Medicine - Infectious disease Flashcards
Which hepatitis viruses can be faeco-orally transmitted?
fAEco-oral
Hep A
Hep E
What is the triad of symptoms seen in acute viral hepatitis?
Jaundice
RUQ pain
Fever
nb. Is same as Charcot’s triad for cholangitis
Which type of hepatitis is associated with polyarteritis nodosa?
Hep B
How is Hep B transmitted?
Vertically, sex, blood products
Recall the HBV antibodies that will be positive in current, past and vaccinated Hep B
Current: sAg, cAb
Past: cAb, sAb
Vaccinated: sAb
Which hepatitis viruses are associated with hepatocellular carcinoma?
HBV and HCV
What are the signs and symptoms of hep D infection?
Fulminant acute hepatitis
What is the most common form of hepatitis virus in the UK?
Hep E
What is the standard pulmonary TB therapy?
Rifampicin, isoniazid, pyrizinamide and ethambutol for 2 months
then
Rifampicin and isoniazid for 4 more months
Recall the side effects of each TB medication
ONLY rifampicin --> Orange secretions isoniazid --> Neuropathy (peripheral) pyrizinamide --> Liver (hepatotoxicity) ethambutol --> eYes (visual disturbance)
Which of the TB drugs is a CYP450 inducer?
Rifampicin
What are the classical symptoms of primary syphillis?
Painless ulcer and painless lymphadenopathy
What are the classical symptoms of lymphgranuloma venereum?
Painless ulcer and painFUL lymphadenopathy
What is the causative organism in lymphgranuloma venereum?
C trachomatis
What are the typical symptoms of chancroid?
Painful ulcer and painful lymphadenopathy
What is the causative organism in chancroid?
Haemophilus ducreyi
Which 2 streptococcal species are alpha haemolytic?
Strep pneumoniae
Strep viridans
Recall 5 conditions that are most commonly caused by Strep pyogenes (GAS)
Erysipelas Impetigo Cellulitis T2 necrotising fasciitis Pharyngitis/tonsilitis
Recall 2 haematological abnormalities that are seen in malaria
Thrombocytopaenia
Anaemia
How should malaria be investigated?
3 thick and think blood films
What drug is used as malaria prophylaxis?
Quinine
What is the first line treatment for falciparum malaria?
IV artesunate
Recall 4 possible complications of typhoid fever
GI perforation
Myocarditis
Hepatitis
Nephritis
What are the key signs and symptoms of typhoid?
Fever
Bradycardia
Anorexia
Diarrhoea OR constipation
What is Sphygmothermic dissociation / Faget’s sign?
Unusual pairing of fever and bradycardia that can be seen in typhoid fever
What is the 1st line treatment for typhoid fever?
IV ceftriaxone
Recall 3 abnormalities on an FBC in degue fever
Low WCC
low plts
low Hb
What are the key signs and symptoms of dengue fever?
Headache (retro-orbital)
Sunburn-like rash
High fever and myalgia
What is the most helpful intervention in dengue haemorrhagic fever?
Fluid resuscitation
What is the gold-standard investigation for dengue fever?
PCR viral antigen
Serology IgM
What is the causative pathogen in Q fever?
Coxiella burnetti
What is the typical natural history of Lyme disease?
Rash –> malaise, carditis, meningitis –> CNS signs
What is the proper term for sleeping sickness?
Trypanosoma
How long after primary infection does seroconversion occur in HIV?
3-12 weeks
How long after exposure can you do an HIV test?
At 4 weeks offer a test, if negative offer a repeat test at 12w as 99% of people will have antibodies at 12w
Recall some ways you can differentiate between toxoplasmosis and primary CNS lymphoma
Toxoplasmosis: multiple lesions, ring enhancement
CNS lymphoma: single lesion, homogeous enhancement
What 2 drugs are used to treat CNS toxoplasmosis?
Sulfadiazine
Pyrimethamine
What is the investigation of choice for encephalitis?
CT (oedematous brain)
Recall 2 investigations that can be used for cryptococcus
CSF: india ink test positive
CT: cerebral oedema, meningeal enhancement
How should meningococcal sepsis patients be treated if they are penicillin-allergic?
