Opportunistic infections and Malignancy in HIV Flashcards
Define and Opportunistic Infection in relation to HIV
Opportunists: Microbes that do not (generally) cause disease in a healthy
HIV-related immunosuppression significantly increases the risk of infection due to bacteria, viruses, fungi and protozoa
HIV virus infects T-helper (CD4) cells critical to cell-mediated immunity
What are the role of CD4 T cells?
Part of cell mediated immunity
CD4 T cells interact with dendritic cells (or macrophages)
They present MHCII
They recruit/orchastrate cell mediated immunity
dendritic cells -> naiive t cells-> mature t cells
What is the natural history of T cells?
CD4 declines to less than 500 cells in a year
that equates to approx a 50 cell per year loss
NB, HIV elite controllers
Initial spike in viral load. Body reacts to the initial spike inj viral load
Then clinical latency occurs
Constitutional symptoms occur (like weight loss and fevers)
Name some of the diseases that are associated with HIV?
Bacterial-> S.pneumoniae
Vira-> HIV, Herpes simplex
PROTOZOA-> toxoplasma
fungal-> cryptococcus
misalaneous-> diarrhoea
Different infections present at different stages
CLINICAL STAGE 1: What is HIV seroconversion illness?
This is the early stage of viral infection, when the body is just releasing antibodies against HIV
- 10-60% asymptomatic
- Incubation- 2-4 weeks
- Symptoms: acute retroviral syndrome
- Flu-like illness
- (fever, fatigue, headache, muscle ache, sore throat)
- Lymphadenopathy
- Rash
- Oral and genital ulcers
- Can manifest as meningitis (headache and stiffness)
- Flu-like illness
Remember that all of these symptoms are very non-specific
What are the physical presentations of HIV SEROCONVERSION ILLNESS?
HIV Seroconversion rash
Described as a maculopapular rash (mix of raised and flattened spots)
Many viral infections could give rise to this
Rash spreads throughout the entire body
What arethe laboratory features of HIV seroconversion illness?
- •HIV VL >100,000 copies/ml
- •Transient CD4 drop (and a rise in viral load)
- •Diagnosis: reactive p24 antigen/ antibody immunoassay+ detectable viraemia (RT-PCR)
- Time to + 15-20d (ELISA)
- 10-15d (HIVVL)
- If you get HIV a week ago, then it would be too early to diagnose with ELISA
- The way HIV is diagnosed now, is through a HIV viral load
- When the viral load spikes, you get antibodies
- This may not be available in a low resource setting (in LICs)
- E.g. in SSA, they utilise clinical staging
- Time to + 15-20d (ELISA)
What are some of the infections that take place in clinical stage 2?
Bacterial pneumonia
shingles: varicella zoster
Dermatitis
Lobar pneumonia
papular enteric eruption
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Describe the pneumonia aspect of clinical stage 2
Usual agent is S.pneumoniae
Treatment: Amoxixillin/ penicillin
Prevention= vaccination
If you see lobar pneumonia in a young, sexually active person, it is worth offering HIV tests . however it is a vaccine preventable disease
Describe the shingles aspect of clinical stage 2:
Shingles is normal in the elderly becuase they are often immunocompromised
Uncommon in young people
Shingles occurs on one side of the body
If you see this in a young person, offer a HIV TEST
Runs along dermatomes
Describe some of the diseases present in clinical stage 3
Chronic diarrhoea
Candidiasis (oral and vulvovaginal). (recurrent)
Oral hairy leukoplakia
TB
Describe the chronic diarrhoea aspect of clinical stage 3
- Common in advanced HIV
- Causes:
- Cryptosporidium
- CMV
- HIV itself
- Investigation:
- Stool microscopy with special stains. Here you can observe the spores under the microscope (protozoa)
- upper and lower GI endoscopy and biopsy
Describe the candidiasis- oral and vulvovaginal (recurrent) aspect of clinical stage 3
Candida is carried in women in the lower vagina, but in everyone else, it is carried in the gut
This can cause oesophageal candida when they spread to the oesophagus
It can be a symptom of HIV however some women get this anyway due to prolongued antibiotic usage
It can also be associated with diabetes
TREATMENT: Clotramazole
Describe oral hairy leukoplakia in clinical stage 3
Caused by EBV
No treatment (except for Immune resterorative via ART)
this condition looks different to candida
Pathoneumonic sign to HIV
This EBV (epstein-bar virus) causes glandular fever
It latently infects 80% of us
Doesn’t cause a problem unless severely immunocompromised
Describe TB and HIV aspect of clinical stage 3
World wide infection
Pulmonary TB is present in clinical stage 3
Extrapulmonary TB is evident in clinical stage 4 (advanced stage of HIV infection)
It disseminates from the original source
When diagnosing someone with TB, you must also perform a HIV test
When treating TB with the 4 DRUG COMBINATION, you would wait 3-4 weeks before treating HIV
