Optimal Discrimination of Mild Hyperparathyroidism with Total Serum Calcium, Ionized Calcium and Parathyroid Hormone Measurements

Abstract Background Preeclampsia is a well-known cause of maternal mortality and morbidity in Ethiopia. The exact pathophysiology has not been fully understood. Calcium and magnesium deficiencies have been given emphasis to play roles in the pathophysiology. Although evidence is abundant, they are equivocal. The study aimed to see the association of dietary calcium intake, serum total calcium level and ionized calcium level with preeclampsia. It also evaluated the association between dietary calcium intake and serum calcium levels. Materials and methods An unmatched case–control study was conducted in Gandhi Memorial, Tikur Anbessa, and Zewditu Memorial Hospitals, all in Addis Ababa, between October to December, 2019. Cases were 42 women with preeclampsia and controls were 42 normotensive women. The medical and obstetric history was gathered using a structured questionnaire and the dietary calcium intake information using a 24-h dietary recall. The serum levels of total serum calcium and ionized (free) calcium were measured using an inductively coupled mass spectrophotometer. Bivariate and multivariate logistic regression and Pearson correlation test were utilized during data analysis. Results In comparison with controls, women with preeclampsia had lower mean (± 1SD) levels of ionized calcium level (1.1 mmol/l ± 0.11), total serum calcium level (1.99 mmol/l ± 0.35) and lower median (IQR) dietary calcium intake (704 mg/24 h,458–1183). The odds of having preeclampsia was almost eight times greater in those participants with low serum ionized calcium level (OR 7.5, 95% CI 2.388–23.608) and three times higher in those with low total serum calcium level (OR 3.0, 95% CI 1.024–9.370). Low dietary calcium intake also showed statistically significant association with preeclampsia (OR 3.4, 95% CI 1.092 -10.723). Serum ionized calcium level and total serum calcium level showed positive correlation of moderate strength (p = 0.004, r = 0.307), but no correlation was found between dietary calcium intake with both forms of serum calcium levels. Conclusion This study showed significant association between low dietary calcium intake and low serum calcium levels with preeclampsia, hence this can be used as a supportive local evidence for the current context-specific recommendation of calcium supplementation in societies with low-dietary calcium consumption in an attempt to prevent preeclampsia, therefore implementation study should be considered in Ethiopia to look for the feasibility of routine supplementation.

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Hysteresis of the parathyroid hormone response to hypocalcemia in hemodialysis patients with low turnover aluminum bone disease.

Journal of the American Society of Nephrology ◽

10.1681/asn.v261136 ◽

1991 ◽

Vol 2 (6) ◽

pp. 1136-1143

Author(s):

A J Felsenfeld ◽

D Ross ◽

M Rodriguez

Keyword(s):

Parathyroid Hormone ◽

Serum Calcium ◽

Bone Disease ◽

Calcium Concentration ◽

Hemodialysis Patients ◽

Ionized Calcium ◽

Total Serum ◽

High Calcium ◽

The Mean ◽

Pth Level

During the study of parathyroid function in 19 hemodialysis patients with low turnover aluminum bone disease, it was observed that serum parathyroid hormone (PTH) levels were higher during the induction of hypocalcemia than during the recovery from hypocalcemia. This type of PTH response has been termed hysteresis. Hypocalcemia was induced during hemodialysis with a calcium-free dialysate. When the total serum calcium level decreased to 7 mg/dL, the dialysate calcium concentration was changed to 3.5 mEq/L and the dialysis session was completed. One week later, hypercalcemia was induced during hemodialysis with a high-calcium dialysate. The mean basal PTH level was 132 +/- 37 pg/mL (normal, 10 to 65 pg/mL; immunoradiometric (IRMA), Nichols Institute, San Juan Capistrano, CA) and increased to a maximal PTH level of 387 +/- 91 pg/mL during hypocalcemia. For the same ionized calcium concentration, the PTH level was higher during the induction of hypocalcemia than during the recovery from hypocalcemia. Conversely, for the same ionized calcium concentration, the PTH level was greater when hypercalcemia was induced from the nadir of hypocalcemia than when hypercalcemia was induced from basal serum calcium. The set point of calcium (defined as the serum calcium concentration required to reduce maximal PTH by 50%) was greater during the induction of hypocalcemia than during the recovery from hypocalcemia (4.44 +/- 0.10 versus 4.25 +/- 0.09 mg/dL; P = 0.03). The mean basal ionized calcium concentration and the mean ionized calcium concentration at the intersection of the two PTH-calcium curves were the same (4.61 +/- 0.13 versus 4.61 +/- 0.12 mg/dL).(ABSTRACT TRUNCATED AT 250 WORDS)

