STOPPING MEDS BEFORE TESTING FOR ALDOSTERONOMA 23 Feb 2015

STOPPING  MEDS  BEFORE  TESTING  FOR  ALDOSTERONOMA  23 Feb 2015

QUESTION-I have a 44 year old female who has primary hyperaldosteronism. She ceased spironolactone 6 weeks prior to AVS and amiloride one week ago. Despite increasing KCL tablets to 16 per day, she was admitted to hospital with hypokalaemia (K -2.4 mmol/L). my question is :

Is it imperative that amiloride be ceased prior to AVS? If so what is the minimum length of time that it needs to be stopped for?  Nirupa Sachithanandan,MBBS FRACP PhD  Diabetes, Endocrine, Pituitary and Familial Cancer Clinic

RESPONSE-Dear Dr. Sachithanandan, Your enquiry about your patient was  forwarded to me for comment.  The first  points is actually whether AVS in needed in this patient. She is young (43 years of age) and appears to have profound hypokalemia.  I am assuming also that the PA/PRA ratio was very abnormal since I would guess that the aldosterone level would be quite high and the PRA level undectable.  In such young patients if there is a clear cut lipid rich adenoma on one gland and the contralateral gland is anatomically normal  the diagnosis of an APA seems secure and I would directly refer such a patient to adrenalectomy without  AVS sampling.

In older patients or subjects with bilateral adrenal nodularity AVS is clearly needed.  Spironolactone may need to be stopped for up the 3 months, that is until the PRA has again become suppressed. Amiloride would also need to be stopped for weeks since its effect on PRA secretion is identical to that of spironolactone.  In such cases I check a PRA level prior to the AVS to be certain that the PRA level is not in the normal, detectable range( since it would impact on lateralization). A good strategy in such patients would be to stop both agents and check a PRA level monthly before proceeding to AVS.  The down side of stopping these agents is what you have encountered, that is, severe hypokalemia that is difficult to reverse with potassium supplementation. I hope this helps in the care of your patient. Dr RH Dluhy

 

HYPERCALCEMIA–?FHH, HPTH, OR OTHER

QUESTION---Patient (64yo F) is followed for hypercalcemia of uncertain etiology, dating back to 2008.  When I saw her I took her off the hydrochlorothiazide.  Her calcium remains elevated and her parathyroid home concentration remains at the low end of normal at about 20. I think the differential dx is either: Malignancy, familial hypocalciuric hypercalcemia, primary hyperparathyroidism. I don't believe she has a malignancy given the fact that the hypercalcemia dates back 7 years, and is stable. Parathyroid hormone related peptide was low. I don't believe she has familial hypocalciuric hypercalcemia given the fact that the parathyroid hormone level is at the low end of normal. I thought (this is the question) that the [PTH] is high/normal in patients with FHH.  Her parents are deceased.  She has one sister but we do not know if her sister was ever hypercalcemic.

Labs:

DATE        Cr        calcium   TSH       PTH       VitD-25OH phos      albumin   Ca2+      PTHrp   1,25(OH)2D

02/03/15    1.10     H10.7                                                                          36 (nl)

01/13/15             H10.8                20.0                4.3

11/22/14    1.10     H10.2      0.506     20.9                4.1       4.3      H1.32      <2.0

07/23/14             H11.3                                    4.7

06/04/14    1.10     H11.2      0.659    L8.5       43

05/28/14    1.10     H11.2      0.381

06/12/13    1.00     H10.7      0.643

06/04/12    0.80     H10.2      0.696

06/15/11    0.90     H10.3      0.848

06/29/10    0.70     H10.4      0.699

05/12/09    0.80      9.9

06/04/08    1.00     H10.3

03/20/08    0.90     H10.7      0.39

DATE        U24 Calcium     Calcium         PTH 

07/30/14   113

11/22/14                   H10.2            20.9

01/13/15                   H10.8            20.0

02/03/15    90             H10.7                       4 glasses of milk

Calculated Fractional Excretion of Calcium = 0.010
Thus urine test is c/w FHH.
So, does the patient have FHH with a low [PTH]?
I am going to do a cinacalcet suppression test, as a way to assess if this is a PTH responsive hypercalcemia (but I am well aware this is not a validated test.)  Hayward Zwerling, M.D.

RESPONSE-- Your question has been referred to me by Dr. DeGroot. I am pleased to respond.Long-standing, well documented hypercalcemia essentially rules out malignancy, as you point out.FHH is highly unlikely for the facts that she is 61 years old, there is no family history, and the PTH is where it is. FHH virtually always surfaces by the age of 30 and the PTH is invariably in the upper range of normal or frankly elevated. The urinary cal/cr ratio of 0.01 could be compatible with PHPT as well as FHH. PHPT. This is the most likely diagnosis. Why the PTH is as low as it is, I don't know but we see it. Is she taking biotin? Biotin has been shown to interfere with the PTH assay and in patients with PHPT taking the biotin, the PTH can be low. (Waghray A et al. Endocr Practice 2013;19:451-455). As for the "cinacalcet supression test" it is not validated.
Assuming she has PHPT, you have not indicated whether she has any guidelines to recommend surgery. What is her BMD? Hx of kidney stones?  If she doesn't meet guidelines for surgery, then a conservative course might be best advised. John Bilezikian, MD