Infectious Disease Flashcards
In a patient with pneumonia, what investigation should be included to identify atypical bacterial causes?
Blood serology- mycoplasma, legionella, 2 chlamydias
Will give co-amoxicillin (streps) + clarithromycin (atypicals)
Gram +ve Diplococci identified on sputum on a patient with a pneumonia, causative organism?
Strep pneumonia
Who are particularly at risk of streptococci pneumoniae?
Hyposplenic patients (encapsulated like neisseria meningitidis)
Type of streptococci causing brain abscess:
Strep milleri
6 weeks of penicillin + anaerobe cover- metronidazole
Which organisms causing osteomyelitis have a predilection for spine?
TB
Brucella
Staph aureus is always a common cuase of osteomyelitis
Sodium fusidate/fusidic acid can help antibiotic uptake in bone
MRSA treatment?
Vancomycin, Teicoplanin, Penems
Contact isolation
Investigations for TB:
Sputum- acid fast bacilli
Skin test- Mantoux (may be -ve if sick patient)
Interferon-gamma release assay- cultures patient’s T cells to different antigens and measures response
Under what circumstances do you isolate a TB patient?
If they are infectious- organism seen on sputum
Coughing + sick
Side effects of quinine given for malaria:
Hypoglycaemia (mimics insulin)
Tinnitus
3 sequelae of group A streptococcal infection:
Scarlet fever
Glomerulonephritis
Rheumatic fever
What is the commonest type of Nisseria Meningitidis (the one we get immunised against) + Rx:
Type B
(Type A- is in developing countries)
Rx: Ceftriaxone Respiratory isolation (droplet spread)
STI caused by gram negative diplococci?
Neisseria gonorrhoea
3 organisms potentially causing neonatal sepsis?
Group B strep- (pneumoniae)
E Coli
Listeria
Rx: Benzylpenicillin + Gentamicin
Investigation to confirm post-surgical abdominal abscess?
Ultrasound is best
No need for CT
Aspirate abscess
Abdominal abscess following surgery to the gut, what are likely type of organisms?
Gut flora- gram negative aerobes (E Coli, Klebsiella etc)
Anaerobes
Rx: Co-amoxiclav (has anaerobic activity)
Can add gentamicin to mop up bacteria in the blood stream- good for resistant Gram Negative
Antipseudomonal antibiotics
CAMP
Ciprofloxacin Ceftazadime (3rd gen cephalosporin) Aminoglycoside Meropenem Pipercillin Tazabactam (tazocin)
Which antibiotics cause C Diff?
All the C's Co-amoxiclav Ciprofloxacin Cephalosporins Clindamycin
What level of dilatation does large bowel obstruction become toxic mega colon?
9cm is bowel obstruction
12cm is toxic megacolon
Which antibiotics cause cholestasis?
A NIT FLEW and CLAWed to have a Cip
FluCloxacillin
Nitrofurantoin
Clauvanate
Ciprofloxacin (fluoroquinolone)
Live vaccines that should not be given if a patient is immunosupressed?
Tie My BiG Yellow Pole (aka Oli):
Typhoid MMR BCG Yellow fever Polio
Name some tropical diseases with a short incubation time?
<10 days
Dengue
Rickettsia- tick typhus
Borella- relapsing fever (lyme)
Name some infectious diseases with an intermediate incubation period?
10-21 days
Malaria
Typhoid- salmonella typhi (enteric fever)
Typanosomiasis (protozoa) Chagas disease (another type of trypanosome) Brucellosis- unpasteurised milk Leptospirosis Q fever- coxiella
Infections with long incubation period?
>21 days
Malaria Amoebic liver abscess Leishmaniasis Hepatitis HIV
Patient who has a fever + a rash, onset on last day of 7 day holiday in thailand, no sexual contacts. Possible cause?
Dengue fever- short incubation period
Malaria would be more like 10+ days to occur
Get low platelets and low lymphocytes, with transaminitis
What kinds of rash occur with Dengue fever?
Early- erythroderma
Petechiae
Late- desquamation
Patient swims in lake malawi and now has haematuria, probable cause?
IHx to confirm diagnosis?
Schistosomiasis
Eosinophilia
ELISA +ve
Cystoscopy +bladder biopsy
3 types of helminth?
Nematodes- roundworm
Soil transmitted = ascaris, hookworm, strongyloides
Filaria = bancroftian, onchocerca (may obstruct lymphatics)
Trematodes- flukes
Schistosoma
Cestodes- tapeworms
Hydatid
Cysticercosis
Out of the soil transmitted helminths (roundworms), which are faeco-oral transmitted and which are percutaneously transmitted?
Faeco-oral: ascaris
Percutaneous: hookworm, strongyloides
In suspected a tropical infectious disease, when would you do a urine MC+S rather than a stool parasites + ova?
In suspected schistosoma haemotobium
What does the thick film and thin film tell you in malaria?
Thick film- sensitivity
Thin film- severity + species of falciparum
Can do a ‘rapid diagnostic test’ also
Name some opportunistic infections with low pathogenicity that cause problems for those immunocompromised
Normally low pathogenicity:
Coagulase negative staphlococci (S. epidermidis) Pseudomonas Candida albicans Pneumocystic jiroveci CMV
A CD4 count under 100 puts HIV patients at risk of which diseases?
Toxoplasmosis
Cryptosporidiosis
Cryptococcus
CMV
Mycobacterium avium (<50)
Rx of cerebral toxoplasmosis?
Sulphadiazine
Pyrimethamine
Folinic acid
An immunocompromised patient has a blood culture which shows a gram positive rod, name the likely organism:
Listeria
Rx: amoxicillin
What CD4 count in HIV do you start giving co-trimoxazole to prevent PCP?
<200
Why does penicillin not affect gram negative bacteria?
They have a lipopolysaccharide layer around the peptidoglycan wall, which protects it from antibiotic attack
Amoxicillin is semi-synthetic and between able to permeate this layer so is more effective against gram negatives
What antibiotic is needed for pseudomonas or extended-spectrum beta lactamase microbes (can get around flucloxacillin + co-amoxiclav)
Piperacillin + tazobactam
Or other z-containing drugs
For staph aureus and staph epidermidis that are methicillin resistant, which antibiotic is recommended?
Glycopeptides- inhibit synthesis of peptidoglycan wall
Vancomycin or Teicoplanin
If resistant to this too, Linezolid
Which antibiotics work on pseudomonas?
Ciprofloxacin (quinolone, prevents supercoiling, 50% resistant)
Gentamicin, ceftaZadime, taZocin, meropenem
In a patient with gastroenteritis, what makes campylobacter more likely than shigella/salmonella/ E Coli, and how is Rx different?
PC: Severe abdominal cramps
3 day incubation period (whereas the other’s have a 2 day incubation)
IHx: gram negative spirals, the others are gram negative rods
Rx: macrolide, whereas salmonella, E Coli etc, you use ciprofloxacin
What side effect occurs in long term metronidazole?
Peripheral nephropathy- interferes with B6 metabolism (pyridoxine)
