HIV Flashcards
Factors which reduce vertical HIV transmission in pregnancy
- maternal antiretroviral therapy (zidovudine)
- caesarean section
- neonatal antiretroviral therapy (zidovudine)
- bottle feeding
CMV retinitis affects HIV patients with a CD4 count below what level?
< 50
Clinical features of CMV retinitis
‘blurred vision’
retinal haemorrhages/ necrosis on fundoscopy
Management of CMV retinitis in HIV
IV ganciclovir
alternative: IV foscarnet or cidofovir
Causes of diarrhoea in HIV
- HIV enteritis
Opportunistic infections:
- Cryptosporidium + other protozoa
- CMV
- Mycobacterium avium intracellulare
- Giardia
Below what CD4 count in HIV does Mycobacterium avium intracellulare cause infection?
< 50.
Clinical features of Mycobacterium avium intracellulare in HIV
fever
sweats
abdominal pain
diarrhoea
may be hepatomegaly and deranged LFTs
Diagnostic investigations for mycobacterium avium intracellulare
- blood cultures
- bone marrow examination
Management of mycobacterium avium intracellulare
Rifabutin
ethambutol
clarithromycin
Vaccines given to ALL HIV infected adults
Hepatitis A
Hepatitis B
Haemophilus influenzae B (Hib)
Influenza-parenteral
Japanese encephalitis
Meningococcus-MenC
Meningococcus-ACWY I
Pneumococcus-PPV23
Poliomyelitis-parenteral (IPV)
Rabies
Tetanus-Diphtheria (Td)
Vaccines given to HIV patients with CD4 counts <200
Measles, Mumps, Rubella (MMR)
Varicella
Yellow Fever
Vaccines which are contraindicated in HIV
Cholera CVD103-HgR
Influenza-intranasal
Poliomyelitis-oral (OPV)
Tuberculosis (BCG)
What viral infection causes Kaposi’s sarcoma in HIV patients?
HHV-8 (human herpes virus 8)
purple papules or plaques on the skin or mucosa (e.g. GI and respiratory tract)
Respiratory involvement may cause massive haemoptysis and pleural effusion
Kaposi’s sarcoma
Management of Kaposi’s sarcoma
radiotherapy + resection
Typical combination of drugs used in anti-retroviral therapy
3 drug combo
2 nucleoside reverse transcriptase inhibitors (NRTI)
+ protease inhibitor (PI)
OR
+ non-nucleoside reverse transcriptase inhibitor (NNRTI)
These agents prevent HIV-1 from entering and infecting immune cells
Entry inhibitors
maraviroc
enfuvirtide
Examples include:
- zidovudine
- zalcitabine
- tenofovir
Nucleoside analogue reverse transcriptase inhibitors (NRTI)
nevirapine, efavirenz
Non-nucleoside reverse transcriptase inhibitors (NNRTI)
Examples include:
- indinavir
- nelfinavir
- ritonavir
Protease inhibitors (PI)
These antivirals blocks the insertion of the viral genome into the DNA of the host cell
Integrase inhibitors
e.g. raltegravir, elvitegravir, dolutegravir
NRTI side effects
Peripheral neuropathy
NNRTI side effects
P450 enzyme interaction
Rash
Protease inhibitor side effects
diabetes
hyperlipidaemia
buffalo hump
central obesity
P450 enzyme inhibition
Common cause for cerebral lesions in HIV
Toxoplasmosis
Presentation of toxoplasmosis in HIV
Constitutional symptoms
- headache
- confusion
- drowsiness
Appearance of Toxoplasmosis on CT
single or multiple ring enhancing lesions
+/- mass effect
Management of Toxoplasmosis in HIV
sulfadiazine and pyrimethamine
Causes of viral encephalitis in HIV?
CMV
HIV itself
HSV (rare)
Viral encephalitis appearance on CT?
oedematous brain
Most common fungal infection of CNS in HIV
Cryptococcus
CSF
high opening pressure
elevated protein
reduced glucose
normally a lymphocyte predominance but in HIV white cell count many be normal
India ink test positive
CT: meningeal enhancement, cerebral oedema
meningitis is typical presentation but may occasionally cause a space-occupying lesion
Clinical features of cryptococcus infection
headache
fever
malaise
nausea/vomiting
seizures
focal neurological deficit
CSF findings in cryptococcus infection in HIV
high opening pressure
high protein
low glucose
lymphocyte predominance
India ink test positive
CT findings in cryptococcus infection
meningeal enhancement
cerebral oedema
Viral cause of Progressive multifocal leukoencephalopathy (PML)
JC virus (a polyoma DNA virus)
Pathopysiology of Progressive multifocal leukoencephalopathy
infection of oligodendrocytes
=> widespread demyelination
Symptoms of Progressive multifocal leukoencephalopathy
behavioural changes
speech/motor/visual impairment
CT / MRI findings in Progressive multifocal leukoencephalopathy
CT:
- single or multiple lesions
- no mass effect
- lesions don’t enhance.
MRI
- high-signal where demyelinating white matter lesions are seen
CT appearances in AIDS dementia complex
cortical and subcortical atrophy
Common infections in HIV if CD4 count 200-500 cells
Thrush (Candida)
Shingles (herpes zoster)
Hairy leukoplakia (EBV)
Kaposi sarcoma (HHV-8)
Common infections in HIV if CD4 count 100-200 cells
Cryptosporidiosis
Toxoplasmosis
Progressive multifocal leukoencephalopathy (JC virus)
Pneumocystis jirovecii pneumonia (PJP)
Common infections in HIV if CD4 count 50-100 cells
Aspergillosis
Oesophageal candidiasis
Cryptococcal meningitis
Primary CNS lymphoma (EBV)
Common infections in HIV if CD4 count <50
CMV retinitis
Mycobacterium avium-intracellulare
What type of organism is PJP?
unicellular eukaryote
- classified as a fungus but some consider it a protozoa
Features of PJP infection
dyspnoea
dry cough
fever
very few chest signs
Common complication of PJP which causes dyspnoea and acute chest pain
Pneumothorax
Extrapulmonary manifestations of PJP
hepatosplenomegaly
lymphadenopathy
choroid lesions
CXR findings in PJP
- bilateral interstitial pulmonary infiltrates
- lobar consolidation
- May be normal
Diagnostic investigation for PJP
- bronchoalveolar lavage
(silver stain shows characteristic cysts)
Management of PJP
co-trimoxazole
IV pentamidine in severe cases
steroids if hypoxic (reduce risk of respiratory failure)
How does HIV seroconversion typically present?
glandular fever-type illness
- sore throat
- lymphadenopathy
- malaise, myalgia, arthralgia
- maculopapular rash
- mouth ulcers
When does HIV seroconversion usually occur?
3-12 weeks after infection
Tests used to diagnose HIV
HIV antibody and HIV antigen
- most develop antibodies at 4-6 weeks but 99% do by 3 months
HIV RNA (qualitative or quantitative)
- useful for diagnosis of neonatal HIV infection and screening blood donors
What type of virus is HIV?
RNA retrovirus of the lentivirus genus (long incubation period)
Which subtype of HIV has a lower transmission rate anf slower progression to AIDS?
HIV-2
(more common in west Africa)
What types of white cells can HIV infect?
CD4 T cells
macrophages
dendritic cells
How does HIV replicate in the host?
reverse transcriptase creates dsDNA from the RNA for integration into the host cell’s genome
