Infectious disease Pathology Flashcards
which class of antibiotics target cell wall synthesis ? (2)
- beta lactams
- glycopeptides
name some beta lactams ?
- penicillins
- cephalosporins
tazocin is a mix of what ?
- piperacillin (abx)
- tazobactam (beta lactam inhibitor)
name some glycopeptides ?
- vancomycin
- teicoplanin
what is the pathogen in TB ?
mycobacterium tuberculosis
(bacteria)
what staining does TB have ? (2)
- acid fast bacillus with waxy coating (so gram stain ineffective)
- zeihl-neelsen (red)
TB epidemiology: in who more common ?
- south East Asian
- immunocompromised (HIV)
- close TB contact
what does the slow growing of TB mean ?
slow reproduction => slow onset of disease and slow response to treatment
- difficult to culture and treat
what is primary TB ?
bacteria has initial contact with alveolar macrophage => uses macrophages to proliferate => then to lymph nodes => cell mediated immunity
what is active TB ?
where there is active infection in parts of the body
what is latent TB ? bodys response ?
immune system encapsulates site of infection (granuloma) => slow progression
what happens to the granulomas in TB ?
provides area for TB to grow + block from systemic infection => latent, dormancy §
what is secondary TB ?
when latent TB reactivates
what is miliary TB ?
immun system unable to control disease
where are the most common site for TB ? why ?
- lungs - apex (plenty of oxy and low blood => low immune cells)
name some locations of extra pulmonary TB ?
- lymph nodes
- pleura
- CNS
- pericardium
- GI/GU system
BCG vaccine: who offered to ?
- neonates with a FHx
- healthcare workers
- <35 with close contact to TB
TB Px ?
Hx of chronic gradually worsening sx (mostly pulmonary)
- lethary
- fever
- weight loss
- cough (+/- haemoptysis)
- lymphadenopathy
- spinal pain
what is gold standard Ix for active TB ?
- sputum culture
why would you do NAAT acid fast test for TB ?
sputum culture takes 2-3 weeks
whereas NAAT takes 24-48 hrs (alot quicker but less specific)
what test is done to screen for latent TB ? (2)
- Mantoux test
(indicates prev vaccination/latent/active) - interferon-gamma blood test
what imaging would be done for active TB px ? what would this show ?
CXR
- primary TB: pleural effusions
- reactivated: nodular consolidation with cavitations
- disseminated miliary (millet seeds)
latent TB Mx ?
if at risk of reactivation
- isoniazid + rifampicin (3 months)
acute active pulmonary TB Mx ? how long of each
6 months
- rifampicin + isoniazid
2 months
- pyrazinamide + ethambutol
what else should you test for when pt has TB ? (5)
- hep B/C
- HIV
- test contacts for TB
- notify public health
- isolate during active TB
rfiampicid SE ?
- red/orange discolouration of secretions
isoniazid SE ?
peripheral neurophathy
which Tb med can cause peripheral neuropathy ? what do you give alongside ?
pyridoxone prophylaxis (isoniazid causes it)
ethambutol SE ?
colour blindness
which TB drugs cause hepatotoxicity ?
RIP
what cells does HIV target ? what does this cause ?
damages CD4 presenting cells of the immune system
(T-helper cells, monocytes, macrophages, dendritic cells)
=> makes body prone to opportunistic disease + cancer
what is AIDS ?
acquired immunodeficiency syndrome
- describes a group of potentially life threatening infections + diseases that happen when immune system is compromised (because of HIV)
what determines when someone has AIDS ?
when CD4 count is <200 (should be above 500)
HIV sx ?
short flu like illness (2-6 weeks after infection)
- headache, fatigue, ulcers in mouth/anus/genitals
- red rash that doesn’t itch
which pregnant women get HIV antenatal testing ?
every pregnant women
what is first line for HIV screening ?
HIV antibody and HIV antigen (p24 antigen)
HIV treatment ? aim of it ?
try to decrease viral load (undetectable) and increase CD4 count
what is the most common opportunistic infection in HIV ?
pneumocystis pneumonia (PCP)
what is kaposis sarcoma ? caused by what pathogen ?
