1. You are asked to urgently review a 52-year-old alcoholic man who was
admitted a few hours earlier with a massive variceal haemorrhage. He is on
his 6th unit of blood, and has begun to complain of pins and needles affecting
his fingers and toes along with spasms of both wrists and his toes. When you
review him he appears to have carpopedal spasm and is significantly
distressed.
Which of the following is the most likely cause of his spasm?
A. Hypoxia
B. Hypophosphataemia
C. Hyperventilation syndrome
D. Hypocalcaemia
E. Hypokalaemia
Answer: D
Explanation: Key learning points
Clinical Sciences
● Hypocalcaemia is seen as a result of massive blood transfusion because of
the high citrate load, and can lead to tetany.
Explanation
The answer is hypocalcaemia. The clue here is the multiple blood transfusions which
represent a significant citrate load. This leads to chelation of calcium ions and thus
can precipitate a large fall in ionised calcium and symptoms of hypocalcaemia
including pins and needles and tetany. This presentation should precipitate urgent
ECG monitoring with a VBG to check ionised calcium, and appropriate IV calcium
replacement.
Hypokalaemia may also be seen as a result of massive blood transfusion, but it is
not a cause of tetany.
,Hypophosphataemia is seen in alcoholic patients as a result of refeeding with high
carbohydrate feeds which are low in dietary phosphate, but again, does not present
with tetany.
Although hyperventilation syndrome is a cause of tetany, it is unlikely to be
responsible here, given that citrate loading is a possibility and hyperventilation would
be obvious on examination.
2. A new rapid test is developed for the screening of leptospirosis.
Blood from 100 patients was analysed by the gold standard laboratory technique and
by the new method. There were 20 positive results with the gold standard technique
but there were 40 positive results using the new technique. Retesting of the 40 cases
identified by the new technique using the gold standard demonstrated 20 positive
and 20 negatives.
Approximately which of the following values reflects the positive predictive value of
the new technique?
A. 90%
B. 33%
C. 75%
D. 50%
E. 66%
Answer:D
Key learning points
Statistics
● The positive predictive value is number of true positives/(number of true
positives + false positives).
,Explanation
The positive predictive value is number of true positives/(number of true positives +
false positives).
In the new technique there were 20 true positives and 20 false positives.
Thus the positive predictive value is 20/ (20 + 20) = 50%.
3. A 64-year-old man presents with haematuria.
Cystoscopy discovers a transitional cell carcinoma of the bladder.
Occupational exposure to which of the following is a recognised risk factor for
bladder cancer?
A. Aniline dye
B. Aflatoxin
C. Mercury
D. Beryllium
E. Strongyloides stercoralis
Answer: A
Key learning points
Oncology
● Risk factors for bladder cancer include exposure to aniline dyes in the printing
and textile industry.
Explanation
Risk factors for bladder cancer include:
● Smoking
● Exposure to aniline dyes in the printing and textile industry
● Rubber manufacture
● Cyclophosphamide
● Schistosomiasis - a risk factor for squamous cell carcinoma of the bladder,
rather than transitional cell carcinoma, which is the most common histology
for bladder carcinoma
Further Reading:
van der Meijden AP. Bladder cancer. BMJ 1998;317:1366-9.
, 4. A 57-year-old woman presents to the clinic with increasing shortness of breath.
She has a history of hypertension for which she takes amlodipine, reflux
oesophagitis, and Raynaud's phenomenon.
On examination you notice that her skin has a speckled appearance, and she has
peripheral calcinosis on examination of her hands. Respiratory examination reveals
inspiratory crackles consistent with pulmonary fibrosis.
Investigations reveal:
Haemoglobin 104 g/L (115-160)
White cell 9.2 ×109/L (4-10)
count
Platelets 190 ×109/L (150-400)
Sodium 140 mmol/L (134-143)
Potassium 4.9 mmol/L (3.5-5)
Creatinine 139 μmol/L (60-120)
SaO2 on air 94% (≥96%)
CXR Interstitial shadowing consistent with
fibrosis
Which of the following autoantibodies is most associated with her respiratory
picture?
