infectious disease Flashcards
Pt presents with Nonspecific fever, myalgia and erythema migraines. What is the 1st line medication and duration for management ?
Doxyclycline
2-3 weeks
Erythema migrans = bullseye rash
Lyme disease is endemic I northern Europe
A normally fit and well pt presents at ES with vomiting and non-bloody diarrhoea. During the Hx she mentioned eating reheated rice and curry the night before. She is appyrexial. What is the lost likely cause?
Bacillus cereus
Think cereus - cereal (e.g. cocopops). Bacillus cereus
- 30mins - 6hrs post food
- profuse vomiting
- Apyrexial
22 yo male presents with 1wk sore throat & fatigue. On examination, he has Tonsillitis enlargement with exudate
Lab results show elevated liver enzymes and positive heterophike antibody test
What is the most likely causenof the presentation
EBV - mono
Mono presentation: young adults, sore throat, fatigue, LYMPHADENOPATHY, HEPATOSPLENOMEGALY (hence elevated liver enzymes), and rash
Ix -
Elevated liver enzymes
Leukocytes
Positive heterophile antibody test = moonspot test
Tx - supportive: rest, hydration, paracetamol
What is the heterophile antibody test also known as.
What infective organism causes a positive finding?
Heterophile antibody test = Monospot test
Positive in EBV infection
Potts disease aka […]
Is found in what condition?
What are
- clinical features
- Xray
- biopsy
Potts disease of the spine = tuberculosis spondylitis ( extrapulmonary manifestation of TB)
Clinical features: localised back pain, neurological deficits
Xray: vertebral body involvement (e.g. reduction of vertebral height)
Biopsy: granuloma
Cholera mx
Aggressive fluid resus - IV Hartmanns
Abx - Doxyclcije / Co- trimoxazole
When should pts with Whooping cough be admitted into hospital
If <6m old / sig. Resp sx or complications
Otherwise supportive/ symptomatic management
Can use macrolides, to reduce infectivity but doesn’t affect condition
When should pts with Whooping cough be admitted into hospital
If <6m old / sig. Resp sx or complications
Otherwise supportive/ symptomatic management
Can use macrolides, to reduce infectivity but doesn’t affect condition
What is the treatment for pt who presents with vaginal discharge and a fishy odour.
She is sexually active but uses barrier protection with one longterm partner
Bacterial vaginosis - imbalance of microbiome –> overgrowth of anaerobic bacteria & loss of lactobacilli
1 risk factor: smoking
What are the features of Amsel criteria?
Amwell criteria - used to diagnose bacterial vaginitis
Vag pH >4.5
Homogenous grey/ Milky discharge
Positive whiff test
Clue cells
Tx in Bacterial vaginosis
Metronidazole or clindamycin
describe Mhycobacterium tuberculosis
- appearance
- what stain is used
- what is the finding on the staining
M. tuberculosis
small rod-shaped bacillus
Ziehl-Neelsen stain: bright red against blue backrground
( m. tuberculosis is an acid-fast bacillius - as waxy coating makes them resistant to acids)
TB is spread through inhaling saliva droplets from infected people. in most cases its cleared, what are the 4 stages of TB in patients in which it remains
Primary active TB
Latent TB (immune system encapsulates bacteria, progression does not occur in most patients)
Secondary TB (typically in immunosuppresion)
Miliary TB - disseminated & severe disease
what test is conducted prior to giving the BCG vaccine
Mantoux test ( -ve = <5cm bleb growth on skin after injecting the proteins)
check for immunosuppression( vaccine live)
In addition to culturing the bacteria, what Ix can be conducted in
- latent or active TB
- active disease alone
latent/ active
- mantoux test
- interferon-gamma release assay
- active
CXR
cultures
what are the chest X-ray findings in
-primary TB
- secondary TB
- Miliary TB
primary
- patchy consolidation
- pleural effusions
- hilar lymphadenopathy
secondary
- patchy/nodular consolidation with cavitation ( gas-filled space)
miliary TB
- appearance of millet seeds (many small nodules disseminated throughout lung fields) uniformly distributed acoss ung fields
Medication and duration for latent TB
isoniazid & rifampicin - 3m
OR
isoniazid - 6m
(active TB 6:RI, 2:PE)
what medication should be co-presribed with the RIPE regime?
