I wouldn't worry about the fact that the PTH is 0.6 and not lower (she will
have a load of PTH fragments which will still be detected at the low end,
particularly given her CRF, and most PTH assays don't work that well down
there anyway).

The critical fact is that her hypoercalcaemia has improved.
I would repeat the 1,25D assay again on a previous sample if you have any.
You didn't say that she was not taking alfacalcidol or calcitriol therapy
when severely hypercalcaemic. Common things are common, and renal physicians
commonly poison their patients with alfacalcidol or calcitriol (renal
patients may have a stock of these, and the fact that she had been taking
them might not have been recorded in her notes). Not sure why a Sestamibi
scan was done.

Aubrey

----- Original Message -----
From: "David Cook" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, January 24, 2003 5:03 PM
Subject: Re: Unexplained Hypercalcaemia


> Is that PTH (0.6) inappropriate for such a high calcium (3.35)?
>
> Regards
>
> David Cook
>
>
> -----Original Message-----
> From: clinical biochemistry discussion list
> [mailto:[log in to unmask]] On Behalf Of Keith Wakelin
> Sent: 24 January 2003 16:24
> To: [log in to unmask]
> Subject: Unexplained Hypercalcaemia
>
> Dear All,
> Apologies, previous sent before complete.
>  I would be very grateful for any help with a case of unexplained
> hypercalcaemia. We have done all investigations we can think of and the
> aetiology is still not clear to us.
>  74 years old lady with CRF, presumed 2ndry to nephrocalcinosis.
> Creatinine 249 (2.8 for American colleagues), MDRD-GFR 17.5 ml/min
> PMH of TB in 1943. Non-functioning L-kidney on isotope scans, small
> R-kidney on U/S. CXR shows quite marked calcification of paratracheal
> glands and calcification in R-upper lobe, consistent with old TB. She is
> clinically completely well and asymtomatic without evidence of active TB
>  Her Calcium has been as high as 3.35 with an albumin of 46. PTH is 0.6
> (0.5-4.4). Immunoglobulins are normal and no paraprotein has been
> detected. Serum ACE levels are normal, PTH-rp was normal, 25OHVitD was
> normal, 1,25 dihydroxy VitD was normal ( 49 pmol/L [ Ref 43 to 144
> pmol/L]), Vit A was normal, TFT's were normal, Aluminium was 0.29
> micromol/L.
> 24-hours Calcium excretion was slightly high (appropriately) at 8.3
> (2.5-7.5), making familial hypercalcaemic hypocalciuria unlikely. Short
> Synacthen test was normal.
>  An isotope Bone Scan was normal apart from non-functioning L-kidney.
> Mammogram normal. Sestamibi scan did not show any uptake suggesting
> parathyroid abnormality.
> A CT scan of chest, abdomen en pelvis confirmed calcifications in chest,
> consistent with old TB, the L-kidney was shrunken and calcified, typical
> for tuberculous autonephrectomy. There was also some calcification
> within the R-kidney. No lymphadenopathy seen. Normal liver and spleen.
>  A detailed dietary history by our renal dieticians revealed -if
> anything- a rather low daily Ca intake. No supplements or vitamins. A
> course of steroids made no difference, making any form of granulomatous
> disease less likely, however I understand hydrocortisone 40 mg was given
> per day for 10 days, ? sufficient.. Her PTH seems appropriately
> suppressed.
>  She has had this problem for over a year and we feel if it was due to
> malignancy we would have found out by now. As said before, she is
> completely well.
> We have noted that her calcium in December has decreased to 2.6 ( no
> active Rx ). Might this be secondary to seasonal changes in Vit D ? It
> has been suggested that her 1,25 (OH)VitD may be inappropriately normal
> for her degree of renal failure. Does anyone have any information as to
> what 1,25(OH)VitD levels we would expect with this degree of renal
> failure ? Could she still have an underlying granulomatous condition ?
> Any suggestions or bright ideas would be very welcome.
> Many thanks
> Keith Wakelin
> Dorchester.
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