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Ionized Calcium, Cardiac Function, and Electrocardiogram in Preterm Neonates

PEDIATRICS ◽

10.1542/peds.78.3.541a ◽

1986 ◽

Vol 78 (3) ◽

pp. 541-542

Author(s):

JENS MÖLLER ◽

F. K. TEGTMEYER

Keyword(s):

Cardiac Function ◽

Causal Relationship ◽

Serum Calcium ◽

Cardiac Failure ◽

Calcium Level ◽

Ionized Calcium ◽

Preterm Neonates ◽

Total Serum ◽

Total Serum Calcium

To the Editor.— We would like to add some comments on the article by Venkataraman et al.1 In one respect it might be quite dangerous not to measure the ionized calcium in preterm neonates. If you find prolongation of QTc or QoTc intervals in the ECG during cardiac failure in these infants and find subnormal total serum calcium levels, you might make a wrong conclusion on causal relationship. Until now, we have seen five preterm neonates with OTc/QoTc prolongation and profound low total serum calcium levels, whereas the measured ionized calcium level was normal.

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OCCULT PRIMARY HYPERPARATHYROIDISM: A CASE REPORT AND REVIEW OF PARATHYROID ULTRASONOGRAPHY

AACE Clinical Case Reports ◽

10.4158/accr-2019-0523 ◽

2020 ◽

Vol 6 (3) ◽

pp. e127-e131

Author(s):

Matthew C. Moccia ◽

Eli E. Miller ◽

Cherie L. Vaz

Keyword(s):

Parathyroid Hormone ◽

Primary Hyperparathyroidism ◽

Reference Range ◽

Relevant Literature ◽

Hashimoto Thyroiditis ◽

Neck Mass ◽

Ionized Calcium ◽

Total Serum ◽

Radiologic Evaluation ◽

Total Serum Calcium

Objective: To discuss the diagnosis and management of occult primary hyperparathyroidism. Methods: We present the biochemical and radiologic evaluation, treatment, and outcome of a woman with occult primary hyperparathyroidism which presented as an unusual neck mass on ultrasound. We also present a relevant literature review. Results: A 52-year-old female presented with Hashimoto thyroiditis and a 1.2-cm, hypoechoic oval nodule in the left upper lateral portion of the thyroid. She returned a decade later with a 2.2-cm, hypervascular mass on ultrasound. Parathyroid hormone was mildly elevated at 90 pg/mL (reference range is 15 to 65 pg/mL), but she had persistently normal levels of total serum calcium at 9.9 mg/dL (reference range is 8.7 to 10.3 mg/dL), phosphorus at 3.5 mg/dL (reference range is 2.1 to 4.5 mg/dL), and albumin at 4.4 g/dL (reference range is 3.6 to 4.8 g/dL). She had elevated ionized calcium of 5.9 mg/dL (reference range is 4.5 to 5.6 mg/dL). Computed tomography with contrast of the neck revealed an enhancing oval lesion abutting the superior pole of the left thyroid with attenuation characteristics similar though slightly different from the thyroid. 99mTc-Sestamibi scan showed increased uptake posterior to the superior aspect of the left thyroid. Bone densitometry showed osteoporosis of the left distal radius and osteopenia of the left femoral neck. Minimally invasive radio-guided parathyroidectomy was performed with normalization of parathyroid hormone. Pathology confirmed a 1.715-g parathyroid adenoma. Conclusion: Despite normal total calcium levels, clinically significant primary hyperparathyroidism may present as a large adenoma which could appear as a hypervascular neck mass on ultrasound. A high index of suspicion based on ultrasound features and measurement of ionized calcium may be helpful in diagnosing occult, but clinically relevant primary hyperparathyroidism.

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Serum ionized calcium and corrected total calcium in borderline hyperparathyroidism.