Vitamind B6 (pyridoxine)
Isoniazid –> peripheral neuropathy
this is prevented by Vi B6
what micro-organism causes lyme disease
borrelia burgdoferi ( transmitted by ixodes tics)
3 key Sx which indicate nephritic syndrome
HTN, haematuria and oedema
3 findings of nephrotic syndrome
ne-frothy urine
- protein urea
*hyperlipidaemia - hypoalbunaemia
most common cause of nephritic syndrime
Post-strep glomerulonephritis ( if throat/skin infection 1-3 weeks prior)
other: IgA nephropathy
name the medication used to treat TB
Rifampicin
isoniazid
pyrazinamide
ethambutol
A pt completes 6months of the RIPE regiem and starts complaining of bilateral lower limb numbness, and intermittent paraesthesia .
what S/E is he suffering from?
what medication should he be Rx?
S/E: peripheral neuropathy (isoniazid)
Rx: Vit B6 should be co-prescribed to prevent depletion
A pt completes 6months of the RIPE regiem and starts complaining of bilateral lower limb numbness, and intermittent paraesthesia .
what S/E is he suffering from?
what medication should he be Rx?
S/E: peripheral neuropathy (isoniazid)
Rx: Vit B6 should be co-prescribed to prevent depletion
A 2-year-old girl presents to her GP with a 10-day history of a cough, sore throat and mild fever. For the last 2 nights, the cough started to take on a ‘dry, hacking’ quality. She has a continuous cough with short interspersed high-pitched gasps for breath. .
what is the most likely responsible organism?
Bordetella Pertussis
what is the most common cause of urethritis in males?
(condition, causative organism)
gonorrhoeae
N. gonorrhoeae
what is the main ophthalmic S/E of one of the TB medications?
vision disturbance (esp. red-green colour detection)
ethambutol
what type of bacteria (e.g g+ve/egative, rod etc) causes the most common cause of urethritis in males
G-ve diplococcus
what are the findings in CSF of viral meningitis
- lymphocytes/neutrophils
- protein count
- glucose level
viral meningitis: lymphocytes, slightly raised protein count, normal glucose
name and describe the presentation of the organism which causes TB
mycobacterium tuberculosis
small, rod-shaped bacteria (bascillus)
what stain is used in TB
what colour does M. tuberculosis tunr
Ziehl-Neelsen stain
Red against a blue background
TB = acid-fast basiclli
A patient attends with a chronic cough and night sweats.
Sputum culture grows acid-fast bacilli that stain red with the Zeihl-Neelsen staining. what condition do you suspect
TB
describe the 4 outcomes of TB
1. most likely
2. primary active TB
3. latent TB
4. secondary TB
most cases: Immediate clearance of the bacteria
* Primary active TB - active infection after exposure
* Latent tuberculosis ASx & non-contagious presence of the bacteria
* Secondary tuberculosis (reactivation of latent TB to active infection)
what tests need to be conducted before providingthe BCG vaccine
Mantoux test ( can give vaccine if -ve)
assess for immunosuppression
assess for HIV
24 yo male presents pyrexic, bilateral jaw pain and parotid swelling. what complication is he most likely to get
orchitis
presentation - mumps ( parotid swelling = mumps)
in post-pubescent males, the most likely complication is orchitis
what is the difference between cellulitis and erysipelas
cellulitis - dermis and subcut infection
eyrysipelas - dermis and upper subcut tissue
2 causes of cellulitis / erysipelas
GAS
Staph. aureus
1st line in cellulitis/ erysipelas
mild-mod
severe
mild-mod: fluclox
severe: flucloxacillin + benzylpenicillin
2nd line in cellulitis
clarithromycin/ clindamycin
2nd line in erysipelas
erythromycin
signs and symptoms
- Pain disproportionate to clinical signs.
