What are the causes of altered mental status in a patient with Human Immunodeficiency Virus (HIV)?

From the Guidelines

Altered sensorium in HIV patients is most commonly caused by a combination of direct HIV effects on the brain, comorbidities, and medication effects, as highlighted in the 2023 study published in Nature Reviews Neurology 1. The causes of altered sensorium in HIV patients can be multifactorial, including direct effects of HIV on the brain, referred to as HIV-associated brain injury (HABI), as well as other comorbidities and medication effects. According to the study, HABI can result from various pathological mechanisms, including persistent immune activation, blood–brain barrier dysfunction, and direct virus-induced neurotoxicity 1. Some key points to consider when evaluating an HIV patient with altered sensorium include:

• Opportunistic infections of the central nervous system, such as cryptococcal meningitis and toxoplasmosis, which can cause altered mental status
• HIV-associated neurocognitive disorders (HAND), which can range from mild cognitive impairment to severe HIV-associated dementia
• Primary CNS lymphoma, a malignancy more common in HIV patients, which may present with confusion and altered consciousness
• Metabolic derangements, such as hypoglycemia, electrolyte imbalances, and uremia, which can contribute to altered sensorium
• Medication side effects from antiretrovirals or treatments for opportunistic infections, which may cause neurological symptoms
• Substance abuse and psychiatric conditions, including depression and psychosis, which are more common in HIV patients and may present with altered mental status. As recommended by the 2023 study, a classification of cognitive impairment in people living with HIV should encompass all potential causes of brain injury, regardless of whether HABI is the cause or even a contributing factor in any given case 1.

From the Research

Causes of Altered Sensorium in HIV Patients

• Altered mental status (AMS) in HIV-infected patients can be caused by various factors, including the effects of HIV itself, immune dysfunction, associated systemic illness, comorbid psychiatric disorders, and complicated medication regimens 2
• Central nervous system (CNS) opportunistic infections (OIs) and HIV-associated dementia are also potential causes of altered sensorium in HIV patients 2
• Toxoplasma encephalitis is a common opportunistic infection of the CNS in patients with AIDS, and its treatment with sulfadiazine and pyrimethamine can lead to complications such as sulfadiazine-induced crystalluria 3, 4
• Immune reconstitution events developing in the early weeks and months after initiating antiretroviral therapy (ART) may also affect the brain and cause altered sensorium in HIV patients 2
• Other potential causes of altered sensorium in HIV patients include hypoglycemia, hyponatremia, and hepatic encephalopathy, as well as structural neurological abnormalities such as cerebral vasculitis and hypoxic-ischemic brain injury 5

Opportunistic Infections and Altered Sensorium

• Opportunistic infections (OIs) continue to be a cause of morbidity and mortality in HIV-infected patients, despite the advances in antiretroviral therapy 6
• OIs often arise due to severe immunosuppression resulting from poor adherence to antiretroviral therapy, failure of antiretroviral therapy, or unawareness of HIV infection by patients whose first clinical manifestation of AIDS is an OI 6
• Prevention and treatment of OIs are crucial in managing altered sensorium in HIV patients, and may involve the use of antimicrobial agents and other therapies 6