A 91 year old lady on a geriatric ward. Serum results are
Sodium: 144 mmol/L
Potassium: 4.6 mmol/L
Urea: 9.4 mmol/L (2.8 - 7.0)
Creatinine: 143 umol/L (62 - 133)
Albumin: 33 g/L (35 - 49)
Adjusted calcium: 2.46 mmol/L 2.10 - 2.55)
Intact parathyroid hormone: 13.7 pmol/L (1.1 - 7.6)
Clinical information given is 'high calcium'. Results two weeks previously
were
Sodium: 145 mmol/L
Potassium: 5.2 mmol/L
Urea: 15.9 mmol/L
Creatinine: 123 umol/L
Albumin: 32 g/L
Adjusted calcium: 2.68 mmol/L.
This Case attracted 32 participants.
11 would contact the Physician, [1.0]
4 enquiring about drug use, [1.0]
and 4 enquiring about food and hydration status. [1.5]
3 asked why this PTH had been measured. [1.3]
6 thought that the first high calcium was likely to be associated with
dehydration; [1.0]
2 thought the results from the previous sample were likely to be
artefactual. [-0.5]
4 thought the results suggested hyperparathyroidism; [0.6]
3 commented on the difficulty of interpretation of this PTH value. [1.5]
6 thought that the results suggested primary hyperparathyroidism; [0.8]
4 suggested (co-existing) Vitamin D deficiency; [0.3]
3 suggested secondary hyperparathyroidism; [-0.3]
2 each suggested
renal dysfunction; [-0.3]
malignancy; [0.3]
tertiary hyperparathyroidism. [-0.8]
12 would repeat the serum calcium; [0.8]
3 of these would also measure phosphate; [0.8]
3 would also measure PTH; [0.3]
2 would also measure alkaline phosphatase; [0.8]
1 would also measure magnesium [0.5]
3 would carry out serum protein electrophoresis; [0.5*]
2 would measure (25-OH) Vitamin D; [0.5]
1 would also measure 1,25-OH Vitamin D. [0.0]
2 would ask for a 24 hour urine for calcium. [0.0]
1 suggested skull and hand x-ray; [0.0]
1 suggested assessment for kidney stones. [-0.8]
I had considerable difficulty in commenting on this Case, because first, I
do not know what happens to serum PTH in extreme age (I know it is likely
to rise after an abrupt fall in calcium); and second, I am always wary
about suggesting considerable further investigation in very old patients
unless there is a clear clinical need for this.
My comment was
'Now normocalcaemic. PTH may be slightly raised relative to current
calcium; but was previous high calcium associated with dehydration?
Possibly secondary hyperparathyroidism related to mild renal impairment or
to Vitamin D deficiency.'
We have had no further samples from this patient, so I do not know the
current clinical position. In response to those who queried the wisdom of
measuring PTH on this sample, I to some extent agree. A year ago, in my own
Department we would have waited to see what the current calcium was before
deciding whether to proceed to a PTH. With ever-increasing pressure to
improve turn-round times (and, I hate to add, reduce the number of
decision-making processes involved in analysis), we currently do not do
this. Right or wrong?
Best wishes to all - Case 51 should appear in around three weeks. We will
try and produce the overview of Cases 26 - 50 tomorrow.
Best wishes
Gordon Challand
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