- Mild inflammation of the overlying skin at the initial stages.
- Crepitus upon palpation and potential visibility of gas on imaging (in gas-forming organisms).
- skin changes: dark discoloration, blistering, and necrosis.
- Pain subsides (nerve damage).
- Widespread oedema (beyond the area of erythema).
- Systemic illness (fever, tachycardia, tachypnoea, and hypotension).
describe the types of necrotising fasciitis
3 types
- Type 1: polymicrobial, (anaerobes).
- Type 2: monomicrobial, (GAS/ Staph. aureus) .
- Type 3: gas-forming organisms such as Clostridium perfringens –> ‘gas gangrene’. (gas gangrene = muscle tissue & lots of gas, nec. fasc. is fascia, not muscle tissue)
3 aspects of Mx in nec. fasc
Surgical debridement ( immediate - amputation where necessary)
Broad spec Abx (IV clindamycin/meropenem/ vancomycin)
haemodynamic support
which form of HIV is most commonly found in west africa
HIV-2
(HIV-1 is the most common type)
what immune cells do the HIV viruses enter
CD4 T-helper cells
AIDS-defining illnesses occured when the CD4 count is low enough to allow for opportunistic infections/malignancies. give 6 examples of AID-defining illnesses
Kaposi’s sarcoma
Pneumocystitis jirovecii pneumonia
CMV
Candidiasis
Lymphomas
TB
e.g. “A pts CD4 count is 180/mm3, what medication should be added to his anti-virals? Co-trimoxazole” - due to PCP risk (* Under 200 cells/mm3 puts the patient at high risk of opportunistic infections)
normal CD4 t-helper cell range
- 500-1200 cells/mm3
under what CD4 t-helper cell level are HIV patients at high risks of opportunistic infections
under 200 cells/mm3
give an example of antiretroviral therapy
combo of meds given to all with HIV status, despite CD4 count/ Viral load
(e.g., tenofovir plus emtricitabine) plus a third agent (e.g., bictegravir).
what medication should be given in addition to ART in HIV positive patients with a CD4 count under 200/mm3
co-trimoxazole
PCP protection
what should be the mode of delivery in a viral load of <50copies/ml during labour?
normal vaginal
what should be the mode of delivery in a viral load of >50copies/ml during labour?
consider pre-labour C-section
what should be the mode of delivery in a viral load of >400copies/ml during labour?
Pre-labour c-section
what medication is given as an infusion during labour if the mother’s viral load is unknown/ above 1000copies/ml
IV Zidovudine
what HIV prophylaxifs is given to babies who’s maternal viral load is <50copes/ml ( low risk babies)
zidovudine (2-4wks)
what HIV prophylaxis is given to babies who’s maternal viral load is high ( highrisk babies)
zidovudine & lamivudine & nevirapine 4 wks
Breastfeeding in HIV
should be avoided, inspite of low viral load
can be done but needs close monitoring
within what time window should PEP be taken
<72hrs
What medications make up PEP (post exposure prophylaxis - HIV) ?
raltegravire, & emtricitabine/tenofovir ( Truvada)
what medications make up PrEP ( pre-exposure prophylaxis)
emtricitabine/tenofovir (truvada)
what is the most common opportunistic infection in HIV
Pneumocystis jiroveci pneumonia
presentation of pneumocystitis jirovecii pneumonia (x4)
Dyspnoaea, dry cough, fever, very few chest signs
what is a common complication of the most common opporunistic infection in HIV
pneumothorax
(PCP is the most common opportunistic infection)
what is typical of the oxygen sats in PCP?
