Infectious Diseases Flashcards

1
Q

TB risk factors

A
  • HIV
  • immunosuppression
  • overcrowed living
  • ethnic minorities
  • malnutrition
  • IVDU
  • chronic lung disease
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2
Q

TB pulmonary presentation

A
  • constitutional symptoms (weight loss, night sweats, fatigue, fever and chills)
  • lymphadenopathy
  • Cough ± haemoptysis
  • SOB
  • chest pain
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3
Q

Extra-pulmonary symptoms of TB

A

Neuro: meningisms
Opthalmology: blurred vision, red eyes
GU: dysuria, haematuria
GI: abdo pain, abdo mass
rheum: arthritis
osteo: osteomyelitis

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4
Q

How is TB diagnosed

A
  • Sputum sample alcohol and acid fast bacilli (AAFB)
  • Rapid PCR - immediate confirmation of species and early implication of rifampicin sensitivity
  • Nucleic acid amplification tests (NAAT) rapid diagnosis of mycobacterium complex
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5
Q

What is the management of TB

A

Rifampicin 6/12 *red urine, CI OC*
Isoniazid 6/12 *perupheral neuropathy*
Pyrazinamide 2/12 *liver toxicity*
Ethambutol 2/12 *optic neuritis*

Contact screening

  • mantoux test or interferon gamma release assay
  • if +ve -> CXR
  • if -ve 3/12 prophylaxis
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6
Q

what is multi-drug resistant TB

A

TB that is resistant to at least izoniazid and rifampicin normally due to poor compliance or incomplete courses

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7
Q

how is multi-drug resistant TB managed

A

combo of 5-8 drugs for up to 2 years

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8
Q

HIV transmission

A
  • sexual
  • vertical
    • untreated risk 25-40%
    • treated risk <1%
    • C-section if mother has detectable viral load at birth
  • needles
  • blood products
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9
Q

HIV pathology

A

*RNA retrovirus*

  1. virus becomes part of host cell
  2. transcriptase enzyme transcripts RNA-> DNA
  3. Integrase integrates virus DNA into hosts
  4. host cells produces/releases virons (cleaved by protease)
  5. Virons infect any cells with CD4 receptor by binding with GP120 glycoprotein
  6. CD4 receptor cells now release virons
  7. infection progressed, CD4 cells destroyed, reduced host immune system
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10
Q

Which cells have CD4 receptors?

A

T cells, macrophages, monocytes, neurons

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11
Q

How is HIV diagnosed?

A
  • serology for antibodies and antigens at 4 weeks (2-3 weeks where tests will be -ve because no Ab response yet)
  • P24 antigen
  • IgG and IgM
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12
Q

HIV monitoring

A

CD4 normal range 450-1600

Viral Load = quantity of virus in serum
Undetectable VL = Untransmittable disease

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13
Q

HIV Management

A

2 NRTI + NNRTI OR PI

NRTI (nucleoside reverse transcriptase inhib)- zidovudine, abacavir

NNRTI (non-NRTI)- nevirapine, etravirine

PI (protease inhib)- indinavir, lopinavir

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14
Q

HIV prophylaxis

A

PrEP - pre exposure prophylaxis

  • Truvada
  • daily or when needed 12 hours before sex

PEP - post exposure prophylaxis

  • Truvada
  • given to pt after high risk exposure for 4 weeks
  • follow up test
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15
Q

What is truvada

A

tenofovir and emtricitabine

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16
Q

When does a person have AIDS

A

when their CD4 count is less than 200 or presence of an aids defining condition

17
Q

AIDS defining conditions

A

Resp: TB, PCP

Gastro: persistent cryptosporidiosis

opthal: CMV retinitis

Malig: Kaposis sarcoma, non-hodgkins lymphoma, cervical cancer

Neuro

  • cerebral toxoplasmosis
  • primary cerebral lymphoma
  • crytococcal meningitis
  • progressive multifocus leucoencephalopathy
18
Q

AIDS management

A

Co-trimazole - PCP, toxoplasma, bacterial infection

pentamidine - PCP

azithromycin - Mycobacterium Avium Intracellulare

ganciclovir - CMV

19
Q

Hepatitis transmission

A

B- vertical, sexual, blood, needles

D- blood and body fluids

C- blood and body fluids

A - faeco-oral

E- faeco-oral (water)

20
Q

Hep B presentation

A

fever
malaise
upper abdo discomfort
jaundice

can be asymp then cirrhosis and liver failure

21
Q

Hep C presentation

A

85% asymptomatic/mild symptoms forllowing infection (develop chronic HCV: also asymptomatic or nonspecifc - malaise, fatigue, RUQ pain)

15% malaise, nausea, RUQ pain, jaundice (more likely to clear disease)

22
Q

Presentatio of Hep A

A

anorexia, nausea, jaundice

23
Q

presentation of hep E

A

abdo pain, jaundice, fever, fatigue

24
Q

Diagnosis of hep C

A

enzyme immunoassay -> immunoblot assay

if +ve confirmed by HCV RNA test by PCR

25
Q

Hep C monitoring

A

Baseline liver fibrosis assessment

  • all patients- no need for biopsy

Every 6/12 ATP (alpha fetoprotein - HCC marker) and liver USS

  • patient with evidence of advanced fibrosis or cirrhosis

OGD

  • pt with evidence of portal HTN
  • screening for varices
26
Q

Hep C management

A
  • Direct acting antiviral drugs (DAA)
  • fixed dose combined tablets for 8-16 weeks
  • Aim - undetectable HCV RNA in blood 12 weeks post treatment finishing
  • if unsuccessful
    • vosevi OD 12 weeks if no decompensated cirrhosis
    • epclusa + RBV 24 weeks if decompensated cirrhosis
27
Q

What methods are used to prevent vertical transmission of HIV in birth

A

1) C section
2) bottle feed
3) zidovudine

28
Q

SE of vidozudine

A

haemolytic anaemia

29
Q

How do you prevent HIV transmission?

A

Prep: Truvida either daily or 12 hours before

Pep: Truvida 4 weeks

30
Q

Malaria investigations

A

Thick (how much parasite) and thin (which parasite) blood films

Antigen detection test

Rapid diagnostic tests - dipstick based, only for P falciparum and P Vivax

31
Q

why is p. falciparum worse

A

sticks to blood vessels (doesnt just infect RBC) so falsely low viral load (survives longer because not broken down by spleen)

can cause vascular ischaemia -> encephalopathy

32
Q

Complications of severe malaria

A

Haemolytic Anaemia

Cerebral Malaria

AKI

Hypoglycaemia

DIC