Ceftriaxone
In HIV+ patients, when should PCP prophylaxis begin?
When CD4 <200
What extra piece of information do you always need to interpret CSF results following an LP?
Plasma glucose
What is the most common complication of bacterial meningitis?
Sensorineural deafness
What is the antibiotic of choice for bacterial meningitis in hospital (if the organism has not yet been isolated)?
IV ceftriaxone
What antibiotic is used as chemoprophylaxis of meningococcal sepsis for close contacts of people with meningococcal disease?
Rifampicin (or ciprofloxacin as alternative)
Which form of HSV typically causes meningitis vs encephalitis?
Meningitis = HSV2 Enephalitis = HSV1
What is the likely cause of meningitis if the patient has a swollen face?
Mumps - as this is likely due to parotitis
Which antibiotic is known to have an antabuse effect?
Metronidazole
In what 2 ways should vancomycin be monitored?
- Check trough levels, aim for 15-20
2. Monitor renal function
What are the 3 components of the qSOFA score, and what is it used for?
GCS <15
SBP <100
RR >22
Used to judge likellihood of someone needing ITU (eg in sepsis)
What is the most common pathogen to infect a central line?
Staph epidermidis
What is the most important initial step in managing necrotising fasciitis?
Debridement of affected tissues
Following rabies exposure, what should be done?
Give rabies immunoglobulin + full course of vaccination
Which antibiotics are used to treat legionella pneumonia?
Macrolides eg clarithromycin
What is the post-exposure prophylaxis for Hep B in a person who has had a full course of Hep B vaccination and was a known responder?
Vaccine booster dose
When should antibiotics be given for an animal bite, and which antibiotics should be chosen?
Give abx when:
- A human bite that has drawn blood or broken the skin in a high-risk individual
- A cat bite that has drawn blood or appears to be deep
- A dog bite that has caused considerable tissue damage or is contaminated
Abx = Co-amoxiclav
How should a tick bite be treated?
If asymptomatic - reassure and safety net
If symptomatic for Lyme disease –> single dose of doxycycline
If a patient is penicillin-allergic, what other class of antibiotic should you avoid giving?
Cephalosporins (due to cross reactivity)
Which population group is most at risk of leptospirosis?
Sewage workers (due to exposure to rat urine)
If discitis is due to staphylococcus, what extra investigation must be done?
Echo to look for endocarditis
What is the investigation of choice for genital herpes?
NAAT
How should toxoplasmosis be managed?
Immunocompetent patients: no treatment
Immunocompromised patients: pyrimethamine and sulfadiazine
Which tropical disease can cause lactose intolerance?
Giardia
What is the first line treatment for amoebiasis?
Metronidazole
What is the most common cause of traveller’s diarrhoea?
E coli
Which organism causes gas gangrene?
Clostridium perfringens
What is the antibiotic regime of choice in neutropenic sepsis?
IV Tazocin
What should be conducted at time of HIV diagnosis?
Full STI, Hep C & TB screen
What CD4 count is required for AIDS?
CD4 < 200cells/ml
What are the HIV complications by CD4 count?
500 - hodgkin’s, cervical cancer
400 - TB, Oropharyngeal candida, seborrhoeic dermatitis, fungal infections (lymphadenopathy, sweats)
300 - oral hairy leukoplakia, shingles, pneumocystis pneumonia, persistent herpes complex - non hodgkin’s, weight loss
200 - oesophageal candida, cerebral toxoplasmosis, cryptococcal meningitis, cryptosporidiosis, kaposi’s sarcoma, diarrhoea, wasting
100 - primary cerebral lymphoma, cmv infection, atypical mycobacterial infection - dementia
Type of virus HIV is?
retrovirus
HIV 1 = common
HIV 2 = west africa
Papilloedema, meningism, neurological signs in the context of HIV
Cryptococcal meningitis
serum cryptococcal antigen (CrAg)
rasied opening pressure on LP
Acute worsening of infection after starting ART
Immune Reconstitution Inflammatory Syndrome (IRIS) - worsening of infection
What drugs are given to treat HIV?
