EMQs in Clinical Medicine.pdf - Peshawar Medical College

230 Miscellaneous
ANSWERS
85 Antibiotics
Answers: A H I D G
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A 35-year-old man with a hot swollen knee where septic arthritis is
suspected.
This is a medical emergency and urgent Gram staining and culture are
indicated. Staphylococcus aureus is the most common infecting pathogen
in septic arthritis. Intravenous benzylpenicillin plus flucloxacillin is the
preferred treatment until sensitivities are known. Remember the possibility
of opportunistic infection if the patient is immunocompromised,
e.g. HIV positive.
A 54-year-old patient on the ward requires drug therapy for systemic
MRSA infection.
Vancomycin is a glycopeptide antibiotic and is indicated for the
treatment of MRSA infection. It should be given only intravenously for
systemic infection because it is not significantly absorbed when given
orally. Teicoplanin is a similar glycopeptide antibiotic with a longer
duration of action (so it can be given once daily).
A 23-year-old pregnant woman requires treatment for an
uncomplicated urinary tract infection (UTI).
Trimethoprim should not be given in pregnancy because it is a folic acid
antagonist and teratogenic.
Quinolones and tetracycline should also be avoided. The adverse effects
of nitrofurantoin include diarrhoea, vomiting, neuropathy and fibrosis.
Nitrofurantoin should be avoided in pregnant mothers at term and in
breast-feeding mothers.
A 45-year-old woman requires antibiotic prophylaxis for a
cholecystectomy.
Intravenous co-amoxiclav is an alternative prophylactic antibiotic
regimen for abdominal surgery.
A 25-year-old woman presents with sore throat and hoarseness of
voice followed by pneumonia. Chlamydia serology is positive.
Tetracycline is first-line treatment for chlamydia infection. Tetracycline
is absolutely contraindicated in pregnancy and when breast-feeding.
Tetracyclines are deposited in growing bone and can lead to permanent
staining of teeth and dental hypoplasia. Patients treated with tetracycline
are told to avoid milk products because these decrease absorption of
the drug.