Infectious Disease Flashcards by Chrissy Bolton

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)

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Gram +ve Diplococci identified on sputum on a patient with a pneumonia, causative organism?

Strep pneumonia

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Who are particularly at risk of streptococci pneumoniae?

Hyposplenic patients (encapsulated like neisseria meningitidis)

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Type of streptococci causing brain abscess:

Strep milleri

6 weeks of penicillin + anaerobe cover- metronidazole

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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

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MRSA treatment?

Vancomycin, Teicoplanin, Penems

Contact isolation

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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

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Under what circumstances do you isolate a TB patient?

If they are infectious- organism seen on sputum

Coughing + sick

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Side effects of quinine given for malaria:

Hypoglycaemia (mimics insulin)

Tinnitus

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3 sequelae of group A streptococcal infection:

Scarlet fever
Glomerulonephritis
Rheumatic fever

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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)

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STI caused by gram negative diplococci?

Neisseria gonorrhoea

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3 organisms potentially causing neonatal sepsis?

Group B strep- (pneumoniae)
E Coli
Listeria

Rx: Benzylpenicillin + Gentamicin

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Investigation to confirm post-surgical abdominal abscess?

Ultrasound is best
No need for CT

Aspirate abscess

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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

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Antipseudomonal antibiotics

CAMP

Ciprofloxacin
Ceftazadime (3rd gen cephalosporin)
Aminoglycoside
Meropenem
Pipercillin Tazabactam (tazocin)

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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)