2 NRTI + one more agent
Side effects of ART
Hypersensitivity Lipodystrophy
Lipoatrophy
T2DM
Hyperlipidaemia
HIV: reduced visual acuity and perivascular infilitrates
CMV retintis
HIV: odonophagia and white mucoasl plaques at endoscopy
Oesophageal candidiasis
HIV: Violaceous plaques and HHV8
Kaposi’s sarcoma
First line Ix for HIV
HIV antibodies + p24 antigen
- repeat to confirm if +ve in 12 weeks and commence AV therapy
- repeat in 12 weeks if -ve
What causes Syphilis?
Treponema pallidum
Why CSF and CXR in syphilis?
csf - neurosyphilis - csf vdrl
CxR - aortic aneurysm / calcification
What are the signs of neurosyphilis?
visual disturbance, tabes dorsalis, gneral paresis
How is neurosyphilis treated?
IV aqueous Benzylpenicillin
How is latent +ve and -ve syphilis treated?
IM benzathine benzylpenicillin (+ve) - once
-ve = three doses over two weeks
What is a Jarisch-Herxheimer reaction?
acute febrile illness within 24 hrs of starting syphilis treatment
acute fever, headache, myalgia
How does syphilis present under microscopy?
Coiled spirochaete bacterium with corkscrew appearance and motility
only use if lesion present, if not then do trep serology - check HIV
Treatment for CNS involvement with TB
12 months (extra 4 month now 10) + 4-8 weeks po steroids
What patients with TB should be managed by a MDT
HIV
Diabetes
CKD 4-5
Severe Liver Disease
Pregnancy
Patients with latent TB should be tested for what?
HIV, Hep B/C
If latent TB comes back +ve after IGRA
3 months R/I
or
6 months I/P
CSF low glucose, high protein and lymphocytes
TB Meningitis
First line for active TB
CXR & Sputum
What type of organism is C.difficile
Gram +ve spore forming anaerobic bacillus
What are the main drugs C.Difficile is associated with?
Cephalosporins
Quinolones
Penicillins
RF for C.Difficile
Older age 65
AB treatment & PPI
Prolonged hospitalisation
previous history
When is relapse defined?
<12 weeks
How are mild - moderate C.Difficle treated?
mild - supportive + PO Vancomycin 10-14 days
moderate - 3-5 stools - fidaxomicin if vanco fails - relapse
What are associated features of Severe and life threatening C.Difficile?
Severe - AKi, Temp >38.5, severe colitis, WBC >15
LT - Colitis, HTN, Ileus, Toxic Megacolon
How is LT C.Difficile treated?
PO / NG Vancomycin (PR if Ileus) + IV Metronidazole + Surgery
Poly-arthralgia, conjunctivitis, mucosal ulcers
Reactive arthritis
Chronic abdo pain, altered bowel habit with no identifiable cause
Post-infectious IBS
Do you need to wait to treat c.difficile if clinically suspected?
No
Incubation periods for all types of Malaria?
Falciparum - 12-14
Vivax & Ovale - 14, could occur months after due to hypzonite reactivation
Malariae = 18 days - low grade fever for yrs tho
Sign of severe Malaria
Hyperparasitaemia > 10%
List some complications of Malaria
CNS - low glucose csf, cerebral oedema
liver - jaundice
Haem - bleeding, DIC
Pulmonary oedema, ARDS
Shock
What organism causes Dengue? Incubation period?
Aedes aegypti
3-14 days
Main test for Infectious mononucleosis
monospot test
Main sign of rocky mountain spotted fever
tick bite - treat with doxycycline
General malaise, relative bradycardia, rose spots
Salmonella typhi
Bulls eye rash
Erythema chronicum migrans
Lyme disease
Main signs and investigations for cryptococcal meningitis + treatment
high opening pressure with CNS signs
India ink stain
Amphotercin B + Flucytosine
Main investigation finding of TB Meningitis
High lymphocyte count, high protein and low glucose
Sign of brain imaging for progressive multifocal leukoencephalopathy
demyelination, no mass effect and no contrast enhancement on MRI
treat with ART
CXR signs of PJP
diffuse bilteral interstitial infiltrates
treat with trimethoprim + sulfamethoxazole
Main complication of ETEC
reactive arthritis
Campylobacter complications
bacteraemia
colitis
reactive arthritis
GBS
GI perforation
azithromycin in severe
How is Shigella treated
fluoroquinolones
How is salmonella treated?
