HIV and Posterior Reversible Encephalopathy Syndrome (PRES)
HIV infection can cause PRES, though it is a rare complication that occurs through HIV-associated endothelial dysfunction and cerebrovascular reactivity, independent of traditional risk factors like hypertension.
Direct HIV-Mediated PRES Mechanism
HIV infection, particularly when untreated, causes endothelial dysfunction and disruption of the blood-brain barrier that can precipitate PRES even in the absence of classical risk factors 1, 2. This represents a distinct pathophysiological pathway where:
- HIV-induced endothelial damage alone may be sufficient to trigger PRES without hypertension, sepsis, or other typical precipitants 2
- The inflammatory state and cerebrovascular reactivity persist even in virologically suppressed patients on antiretroviral therapy (ART) 1
- Endothelial dysfunction may be further exacerbated by central nervous system infections in HIV-positive patients 3
Clinical Context and Risk Stratification
PRES in HIV-infected patients occurs across different disease states:
In untreated/advanced HIV:
- Direct HIV-mediated endothelial dysfunction is the primary mechanism 2, 4
- May occur with concurrent opportunistic infections (e.g., disseminated VZV) 3
- Inflammatory status predisposes to acute hypertensive crises that trigger PRES 4
In virologically suppressed patients:
- PRES can still occur despite viral suppression and immune reconstitution 1
- Persistent cerebrovascular reactivity remains an undetected risk factor 1
- Poor medication adherence (ART, antihypertensives) increases risk 5
Important Clinical Caveats
The absence of classical PRES risk factors does not exclude the diagnosis in HIV-infected patients 1. Traditional triggers like hypertension, renal failure, or immunosuppressive agents may be absent, making HIV-associated endothelial dysfunction the sole precipitant.
PRES in HIV can involve atypical locations including basal ganglia and brainstem with microhemorrhages 4, expanding beyond the typical posterior white matter distribution.
Management Approach
Treatment focuses on:
- Supportive care with aggressive management of underlying causes 3, 6
- Blood pressure control when hypertension is present
- Ensuring ART adherence in virologically suppressed patients 5
- Treating concurrent opportunistic infections if present 3
- Recognition that prognosis is generally favorable with prompt intervention, though PRES is not always reversible despite its name 5, 6
The mortality risk is substantial if unrecognized, but reversibility occurs within 72 hours with appropriate supportive management in most cases 3.