MISC - HIV Flashcards
Luke, 23, has had severe anal pain for a week. When you examine him: •Anus appears normal. •Too tender to insert a proctoscope. •Tender inguinal lymph nodes.
DDx?
- anal fissure,
- thrombosed external pile,
- inflammatory bowel disease confined to the rectum
- herpes simplex
What questions would you like to ask in a suspicious HIV pt?
When did you last have sex?
- Male or female partners?
- Any anal or vaginal sex without condoms?
- Partners from poorer countries? (Mainly a question for heterosexuals. Sweden = low risk, Africa or PNG = high risk)
- Have you ever injected yourself with drugs or steroids?
Tests for sexually transmitted infections
- Anal swab for PCR* for herpes simplex, Neisseria gonorrhoeae, Chlamydia trachomatis
- Throat swab for N. gonorrhoeae PCR
- First pass urine for Chlamydia trachomatis PCR
- Serology for syphilis, HIV and hepatitis A&B – consider when this should be done?
- (Treat suspected sexually-acquired proctitis for herpes, gonorrhoea and chlamydia at the initial consultation, rather than waiting for the results.)
When should you consider HIV in infections? Give (3) major groups of examples
Those that suggest impaired cell-mediated immunity
•Classical opportunistic infections (AIDS):
–eg cerebral toxoplasmosis,
–CMV retinitis,
–cryptococcal meningitis,
–Pneumocystis pneumonia,
–Mycobacterium avium complex (MAC) infections etc etc
•Atypical or severe skin or oral infections, especially if risk factors
–Shingles in a young person
–Intra-oral warts, widespread facial warts, severe anogenital warts
–severe or widespread herpes simplex,
–facial molluscum contagiosum,
–Oral candidiasis, oral hairy leukoplakia, necrotising gingivitis
•TB
What are classical opportunistic infections (AIDS)
–eg cerebral toxoplasmosis, –CMV retinitis, –cryptococcal meningitis, –Pneumocystis pneumonia, –Mycobacterium avium complex (MAC) infections etc etc
When should you also consider HIV apart from infections & anal pain?
•Cancers: Some cancers more common in HIV (lymphomas, Kaposi’s Sarcoma, anal cancer)
•Unexplained weight-loss, especially if risk factors
•Infections with same risk factors:
-Other STIs: syphilis, gonorrhoea, anal STI in men, STI acquired abroad,
-Hepatitis B or C
- High-risk exposure, high-prevalence populations eg much of Africa
- When transmission can be prevented: pregnancy, organ or blood donation, needlestick injury
What are key messages to the pt at diagnosis of HIV?
- You have HIV, not AIDS
- HIV is readily treatable, with only moderately increased risk of some diseases or complications. You may outlive your doctor.
- It should not interfere greatly with your future plans. You will need to schedule regular medical checks.
- Use condoms – may only require brief mention on day one, but safer sexual practices should be discussed in some detail when the patient is ready for this.
Describe the natural history of untreated HIV
- cells affected
- effect
- earlier stage
- AIDS defining illness common when
- HIV infects & destroys CD4+ immune cells (monocytes, macrophages, glial cells, CD4+ T lymphocytes)
- gradually CD4+ cells are depleted
- weakened cell-mediated immunity -> existing & new infections, tumour
- earlier stage (CD4 200-500 cells/uL): often asymptomatic or mild skin/oral conditions e.g. genital herpes, tinea pedis, folliculitis, warts
- AIDS defining illnesses: more common when CD4 counts less than 100. Rare now due to HAART
What questions should you ask pt at diagnosis of HIV?
- Have you donated blood/semen in the last year?
- Are any sexual partners from the last year contactable? Could you call them and recommend a test?
- Who can you talk to for support?
- It is sometimes useful to ask about symptoms of a seroconversion illness. This might give a clue to the duration of infection.
Describe HIV seroconversion illness
Febrile illness often assumed to be flu/glandular fever during the period of seroconversion (HIV antibody test converting from -ve to +ve during 3-5 weeks after transmission). Symtoms include fever, sore throat, rash, diarrhoea & weight-loss.
- Often very high levels of plasma viral RNA >10^6
- A good description of a seroconversion illness suggests infection occurred about a month previously.
How (7) do you initially assess HIV pts?
1 Work, relationships, accommodation, mood, drug/alcohol/tobacco
2 Sexual transmission risks: STI tests
3 Co-infections: TB – consider chest X ray, TB ɣ-ifn assay, Hep B & C serology
4 Examine for skin/mouth/anogenital infections, TB or cancers: Kaposi’s sarcoma on skin or palate, lymph node enlargement, (gay men: anal cancer, women: Pap smear).
5 Weight
6 CD4 T cell count
7 HIV viral load and genotype sequencing for drug-resistance mutations
Effects of CD4 amount on symptoms
> 500 = normal
500 – 200 = mild immunosuppression
Less than 200 = risk of AIDS
HIV pt presents with:
•While telling you about his travels, he pauses frequently in mid-sentence, for a breath.
•His clothes seem loose and ill-fitting.
•He quit smoking two weeks ago but this nagging cough, has if anything, become worse.
•He needs it fixed as he starts teaching on Monday at the local Catholic primary school.
•Examination: temp 37.8, some scattered crackles and wheezes – nothing too obvious, evidence of weight-loss.
•No blood tests for 18 months
Dx?
Mx?
PCP = Pneumocystis jiroveci pneumonia
cotrimoxazole (Trimethoprim/sulfamethoxazole) and starts antiretroviral therap
Principles of antiretroviral therapy (ART)
Suppress viral replication to:
a) Prevent viral infection of CD4 cells
b) Allow reconstitution of cell-mediated immunity
c) Stop reverse transcriptase generating random drug-resistant mutations
Adequate suppression requires enough potent drugs (usually three) that a person can tolerate and remember to take eg a few pills once a day.
Increased likelihood of immune reconstitution if ART started at CD4 >200 cells/μL
Lifelong viral suppression appears better than intermittent therapy even at higher CD4 counts
Discuss crucial points of Antiretroviral therapy (ART) in practice
Aim for 100% adherence (compliance) -> otherwise resistance builds very quickly and the pt has to switch all drugs.
Monitor viral load. It should fall quickly and stay less than 200 RNA copies/ml
A rising viral load while on treatment suggests non-adherence, resistance and probably both.
Beware interactions with protease-inhibitors (eg. ritonavir) and NNRTI drugs (eg. efavirenz)
