Infectious Diseases & Antibiotics Flashcards
Which causes of gastroenteritis are relate to uncooked poultry?
Salmonella (non-typhoid)
Campylobacter
What is the most common bacterial cause of gastroenteritis?
Campylobacter
What is the most common infective cause of bloody diarrhoea without fever?
E. coli
What is the main complication of E. coli? What does it consist of?
Haemolytic uraemic syndrome - triad of
Haemolytic anaemia
Acute kidney injury
Thrombocytopenia (low platelets)
What is the name of the toxin produced by E. coli?
Shiga toxin
How does typhoid fever present?
Systemic upset – headache fever Arthralgia
Relative bradycardia (pulse is lower than expected for temperature)
Abdominal pain and distension
Constipation or diarrhoea (pea soup diarrhoea)
Rose spots (more common in paratyphoid)
How is typhoid fever treated?
Ciprofloxacin
How is Shigella transmitted?
Faeces contaminated water/food
How does shigella present?
Bloody diarrhoea
Abdominal cramps
Fever
Vomiting
Can cause haemolytic uraemic syndrome - AKI, haemolytic anaemia, low platelets
How is shigella infection treated?
Management is mostly supportive
If severe azithromycin/ciprofloxacin can be used
How does dengue fever present?
Retro-orbital headache
Facial flushing
Maculopapular rash
Fever Myalgia Arthralgia Pleuritic pain Lymphadenopathy
How is dengue fever treated?
Supportive treatment with fluids and potentially blood transfusions
What is giardiasis?
A parasitic infection caused by the protozoa giardia lamblia
How is Giardiasis transmitted?
Faeco-oral
How does Giardiasis infection present?
Long-lasting diarrhoea with associated weight loss due to malabsorption
Steatorrhoea
Associated with lactose intolerance - this may continue beyond treatment
Abdominal pain and excess flatulence
Vomiting and fever are uncommon
How is Giardiasis treated?
Metronidazole
Note: After treatment there can be transient lactose intolerance
What antibiotic is used for rheumatic fever?
Stat dose IV Benzylpenicillin
Oral Penicillin V
What antibiotics are used for the initial management of IE (no culture)?
Native valve -> Amoxicillin
Prosthetic valve -> Vancomycin + Rifampicin + Gentamicin
What antibiotics are used for IE which has been confirmed to be caused by a staph infection?
Native valve -> Flucloxacillin
Prosthetic valve -> Flucloxacillin + Rifampicin + Gentamicin
What organism causes cellulitis and which antibiotics are used?
Most common organism = staph aureus
1st line = Flucloxacillin (Clarithromycin/Erythromycin if pen allergic)
If severe = Co-amoxiclav or a cephalosporin
What organism causes Erysipelas and what antibiotic is used?
Usually caused by strep pyogenes
First line is Fluclox
What is the first and second line treatment for impetigo? What about if it’s widespread?
- Hydrogen peroxide cream
- Topical fusidic acid
- Oral flucloxacillin
What organism most commonly causes acute otitis media and wha is the antibiotic of choice?
Organism = strep pneumoniae/haem influenzae
Abx = Amoxicillin (or Clarithromycin)
What are indications for Abx in acute otitis media?
Symptoms lasting more than 4 days
Systemically unwell
Immunocompromised
Under 2 years with bilateral otitis media
Perforation/discharge
What is the most common organism that causes otitis externa and what is the antibiotic of choice?
Organism = Pseudomonas and staph aureus
Abx = topical Neomycin + Dexamethasone
If tympanic membrane is perforated = Ciprofloxacin + Dexamethasone
How is malignant otitis external managed?
IV Ciprofloxacin
What is the most common organism that causes tonsillitis and what is the antibiotic of choice?
Organism = strep pyogenes
Abx = Penicillin V (or Clarithromycin)
What is the triple eradication therapy for H.pylori?
PPI + Amoxicillin + Clarithromycin/Metronidazole
If pen allergic - PPI + Clarithromycin + Metronidazole
What antibiotic is used for diverticulitis?
Oral co-amoxiclav
If no improvement -> IV Ceftriaxone + metronidazole
What is the most common organism that causes peritonitis and what is the antibiotic of choice?
