Category: Calcium/Bone Disorders

Monitor: 16

16 - A DIAGNOSTIC CONUNDRUM OF ELEVATED SERUM CALCIUM

Saturday, Apr 27
10:30 AM – 11:00 AM

Objective :

The objective of this report is to describe a case of Familial hypocalciuric hypercalcemia (FHH) with evaluation confounded by Vitamin D (VitD) insufficiency and emphasize the significance of thorough family history (FHx) in hypercalcemia evaluation.


Methods : This is a descriptive report of an FHH case diagnosed at the endocrinology office. A review of the topic “FHH” was done using PubMed to include relevant learning points under discussion.


Results :

A 64-year-old female with a history of hypertension presented complaining of fatigue. Initial blood work was significant for a corrected total Calcium(Ca) of 11.3mg/dL (8.7-10.8). Home medications were reviewed and did not include Ca supplement or thiazide diuretic. Additional workup revealed high ionized Ca, and unremarkable creatinine (Cr), thyroid-stimulating hormone, alkaline phosphatase. The patient reported a history of high Ca level in her blood, attributed to dehydration, and FHx of parathyroidectomy (PTX) in her father, sister and a paternal aunt for “abnormal Ca levels” without successful normalization of Ca levels after surgery. Further workup showed an intact PTH concentration of 136.2pg/mL (14.0-72.0), 25-hydroxy VitD level of 26.5ng/mL (30.0-100.0) and unremarkable neck ultrasound. The patient was started on ergocalciferol for VitD insufficiency. At this point, her hypercalcemia was attributed to primary hyperparathyroidism (HPT). Given her FHx, 24-hour (Hr) urinary Ca measurement was ordered after normalization of VitD level, to rule out FHH, and was less than 5mg/24-hr (42-353). A repeat 24-hr urine Ca tested after seven days was low with a calculated 24-hr urine Ca/Cr clearance ratio of 0.006. The diagnosis of FHH was made and the patient did not undergo PTX.


Discussion :

Asymptomatic hypercalcemia often poses a diagnostic challenge. Clinicians typically rule out malignancy, HPT and medications as a cause of hypercalcemia. However, it is also important to obtain a detailed FHx, which plays a key role in diagnosing FHH. In this case, multiple family members underwent PTX, which could have been averted with a thorough FHx and prompt diagnosis. A 24-hr urine Ca/Cr clearance ratio helps to differentiate FHH from Primary HPT, and a ratio of less than 0.01 is highly suggestive of FHH. Additionally, confirmation with Ca-sensing receptor gene testing helps to determine the need for further evaluation of familial causes of hypercalcemia.


Conclusion : FHH is a lifelong benign condition characterized by mild, asymptomatic, long-standing hypercalcemia that does not require medical or surgical treatment. Early diagnosis of FHH is crucial to avoid unnecessary surgical intervention and associated healthcare expenditure.

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Monisha Priyadarshini Kumar

Resident Physician, PGY2
Cleveland Clinic Akron General
Akron, Ohio

NA

Nairmeen Haller

Director of Research
Cleveland Clinic Akron General
AKRON, Ohio

NA

Michael Morocco

Attending Physician
Cleveland clinic Akron General
Akron, Ohio

NA

Monisha Priyadarshini Kumar

Monisha Priyadarshini Kumar

Resident Physician, PGY2
Cleveland Clinic Akron General
Akron, Ohio

NA