Clinical Chemistry ◽

10.1093/clinchem/24.11.1962 ◽

1978 ◽

Vol 24 (11) ◽

pp. 1962-1965 ◽

Cited By ~ 47

Author(s):

L Larsson ◽

S Ohman

Keyword(s):

Serum Calcium ◽

Reference Range ◽

Reference Group ◽

Ionized Calcium ◽

Total Serum ◽

Albumin Concentration ◽

Serum Calcium Concentration ◽

Normal Limits ◽

Total Serum Calcium ◽

Serum Ionized Calcium

Abstract We studied 25 borderline-hyperparathyroidism patients whose total serum calcium concentration was within normal limits (reference range: 2.25--2.75 mmol/liter) but whose concentrations of serum ionized calcium were above normal (reference range: 1.03--1.23 mmol/liter). Their hyperparathyroidism was histopathologically verified. To compare the discriminating value of corrected serum calcium with ionized calcium, we studied the serum calcium and albumin concentrations in a reference group of 2098 patients. After patients from endocrine and dialysis departments were excluded from the reference group, we obtained the range (mean +/- 2 SD) 2.05--2.71 mmol/liter for uncorrected serum calcium and 2.11--2.63 mmol/liter for corrected serum calcium. The correction factor for calcium on albumin was 20 mumol/g. Even with this limit for corrected serum calcium, 13 of 25 borderline hyperparathyroidism patients had values that fell within the reference range. We conclude that correcting total serum calcium values for serum albumin concentration improves discrimination of borderline hyperparathyroid patients, but that measurement of ionized calcium in serum discriminates better.

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Ionized Calcium in Calf Serum: Relation to Total Serum Calcium, Albumin, Total Protein and pH

Journal of Veterinary Medicine Series A ◽

10.1111/j.1439-0442.1993.tb00673.x ◽

1993 ◽

Vol 40 (1-10) ◽

pp. 605-608 ◽

Cited By ~ 6

Author(s):

F. AGNES ◽

P. SARTORELLI ◽

M. C. BISSO ◽

S. DOMINONI

Keyword(s):

Serum Calcium ◽

Total Protein ◽

Calf Serum ◽

Ionized Calcium ◽

Total Serum ◽

Total Serum Calcium

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Clinical Approach to Hypocalcemia in Newborn Period and Infancy: Who Should Be Treated?

International Journal of Pediatrics ◽

10.1155/2019/4318075 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Dogus Vuralli

Keyword(s):

Preterm Infants ◽

Serum Calcium ◽

Gestational Age ◽

Late Onset ◽

Ionized Calcium ◽

Total Serum ◽

Specific Reference ◽

Clinical Approach ◽

Newborn Period ◽

Total Serum Calcium

Introduction. Hypocalcemia is a common metabolic problem in newborn period and infancy. There is consensus on the treatment of the symptomatic cases while the calcium level at which the treatment will be initiated and the treatment options are still controversial in asymptomatic hypocalcemia. Methods. This review article will cover hypocalcemia with specific reference to calcium homeostasis and definition, etiology, diagnosis, and treatment of hypocalcemia in newborn and infancy period. Results. Hypocalcemia is defined as total serum calcium <8 mg/dL (2 mmol/L) or ionized calcium <4.4 mg/dL (1.1 mmol/L) for term infants or preterm infants weighing >1500 g at birth and total serum calcium <7 mg/dL (1.75 mmol/L) or ionized calcium <4 mg/dL (1 mmol/L) for very low birth weight infants weighing <1500 g. Early-onset hypocalcemia is generally asymptomatic; therefore, screening for hypocalcemia at the 24th and 48th hour after birth is warranted for infants with high risk of developing hypocalcemia. Late-onset hypocalcemia, which is generally symptomatic, develops after the first 72 h and toward the end of the first week of life. Excessive phosphate intake, hypomagnesemia, hypoparathyroidism, and vitamin D deficiency are commonest causes of late-onset hypocalcemia. Hypocalcemia should be treated according to etiology. Calcium replacement is the cornerstone of the treatment. Elementary calcium replacement of 40 to 80 mg/kg/d is recommended for asymptomatic newborns. Elementary calcium of 10 to 20 mg/kg (1–2 mL/kg/dose 10% calcium gluconate) is given as a slow intravenous infusion in the acute treatment of hypocalcemia in patients with symptoms of tetany or hypocalcemic convulsion. Conclusion. Since most infants with hypocalcemia are usually asymptomatic, serum total or ionized calcium levels must be monitored in preterm infants with a gestational age <32 weeks, small for gestational age infants, infants of diabetic mothers, and infants with severe prenatal asphyxia with a 1 min Apgar score of <4. The treatment of hypocalcemia should be initiated immediately in infants with reduced calcium levels while investigating the etiology.

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