Ciprofloxacin
How is Giardia treated?
Tinidazole
What is a Treponema Pallidum specific test?
TP - EIA
Causes of false +ve non-treponemal tests
Pregnancy
SLE, anti-phospholipid
TB
Leprosy
Malaria
HIV
how if -ve with +ve speific test = successfully treated syphilis
What AB can be used to treat MRSA?
Vancomycin
Teicoplanin
Linezolid
Organisms that cause post splenectomy sepsis
Strep Pneumoniae
Haemophilus Influenzae
Meingococci
treat with vaccines + PenV 500mg or Amox 250mg
decrease phagocutosis and complement activation
Flaccid paralysis, complex ophtalmoplegia, IVDU
Botulism
c. botulinum - antitoxin
Chlamydia treatment
7d - Doxycycline
Macrolides secondary - pregnant = first
Adverse effects of Metronidazole
Disulfiram reaction with alcohol
Increases the anticoagulant effect of warfarin
Dysentery, liver abscesses, colonic abscesses, inflammatory masses in colon
Entamoeba histolytica
trophozoites, oral metronidazole + luminal agent diloxanide furoate
What is the organism for Bacterial Vaginalis?
Gardnerella vaginalis
use clinda if metronidazole cannot be used
oral met 5 - 7 days for treatment, alkaline, stippled, whiff
Causes of acute food poisoning
staph (severe, short incubation), bacillus (rice), clostridium perfringens
How is legionella pneumophilia best diagnosed
Urinary antigen
questions hint at air conditioning or foreign holidays
Features of legionella
dry cough
relative bradycardia
confusion
lymphopaenia
hyponatraemia
deranged liver function tests
pleural effusion: seen in around 30% of patients
CXR signs of legionella
mid to lower zone predominance of patchy consolidation
How is legionella treated?
Erythromycin / clarithromycin
Gold standard investigation for TB
sputum culture
NAAT = rapid diagnosis but less sensitive
What decreases the sensitivity of sputum smear in TB
decreased in individuals with HIV
50 to 20%
What is a classical finding of reactivated TB
upper lobe cavitation
What does mantoux test? What causes false negatives?
latent Tb
FN:
miliary TB
sarcoidosis
HIV
lymphoma
very young age (e.g. < 6 months)
Uti in third trimester
7 days amoxicillin / cefalexin
Adverse effects of tetracycline
discolouration of teeth
photosensitivity
angioedema
black hairy tongue
When is staph the most common cause of pneumonia
After the influenza infection
what is a specific feature of pneumococcal pneumonia
herpes labialis
cold sores
Name local complications to gonorrhoea
urethral strictures, epididymitis, inferility
Treatment order for gonorrhoea
IM ceftriaxone 1g
oral ciprofloxacin 500mg
needle phobic:
- oral cefixime 400mg + oral azithromycin 2g
Key features of DGI
tenosynovitis
migratory polyarthritis
dermatitis
What organism is associated with oral herpes
HSV-1
What is a calcified ghon complex a sign of?
Latent TB
RF for developing active TB from latent TB
silicosis
chronic renal failure
HIV positive
solid organ transplantation with immunosuppression
intravenous drug use
haematological malignancy
anti-TNF treatment
previous gastrectomy
First line for borrelia burgdorferi Ix
ELISA
How to treat tic bites
remove it is using fine-tipped tweezers, grasping the tick as close to the skin as possible and pulling upwards firmly. The area should be washed following
Causes of viral meningitis
non-polio enteroviruses e.g. coxsackie virus, echovirus
mumps
herpes simplex virus (HSV), cytomegalovirus (CMV), herpes zoster viruses
HIV
measles
key findings of viral meningitis on LP
lymphocytes
normal glucose
raised wbC
normal protein
What are the features of yellow fever?