Organism = E.coli
Abx = IV Cefotaxime / Tazocin
What prophylaxis do patients who have had an episode of spontaneous bacterial peritonitis require?
Oral Ciprofloxacin
What is the first line management for C.diff? What if it is life-threatening? What indicates a life-threatening infection?
First line = oral Vancomycin
Life-threatening = oral Vancomycin + IV Metronidazole
Life-threatening = hypotensive
What antibiotics are used for neutropenic sepsis?
IV Tazocin
What is used to treat encephalitis?
IV Aciclovir
What is the most common cause of meningitis and how is it treated?
Organism = Neisseria meningitidis
<3 months = IV Cefotaxime + Amoxicillin
3m-50 years = IV Cefotaxime
>50 years = IV Cefotaxime + Amoxicillin
Ceftriaxone is an alternative to Cefotaxime
Not Cefuroxime
What prophylaxis are close contacts of someone with diagnosed meningitis given?
Oral ciprofloxacin or rifampicin
What is the antibiotic used for intrapartum prophylaxis of Group B strep?
IV Benzylpenicillin
What is the causative organism of UTI and what is the antibiotic of choice?
Nitrofurantoin/Trimethoprim
1st and 2nd trimester = Avoid trimethoprim
At term = Avoid nitrofurantoin
What is the causative organism and treatment for osteomyelitis?
Organism = staph aureus
Abx = 6 weeks fluclox IV (or clindamycin)
What is the causative organism and antibiotic of choice for septic arthritis?
Organism = staph aureus
Abx = flucloxacillin + rifampicin
What is the antibiotic of choice for BV?
Metronidazole
What is the antibiotic of choice for Trichamonas?
Metronidazole
What is the antibiotic of choice for Chlamydia?
Doxycycline
In pregnancy = Azithromycin/erythromycin
What is the antibiotic of choice for Gonorrhoea?
IM Ceftriaxone
What is the antibiotic of choice for Syphilis?
IM Benzathine Benzylpenicillin
What antibiotic is used for COPD exacerbations?
Amoxicillin / Doxycycline / Clarithromycin
What is the most common organism which causes COPD exacerbations?
Haemophilus influenzae
What antibiotic can be used for acute bronchitis and when is it used?
Doxycycline
If raised CRP >100 / systemically unwell / co-morbidities (asthma/COPD)
What antibiotics are used for community-acquired pneumonia?
CURB-65 score
0/1 -> Amoxicillin
2 -> Amoxicillin + Clarithromycin (admission)
3-5 -> IV Co-Amoxiclav + Clarithromycin (admission)
What antibiotic is used for hospital-acquired pneumonia?
Co-amoxiclav
If severe -> Tazocin
Which antibiotics are used for aspiration pneumonia?
IV Cephalosporin + Metronidazole
Which antibiotics are used for TB?
Isoniazid 6m
Rifampicin 6m
Pyrazinamide 2m
Ethambutol 2m
What antibiotic is first line for campylobacter? When should it be given?
Clarithromycin, if immunocompromied
What are complications of camylobacter infection?
Guillan barre syndrome
Reactive arthritis
Which type of pneumonia is predisposed by a preceding influenza infection?
Staph aureus
Which type of pneumonia is classically in alcoholics?
Klebsiella
Which pneumonia classically causes a bilateral consolidation and potentially haemolytic anaemia/erythema multiforme (target lesions?
Mycoplasma pneumoniae
Which bacteria is most commonly associated with eating undercooked rice?
Bacillus cereus
Pneumonia symptoms + pain in extremities?
Mycoplasma pneumoniae
Due to autoimmune haemolytic anaemia
What is the most common type of Malaria?
Plasmodium Falciparum
How does Malaria typically present?
Returning traveller High fever Malaise Myalgia Headache Jaundice
What are complications of malaria?
Hypoglycaemia
Cerebral malaria (seizures)
ARDS
Acute renal failure
DIC
How is malaria diagnosed?
Schizonts on blood film
How can malaria be excluded?
Need at least 3 blood samples on 3 different days
What are signs of malaria?
