HIV I Flashcards by Veronica Haughey

What is HIV?

Retrovirus that causes AIDS = leads to opportunistic infections and AIDS related cancers

How well did you know this?

Not at all

Perfectly

What is the single highest predictor of mortality in HIV?

AIDS related complications

How well did you know this?

Not at all

Perfectly

What is the life expectancy of people with treated HIV?

Near normal life expectancy

How well did you know this?

Not at all

Perfectly

What are the types of HIV?

HIV-1 = group M responsible for global pandemic 
HIV-2 = less virulent

How well did you know this?

Not at all

Perfectly

What are the targets of HIV?

CD4+ receptors

How well did you know this?

Not at all

Perfectly

What is CD4?

Glycoprotein found on surface of T helper cells, dendritic cells, macrophages and microglial cells

How well did you know this?

Not at all

Perfectly

What are CD4+ T helper cells essential for?

Induction of adaptive immune response = recognition of MHC II, activation of B cells and CD8+ T cells, cytokine release

How well did you know this?

Not at all

Perfectly

What are the normal CD4+ levels?

500-1600 cells/cubic mm = opportunistic infection risk if <200 cells/cubic mm

How well did you know this?

Not at all

Perfectly

How does HIV affect the immune response?

Sequesters cells in lymphoid tissues 
Reduces proliferation of CD4+ cells 
Reduces CD8+ T cell activation
Reduction in antibody class switching
Chronic immune activation

How well did you know this?

Not at all

Perfectly

What does the sequestering of cells in lymphoid tissues have?

Reduces circulating CD4+ cells

How well did you know this?

Not at all

Perfectly

What effect does reduced CD8+ T cell activation have?

Dysregulated cytokine expression

Increased susceptibility to viral infections

How well did you know this?

Not at all

Perfectly

How does HIV replicate?

Rapid replication in very early and very late infection = new generation every 6-12 hours

How well did you know this?

Not at all

Perfectly

What is the average time till death in untreated HIV?

9-11 years

How well did you know this?

Not at all

Perfectly

How does HIV infection become established?

Infection of mucosal CD4 cell = Langerhans and dendritic cells
Transport to regional lymph nodes
Infection established within 3 days of entry

How well did you know this?

Not at all

Perfectly

How long does it take primary HIV infection to present?

Onset 2-4 weeks after infection= up to 80% present with symptoms, very high risk of transmission

How well did you know this?

Not at all

Perfectly

What are the symptoms of primary HIV infection?

Fever, maculopapular rash more marked on trunk, myalgia, pharyngitis, headache/aseptic meningitis

How well did you know this?

Not at all

Perfectly

What are some features of asymptomatic HIV infection?

Ongoing viral replication, CD4 count depletion and immune activation
Risk of onward transmission if remains untreated

How well did you know this?

Not at all

Perfectly

What are opportunistic infections?

Infection caused by a pathogen that doesn’t normally produce a disease in a healthy individual

How well did you know this?

Not at all

Perfectly

What is pneumocystis pneumonia?

Pneumocystis jiroveci infection = occurs if CD4 <200

How well did you know this?

Not at all

Perfectly

What are the symptoms of pneumocystis pneumonia?

Insidious onset SOB, dry cough and exercise desaturation

How well did you know this?

Not at all

Perfectly

What does a CXR of pneumocystis pneumonia show?

May be normal

Can show interstitial infiltrates and reticulonodular markings

How well did you know this?

Not at all

Perfectly

How is pneumocystis pneumonia diagnosed?

BAL and immunofluorescence +/- PCR

How well did you know this?

Not at all

Perfectly

What is the treatment for pneumocystis pneumonia?

High dose co-trimoxazole (+/- steroids)

Prophylaxis with low dose co-trimoxazole

How well did you know this?

Not at all

Perfectly

What is an example of an opportunistic infection that shows epidemiological synergy with HIV?

Tuberculosis

How well did you know this?

Not at all

Perfectly

What causes cerebral toxoplasmosis?

Toxoplasma gondii infection = occurs when CD4 threshold <150

What does a reactivation of cerebral toxoplasmosis cause?

Multiple cerebral abscesses

What are the symptoms of cerebral toxoplasmosis?

Headache, fever, focal neurology, seizures, reduced consciousness, raised ICP

What causes cytomegalovirus?

Reactivation of latent CMV infection = due to retinitis, colitis or oesophagitis Occurs when CD4 threshold <50

What are the symptoms of cytomegalovirus?

Reduced visual acuity, floaters, abdominal pain, PR bleeding, diarrhoea

What should all patients with a CD4 threshold <50 receive?

Ophthalmic screening

What are some skin infections that can occur in HIV?

Herpes zoster = multidermatomal, recurrent Herpes simplex = hypertrophic, aciclovir resistant HPV = extensive, recalatriant, dysplastic Penicillinosis and histoplasmosis

What is HIV associated neurocognitive impairment?

