3.10.7 HIV

3.10.7 HIV

Neuropsychiatric Manifestation of Human Immunodeficiency Virus (HIV)

HIV will affect over 38 million people worldwide at the end of 2021 (WHO, 2021).

HIV is virally transmitted through bodily fluids. This allows it to be a sexually transmitted virus, but it can also be spread from mother to child (vertical transmission), or through the transfusion of tainted blood. If left untreated, the virus will keep replicating in the body and develop into a more advanced form. Once HIV affects the cells of the immune system it can lead to the development of acquired immunodeficiency syndrome (AIDS). This frequently causes a multitude of neurological issues. Within the brain, HIV mainly infects microglia and macrophages.

The virus uses receptors on T-cells to target the person’s immune system.

Even with present-day medicine, the average untreated survival time from HIV infection is 9-11 years.

Immunocompromised individuals are at risk of opportunistic infections to take hold such as:

  • Cytomegalovirus
  • Herpes simplex virus
  • Varicella zoster virus
  • Polyomavirus
  • Toxoplasmosis
  • Cryptococcus
  • Candida albicans

In addition to harm brought on by the virus itself, various side effects of HIV and AIDS, such as malignancies linked to these diseases, may potentially induce neurological issues. While seeking to slow the virus’s rapid spread, several medications for HIV and AIDS can also lead to neurological issues. The likelihood of neurological adverse effects from HIV medications can be affected by specific hereditary variables.

Central nervous system entry:

HIV-1 receptors are CD4 and CD8. CD4+ helper T lymphocytes are the main route of multiplication and entry. For HIV-1 to enter the brain it must cross the blood-brain barrier. The exact mechanism is still unclear. One accepted model is the ‘trojan horse hypothesis’ where HIV enters the central nervous system as a passenger within cells trafficked to the brain via CD4 T-cells or monocytes.

Symptoms:

Neurological issues usually don’t appear until HIV has progressed, which occurs when a person has AIDS. About 50% of AIDS-affected adults experience neurological effects from HIV. Known as HIV-associated neurocognitive disorder (HAND).

HAND is a common manifestation of HIV infection and can range from mild cognitive impairment to severe dementia. The symptoms of HAND can include memory loss, difficulty with concentration, problems with executive function (such as decision-making and planning), and a decline in motor skills. The exact mechanisms underlying HAND are not well understood, but it is thought to involve the direct effects of HIV on the brain, as well as inflammation and oxidative stress.

In addition to HAND, HIV can also cause a range of psychiatric symptoms, including depression, anxiety, and behavioural changes. These symptoms can be a direct result of the virus or a result of the chronic stress and stigma associated with living with HIV.

HIV also causes inflammation, which can harm the central nervous system, including the brain and spinal cord, and result in neuropsychiatric symptoms such as:

  • Depression
  • Short-term memory impairment
  • Poor concentration and failure to focus lead to behavioural modifications
  • Behaviour and personality changes including apathy and social withdrawal
  • Headache
  • Issues with movement (loss of movement control), such as poor coordination and trouble walking (leg weakness) (Cole et al., 2017).

Assessment and investigation:

Clinicians may choose to include the following assessments and investigations:

  • Cognitive testing
  • Cytokine and interleukin concentrations in blood and CSF
  • Neuroimaging

Important to consider investigations to rule out other causes of cognitive impairment (Nelson, 2011).

Treatment:

Antiretroviral As a strategy to control HIV infection, the management of HIV/AIDS often includes the use of various antiretroviral medications.  Antiretroviral drugs are classified into many groups that target distinct stages of the HIV life cycle. Highly active antiretroviral therapy  (HAART) is the use of numerous medicines that act on diverse viral targets. HAART reduces the patient’s total HIV burden, keeps the immune system functioning, and prevents opportunistic infections, which often result in death. HAART also prevents HIV transmission between same-sex and opposite-sex partners as long as the HIV-positive partner has an undetectable viral load. (ART):

The fundamental goal of HAART is to reduce the viral load to undetectable levels (50 copies per millilitre).  This should happen within 24 weeks of beginning therapy.  Monitoring viral load is the most important predictor of response to HAART treatment (Underwood, 2016).

References:

(1) Nelson, M., Dockrell, D. and Edwards, S. (2011). British HIV Association and British Infection Association guidelines for the treatment of opportunistic infection in HIV-seropositive individuals 2011. HIV Medicine, 12, pp.1–5. doi:10.1111/j.1468-1293.2011.00944_1.x.

(2) Underwood, J. and Winston, A. (2016). Guidelines for Evaluation and Management of Cognitive Disorders in HIV-Positive Individuals. Current HIV/AIDS Reports, 13(5), pp.235–240. doi:10.1007/s11904-016-0324-x.

(3) www.who.int. (n.d.). HIV/AIDS. [online] Available at: https://www.who.int/data/gho/data/themes/hiv-aids#:~:text=Globally%2C%2038.4%20million%20%5B33.9%E2%80%93.