MRCP Question Bank, 2003
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Gliclazide dosage should be reduced in mild renal failure, and should be stopped in severe renal disease.
Lansoprazole is safe to use in renal impairment (caution in liver impairment), at a dose of 15-30mg/day.
Lisinopril should be used with caution in renal impairment. It may potentiate hyperkalaemia and hypotension, therefore
the dose should be reduced to 10-20mg/day, rather than 20-40mg/day.
Metformin predisposes to lactic acidosis, therefore should be stopped even with mild renal impairment and general
advice suggests stopping with a creatinine above 150.
A 16 year old girl is seen in clinic as she is concerned due to areas of hair loss on the scalp. Past medical history
includes atopic eczema and she has a number of depigmented areas on her hands. What is the most likely
diagnosis?
Available marks are shown in brackets
1 ) Alopecia areata [100]
2 ) Hypothyroidism
3 ) Seborrhoeic dermatitis
4 ) SLE
5 ) Trichotillomania
Comments:
This girl has a compination of vitaligo and alopecia areata which can sometime co exist and have a similar autoimmune
aetiology. Discrete areas of hair loss and normal texture on the scalp are highly suggestive of alopecia areata.
A 15-year-old girl is referred to clinic complaining of generalised muscle weakness, fatigue and polyuria. Her
blood pressure in clinic is measured at 90/74 mmHg. Investigations:
| Serum sodium | 127 mmol/l |
| Serum potassium | 3.0 mmol/l |
| Serum urea | 7.2 mmol/l |
| Serum creatinine | 110 umol/l |
| Serum chloride | 92 mmol/l (NR 97-108 mmol/l) |
| Serum bicarbonate | 34 mmol/l (NR 22-28 mmol/l) |
| 82 mmol/l (NR 0.8-1.1 mmol/l) | |
| Urine sodium | 160 mmol/l (NR 40-130 mmol/l) |
| Urine calcium | 8.0 mmol/24hr (NR 2.5-8.0 mmol/24hr) |
Which of the following is the most likely diagnosis?
Available marks are shown in brackets
1 ) Addison's disease
2 ) Bartter's syndrome [100]
3 ) Laxative abuse
4 ) Liddle's syndrome
5 ) Thiazide diuretic abuse
Comments: A difficult question! This patient has a hypochloraemic alkalosis, with high urinary sodium and potassium
loss. Laxative abuse tends to cause low urinary sodium and potassium, with low serum bicarbonate, due to GI losses.
Thiazide diuretic abuse would fit with the serum findings, but the urinary sodium and potassium is normal (as water
will follow the electrolytes).
Liddle's syndrome is a congenital form of salt-sensitive hypertension characterised by a very high rate of renal sodium
uptake, despite low levels of aldosterone, secondary hypokalaemia and metabolic acidosis. It is caused by a congenital
mutation, which causes a constitutive hyper reactivity in the epithelial sodium channel (ENaC).
The increased sodium uptake is accompanied by an increased water uptake, leading to an increase in blood volume, and
secondary hypertension.
Addison's disease is primary adrenal insufficiency. The most common cause in the western world is autoimmune
adrenalitis, and worldwide causes include TB, fungal infections (histoplasmosis, cryptococcus) and cytomegaloviru
Patients with Addison's disease have glucocorticoid and mineralocorticoid deficiency. This leads to hypotension,
hyponatraemia (in 90%) and hyperkalaemia (in 65%).
Bartter's syndrome is a rare, autosomal recessive disorder, caused by one of three mutations of the ion transporter or ion
channel present in the thick ascending limb of the distal nephron. Type I and II mutations present in infancy (often
following premature birth and polyhydramnios) with severe dehydration, hypokalaemic alkalosis, hypercalciuria and
nephrocalcinosis.
Mortality is high. Type III mutations present with a more varied clinical picture to type I and II, ranging in severity
from near fatal volume depletion with hypokalaemic alkalosis and respiratory arrest, to mild disease presenting in
teenagers with weakness and polyuria. Nephrocalcinosis has not been described in type III mutations, therefore it can
differentiate between type I and II disease, and type III disease. Management is with long term potassium
supplementation and care to avoid dehydration. The long term prognosis is uncertain.
A 17 year old male with glucose-6-phosphate dehydrogenase deficiency presents with tiredness and is noticed to
be jaundiced. These features have developed since he developed a mild chest infection one week ago. Which one
of the following is the most likely haematological finding?
Available marks are shown in brackets
1 ) Haemoglobinuria [100]
2 ) low mean cell volume
3 ) Positive direct antiglobulin test
4 ) Reduced reticulocyte count
5 ) Spherocytes present on blood film
Comments: G6PD deficiency is a red cell enzymopathy that can lead to acute intravascular haemolysis after exposure
to certain drugs, infection etc. You would therefore get haemoglobinuria but would not get a positive direct antiglobulin
test. The MCV and reticulocyte count would be high due to haemolysis. There is a form of G6PD deficiency where
there is a chronic low level haemolysis, where there are spherocytes seen- but the clinical information points to
intravascular haemolysis after an infection.
A 32 year-old man presented to hospital with a four week history of progressively worsening dyspnoea on
exertion. He also complained of a non-productive cough. Over the two days preceeding admission the patient
had become breathless at rest and was started on oral co-amoxiclav by his general practitioner.
On examination he was febrile 38°C and looked unwell. Candida was noted on the tonsilar pillars. No wheeze or
crackles were heard in his chest. His chest radiograph is shown. Oxygen saturation was 95% on room air, but
fell to 85% following about of coughing. Arterial blood gases show pO2 of 59 mmHg.
What treatment shold be given?
Available marks are shown in brackets
1 ) Co-amoxiclav + clarithromycin
2 ) Co-trimoxazole + prednisolone [100]
3 ) Vancomycin + ceftazidime
4 ) Cefuroxime + metronidazole
5 ) Benzylpenicillin + flucloxacillin
Comments:
Oral candidiasis is never normal and should always raise the possibility of AIDS and the history in this case is
characteristic of Pneumocystis carinii pneumonia. There are several agents that can be used to treat PCP, though cotriomoxazole is clearly the most effective and is the treatment of first choice. Patients often deteriorate after starting
therapy for PCP as the pneumonitis worsens due to the inflammation associated with dying pneumocysts. In patients
with a pO2<60 mmHg, oral prednisolone is added to reduce the inflammatory effect.
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A 47-year-old man presented to the Accident & Emergency department following sudden onset left posterior
auricular pain while in his garage working under his car. On examination he had a degree of neck pain and
stiffness and also impaired coordination of left hand and weakness and increased tone in his right limbs. What is
the most likely diagnosis?
Available marks are shown in brackets