HIV-1 infection = reduced short term memory +/- motor dysfunction

What causes progressive multifocal leukoencephalopathy?

Reactivation of latent John Cunningham Virus = occurs when CD4 threshold <100

What are the symptoms of progressive multifocal leukoencephalopathy?

Rapidly progresses = focal neurology, confusion, personality change

What are some neurological presentations of HIV?

Distal sensory polyneuropathy, mononeuritis multiplex, vacuolar myelopathy, aseptic meningitis, GB syndrome, viral meningitis, cryptococcal meningitis, neurosyphilis

What are some aetiologies of HIV associated wasting?

Metabolic = chronic immune activation | Anorexia, malabsorption, hypogonadism

What are some examples of AIDS related cancers?

Kaposi's sarcoma, non-Hodgkin's lymphoma, cervical cancers

What causes Kaposi's sarcoma?

Human Herpes virus (HHV) 8 = causes vascular tumour May be cutaneous, mucosal or visceral (pulmonary, GI)

What is the treatment of Kaposi's sarcoma?

HAART, local therapies, systemic chemotherapy

What are some examples of non-Hodgkin's lymphomas?

Burkitt's lymphoma, primary CNS lymphoma

What causes non-Hodgkin's lymphomas?

Epstein Barr virus = same diagnosis and treatment as for HIV negative patients (add HAART)

What are the symptoms of non-Hodgkin's lymphomas?

More advanced B symptoms, bone marrow involvement, extranodal disease, CNS involvement

What causes cervical cancers?

Persistent HPV infection = test for HIV in all complicated HPV cases Rapid progression to severe dysplasia and invasive disease

What are some non-opportunistic infections and other conditions that can occur in HIV?

Mucosal candidiasis, seborrhoeic dermatitis, diarrhoea, fatigue, worsening psoriasis, lymphadenopathy, parotitis, STIs, hepatitis B or C

What are some haematological conditions that can occur in HIV?

Anaemia affects up to 90% | Thrombocytopenia occurs when CD4 is 300-600

How common is sexual transmission of HIV?

Accounts for 95% of new infections in the UK

What are some factors that increase risk of sexual transmission of HIV?

Anoreceptive sex, trauma, genital ulceration, concurrent STI

What causes parenteral transmission?

Injection drug use = accounts for 2% of new diagnoses in the UK (quite uncommon) Infected blood products or iatrogenic

When can mother to child transmission occur?

In utero, during delivery or via breast feeding

What is the risk of mother to child transmission occurring?

1 in 4 at-risk babies will become infected | Risk <0.1% when viral load undetected at delivery

What is the prognosis of "congenital" HIV?

1 in 3 HIV positive babies will die before their first birthday if untreated

What is the prevalence of HIV in the UK?

1.6/1000 in people >= age 15

What is the prevalence of HIV in different risk groups?

Male/male sex = 1:17 Heterosexuals age 15-44 = 1:1000 IV drug users aged 15-44 = 1:263

How common is undiagnosed HIV?

7% of people living with HIV in UK are undiagnosed | Heterosexual men are most likely to be undiagnosed

Where is universal HIV testing done?

In high prevalence areas (>0.2%) = recommended to all general medical admissions and all new patients registering at GP

Where are some places that opt out HIV testing is done?

Abortion services, GUM clinics, drug dependency services, antenatal services, assisted conception services

What are some high risk groups that should be offered HIV testing?

Gay men and female partners of bisexual men People who inject drugs Partners of people living with HIV Adults and children from endemic areas Sexual partners from endemic areas History of iatrogenic exposure in endemic area

What are some areas of high prevalence?

Sub-Saharan Africa, Caribbean, Thailand

When is it acceptable to test for HIV on clinical grounds?

When HIV falls within the differential diagnoses

What are some features of taking an HIV test?

Document consent or refusal = request via ICE | Obtain venous sampling for serology

How should testing for HIV be done in a patient who is incapacitated?

Only test if in patient's best interests Consent from relative not needed Wait until patient regains capacity of safe to do so

What are some features of third generation HIV antibody tests?

HIV-1 and HIV-2 antibody = detect IgG and IgM Very sensitive in established infection Window period of 20-25 days

What are some features of fourth generation HIV antibody tests?

Combined antigen and antibody (p24) | Shortens window period to 14-28 days

What are some features of a rapid HIV test (POCT)?

Fingerprick blood sample or saliva Results within 20-30 mins Third or fourth generation

What are the advantages of a rapid HIV test (POCT)?

Simple to use and no lab required No venepuncture needed Reduce follow up and good sensitivity

What are the disadvantages of a rapid HIV test (POCT)?

Expensive (£10) and difficult to quality control Poor predictive value in low prevalence settings Not suitable for high volume Unreliable in early infection

HIV I Flashcards

(66 cards)