Infectious Diseases Flashcards
TB risk factors
- HIV
- immunosuppression
- overcrowed living
- ethnic minorities
- malnutrition
- IVDU
- chronic lung disease
TB pulmonary presentation
- constitutional symptoms (weight loss, night sweats, fatigue, fever and chills)
- lymphadenopathy
- Cough ± haemoptysis
- SOB
- chest pain
Extra-pulmonary symptoms of TB
Neuro: meningisms
Opthalmology: blurred vision, red eyes
GU: dysuria, haematuria
GI: abdo pain, abdo mass
rheum: arthritis
osteo: osteomyelitis
How is TB diagnosed
- 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
What is the management of TB
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
what is multi-drug resistant TB
TB that is resistant to at least izoniazid and rifampicin normally due to poor compliance or incomplete courses
how is multi-drug resistant TB managed
combo of 5-8 drugs for up to 2 years
HIV transmission
- sexual
- vertical
- untreated risk 25-40%
- treated risk <1%
- C-section if mother has detectable viral load at birth
- needles
- blood products
HIV pathology
*RNA retrovirus*
- virus becomes part of host cell
- transcriptase enzyme transcripts RNA-> DNA
- Integrase integrates virus DNA into hosts
- host cells produces/releases virons (cleaved by protease)
- Virons infect any cells with CD4 receptor by binding with GP120 glycoprotein
- CD4 receptor cells now release virons
- infection progressed, CD4 cells destroyed, reduced host immune system
Which cells have CD4 receptors?
T cells, macrophages, monocytes, neurons
How is HIV diagnosed?
- 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
HIV monitoring
CD4 normal range 450-1600
Viral Load = quantity of virus in serum
Undetectable VL = Untransmittable disease
HIV Management
2 NRTI + NNRTI OR PI
NRTI (nucleoside reverse transcriptase inhib)- zidovudine, abacavir
NNRTI (non-NRTI)- nevirapine, etravirine
PI (protease inhib)- indinavir, lopinavir
HIV prophylaxis
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
What is truvada
tenofovir and emtricitabine
When does a person have AIDS
when their CD4 count is less than 200 or presence of an aids defining condition
AIDS defining conditions
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
AIDS management
Co-trimazole - PCP, toxoplasma, bacterial infection
pentamidine - PCP
azithromycin - Mycobacterium Avium Intracellulare
ganciclovir - CMV
Hepatitis transmission
B- vertical, sexual, blood, needles
D- blood and body fluids
C- blood and body fluids
A - faeco-oral
E- faeco-oral (water)
Hep B presentation
fever
malaise
upper abdo discomfort
jaundice
can be asymp then cirrhosis and liver failure
Hep C presentation
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)
Presentatio of Hep A
anorexia, nausea, jaundice
presentation of hep E
abdo pain, jaundice, fever, fatigue
Diagnosis of hep C
enzyme immunoassay -> immunoblot assay
if +ve confirmed by HCV RNA test by PCR
Hep C monitoring
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
Hep C management
- 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
What methods are used to prevent vertical transmission of HIV in birth
1) C section
2) bottle feed
3) zidovudine
SE of vidozudine
haemolytic anaemia
How do you prevent HIV transmission?
Prep: Truvida either daily or 12 hours before
Pep: Truvida 4 weeks
Malaria investigations
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
why is p. falciparum worse
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
Complications of severe malaria
Haemolytic Anaemia
Cerebral Malaria
AKI
Hypoglycaemia
DIC
