HIV in critical care

Question 1

What is HIV?

Answer 1

Retrovirus affecting CD4+ helper T-lymphocytes.
Causes reduced immune surveillance and immune response to infection. This leads to increased risk of malignancy and opportunistic infection.
It can be transmitted horizontally or vertically.

Question 2

How is HIV classified?

Answer 2

Centres for Disease Control and Prevention classification:

Group 1: Acute seroconversion illness: High viral load, non-specific symptoms, 3 month period during which IgG not detectable.

Group 2: Asymptomatic infection

Group 3: Persistent generalised lymphadenopathy

Group 4: Symptomatic HIV infection: low CD4 count (<200 cells/mm3), opportunistic infection or AIDS defining illness.

Question 3

How do patients with HIV present to critical care?

Answer 3

1. Respiratory failure
   - Most common cause
   - PCP (25-50% of respiratory HIV admissions)
   - TB
2. CVS
   - IHD (atherosclerosis may be exacerbated by HAART)
   - endocarditis/myocarditis
3. Liver failure
   - co-infection with Hep B or C
   - hepatotoxicity from NRTI/NNRTI
4. GI
   - CMV colitis
5. Renal
   - HIV-associated nephropathy (HIVAN)
6. Neurological
   - Opportunisitic infections inc fungal, TB
   - lymphoma, aspregilloma, toxoplasmosis, abscesses
   - Progressive multifocal leukoencephalopathy.

Question 4

What is the prognosis HIV patients admitted to ICU?

Answer 4

Depends upon the stage of their disease and their state of immunocompromise/CD4 count.
HIV positive patients on treatment have a normal life expectancy.
Those with AIDS defining disease or infection have a poorer prognosis.

Question 5

What is PCP? How is it treated?

Answer 5

Fungal infection caused by Pneumocystis jirovecii.
Presents with breathlessness and dry cough.
Examination is unremarkable, ABG shows hypoxia, CXR shows bilateral hilar/widespread opacifications.
Antimicrobial treatment includes: Co-trimoxazole, pentamidine, primaquine, dapsone.
Steroids given early reduces need for invasive ventilation and death (in those with HIV).

Question 6

How is HIV treated?

Answer 6

Prevention
Active therapies include HAART (highly active anti-retroviral therapy):
- NRTI (nucleoside reverse transcriptase inhibitors) - lactic acidosis, hepatic steatosis.
- NNRTI (non-nucleoside reverse transcriptase inhibitors) - Hepatotoxicity
- Protease inhibitors - SJS, Dyslipidaemias
- Fusion inhibitors - GI side effects

Question 7

What are the challenges of HIV treatment on the ICU?

Answer 7

Same as in other patients with the addition of immunocompromise and HAART.

Immunocompromise:
- need to cover opportunistic infections

HAART:

• Drug delivery - most can only be given enterally
• Impaired absorption - PPIs, low gut motility, interruptions to feed.
• Dosing - Hepatic insufficiency reduces available dosing
• Drug interactions
• Toxicity complications
• should only be initiated if:
  1. AIDS defining illness
  2. CD4 <200
  3. Anticipated long ICU stay
  4. Deterioration despite optimal ITU therapy.

Question 8

What is immune reconstitution syndrome? How is it managed?

Answer 8

IRIS can occur following the initiation of HAART and recovery of the immune response results in widespread inflammatory syndrome.

Treatment involves appropriate management for the opportunistic infection, steroids and supportive management.