A cohort study is being designed to look at the relationship between smoking and breast cancer.
What is the usual outcome measure in a cohort study?
Correct Answer C: Cohort studies - relative risk.
Study design: The following table highlights the main features of the main types of study:
Each one of the following may raise ESR, except:
Correct Answer C:
Erythrocyte sedimentation rate (ESR):
The ESR is a non-specific marker of inflammation and depends on both the size, shape and number of red blood cells and the concentration of plasma proteins such as fibrinogen, alpha2-globulins and gamma globulins.
Causes of a high ESR:
Causes of a low ESR:
A 25-year-old woman presents for review. She has a history of depression and is currently prescribed citalopram. Despite returning from a recent holiday in Spain she complains of feeling tired all the time. On examination you notice a slightly raised red rash on the bridge of her nose and cheeks. Although she complains of having 'stiff joints' you can find no evidence of arthritis. You order some basic blood tests:
What is the most likely diagnosis?
Correct Answer A: The malar rash, arthralgia, lethargy and history of mental health points towards a diagnosis of SLE. Remember that the CRP (in contrast to the ESR) is typically normal in SLE.
SLE: features: Systemic lupus erythematosus (SLE) is a multisystem, autoimmune disorder. It typically presents in early adulthood and is more common in women and people of Afro-Caribbean origin.
General features:
Skin:
Musculoskeletal:
Respiratory:
Renal:
Neuropsychiatric:
You are speaking to a 24-year-old man who is known to have haemophilia A. He asks you what the chances are of his future children developing haemophilia.
What is the correct answer?
Correct Answer A: X-linked recessive conditions - there is no male-to-male transmission. Affected males can only have unaffected sons and carrier daughters.
You should of course also discuss with him that any daughters that he has will be carriers of the condition.
X-linked recessive: In X-linked recessive inheritance only males are affected. An exception to this seen in examinations are patients with Turner's syndrome, who are affected due to only having one X chromosome. X-linked recessive disorders are transmitted by heterozygote females (carriers) and male-to-male transmission is not seen.
Affected males can only have unaffected sons and carrier daughters.
Each male child of a heterozygous female carrier has a 50% chance of being affected whilst each female child of a heterozygous female carrier has a 50% chance of being a carrier.
The possibility of an affected father having children with a heterozygous female carrier is generally speaking extremely rare. However, in certain Afro-Caribbean communities G6PD deficiency is relatively common and homozygous females with clinical manifestations of the enzyme defect are seen.
A patient is seen in clinic complaining of abdominal pain. Routine bloods show:
What is the anion gap?
Correct Answer E:
The anion gap may be calculated by using (sodium + potassium) - (bicarbonate + chloride) = (142 + 4.0) - (104 + 19) = 23 mmol/L
Anion gap: The anion gap is calculated by:
Causes of a normal anion gap or hyperchloraemic metabolic acidosis:
Causes of a raised anion gap metabolic acidosis:
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