Haemolytic anaemia
Hepatosplenomegaly
Jaundice
Low platelets
What is the most common non-falciparum malaria?
Plasmodium vivax
Malaria with cyclical fever every 48 hours?
Plasmodium vivax / plasmodium ovale
How is malaria treated?
Chloroquine
Patients with ovale/vivax need Primaquien following acute treatment
How does amoebiasis present?
Can be asymptomatic, present with amoebic dysentry or liver abscessess
Amoebic dysentry = Profuse bloody diarrhoea
If amoebiasis liver abscess - fever, RUQ pain
How does Cholera present?
Traveller’s diarrhoea
Profusely watery diarrhoea
Abdominal cramps
Patient will be severely dehydrated
How does leprosy present? How is it treated?
Patches of hypopigmented skin with sensory loss over the patches
Triple therapy - Rifampicin/Dapsone/Clofazimine
What is leptospirosis? Who does it occur in and how does it present?
Infection which is spread by infected rat urine
In sewage workers/farmers/vets
Fever, flu-like symptoms
Red eyes
AKI
Hepatitis
What is the causative organism of Lyme disease?
Borrelia Burgdorferi
How does Lyme disease present?
Early features = Erythema migrans (bulls-eye rash)
Usually 1-4 weeks after bite
PAINLESS
May be systemic features - headache, lethargy, fever
Late features = Heart block/pericarditis/facial nerve palsy/meningitis
How is Lyme disease diagnosed?
Usually can be diagnosed clinically with erythema migrans
How is Lyme disease treated?
Doxycycline
Amoxicillin if Doxy is CI
What is the usual carrier of Toxoplasmosis?
Cat
How does Toxoplasmosis present?
Resembles mononucleosis
Fever
Malaise
Lymphadenopathy
How can Toxoplasmosis affect patients with HIV?
Can cause CNS symptoms - headache/confusion/drowsiness
Will present on CT as ring-enhancing lesions
How is Toxoplasmosis treated?
Pyrimethamine + Sulphadiazine
What are the two causes of pneumonia + deranged LFTs?
Legionella
Mycoplasma
How does legionella pneumonia present?
Dry cough
Deranged LFTs
Low lymphocytes
Low sodium
How is legionella diagnosed?
Urinary antigen
How is mycoplasma diagnosed?
serology
How does mycoplasma pneumonia present?
Flu like symptoms
Dry cough
Bilateral consolidation
Cold autoimmune haemolytic anaemia
Erythema multiforme
How is Legionalla + Mycoplasma treated?
Macrolide
What is the first line treatment for MRSA?
Vancomycin
What pathogen causes TB?
Mycobacterium tuberculosis
How is primary TB seen on a CXR?
Ghon focus (caseating granuloma)
How is TB meningitis seen on lumbar puncture?
Raised protein
Low glucose
Raised lymphocytes
How is latent TB diagnosed?
Mantoux test or Interferon-gamma blood test
How is active TB diagnosed?
Sputum culture = gold standard but this can take a long time
Ziehl-Neelsen stain is often used
What are options for malaria prophylaxis?
Doxycycline
Mefloquine
Proguanil + Atovaquone
Which types of hepatitis are spread faeco-orally?
Hepatitis A
Hepatitis E
Which types of hepatitis are spread bloodbourne?
Hepatitis B
Hepatitis C
Hepatitis D
Hepatitis B antibodies: HbsAb(Anti-HbS) positive
Immunised
Hepatitis B antibodies: HBcAb and HBsAb
Previous infection and now resolved
Hepatitis B antibodies: HBsAg and HBcAb
Chronic infection
How to manage a neonate whose mother has Hepatitis B?
HBIG within 24 hours of birth
Full course of vaccinations
How is HIV monitored?
CD4 T-cell count
HIV viral load
What is the progression of HIV?
Acute primary infection (seroconversion) = fever, malaise, lymphadenopathy
Usually 2-4 weeks post exposure
Asymptomatic phase - progressive loss of CD4 T cells
Early symptomatic phase
AIDS
What are AIDS defining illnesses?