exercise induced desaturation
Mx of PCP
cotrimoxazole
IV pentamidine in severe cases
steroids in hypoxia/ prevention of respiratory failure
what causes toxic shock syndrome
exotoxins from
GAS,Staph, MRSA
what is the presentation for toxic shock syndrome (x3)
fever >38.9
SB <90
multiple system involvement (GI, CNS, Skin )
flu-like sx (possibly nausea & vom)–> high fever –> widespread macular rash
Mx toxic shock syndrome
DR ABCDE, aggressive fluid & electrolyte resus, Abx
Tx infection
- attending to source
IV Abx: Clindamycin +)cephalosporin/meropenem/vancomycin)
surgical: debridement/drainage/ amputation
Tx syphilis
1st line
2nd line
deep IM benzathine benzylpenicillin (or cef/amoxicillin/dox)
doxyclycline
Jarish Herxheimer reaction
reaction to syphilis tx
( fever, rash tachy ( but no wheeze/ hypotension as in anaphylaxis) )
tx - antipyretcs if required
what family of parasites causes malaria
plasmodium family
protozoan parasites - singlye celled- organisms
the most common ( in the UK) and most dangerous type of malaria-causign parasite
Plasmodium falciparum
Sporoziotes (malaria spores) are injected by a mosquio and lay dormant in what part of the body
the liver
lay dormant/ mature in the liver –> then spread to RBCs –> rupture & more spread –> haemolytic anaemia
typical history in patient who has malaria ( location, duration)
travelled to an area with malaria
1-4weeks after ( this is incubation period)
*may be incubated for 4 years (P.vivax and P.ovale) - so travel Hx is important
Sx malaria
high fever (up to 41 degrees) w/ sweats & rigors
fatigue and myalgia
headaches
N&V
- high fever, spikes every 48hrs = malaria
examination findings in malaria (x3)
think, it causes haemolytic anaemia
pallor
hepatosplenomegaly
jaundice
what investigation is used to diagnose malaria and what are the diagnostic findings
malaria blood film
- parasites
- concentration of parasites (>2% RBC involved = severe)
- type
a malaria blood film is conducted on a patient and appears negative. What is the appropriate next step?
conduct 2 more in the next 2 days
3 -ve samples on 3 consecutive days are needed to exclude malaria
parasites are released from RBC every 42-78 hrs (hence spike in fever every 48hrs being typical in malaria), so 3 consecutive measurements should capture the cell rupture & release of parasites
1st line management for malaria
Riamet ( artemether with lumefantrine)
others: Quinine (+ doxycycline/ clindamycine), proquanil with atovaquone, chloroquine, primaquine
(artesunate and quinine are most important to remember
to what antimalarial drug is there increasing drug resistance
chloroquine
which antimalarial can cause severe haemolysis in G6PD pts
primaquine
what are the preventative options against malaria
none are 100% effective alone, so combine:
mosquito spray, nets/ barriers, antimalarial medication
what are the main antimalarial options for preventing malaria
Malarone (Proguanil / atovaquone) - more expensive but less SE.
take: from 2days before travel to 7 days after travel
Doxycycline - broad-spec abx. S/E: diarrhoea, thrush, skin sensitivity to sunlight
take: 2days pre travel until 4weeksafter travel
Mefloquine - S/E psych (anxiety, depression, abnormal dreams)
take: 2weeks before until four weeks after travel to an endemic area
most common cause of gastroentertitis
viral
one important things to do when an inpatient has viral gastroenteritis
isolate them ( spreads easily)
give 3 viral causes of gastroenteritis
Rotavirus
norovirus
adenovirus
abdominal cramps, bloody diarrhoea and vomit after eating an unwashedsalad indicates which infective cause
E. coli
cause - shiga toxin, which destroys blood cells –> causes HUS
what medical intervention increases chance of HUS in patient with E.Colki/ Shigella gastroenteritis
antibiotics
so avoid Abx if this is/ might be the cause
