Clinical aspect of HIV Flashcards
The HIV - CD4 curve
Primary infection drives the CD4 count down.
At the same time the virus replicates so viral RNA increases.
This is the acute HIV syndrome (wide dissemination of virus - seeding of lymphoid organs).
Followed by a clinical latency in which the CD4 cells show a slight increase then drop.
Viral load is increasing so constitutional symptoms present - so chronic infection is now set.
Years later - opportunistic disease and eventually death.
What are the two markers used to monitor HIV infection?
CD4 cell count and HIV viral load.
Signs and symptoms of acute (primary) HIV infection?
Fever, sore throat, headache
Mouth ulcers
Mild lymphadenopathy
Diffuse symmetrical maculopapular rash (raised red lumps)
Differential diagnosis of symmetrical maculopapular rash?
HIV involves the whole body (including face, palms and soles)
Secondary syphilis - rash involves the palms and soles.
What would the antigen test show in acute infection?
Positive - detects circulating AG attached to virus.
What are the non specific symptoms of acute HIV?
Fever*
Sore throat*
Myalgia*
Rash*
Vomiting + diarrhoea
Headache
Lymphadenopathy
Weight loss
In a patient with fever, rash and non-specific symptoms what we need to consider?
Ask about sexual history.
Think of HIV seroconversion.
What is HIV seroconversion?
Seroconversion is a sign that the immune system is reacting to the presence of the virus in the body. It’s also the point at which the body produces antibodies to HIV. Once seroconversion has happened, an HIV test will detect antibodies and give a positive result.
Clinical latency
No symptoms
Persistent Generalised Lymphadenopathy (enlarged lymph nodes involving at least 2 areas of the body for at least 3 months).
~8 years
Accidental finding with screening (antenatal, sexual health)
Shingles and HIV
Reactivation of chickenpox virus (varicella zoster virus)
Occurs in a dermatomal area
In HIV usually more severe and can be multidermatomal
Shingles USUALLY occurs in the elderly, so if you ever see someone outside of the expected age bracket do a HIV test!
Candida infection
Candida (or thrush) is a fungal infection that is relatively common.
Particularly in the mouth or female genital tract.
Thrush that occurs in the mouth without another explanation (ie recent antibiotics, or steroid inhaler) should make you think about doing a HIV test
You wouldn’t expect an otherwise healthy person to develop recurrent thrush or thrush that is difficult to treat
Candida can also be invasive (eg oesophageal, bronchial, bloodstream, CNS) is v unusual and usually associated with immunosuppression
Oral hairy leukoplakia
Can look similar to thrush but cant be scraped off
Caused by EBV (Epstein Barr virus- the same virus that causes glandular fever)
Should make you think about doing a HIV test
Molluscum contagiosum
Caused by a strain of the poxvirus
Common in children, unusual in adults
5-18% of untreated PLWH develop these lesions
Think about ordering an HIV test when faced in a common problem:
In an unexpected patient.
That is recurring.
That has no clear underlying cause.
AIDS
CD4 <200
PCP
Pneumocystis Pneumonia
Fungal pneumonia (Pneumocystis jirovecii)
Fevers, SOB, dry cough, pleuritic chest pain, exertional drop in O2 sat.
This is the most common AIDS defining illness.
What is the key feature of PCP?
An exertional drop in oxygen saturations. This can literally be done by getting the patient to walk up and down the corridor, checking the sats before and after.
There isn’t a diagnostic cut off as such, but a decent enough drop should raise your suspicions.
What are the additional investigations of PCP?
An ABG is important to assess for the severity of the PCP and will help determine the treatment.
To diagnose, get an induced sputum- patient inhales nebulised saline to acquire sputum (as usually a dry cough!). A normal sputum is not sufficient, it needs to be a “deep” sample.
Sent for polymerase chain reaction (PCR) for pneumocystis detection.
PCP findings on X-ray
Can be normal
If abnormal = variable findings, sometimes there is a pneumothorax (collapsed lung)(Classically bilateral interstitial changes in perihilar areas)
First line treatment of PCP
Co-trimoxazole
(2 ABX = trimethoprim and sulfamethoxazole).
