Perhaps we can use some data to help answer the question. Analysing the
last 5 years of hypercalcaemia data from Merseyside GPs we would see the
following-
Your mother is feeling tired and has an ACa of 5.0 mmol/L. She is advised
to drink a little water and get some quick investigations performed!
(Chances of malignancy 88%) On admission to hospital she is rehydrated with
N saline for 48 h minimum and cancer confirmed then hypercalcaemia treated
appropriately with bisphosphonate. Co-existent significant anaemia in 63%
of cases.
She has an ACa of 4.0mmol/L (chances of malignancy 68%). Treatment as above?
She has an ACa of 3.5 mmol/L (chances of malignancy 52%).
She has an ACa of 3.0 mmol/L (chances of malignancy 41%, 1HPT 43%,
ca+Vitamin D toxicity (plus renal impairment usually) 11%).
She has an adjusted calcium betweeen 2.6-3.0 mmol/L (chances of malignancy
23%, 1HPT 55% and Ca+vit D toxicity 19%).
The reason 3.0 mmol/L is often chosen by authors as a cut off value
reflects the data indicating the likelihood of development of
hypercalcaemic crisis which increases above 3 mmol/L and the fact that
urine calcium is greater than 10 mmol/l at this level of serum calcium.
Aubrey is correct that clinical judgement is required but I would be
unhappy if my mother was told to drink a little water while some tests were
done and her ACa was greater than 3.5 mmol/L. Since the chances of
malignancy are far less when the ACa is between 2.6 and 3.5 mmol/L in the
absence of any obvious signs of malignanacy I would agree that GPs should
be able to investigate appropriately with PTH as one of the first line
tests.
The majority of patients will have no problem with calcium and vitamin D in
the one to two tablet doses prescribed in the UK. They can however become
hypercalcaemic if they develop renal failure and/or become dehydrated.
Routine monitoring of this population would be costly for the NHS.
Interestingly the vast majority prescribed such treatment are so calcium
and vit D deficient that their urine calcium is likely to low and remain so
for several months to years. Addition of active vitamin D metabolites is a
different problem and monitoring of patients on alpha calcidol or
calcitriol is mandatory (4 monthly)especially where doses greater than
250ng daily are being used. The single biggest expansion in hypercalcaemia
cases is in this group of patients.
Regards
Bill Fraser
--On 07 July 2003 18:48 +0100 ablumsohn <[log in to unmask]> wrote:
> R> eg Patient feeling tired. Found to have 'elevated' calcium on 'routine'
> R> blood test. At what concentration of calcium (and clinical picture)
> should R> GP admit that day to hospital... or refer OPD?
>
> Most patients will have primary hyperparathyroidism, and will
> have had longstanding undetected hypercalcaemia. If the test was
> truly random ie. could just have easily have been done last week,
> last month or next month, I definitely wouldn't admit with a
> calcium under 3.0mmol/L or so. Arrange some quick outpatient
> investigations, and make sure they drink a bit of water. GP's
> will only rarely see patients with serum calcium much greater
> than 3, and even then, admission would not be in any way
> mandatory. Some exercising of clinical judgement required. What
> would the hospital actually do apart from the usual additional
> dehydrating while waiting around? Patients who are not well or
> who have a recent documented normal serum calcium clearly need
> more attention.
>
> In terms of "referral to OPD", I think simple investigation of
> hypercalcaemia should be within the remit of every GP, and there
> is no reason to think that GP's should not at least try to make a
> rough diagnosis and direct their referral appropriately.
>
> R> If (a different)patient on calcium or calcium/D3 how often do you check
> R> serum calcium? All I've come across is 'monitor calcium on a regular
> basis'
>
> Never (assuming we are talking about a straightforward patient on
> say Calcichew D3 BD). No patients on these sorts of supplements
> get significant hypercalcaemia or Vitamin D toxicity, although
> patients with mild primary hyperparathyroidism might occasionally
> be "unmasked". The BNF refers to the need to monitor patients
> receiving PHARMACOLOGICAL amounts of Vitamin D. This means doses
> of say 40,000 units daily, or 1 hydroxylated Vitamin D
> derivatives. The amount of Vitamin D in calcium
> and vitamin D supplements is not only not pharmacological, but is
> near-homeopathic (200 Units daily or so - compare to around 10
> times that amount obtained by doing a spot of sunbathing).
>
> Aubrey
>
> --
>|| =====================================================
>|| Dr Aubrey Blumsohn
>|| Senior Lecturer in Metabolic Bone Disease
>|| Division of Clinical Sciences (NGHT)
>|| Clinical Sciences Centre
>|| Northern General Hospital, Herries Road
>|| Sheffield S5 7AU, England
>|| email: [log in to unmask]
>|| phone: 114-271 5963 (office), 114 271 4705 (sec)
>|| fax: 0114 261 8775 (fax)
>|| =====================================================
>
> R> Many thanks
>
> R> Rob
>
> R> Dr Robert Lord
> R> Department of Clinical Biochemistry
> R> Rotherham District General Hospital
> R> Moorgate Road
> R> Oakwood
> R> Rotherham
> R> S60 2UD
>
> R> Tel 01709 820000
>
> R> E mail [log in to unmask]
>
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Professor W D Fraser
Department of Clinical Chemistry
The University of Liverpool
4th Floor, Duncan Building
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L69 3GA
Tel: 0151 706 4247/4257
Fax: 0151 706 5813
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