Human immunodeficiency virus infection (HIV) Flashcards
Epidemiology in NZ
https://www.youtube.com/watch?v=wRMdEC2SyWo
3,500 people in NZ have HIV infection.
- 2,800 know they have HIV infection
- 700 who have not been tested and are unaware of their infection.
70% of people with HIV infection are MSM:
- 7% of MSM in New Zealand have HIV infection)
- 1 in 5 men with HIV do not know they have it.
Infection is much less common in heterosexuals (15%). Most have acquired infection before emigrating to NZ.
Transmission is usually through exposure to genital secretions or blood of a person whose HIV infection is not being
Transmission by injecting drug use, paid sex, or perinatal exposure, is very rare in NZ.
The incidence of HIV infection peaked in 2016, and has declined since then;
- probably due largely to the decision by Pharmac to fund PreP for MSM at high risk.
Clinical stages of HIV disease
- Acute seroconversion illness; 50% of pts
- Asymptomatic phase or persistent generalised lymphadenopathy
- often asymptomatic for several years, during which the CD4 helper gradually falls.
- leading to increasing risk of HIV-related conditions and then AIDS illnesses.
- Symptomatic:
- early (e.g. constitutional symptoms, oral candidiasis, herpes zoster)
- late (e.g. pneumocystis pneumonia, Kaposi’s sarcoma)
- advanced (e.g. CMV retinitis, cerebral lymphoma)
Main features of Primary HIV
About 50% have a primary HIV or “HIV seroconversion illness” 3 to 6 weeks after becoming infected.
develop an acute infective illness similar to glandular fever (but it can also be non-specific) within wks of acquiring the virus
The presence of mucocutaneous ulcers is very suggestive.
- fever
- lymphadenopathy
- sore throat
- lethargy
- arthralgia
- headache
- generalised rash.
Symptoms typically last about one week.
Typical common clinical presentation of HIV/AIDS
- Fever of unknown origin
- Weight loss (usually severe)
- Recurrent respiratory infections: due to opportunistic pneumonias (pneumocystis pneumonia may have abrupt or insidious onset)
- Gastrointestinal including oral cavity:
- chronic diarrhoea (many causes) with weight loss or dehydration
- oral candidiasis and oral hairy cell leukaemia
- Neurological disorders e.g.
- headache
- dementia
- ataxia
- seizures
- visual loss
- Unusual disorders e.g., toxoplasma brain abscesses
- Skin conditions such as:
- A common manifestation of the primary HIV infection is an erythematous, maculopapular rash.
- Kaposi’s sarcoma
- shingles esp. multi-dermatomal
- infections (folliculitis / viral, bacterial or fungal)
- seborrhoeic dermatitis
- recurrent oral or genital herpetic lesions
HIV-related conditions
Oral thrush
Diarrhoea
Weight loss
Recurrent respiratory infections
Skin conditions such as shingles, seborrhoeic dermatitis, recurrent oral or genital herpetic lesions, and folliculitis
Unusual neurological disorders e.g., toxoplasma brain abscesses
Consequences of infection:
1 in 2 have a brief glandular fever-like illness about 4 to 6 weeks after becoming infected.
The usual period of asymptomatic infection is about 8 years.
In the absence of Rx the onset of AIDS occurs about 8 years after acquiring infection.
Modern treatment usually;
- eliminates any risk of transmission
- allows recovery of immune function
- prevents onset of AIDS illnesses
- allowing an essentially normal life expectancy
Prognosis
The prognosis has dramatically improved since the 1980s and early 1990s
HIV is now viewed as a chronic infection with a near-normal life expectancy.
However, people with HIV infection, even when well controlled, have an increased incidence of:
- ischaemic heart disease (IHD)
- hepatitis-related diseases
- some cancers.
Assessment
- Identify whether to offer pt a test for HIV infection.
- Gain informed consent for testing.
- Ask about likely onset of infection:
- If pt is principally concerned about transmission of infection in the last 72 hours, consider urgent PEP.
- For non-occupational exposure seePEP pathway.
- For occupational exposure see Blood or Body Fluid Exposures (Needlestick Injury) pathway.
- Recent weeks
- Years
- If pt provided verbal consent, arrange HIV test.
* If likely that infection has been acquired in recent weeks, indicate this on the usual pathology request form. - Explain the process of getting test results:
Tell pt that it will probably be a few days before definitive results are available.
