread to lymph nodes, brain, kidneys, or bones. Symptoms of TB include recurrent fever, night sweats, chronic cough, and weight loss. Other mycobacteria are very commonly found in soil and around the environment, and very rarely would cause problems in healthy individuals; as Opportunistic Infections, they will usually affect the lungs but can spread throughout the body.
6) Pneumocystis Carinii Pneumonia (PCP)
Caused by a fungus pneumocystis carinii, now renamed as pneumocystis jirovecii, this infection is commonly one of the first signs of a late-stage HIV infection. Symptoms would include shortness of breath on exertion, dry cough, and high fever, and if left untreated can be deadly.
7) Salmonella septicemia
Salmonella is a common bacteria that is usually found in contaminated food or water. In healthy individuals, this may cause an acute ‘food poisoning’ with vomiting, diarrhoea, and sometimes fever. However, salmonella as an Opportunistic Infection can spread throughout the body and cause septicemia, or blood poisoning, leading to multi-organ failure and death.
This is caused by a parasite called toxoplasma gondii, which is found in the faeces of certain animals (normally cats, rodents, and birds), and can be found in undercooked red meat such as pork. It can cause infection of the lungs, eyes, liver, and brain.
9) Kaposi’s Sarcoma (KS)
This is a type of abnormal growth/tumor of connective tissue – more specifically, of the capillaries (small blood vessels). It can occur anywhere in the body, but if it arises on the skin or mucous membranes, KS will usually appear as firm reddish or purplish lumps. The cancerous changes in the cells are a result of infection by human herpesvirus 8 (HHV8),
10) Invasive cervical cancer
This is a cancer of the cervix, which is the neck of the womb, or uterus. Malignant changes can occur after infection with certain types of human papillomavirus (HPV), and all women (HIV or not) should be screened regularly with pap smears and HPV testing. It is also recommended to get the HPV vaccine (Gardasil 9), to prevent HPV infection, cervical cancer, and genital warts.
How can Opportunistic Infections be prevented?
As these infections only occur in people with a weakened immune system, the most important way to prevent them would be to treat the underlying HIV infection. Highly Active Antiretroviral Treatment (HAART) is very effective at treating HIV and ensuring the virus is adequately suppressed. With a low or undetectable viral load, the body’s immune system has time to recover – and when the CD4 cells have returned to sufficient numbers, the risk of Opportunistic Infections is lowered drastically. The earlier an HIV infection is diagnosed, the earlier treatment can be started and the better the chances of avoiding Opportunistic Infections.
For patients who are diagnosed with HIV later and have low CD4 counts at diagnosis (<500), it is important to consider Opportunistic Infections prophylaxis while we are waiting for HAART to work. This means starting patients on certain medications (e.g. antibiotics, antifungals, and/or antivirals) to prevent some of these specific infections. It may take 6-12 months for the CD4 counts to recover once HAART has been initiated; once the CD4 counts are improved, these prophylactic medications may be stopped.
Other general advice for people living with HIV would include:
- Reducing or preventing exposure to other sexually transmitted infections
- Getting vaccinated (e.g. HPV vaccine, annual flu vaccine, pneumococcal vaccine, etc.)
- Avoiding undercooked or raw foods (including eggs, meat, unpasteurized milks and cheeses, etc.)
- Avoid drinking untreated water
- Speak to your doctor about any other changes that may need to be made at home, work, or when on vacation to reduce exposure to OI’s
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