ID - HIV Flashcards
What is HIV
Human Immundeficiency Virus
Cytopathic Retrovirus
Preferentially infects CD4+ T-helper cells
Reduced immune surveillance and increased risk of infection and malignancy
Transmitted by sexual contact, blood and products, vertical from mother to baby
What is AIDS
Acquired Immunideficiency Syndrome
CD4 count of less than 200 cells/mm3 OR CD4 % < 14
Or presence of an AIDS defining illness
Classify HIV
CDC class.
Group 1- Acute seroconversion illness
Soon after infection, but many are assymptomatic
High viral loda but 3/12 where no antiHIV IgG detectable
Group 2 - Asymptomatic infection
10% get AIDS in first 3 yeras
Remainder takes a median of 10 years
Group 3 - Persistant Generalised Lymphadenopathy
Group 4 - Symptomatic HIV infection
CD4< 200cells/mm3
Opportunistic infections
Prognostic factors in ICU
Poor if:
High APACHE II
Organ failure and MV
AIDS defining illness
Sepsis plus PCP
Ways in which HIV presents to ICU
Resp failure - most common
PCP
Acute exacerbations of asthma and COPD
Bacterial pneumonia - pseudomonas
TB - prognosis worse than non HIV
CVS - IHD is more common, may be due to HAART
Endo and myocarditis more common in IVDU
Liver - co-infection with HepB/C
Nucleotide and non-nucleotide reverse transcriptase inhibitors are hepatotoxic
GI - CMV colitis cryptospiridial diarrhoea
Pancreatitis
AIDS cholnagiopathy
Renal - HIV assoc. nephropathy
Diabetic and hypertension nephropathy common
Neuro - meningoencephalitis (bacterial fungal virial or tb)
SOL - toxoplasmosis, aspergillomas, abscess, lymphoma
What is PCP
Pneumocystis pneumonia is a yeast like fungus —> pneumocystis jirovecii
Slow and indolent course —> SOB, fever, dry cough
ABG - hypoxia
CXR - diffuse granular opacities like ARDS, pneumothorax
Risk of Ptx higher with nebulised pentamadine
Diagnosis from induced sputum and BAL or lung biopsy
PCR - cannot be cultured.
Treatment of PCP
1) Co-trimaoxazole 120mg/kg/day for 2-3 week +/- IV pentamidine 4mg/kg2)
2) Primaquine and clindamicin Atovaquone Trimethoprim and dapsone
When to use steroids in PCP
Withinb 48-72 hours reduce risk of resp failure, MV, and death
Indications PaO2<9kpa
A:a gradient of >5kPa
Challenges of managing HIV on the ICU
HAART is managed on case by case basis
Involve ID
Monitor viral load
Continue HAART if taking pre ICU, and to continue all elements of it
Issues of drug delivery
What are the drug issues on ICU with HIV
Delivery - Only zidovudine is iv
Others are capsules/tablets so should go NG if not enteric coated/MR
Absorption - decreased motility, continuous feed , use of PPIs and suctioning
Dosing - liver failure reduces metabolism
Renal - imparment reduces clearenceInterations with benzos, PPIs
Toxic - side effects, SJS, IRIS
When to start HAART in ICU
AIDS definining illness
CD4<200cell/mm3
Prolonged ICU stay
Deterioration despite good icu management
What is IRIS
Immune Reconstitution Syndrome
Follows initiation of HAART
Immune function recovers and then responds to previously acquired infections
Overwhelming inflammatory response
Paradoxical worsening of clinical picture.
IF it does unmask an organism - treat.
Supportive care. Steroids if severe.
How it HIV diagnosied
Presence of anti HIV anti IgG antibodies
Are not positive for upto 12 weeks after infection
ALso viral load and p24 antigen
Drug classes for treatment
Nucleotide reverse transcriptase inhibs - Lamuvadine, zidovuddine
Non nucleuoside - Nevirapine
Protease inhibitors - Saquinavir
Fusion inhibitors - Enfurvaratide
Typical HAART regime 3 anti-retrovials usual two NRTI and protease inhib.
What do NRTI work and side effect
False nucleotide and competitive inhibitor
Lactic acidosis
Hepatic steatosis
Rhabo (zudin)