Advise them to make an appointment in 5 to 7 days for F2F consultation to get their results.
- Suggest that may wish to have a support person with them.
- Because many will be significantly distressed if told that they have HIV infection, it has been recommended that +ve results should not be provided by telephone.
- Assess for HIV-related conditions.
- Assess likelihood of high-risk future exposure
The screening test for HIV
The test detects antibodies to HIV and also an HIV antigen.
It is not usually +ve until approximately 3 to 4 weeks after the acquisition of infection, but will then remain +ve for life.
Initial test:
- Labtests performs HIV 1 and 2 antigen/antibody combination immunoassay.
Confirmatory test:
- LabPlus performs a second test.
Definitive -ve results are likely to be available within 24 hours, but definitive +ve results may not be available for several days.
Point of care rapid test and finger prick test is available at the New Zealand Aids Foundation
Informed consent for testing Means the patient:
- agrees to testing on the basis of understanding the testing procedures and reasons for testing
- is able to assess the personal implications of testing.
- Use clinical judgement in securing informed consent.
- It can be an opportunity to:
- find out what the pt knows about HIV
- provide resources and additional information about prevention
Diagnosis
If pts have a -ve infectious mononucleosis test, perform an HIV antigen–antibody test or HIV rapid test, which may have to be repeated in 4 wks or so if negative.
If +ve, confirm diagnosis with western blot test.
Pts invariably recover to enter a long period of good health for 5 yrs or more.
The level of immune depletion is best measured by the CD4 +ve T-lymphocyte (helper T-cell) count—the CD4 cell count.
The cut-off points for good health and severe deficiency disease appear to be 500 cells/μL and 200 cells/μL respectively.
The level determines when to initiate antiretroviral therapy (ART).
Progress of the disease can be measured with the viral load test.
Management
- Considerable psychosocial support, counselling
- Regular assessment from a non-judgmental caring GP
- The holistic approach to life is recommended
- Support groups and continuing counselling
- Medication:
- ASAP, even with CD4+ cell counts >500mL
- should be directed by a HIV specialist.
Medication:
Currently the use of three antiretroviral drugs for ART is preferred:
- usu. 2 from the NRTI class with one from either the NNRTI or the protease inhibitor group.
The HAART (highly active antiretroviral therapy) strategy is a combination of 3 (or more) agents with one or more penetrating the blood–brain barrier.
ART treatment does control HIV and allow a near-normal lifespan
Only two cases of cure have been confirmed as of early 2019.
Ongoing management
- Arrange appropriate screening:
- Screen women with HIV infection annually for cervical cancer.
- Screen MSM aged > 50 years with HIV infection annually by careful digital rectal examination for anal squamous cell carcinoma (SCC).
- Manage co-morbidities and other relevant issues:
- If indicated, aggressively manage insulin resistance and metabolic syndrome.
- Assess for CVD risk factors annually and calculate the CVD risk, especially if smoking.
- HIV infection and antiretroviral medications increase the CV risk above baseline.
- Consider starting a statin at a lower threshold and assess the risk of any drug interactions.
- Psychiatric illnesses, particularly depression, are more prevalent in HIV +ve pts. If concerns, request non-acute adult mental health assessment.
- Drug and alcohol issues.
- Social issues e.g., housing.
- Consider referral to New Zealand Aids Foundation.
- Be aware that secondary care will regularly monitor the HIV viral load but may not need to monitor the CD4 lymphocyte count (T cell counts).
- Manage antiretroviral therapy (ART):
- Consider side-effects of medications and review drug interactions with ART before commencing any new medications, including OTC.
- See The University of Liverpool – HIV Drug Interactions for up-to-date ( https://www.hiv-druginteractions.org/checker)
- Check for renal dysfunction and dental problems.
- Ensure vaccinations are up to date as per the New Zealand Immunisation Schedule. Include:
- hepatitis B
- HPV – encourage all men who have sex with men to have an HPV vaccination.
- influenza
- pneumococcal – Prevenar is subsidised for 4 doses in immunocompromised patients.
- meningococcal vaccine – funded for up to 3 doses plus booster doses (as appropriate).
- A CD4 count of
the recommended testing interval
The earliest time that the HIV enzyme immunoassay (EIA) will become reactive is around 3 to 4 weeks after infection.
For a person with a specific potential risk, arrange an early test at about 4 weeks post-risk.
If the result is negative, do another HIV test at 3 months post-risk before reassuring the patient that they are not infected.
