Hypocalcemia has various presentations and can lead to significant morbidity if left untreated. The most common cause is hypoalbuminemia from conditions like cirrhosis or malnutrition that lower serum calcium levels. Other potential causes include vitamin D deficiency, parathyroid issues, medications, and critical illnesses like sepsis. Treatment involves identifying and addressing the underlying cause, as well as replacing calcium, often intravenously, to resolve symptoms and normalize calcium levels. Calcium levels must be closely monitored during treatment until stabilized.

1. Hypocalcemia
DR IYAN DARMAWAN

2. Background
 Presentations vary widely
 Unrecognized and untreated severe hypocalcemia leads to
significant morbidity and death
 The most common cause is hypoalbuminemia
 Underlying conditions (cirrhosis, malnutriton, nephrosis, burns,
chronic illness and sepsis) low serum calcium is simply due to
hypoalbuminemia
 Other causes include: Vit D deficiency or resistance, PTH deficiency
or resistance, surgical effects, medication, hyperphosphatemia,
hypomagnesemia etc.

3. Homeostasis and Physiological Role
 Total serum Calcium 8.6-10.2 mg/dl (2.15-2.55 mmol/L)
 Ionized Calcium 4.4-5 mg/dl (1.1 -1.25 mmol/L) (Note: 1 mmol Ca++ = 2 mEq Ca++ )
 Bone metabolism, nerve conducton, intracellular signaling, coagulation cascade,
regulation of secretory function
 Total body distribution 99% bone; 1% serum
 Plasma protein binding (80% with albumin)
 Regulated by vitamin D, Phosphorus and PTH
 Dietary intake : enteral 100-1200 mg/day; PN 10-15 mEq/day
Todd W. The A.S.P.E.N. Fluids, Electrolytes, and Acid-Base Disorders Handbook. ASPEN 2015. pp 142-164

4. Prevalence of Hypocalcemia
 18% hospitalized patients; up to 85% ICU patients (15-88%)1
 Fifty percent of hypocalcemic patients in the ICU have sepsis, as
opposed to 25% of normocalcernic patients.2
 Hypocalcemic patients are more likely to need vasopressor support
(41% of hypocalcernic patients as opposed to 14% normocalcernic
patients) 3.
 The mortality rate of hypocalcernic critically ill patients is significantly
greater than that of normocalcernic patients (44% vs. 17%).2
1. Zaloga GP: Hypocalcemia in critically ill patients. Crit Care Med 1992, 20:251-262
2. Desai TK, Carlson RW, Geheb MA. Prevalence and clinical implications of hypocalcernia in acutely ill patients in a medical intensive care setting. Am JMed
1988; 84:209-14.
3. Desai TK, Carlson RW, Thill-Baharozian, et al. A direct relationship between ionized calcium and arterial pressure among patients in an intensive care unit. Crit
Care Med 1988:16:578-82

5. Clinical Presentation of Hypocalcemia
Mild to Moderate Severe
Total Ca 7.5-8.5 mg/dl or < 7.5 mg/dl or
1.9-2.1 mmol/L < 1.9 mmol/L
Ionized Ca 4-4.5 mg/dl or < 4 mg/dl or
1-1.2 mmol/L < 1 mmol/L
Presentation
Paresthesia, muscle cramps,
mental status changes, Chovestek's
sign
Trousseau's sign, and hypotension
tetany, acute heart failure, and
Arrhythmia
1. Kraft MD, Btaiche IF, Sacks GS, et al. Treatment of electrolyte disorders in adult patients in the intensive care unit. Am J Health Syst Pharm. 2005;62:1663-1682
2. Guise TA, Mundy GR. J Clin Endocrinol Metab. 1995;80 :1473– 1478
3. French S, Subauste J, Geraci S. Calcium abnormalities in hospitalized patients. South Med J 2012;105:231-7

6. Trouseau’s sign and Chvostek’s sign
Inflate cuff to SBP will trigger carpopedal spasm

7. Diagnosis
 Assess albumin since serum alb < 4 g/dl, should adjust total serum
calcium calculation
 Corrected Total Serum Ca (mg/dl)= Measured Total Serum Ca
(mg/dl) + [0.8 mg/dl x (4.0 g/dl – measured albumin (g/dl)]
 Example: Measured Total serum Ca 6 mg/dl; alb 2.7 g/dl →
Corrected Total serum Ca = 6 + 0.8 x 1.3 = 7.04 mg/dl (moderate
hypocalcemia)
 Ionized serum calcium < 4.5 mg/dl ( < 1.12 mmol/L) should be used
in critical care setting because albumin-adjusted esdtimation is not
reliable

8. Goals of Therapy
 Total Serum Ca 8.6-10.2 mg/dl (2.15-2.55
mmol/L) or
 Ionized serum Ca > 4.5 mg/dl or > 1.12 mmol/L
 Manage underlying illness

9. Management
 Mild to moderate : Oral supplementation
 IV Calcium
 Intermitten iv boluses for severe symptomatic (total serum ca < 7.5
mg/dl or < 1.9 mmol/L) or ionzied Ca < 4 mg/dl or < 1 mmol/L)
 Symptocatic hypocalcemia is an emergency
 Administer 1 g Calcium chloride or 2-3 g Ca Gluconate iv over 5 -10
minutes
 Asymptomatic hypocalcemia 2-4 g Ca gluconate (1 g/hour)
 Refractory hypocalcemia: Continuous infusion of elemental calcium
 Others: consider vit D preparations

10. Calcium Parenteral Products
CALCIUM PARENTERAL: PRODUCTS
Product Available solutions Elemental
calcium content
per 1000 mg of
solution
Route of
Administration
Calcium
gluconate
10% 92 mg (4.65 mEq) Peripheral/central
Calcium chloride 10% 272 mg (13.6 mEq) Central
• Avoid admixing into parenteral solutions containing bicarbonate or
phosphate
• Maximum infusion rateshould not exceed 1.4 mEq of Calcium per minute

11. Treatment of refractory/severe HypoCalcemia
Elemental Calcium iv 100-300 mg over
5-10 minutes
(1 g Ca Chloride or 3 g Ca Gluconate)
Continue Elemental Calcium iv
(0.25-2 mg/kg/h)
Ionized Calcium normalized?
Symptoms not rersolved
Yes
Maintainance Elemental Calcium
iv (0.3-0.5 mg/kg/h) Consider Oral Calcium
No
Check Ionized Calcium every 1-4 h
Todd W. The A.S.P.E.N. Fluids, Electrolytes, and Acid-Base Disorders Handbook. ASPEN 2015. pp 142-164

12. Monitoring
 Asymptomatic patients treated with oral supplements require
assessment every 24-48 hours (inpatient) or every 2-3 months
(outpatient)
 Acute, symptomatic aggressively treated should be monitored 4-6
hourly until normal levels are obtained
 Given the variety of causes, consultations may include or or more of
the following: internist, endocrinologst, intensivist, surgeon,
oncologist, nephrologist, dietitian and toxicologist