bacteria under a microscope
E.coli
Campylobacter jejuni
E.coli
G-ve rod shaped bacillus
Campylobacter jejuni
G-ve curve/spiral shaped bacteria
Bacillus cereus
G+ve rod (G+ve unlike the others)
Yersinia Enterocolitica
G-ve bacillus
what is the incubation period of C. Jejuni
1-6days
Sx resolve after 3-6 days
what organisms cause a bloody diarrhoea
E.coli
C. jejuni - prodrome headache/ malaise, appendicitis- like abdo pain
Shigella - incubation period of 1-2 days
salmonella - watery diarrhoae , blood/mucus maybe in stool
Mx in C. Jejuni
- normally
- in severe / immunosuppressed cases
normally - self-limiting
severe/ immunosuppressed
1st. clarithromycin
2nd ciprofloxacin/ Azithromhycin
give 3 complications of C. Jejuni gastroenteritis
- GBS
- ReA
- endocarditis
- Arthritis
- septicaemia
what is the incubation period of shigella
1-2 days
Sx resolve in 7 days
incubation period for salmonella
12hrs - 3days
resolves <7days
watery diarrhoea, abdo pain and vomitting suggests which infective organism
salmonella
stool may have mucus/blood
salmonella gastroenteritis Mx
self-limiting
Abx folowing MC&S if severe
what is the incubation period of Bacillus cereus
<5hrs
> 5hrs - crampy abdo pain & vomiting
8hrs - watery diarrhoea ( like salmonella, but shorter incubation period)
<24hrs - resolves
what bacteria is commonly associated with eating raw/ undercooked pork
Yersinia enterocolita - carried by pigs
what parasitic cause of gastroenteritis is acquired through contact with animals
Giardia lmblia - small intestines of animals ( pets, farm animals, humans
what are the post gastroenteritis complications
- Lactose intolerance
- Irritable bowel syndrome
- Reactive arthritis
- Guillain–Barré syndrome
- Haemolytic uraemic syndrome
Ix in Giardiasis
NAAT/ EIA stool testing
Mx in Giardiasis
tiniodazole or metronidazole
define sepsis
SIRS ( systemic inflammatory response syndrome ) to infection
what 2 measurements’ valuessa re used to diagnmose septic shock
- Low mean arterial pressure (<65 mmHg) despite fluid resuscitation (requiring vasopressors)
- Raised serum lactate (> 2 mmol/L)
what score is used to assess the severity of organ dysfunction in sepsis
SOFA
sepsis-related organ failure assessment
- Hypoxia
- Increased oxygen requirements
- Requiring mechanical ventilation
- Low platelets (thrombocytopenia)
- Reduce Glasgow Coma Scale (GCS)
- Raised bilirubin
- Reduce blood pressure
- Raised creatinine
what group of septic patients may present with normal observations?
neutropenic/ immunisuppressed
what bloods should be conducted in sepsis
FBC - WCC & Neutrophils
U&Es - kidney function & AKI
LFTs - liver function, ?source of infection
CRP - inflammation
BM - hyper/hypoglycaemia
Clotting - ?DIC (thrombocytopenia and haemorrhage)
Blood cultures - ?bacteraemia
blood gass - lactate, pH, glucose
how quickly from presentation should a patient with suspected sepsis be managed
<1hr
what is the neutrophil count in a person with neutropenic sepsis
<1 x 10-9/L
what medications may cause neutropenia
Oncology
- chemotherapy
- Rituxumab ( autoimmune/ cancer)
- inflixamab ( autoimmune)
Psych - schizophrenia
- clozapine
MSK - RA
- Hydroxychloroquine
- Sulfasalazine
- Methotrexate
Endo - hyperthryroidism
- Carbimazole
Infectious disease - Malaria
- Quinine
what is the temp threshold for suspecting neutropenic sepsis in a patient with on chemo/ other meds which may cause neutropenia
38 oC
what is the Management in neutropenic sepsis
Sepsis 6
Broad-spec antibiotic ( Tazocin)
close monitoring, .low threshold for escalation
what is the incubation period
Staph aureus/ bacillus cereus
Salmonella/ E.coli
Shigella/ C. Jejuni
Giardiasis/ Amoebiasis
Incubation period
Staph aureus/ bacillus cereus : 1-6hrs
Salmonella/ E.coli: 12-48hrs
Shigella/ C. Jejuni 48-72hrs
Giardiasis/ Amoebiasis: >72hrs
