Pathology EMQ template.

Name: Gary Tse

Theme: Bone, wound and joint infections

 

OPTION LIST

 

A	Streptococcus pneumoniae; cephalosporin and clindamycin	I	Borrelia afzelii; doxycycline
B	Staphylococcus aureus; flucloxacillin	J	Borrelia afzelii; erythromycin
C	Staphylococcus aureus; ceftobiprole	K	Leishmania donovani; pentavalent antimony
D	Staphylococcus aureus; co-trimoxazole (trimethoprim and sulfamethoxazole)	L	Leishmania major; pentavalent antimony
E	Staphylococcus aureus; cephalosporin and clindamycin	M	Leishmania donovani; pentavalent antimony
F	Proteus mirabilis; ciprofloxacin	N	Leishmania major; liposomal amphotericin B
G	Proteus morganii; erythromycin	O	Leishmania donovani; liposomal amphotericin B
H	Proteus morganii; tetracycline	P	Blastomyces dermatitidis; itraconazole

 

 

For each scenario below, identify the most likely causative organism and most appropriate treatment. Each option may be used once, more than once or not at all.

 

1. A 65-year old male with a long history of Type 2 diabetes mellitus presented with ulceration of his right foot. On examination, there was no evidence of malaise and fever, but you noted that the area around his big toe was dull red, diffusely swollen, warm and discharging fragments of bone. Laboratory investigations revealed elevations in C-reactive protein, erythrocyte sedimentation rate and neutrophil count. MRI revealed fat signal-intensity loss on T1-weighted images and high signal intensity on T2-weighted images, along with contrast (gadolinium) enhancement, consistent with marrow oedema associated with inflammation.

 

 

2. A 30-year old pregnant lady, who lives in Southern Scandinavia around the Baltic Sea, presented with redness, swelling with effusion and reduced mobility of her right knee joint. She reported that 3 months ago, she noticed a rash on her right thigh associated with a headache and malaise. On further questioning the patient reported that this was not the first time that she had a ‘knee problem’ but that a similar episode occurred a month ago which subsided without any treatment.

 

 

3. A 50-year old lady has a history of pacemaker implantation and mitral valve replacement following rheumatic fever. The patient was taking anticoagulants preoperatively. Despite converting to low-molecular weight subcutaneous heparin treatment and establishing normal coagulation parameters, she developed a postoperative haematoma on her right breast which was subsequent infected. A blood culture revealed that Gram-, catalase- and coagulase- positive cocci arranged in clusters. Antibiotic sensitivity studies   then demonstrated resistance to methicillin, vancomycin and cephalosporin.

 

 

4. A 75-year old gentleman presented with an infected wound in his groin, which developed at the site where a femoral venous cannula was inserted during cardiopulmonary resuscitation. He lives in a nursing home and has a history of HIV infection. Microbiology studies revealed a facultative, oxidase negative, actively motile, non-spore forming and non-capsulate anaerobic bacilli.

 

 

5. A-45 year old gentleman, who has just returned from Brazil, presented to the Accident and Emergency department at Charing Cross Hospital with a sore on his left forearm. He happens to be an entomologist specializing in the Diptera order and he noted that he was bitten by a sandfly about five weeks ago. A detailed examination revealed no other skin lesions. He has no history of renal disease. Giemsa staining of the organism obtained from the wound revealed a parasite that grows on Schneider Drosophila medium. Montenegro test was positive.

 

 

 

ANSWERS

1. E

2. J

3. D

4. F

5. L