sudden onset high fever, rigors, nausea and vomiting
bradycardia
jaundice
haematemesis
oligouria
councilman bodies - inclusion bodies - hepatocytes
Features seen in behcet disease
oral ulcer, genital, uveitis
VTE
Features of bacterial meningitis
cloudy
low glucose
high protein
raised wcc
atypical lymphocytes on blood film
infectious mononucleosis
Complications of Hep B infection
chronic hepatitis (5-10%). ‘Ground-glass’ hepatocytes may be seen on light microscopy
fulminant liver failure (1%)
hepatocellular carcinoma
glomerulonephritis
polyarteritis nodosa
cryoglobulinaemia
main treatment for hep B
pegylated interferon alpha
Features of Mycoplasma pneumoniae
prolonged and gradual onset disease
flu-like precede a dry cough
bilateral consolidation
Complications of Mycoplasma pneumoniae
cold agglutins (IgM): may cause an haemolytic anaemia, thrombocytopenia
erythema multiforme, erythema nodosum
meningoencephalitis, Guillain-Barre syndrome and other immune-mediated neurological diseases
bullous myringitis: painful vesicles on the tympanic membrane
pericarditis/myocarditis
gastrointestinal: hepatitis, pancreatitis
renal: acute glomerulonephritis
Ix for Mycoplasma pneumoniae
serology
+ve cold agglutination - smear show red blood cell agglutination
treat with doxy / macrolide
Ongoing diarrhoea, lethargy, bloating, flatulence, steatorrhoea, weight loss with recent travel
giardiasis
metronidazole treatment
Indications for delayed lumbar puncture
signs of severe sepsis or a rapidly evolving rash
severe respiratory/cardiac compromise
significant bleeding risk
signs of raised intracranial pressure
focal neurological signs
papilloedema
continuous or uncontrolled seizures
GCS ≤ 12
why is dexamethasone given with treatment of meningitis
improves outcomes by reducing neurological sequelae
If above 50 what ABs should be given for bacterial meningitis
cefotaxime + amoxicillin
gentamicin if listeria
Young adult with sore throat, fever, lethargy, cervical lymphadenopathy persisting > 1 week
Infectious mononucleosis
acute pyelonephritis treatment
broad spec cephalosporin + quinolone
Risk factors for Invasive aspergillosis
HIV, leukaemia, BS antibiotics
Who should be vaccinated for Hep A
- people travelling to or going to reside in areas of high or intermediate prevalence, if aged > 1 year old
- people with chronic liver disease
- patients with haemophilia
- men who have sex with men
- injecting drug users
- individuals at occupational risk: laboratory worker; staff of large residential institutions; sewage workers; people who work with primates
What are genital warts and how are they treated?
Small fleshy protuberances pigmented
topical podophyllum
imiquimod second line
caused by HPV 6 & 11
What bacteria has the shortest incubation period
Bacillus
Staph aureus
How is Jarisch_herxheimer reaction treated
supportively - IV paracetemol
Drug to treat patient with pencillin allergy that gets cellulitis
erythromycin
Indications to send urine culture in non pregnant women
aged 65<
visible or non visible haematuria
only 3 day course of Ab
What is the alternative for doxycycline in CT treatment with a pregnant lady
azithromycin
risk of dental discolouration and enamel hypoplasia
Flagellated protozoa name and treatment
trichomonas vaginalis
metronidazole
What condition does self limiting toxo mimic
infectious mononucleosis
What are common side effects of amoxicillin
diarrhoea and nausea
what is this?
Kaposi’s sarcoma
alternative to lumber puncture on diagnosing meningitis
whole blood pcr and blood cultures
Features of cholra and mx
Profuse rice water diarrhoea
dehydration
hypoglycaemia
oral rehydration therapy and doxy / cipro
cellulitis near the eye treatment
amoxicillin + clavulanic acid aka co-amoxiclav
Patients with uncertain tetanus vaccine should get what
Vaccine + Ig (if severe wound or > 6 hrs)
if more than 10 yrs ago just vaccine, if high risk add Ig
Post treatment for UTI in pregnancy what should be done
Urine culture
risk of pyelonephritis
Target shaped lesion in lung
Aspergilloma
Which patients should be avoided with dexamethasone in Meingitis treatment?