Kaposi's sarcoma Pneumocystis pneumonia CMV infection Oesophageal/bronchial candidiasis Lymphoma TB
How is HIV diagnosed?
p24 antigen
Antibody (takes longer to become positive)
PCR
How is HIV treated?
Triple antiretroviral therapy - NRTI/NNRTI/Protease inhibitor
What is Kaposi’s sarcoma?
AIDS defining illness
Caused by HHV8
Papules/macules/nodules across body
How is PCP treated?
Co-trixomazole
Who needs PCP prophylaxis?
HIV with CD4 count <200
What antibiotic should be given in the case of an animal or human bite?
Oral co-amoxiclav
What is the most common cause of viral meningitis?
Enteroviruses e.g. Coxsackie
What is seen on lumbar puncture in viral meningitis?
Lymphocyte predominant
Normal glucose
Raised protein ???
What is the most common cause of necrotising fasciitis?
Strep pyrogenes
How is necrotising fasciitis treated?
IV Abx + urgent surgical debridement
What is seen on CXR in PCP?
Interstitial pulmonary infiltrates
What might make you suspect meningococcal meningitis?
Non-blanching rash
How is meningococcal meningitis treated in hospital?
Prior to admission = IM benzylpenciilln
In hospital = IV Benzylpenicillin or IV Ceftriaxone
If sensitivity to penicillin and cephalosporins = Chloramphenicol
How is bacterial meningitis (aetiology unknown) treated in hospital?
3yrs-50 years = Cefotaxime/Ceftriaxone
> 50 years = Ceftriaxone/Cefotaxime + Amoxicillin
How long is HIV Post-exposure prophylaxis?
4 weeks
What are side effects of tetracyclines?
Discolouration of teeth Photosensitivity Black hairy tongue Angioedema IIH
Which types of gastroenteritis present within hours of eating the contaminated food?
Staph aureus
Bacillus cereus
What is the incubation period of Salmonella?
24-48 hrs
What is the incubation period of E.coli?
24-48 hours
Which causes of gastroenteritis have an incubation period of more than 7 days?
Giardiasis
Amoebiasis
Which macrolides are safe in pregnancy?
Erythromycin or Azithromycin
NOT Clarithromycin
Which malignancies are associated with EBV?
Burkitt’s Lymphoma
Hodgkin’s Lymphoma
Nasopharyngeal carcinoma
What is the most severe complication of Chagas disease?
Cardiomyopathy
What is the most common cause of pneumonia in patients who have CF?
Pseudomonas
What should be tested for in everyone diagnosed with TB?
HIV
What can cause a false negative Mantoux test in a patient with TB?
Sarcoidosis Immunosuppression - AIDS, steroids Lymphoma Fever Hypoalbuminaemia Anaemia
What can cause a false positive Mantoux test in a patient who does not have TB?
BCG vaccination
HIV + Neuro symptoms – How can you tell the diagnosis from MRI head?
Multiple ring enhancing lesions = Toxoplasmosis
Single homogenous enhanced lesion = Lymphoma
Chancroid vs. Syphilis Chancre vs Lymphogranuloma vereneum?
Painless ulcer and painless lymphadenopathy = Syphilis (Chancre)
Painless ulcer and painful lymphadenopathy = LGV
Painful ulcer and painful lymphadenopathy = Chancroid
Which bacteria stains with India ink?
Cryptococcus
How does cryptococcosis present on LP?
High opening pressure
India ink staining positive
Which types of hepatitis have an increased risk of developing hepatocellular carcinoma?
Hepatitis C (Most common) Chronic hepatitis B
How is hep A managed?
Self limiting
Which drug should be given alongside isoniazid?
Pyridoxine (Vitamin B6)
What is used to treat cytomegalovirus retinitis?
IV Ganciclovir
Which antibiotic used for whooping cough?
Clarithromycin
What is schistosomiasis and how does it present?
Parasitic flatworm infection
Enters from water - from freshwater swimming
Initially presents with a swimmer’s itch
Can then lead to hepatosplenomegaly, RUQ pain
Chronic = haematuria + dysuria
How is schistosomiasis treated?
Praziquantel