Infectious diseases

Question 1

gram postive anaerobes - use pneumonic clap

Answer 1

Use the mnemonic “CLAP”:

C – Clostridium
L – Lactobacillus
A – Actinomyces
P – Propionibacterium

Question 2

most common cause of chest infections

Answer 2

Streptococcus pneumoniae (50%) - gram positive diplococci 
Haemophilus influenzae (20%) - Gram-negative, coccobacillary, facultatively anaerobic

Question 3

on a urine dipstick test for UTI what do you expect to find

Answer 3

E coli breaks nitrates into nitrites
leukocytes seen too WBC - leukocyte esterase, a product of leukocytes that gives an indication to the number of leukocytes in the urine.
MSU

Question 4

causes of UTI

Answer 4

E.COLI GRMA NEAGTIVE ROD

Klebsiella pneumoniae (gram-negative anaerobic rod)
Enterococcus
Pseudomonas aeruginosa
Staphylococcus saprophyticus
Candida albicans (fungal)

Question 5

DURATION of treatment for women with simple LUTI
men , pregnant women or catheter related UTI
and women who immuncompressed

Answer 5

3 days of antibiotics for a simple lower urinary tract infection in women
5-10 days of antibiotics for women that are immunosuppressed, have abnormal anatomy or impaired kidney function
7 days of antibiotics for men, pregnant women or catheter related UTIs

Question 6

Lower UTI symptoms

Answer 6

Lower urinary tract infections present with:

Dysuria (pain, stinging or burning when passing urine)
Suprapubic pain or discomfort
Frequency
Urgency
Incontinence
Confusion is commonly the only symptom in older more frail patients

Question 7

symptoms of pyelonenphritis

Answer 7

Pyelonephritis presents with:

Fever is a more prominent feature than lower urinary tract infections.
Loin, suprapubic or back pain. This may be bilateral or unilateral.
Looking and feeling generally unwell
Vomiting
Loss of appetite
Haematuria
Renal angle tenderness on examination

Question 8

cellulitis causes

Answer 8

the most common causes are:

Staphylococcus aureus
Group A Streptococcus (mainly streptococcus pyogenes)
Group C Streptococcus (mainly Streptococcus dysgalactiae)
Other causes

MRSA

Question 9

1st choice antibiotic against cellulitis

Answer 9

he most common causes are:

Staphylococcus aureus
Group A Streptococcus (mainly streptococcus pyogenes)
Group C Streptococcus (mainly Streptococcus dysgalactiae)
Other causes

MRSA

Question 10

septic arthritis caused by what pathogen

Answer 10

Staphylococcus aureus is the most common causative organism.

Other bacteria:

Neisseria gonorrhoea (gonococcus) in sexually active individuals
Group A Streptococcus (most commonly Streptococcus pyogenes)
Haemophilus influenza
Escherichia coli (E. coli)

TOM TIP: In a young patient presenting with a single acutely swollen joint always think of gonococcus septic arthritis until proven otherwise. Gonorrhoea infection is common and delaying treatment puts the joint in danger. In your exams it might say the gram stain revealed a “gram-negative diplococcus”. The patient may have urinary or genital symptoms to trick you into thinking of reactive arthritis but remember that it is important to exclude gonococcal septic arthritis first as this is the more serious condition.

Question 11

4 differentials of septic arthritis

Answer 11

Gout (fluid shows urate crystals that are negatively birefringent of polarised light)
Pseudogout (fluid shows calcium pyrophosphate crystals that are rod-shaped intracellular crystals positively birefringent of polarised light)
Reactive arthritis typically triggered by urethritis or gastroenteritis and associated with conjunctivitis
Haemarthrosis (bleeding into the joint)

Question 12

antimalarials

Answer 12

Proguanil and atovaquone (Malarone)

Taken daily 2 days before, during and 1 week after being in endemic area
Most expensive (around £1 per tablet)
Best side effect profile

Mefloquine

Taken once weekly 2 weeks before, during and 4 weeks after being in endemic area
Can cause bad dreams and rarely psychotic disorders or seizures

Doxycycline

Taken daily 2 days before, during and 4 weeks after being in endemic area
Broad-spectrum antibiotic therefore it causes side effects like diarrhoea and thrush
Makes patients sensitive to the sun causing a rash and sunburn

Question 13

difference in crystals between gout and pseudo gout

Answer 13

gout - negatively birefrignemtn needle shaped crystals

pseudo- positively birefringement( reflective) rhomboid shaped crystals

Question 14

in the lab they find brown granular casts what could this be

Answer 14

acute tubular necrosis

Question 15

in the lab they find red cell casts what is this a sign of

Answer 15

nephritic syndrome