ITM 2 The Young Adult Flashcards
What type of virus is HIV
RNA virus
Retrovirus
What is the p24 antigen
Early marker of infection in HIV
Capsid response releases p24 but over time disappears as antigens develop against it
What are nucleoside reverse transcriptase inhibitors
Zidovudine phosphorylated by intracellulae thymidine kinase to form active zidovudine 5-triphosphate
Zidovudine 5-triphosphate terminates viral DNA chain elongation via competition with TMP and incorporation into DNA
Resistance via mutations in reverse transcriptase codons
Non nucleoside reverse transcriptase inhibitors
Efavirenz
- diffuses into cell and binds adjacent to active site of reverse transcriptase, leading to conformation change to inhibit
Different site from NRTIs
What do protease inhibitors do in HIV
Virus takes over the cells and produces new viral proteins. Protease enzyme processes these
HIV viral protease is essential for infectivity
Cleaves viral polyprotein into:
- reverse transcriptase
- integrase
- protease
- structural proteins
What are fusion inhibitors
Eg enfuvirtide Similar to segment of viral glycoprotein gp41 Prevents binding of virus to host cell Given IV Very expensive
What is HAART
Highly active antiretroviral therapy
2 nucleoside transcriptase inhibitors and either
- non nucleoside transcriptase inhibitor
Or
- protease inhibitor
Or
- integrase inhibitor
When are fusion inhibitors used
When the patient has been on HAART but have not responded to it (viral load has not been reduced)
When is HIV untransmissable
When the viral load has been undetectable for 6 months
97% of patients diagnosed with HIV are virally suppressed
What is molnupiravir
Pro drug
Ribonucleoside analogue increases the number of mutations in viral RNA
Prevents replication - lethal mutagenesis
Anti coronavirus medication (first oral)
50% reduction in hospital admission
30% reduction in severe complications (for unvaccinated patients)
For patients with at least 1 risk factor
What is remdesivir
Nucleotide prodrug of an adenosine analogue
An inhibitor of the viral RNA-dependent, RNA polymerase
IV
For hospitalised patients
What is HIV
A virus spread through certain body fluids that attacks the immune system
Life long condition
Highly stigmatised
Disproportionately affects vulnerable groups
Very treatable
Pathology of HIV
HIV infects lymphocytes with CD4 receptors
HIV binds to the CD4 receptor and enters cell
Uses enzymes to make copies of itself
CD4 cell destroyed in process
Decline in CD4 cells leads to immunosuppression
Describe the primary / acute infection of HIV
Within 7-21 days HIV becomes detectable in the blood stream- acute HIV symptoms due to extremely high levels of viraemia may occur within weeks to few months of infection
- main target CD4 T helper cells - can fall considerably at this time
- fever, rash, lymphadenopathy, meningitis, rarely opportunistic infections
- by 6 months CD4 recovers to a level as viral load falls to a set point
What are the stages of HIV infection
1) seroconversion: flu like illness shortly after infection. Viral load high, no anti HIV antibodies
2) asymptomatic: stable infection, no symptoms, lasts for years. Viral load low, anti HIV antibodies, stable CD4
3) symptomatic: signs of damaged immune system, infections, tiredness, weight loss, diarrhoea, cancers etc. any viral load, low CD4
What opportunistic infections are common at a CD4 count of >500
Persistent generalised lymphadenopathy
Candidal vaginitis
What opportunistic infections are common at a CD4 count of 200-500
Bacterial pneumonia
Pulmonary TB
Herpes zoster
Oral candidiasis
What opportunistic infections are common at a CD4 count of <200
Pneumocystis jiroveci pneumonia
Miliary / extrapulmonary TB
What opportunistic infections are common at a CD4 count of <100
Candida oesophagitis
Penicillinosis
Toxoplasmosis
Cryptococcosis
What opportunistic infections are common at a CD4 count of <50
Mycobacterium avium complex
Disseminated cytomegalovirus
Side effects of anti HIV medications
GI upset: nausea, diarrhoea Rashes and allergies Renal toxicity Liver toxicity Reduced bone mineral density Lipodystrophy and weight gain Increased cardiovascular risk / blood pressure / lipids / blood sugars Peripheral neuropathy
Drug interactions in anti HIV drugs
Very common with antiretrovirals Induction or inhibition of liver metabolism Gastric pH changing absorption Divalent cations reducing absorption Additive side effects Blocking renal excretion
Why is adherence so important in HIV patients
Need high levels of drugs in the blood all the time to stop virus multiplying
Taking tablets correctly all the time
- no missed doses
- no late doses
- follow food restrictions
Management of the HIV patient
Biannual visit once established on treatment and undetectable
Viral load, clinical chemistry, haematology, lipids, HbA1c, sexual health screening
Height, weight, BP, waist circumferece
Discuss adherence, mood, partners, bone risks, contraception, vaccination