AIDs defining illness
- causes by HHV 8
what pathogen causes cold sores on the mouth ?
mainly HSV1
what pathogen causes genital herpes ?
mainly HSV 2
name some pathogens that cause diarrhoea without blood ? (4)
- norovirus
- rotavirus
- enterotoxigenic E.Coli
- cholera
name some pathogens that cause bloody diarrhoea ?
- shigella
- shiva-toxin producing E.Coli (STEC)
- campylobacter
- salmonella
in a bacterial eye disease, describe:
the secretions ?
other features ?
secretions: prurulent
features: red and swollen
in a viral eye disease, describe:
the secretions ?
other features ?
secretions: watery
features: +/- corneal lesion
bacterial eye disease tx ?
topical abx for 5 days
viral eye disease tx ?
symptomatic
chlamydial eye disease presentaiton ?
mucopurulent secretions
- follicles + papillae on lid
chlamydial eye disease tx ?
azithromycin
what is malaria ? caused by what sort of pathogen ?
infectious disease caused by plasmodium family of protozoan parasites ?
what is the most common pathogen of malaria ? most dangerous ?
most common and dangerous is plasmodium falciparum
how is malaria spread ?
spread through bites from female anopheles mosquito
describe the life cycle of a mosquito in terms of malaria transmission ?
- mosquito bite, usually at night
- sporozoites lie dormant in liver
- mature to merozoites + infect RBC
- RBC rupture
- merozoites relate into blood stream
=> haemolytic anaemia
malaria px ?
lives or travelled to endemic area, 1-4 weeks incubation
- fever, sweats, riggers, malaise, myalgia, headaches, vomiting
- pallor (due to haemolytic anaemia)
- hepatosplenomegaly
- jaundice
how is malaria diagnosis made ? how is dx excluded ?
giemsa-stained thick and thin blood smears (shows ring trophozoites)
- to exclude diagnosis: 3 samples over 3 consecutive days (48 hr cycle)
malaria mx ?
IV artesunate
- IV fluids
- blood transfusion if necessary
falciparum complications ?
- cerebral malaria
- siezures
- reduced consciousness
- AKI
- DIC
- death
what can be used for malaria prophylaxis ?
none 100% effective
- malarone
- nefloquein
- doxycycline
Lyme disease Mx ?
oral doxycycline
how is dengue diagnosed ?
PCR for virus
what pathogen causes typhoid ? what type of pathogen
salmonella typhi
- gram -ve bacillus
typhoid px ?
- gradual onset fever, malaise, dry cough
- rose spots on trunk
important complication of typhoid ?
intestinal perforation => death
what test to diagnose typhoid ?
- blood culture
typed mx ?
- IV ceftriaxone + supportive care (IV fluids, paracetamol, isolation)
What is infectious mononucleosis ? aka? what pathogen ?
kissing disease, glandular fever, mono
- caused by infection with Epstein Barr virus (EBV)
what is typical infectious mononucleosis px? presents following what ?
adolescent with a sore throat who develop itch rash (v v itchy) after taking amoxicillin
(99% of pts with mono who take amoxicillin develop pruritic maculopapular rash)
infectious mononucleosis presentation? (6) typical triad
- fever*
- sore throat*
- lymphadenopathy *
- tonsillar enlargement
- splenomegaly
- fatigue
how is infectious mononucleosis diagnosed ? (2)
- FBC and monospot in the 2nd week of illness
infectious mononucleosis mx ? (3)
- supportive (usually self limiting: 2-3 weeks)
- don’t give amoxicillin
- avoid playing contact sport for 4 weeks after having glandular fever to reduce risk of spenic rupture
EBV causes what condition ? which what cancer is it associated ?
- EBV infection in kids is mild, subclinical
- presents as infectious mononucleosis in adolescence
- associated with burkitts lymphoma
Otitis externa px? (3)
- ear pain
- itch
- discharge
what is seen in otitis external on otoscopy ? (3)
- red
- swollen
- or eczematous canal
otitis externa mx ? if this doesn’t work ?
- topical abx or combine topical abx with a steroid
- if pt fails to respond to topical abx then the patient should be referred to ENT