septic
meningococcal
post surgery
immunocompromised
Asymptomatic BV
No treatment
unless pregnant - oral metronidazole
What is atypical pneumonia treated with
Clarithromycin
What should be added to treat pneumonia if secondary to influenza
flucloxacillin
HIV, diarrhoea, Ziehl-Neelsen stain showing protozoa
Cryptosporidium parvum
If a gram +ve organism coccus is resistant to penicillin what is it
MRSA
vanco, teico, linezolid
How does diptheria present
- recent visitors to Eastern Europe/Russia/Asia
- sore throat with a ‘diphtheric membrane’ - grey, pseudomembrane on the posterior pharyngeal wall
- bulky cervical lymphadenopathy
- may result in a ‘bull neck’ appearanace
- neuritis e.g. cranial nerves
- heart block
IM pen / dip anti-toxin
Best way to assess response for treatment to Hep C
Viral Load / HCV RNA level
What is a common complication of administering rapid intravenous infusion vancomycin
red man syndrome - vanco activates mast cells
stop, then re start at slower rate
Renal transplant + infection
CMV pneumonitis
What test for any mycobacteria
Acid fast bacilli
6 - 60 yrs bacterial meningitis causes
NM
Strep Pneumoniae
HIV, diarrhoea, Ziehl-Neelsen stain showing protozoa
Cryptosporidium Parvum
Main affects of chronic chagas disease
myocarditis leading to dilated cardiomyopathy
GI features - megaoesophagus, megacolon
treat complications and azole
Persistent PUO and lymphadenopathy with high WCC
lymphoma
lymph node biopsy
Sinusitis treatment
Phenoxymethylpenicillin
Acute prostatitis treatment
14 day of ciprofloxacin
Live attenuated vaccines
BCG
MMR
oral polio
yellow fever
oral typhoid
what is the incubation period of yellow fever
7 to 21 days
how many ulcers does chancroid present with
single
if multiple with same symptoms think genital ulcers
Which Hepatitis out of A and B has the shorter incubation period?
A - 15 to 50 days
B much longer
Lab features of pseudomonas aeruginosa
Gram-negative rod
non-lactose fermenting
oxidase positive
Late onset HAP should be treated how?
piperacillin with tazobactam OR a broad-spectrum cephalosporin (e.g. ceftazidime) OR a quinolone (e.g. ciprofloxacin)
Severe campylobacter infection should be treated with what
clarithromycin - macrolide
Negative non-treponemal test + positive treponemal test
Successfully treated syphilis
Positive non-treponemal test + negative treponemal test
consistent with a false-positive syphilis result e.g. due to pregnancy or SLE
Patient has had a full course of tetanus vaccines, with the last dose < 10 years ago
no vaccine nor tetanus immunoglobulin is required, regardless of the wound severity
Patient has had a full course of tetanus vaccines, with the last dose > 10 years ago
if tetanus prone wound: reinforcing dose of vaccine
high-risk wounds (e.g. compound fractures, delayed surgical intervention, significant degree of devitalised tissue): reinforcing dose of vaccine + tetanus immunoglobulin
How does pseudomonas present as a wound infection?
wet with a pale green slough over it and smells damp and offensive
Adverse effects of trimethoprim
myelosuppression
rise in creatinine, inhibits tubular secretion, blocks ENaC channel in distal nephron - hyperkalaemic distal TA
Extensive otitis externa treatment
Flucloxacillin
Fever on alternating days
Malaria
Mechanism of ritonavir
protease inhibitor
navir - navir tease a pro
zidovudine = NRTI, raltegravir = integrase inhibitor
large, keratinised genital wart treatment
cryotherapy
multiple = topical podophyllum
Long incubation period with dysentery
Amoebiasis
oral metronidazole
BCG in children protects against what
TB meningitis
Spinal epidural abscess Ix
full spine MRI to check for skip lesions
Most common cause of dysphagia and odynophagia with HIV disease
Oesophageal candidiasis
Signs of leptospirosis
commonly preceded by flu-like symptoms, associated with subconjunctival suffusion and is a cause of hepatorenal failure
flood, sewage based areas
Signs of chronic schisto
frequency, haematuria, bladder calcification
What is the normal dose of metronidazole for BV
400mg bd for 7 days
Treatment for erysipelas
flucloxacillin
Most common pathogen during anal sex
Hepatitis A