Which of the following anti-retroviral drugs is most characteristically associated with nephrolithiasis?
Correct Answer C:
HIV: anti-retrovirals: Highly active anti-retroviral therapy (HAART) involves a combination of at least three drugs, typically two nucleoside reverse transcriptase inhibitors (NRTI) and either a protease inhibitor (PI) or a nonnucleoside reverse transcriptase inhibitor (NNRTI). This combination both decreases viral replication but also reduces the risk of viral resistance emerging.
Nucleoside analogue reverse transcriptase inhibitors (NRTI):
Non-nucleoside reverse transcriptase inhibitors (NNRTI):
Protease inhibitors (PI):
Each of the following organisms commonly cause respiratory tract infections in patients with cystic fibrosis, except:
Correct Answer E:
Cystic fibrosis:
Cystic fibrosis (CF) is an autosomal recessive disorder causing increased viscosity of secretions (e.g. lungs and pancreas). It is due to a defect in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which codes a cAMP-regulated chloride channel In the UK 80% of CF cases are due to delta F508 on the long arm of chromosome 7. Cystic fibrosis affects 1 per 2500 births, and the carrier rate is c. 1 in 25.
Organisms which may colonize CF patients:
*Previously known as Pseudomonas cepacia.
A 30-year-old man comes for review. He returned from a holiday in Egypt yesterday. For the past two days he has been passing frequent bloody diarrhoea associated with crampy abdominal pain. Abdominal examination demonstrates diffuse lower abdominal tenderness but there is no guarding or rigidity. His temperature is 37.5ºC.
What is the most likely causative organism?
Correct Answer E: Enterotoxigenic Escherichia coli infections do not usually cause bloody diarrhoea. A differential diagnosis would be amoebic dysentery, enterohemorrhagic Escherichia coli and possibly Campylobacter.
Gastroenteritis:
Gastroenteritis may either occur whilst at home or whilst travelling abroad (travellers' diarrhoea) Travellers' diarrhoea may be defined as at least 3 loose to watery stools in 24 hours with or without one of more of abdominal cramps, fever, nausea, vomiting or blood in the stool. The most common cause is Escherichia coli.
Another pattern of illness is 'acute food poisoning'. This describes the sudden onset of nausea, vomiting and diarrhoea after the ingestion of a toxin. Acute food poisoning is typically caused by Staphylococcus aureus, Bacillus cereus or Clostridium perfringens.
Stereotypical histories:
Incubation period:
*Vomiting subtype, the diarrhoeal illness has an incubation period of 6-14 hours.
A 45-year-old man is diagnosed as having primary syphilis. Six hours after receiving his first injection of benzylpenicillin he complains of feeling generally unwell. On examination:
These symptoms settle after around four hours.
Which one of the following is most likely to explain this finding.
Correct Answer B:
Syphilis: management:
Management:
Which one of the following is least likely to cause a pyrexia of unknown origin?
Correct Answer B: Very rarely colorectal cancer may cause endocarditis secondary to Streptococcus bovis, but this is the least likely of the options.
Pyrexia of unknown origin causes:
Defined as a prolonged fever of > 3 weeks which resists diagnosis after a week in hospital.
1- Neoplasia:
2- Infections:
3- Connective tissue disorders.
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