A. Anti-PM/Scl antibodies
B. Rheumatoid factor antibodies
C. Anti-Scl-70 antibodies
D. Anti-centromere antibodies
E. Anti-smooth muscle antibodies
Answer: C
Explanation: Key learning points
Rheumatology
admitted a few hours earlier with a massive variceal haemorrhage. He is on
his 6th unit of blood, and has begun to complain of pins and needles affecting
his fingers and toes along with spasms of both wrists and his toes. When you
review him he appears to have carpopedal spasm and is significantly
distressed.
Which of the following is the most likely cause of his spasm?
A. Hypoxia
B. Hypophosphataemia
C. Hyperventilation syndrome
D. Hypocalcaemia
E. Hypokalaemia
Answer: D
Explanation: Key learning points
Clinical Sciences
● Hypocalcaemia is seen as a result of massive blood transfusion because of
the high citrate load, and can lead to tetany.
Explanation
The answer is hypocalcaemia. The clue here is the multiple blood transfusions which
represent a significant citrate load. This leads to chelation of calcium ions and thus
can precipitate a large fall in ionised calcium and symptoms of hypocalcaemia
including pins and needles and tetany. This presentation should precipitate urgent
ECG monitoring with a VBG to check ionised calcium, and appropriate IV calcium
replacement.
Hypokalaemia may also be seen as a result of massive blood transfusion, but it is
not a cause of tetany.
,Hypophosphataemia is seen in alcoholic patients as a result of refeeding with high
carbohydrate feeds which are low in dietary phosphate, but again, does not present
with tetany.
Although hyperventilation syndrome is a cause of tetany, it is unlikely to be
responsible here, given that citrate loading is a possibility and hyperventilation would
be obvious on examination.
2. A new rapid test is developed for the screening of leptospirosis.
Blood from 100 patients was analysed by the gold standard laboratory technique and
by the new method. There were 20 positive results with the gold standard technique
but there were 40 positive results using the new technique. Retesting of the 40 cases
identified by the new technique using the gold standard demonstrated 20 positive
and 20 negatives.
Approximately which of the following values reflects the positive predictive value of
the new technique?
A. 90%
B. 33%
C. 75%
D. 50%
E. 66%
Answer:D
Key learning points
Statistics
● The positive predictive value is number of true positives/(number of true
positives + false positives).
,Explanation
The positive predictive value is number of true positives/(number of true positives +
false positives).
In the new technique there were 20 true positives and 20 false positives.
Thus the positive predictive value is 20/ (20 + 20) = 50%.
3. A 64-year-old man presents with haematuria.
Cystoscopy discovers a transitional cell carcinoma of the bladder.
Occupational exposure to which of the following is a recognised risk factor for
bladder cancer?
A. Aniline dye
B. Aflatoxin
C. Mercury
D. Beryllium
E. Strongyloides stercoralis
Answer: A
Key learning points
Oncology
● Risk factors for bladder cancer include exposure to aniline dyes in the printing
and textile industry.
Explanation
Risk factors for bladder cancer include:
● Smoking
● Exposure to aniline dyes in the printing and textile industry
● Rubber manufacture
● Cyclophosphamide
● Schistosomiasis - a risk factor for squamous cell carcinoma of the bladder,
rather than transitional cell carcinoma, which is the most common histology
for bladder carcinoma
Further Reading:
van der Meijden AP. Bladder cancer. BMJ 1998;317:1366-9.
, 4. A 57-year-old woman presents to the clinic with increasing shortness of breath.
She has a history of hypertension for which she takes amlodipine, reflux
oesophagitis, and Raynaud's phenomenon.
On examination you notice that her skin has a speckled appearance, and she has
peripheral calcinosis on examination of her hands. Respiratory examination reveals
inspiratory crackles consistent with pulmonary fibrosis.
Investigations reveal:
Haemoglobin 104 g/L (115-160)
White cell 9.2 ×109/L (4-10)
count
Platelets 190 ×109/L (150-400)
Sodium 140 mmol/L (134-143)
Potassium 4.9 mmol/L (3.5-5)
Creatinine 139 μmol/L (60-120)
SaO2 on air 94% (≥96%)
CXR Interstitial shadowing consistent with
fibrosis
Which of the following autoantibodies is most associated with her respiratory
picture?
A. Anti-PM/Scl antibodies
B. Rheumatoid factor antibodies
C. Anti-Scl-70 antibodies
D. Anti-centromere antibodies
E. Anti-smooth muscle antibodies
Answer: C
Explanation: Key learning points
Rheumatology
