obsolete hypocalcemia and hypomagnesemia of newborn

Understanding Obsolete Hypocalcemia and Hypomagnesemia in Newborns

Hypocalcemia, a condition characterized by low calcium levels in the blood, and hypomagnesemia, a condition marked by low magnesium levels, are two related disorders that can affect newborns. While these conditions are still relevant today, their understanding has evolved over time.

Early-Onset Hypocalcemia (EOH)

In the past, early-onset hypocalcemia was recognized as a common issue in newborns, particularly those born prematurely [12][14]. This condition occurs within the first 72 hours after birth and is often asymptomatic. EOH is thought to be an exaggeration of the normal postnatal decrease in calcium levels that occurs in all newborns.

Late-Onset Hypocalcemia (LOH)

Late-onset hypocalcemia, on the other hand, develops after the first 72 hours and towards the end of the first week of life. This condition is generally symptomatic and can be caused by excessive phosphate intake, hypomagnesemia, hypoparathyroidism, or vitamin D deficiency [15].

Hypomagnesemia

Hypomagnesemia, a condition characterized by low magnesium levels in the blood, is often associated with hypocalcemia. Magnesium plays an essential role in calcium homeostasis, and its deficiency can lead to PTH resistance and impaired PTH secretion, resulting in hypocalcemia [11][25].

Causes of Hypocalcemia

The main causes of hypocalcemia in newborns include:

• Increased phosphate load due to cellular damage
• Increased calcitonin production
• Renal failure
• Decreased PTH secretion

In infants born to diabetic mothers, the main cause of hypocalcemia is often hypomagnesemia in both the mother and the infant [10].

Treatment

The treatment of hypocalcemia depends on its underlying cause. In some cases, correcting magnesium levels can resolve the issue, while in others, additional interventions may be necessary.

References:

[1] Avery's Diseases of the Newborn (definition of neonatal hypocalcemia) [10] ETIOLOGY (causes of neonatal hypocalcemia) [11] Neona ypocalcemia 192 Newborn, Volume 1 Issue 1 (January–March 2022) Magnesium plays an important role in calcium homeostasis. [12] Early hypocalcemia — Early hypocalcemia refers to hypocalcemia occurring within the first three days after birth. It is an exaggeration of the normal postnatal decrease in calcium that occurs in all newborns. [14] Calcium homeostasis in the neonatal period is a reflection of the transition from placental regulation to hormonal maturation in the newborn. [15] 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.

Neonatal Hypocalcemia and Hypomagnesemia: Signs and Symptoms

Neonatal hypocalcemia and hypomagnesemia are conditions that occur in newborns, characterized by abnormally low levels of calcium and magnesium in the blood. These conditions can have severe consequences if left untreated.

Common Signs and Symptoms:

• Increased neuromuscular irritability, leading to symptoms such as:
  • Tremors [7]
  • Tetany [7]
  • Convulsions [7][9]
  • Coma [7]
• Other less common symptoms include:
  • Laryngospasm
  • Stridor
  • Apnea [9]

Risk Factors:

• Preterm infants with a gestational age <32 weeks [11]
• Infants of diabetic mothers [11]
• Infants with severe prenatal asphyxia and a 1 min Apgar score of <4 [11]

Importance of Early Detection:

Since most infants with early-onset hypocalcemia are usually asymptomatic, serum calcium should be measured in infants having risk factors for hypocalcemia. Early detection is crucial to prevent complications and ensure timely treatment.

References:

[7] S Lomelino-Pinheiro (2020) - Clinical manifestations of neonatal hypocalcemia [9] Other less common symptoms include laryngospasm, stridor and apnoea in neonates. [11] Since most infants with early-onset hypocalcemia are usually asymptomatic, serum, preferably ionized, calcium should be measured in infants having risk factors for hypocalcemia.

Diagnostic Tests for Hypocalcemia and Hypomagnesemia in Newborns

Hypocalcemia and hypomagnesemia are two common electrolyte imbalances that can occur in newborns. Diagnosing these conditions is crucial to provide appropriate treatment and prevent complications.

Blood Tests

• A calcium concentration blood test is used to diagnose hypocalcemia (1). This test measures the total serum calcium level, which is essential for diagnosing hypocalcemia.
• Serum magnesium levels are also measured to diagnose hypomagnesemia (9).

Other Diagnostic Tests

• Electrocardiogram (ECG) criteria can be used to suspect hypocalcemia, but a diagnosis based only on ECG criteria may yield a high false-positive rate (14).
• A serum calcium level test is recommended for infants suspected of having hypocalcemia or hypomagnesemia due to symptoms such as jitteriness, apnea, feeding intolerance, and seizures (11).

Diagnostic Approach

The diagnostic approach to hypocalcemia involves confirming the presence of hypocalcemia by repeat measurement and distinguishing among the various causes of hypocalcemia (6). A detailed history, including pregnancy and family history, should be obtained in cases of hypocalcemia in the newborn period and infancy (1).

Key Points

• Hypocalcemia is defined as a serum calcium level less than 7 mg/dL or an ionized calcium level less than 4.4 mg/dL (1.1 mmol/L) (7).
• Excessive phosphate intake, hypomagnesemia, hypoparathyroidism, and vitamin D deficiency are common causes of late-onset hypocalcemia (10).
• Calcium replacement is the cornerstone of treatment for hypocalcemia, with elementary calcium replacement of 40 to 80 mg/kg/d recommended for asymptomatic newborns (10).

References

[1] Newborn (2022) Disorders of Mineral Homeostasis in the Newborn, Infant, Child, and Adolescent.

[6] Root AW, Diamond FB. (2008) Disorders of Mineral Homeostasis in the Newborn, Infant, Child, and Adolescent.

[7] Diagnostic Approach to Hypocalcemia in Newborn Period and Infancy.

[10] Excessive phosphate intake, hypomagnesemia, hypoparathyroidism, and vitamin D deficiency are commonest causes of late-onset hypocalcemia.

[11] Similar to hypocalcemia (see Chapter 85, Section I.E) (eg, jitteriness, apnea, feeding intolerance), and may also present as seizures. Clinical signs may be masked as hypocalcemia. If symptoms persist after adequate calcium gluconate therapy, hypomagnesemia should be considered.

[14] A diagnosis of hypocalcemia based only on ECG criteria is likely to yield a high false-positive rate.

Treatment Options for Obsolete Hypocalcemia and Hypomagnesemia in Newborns

Obsolete hypocalcemia and hypomagnesemia in newborns require prompt treatment to prevent complications. The following are the key treatment options:

• Calcium Replacement: Calcium replacement is the cornerstone of treatment for hypocalcemia. Intravenous (IV) calcium infusion is the most effective and rapid means of elevating serum calcium levels [4]. The dosage of elemental Ca is typically 30 to 75 mg/kg/day, titrated to clinical and laboratory parameters [6].
• Vitamin D Supplements: Vitamin D supplements are essential for treating hypocalcemia, especially in cases where vitamin D deficiency is present. Treatment can be further intensified with thiazide diuretics (increasing distal renal tubular calcium reabsorption) and a low salt diet [7][9].
• Magnesium Replacement: Magnesium replacement is crucial for treating hypomagnesemia. The etiology, definition, evaluation, and management of neonatal hypocalcemia are reviewed in the context of magnesium deficiency [8].

Additional Treatment Considerations

• Symptomatic Treatment: Symptomatic treatment is directed toward other underlying etiologies, such as hypomagnesemia, vitamin D deficiency, and hyperphosphatemia.
• Oral Calcium Therapy: Oral calcium therapy is used in asymptomatic patients and as follow-up to IV calcium therapy.

References

[1] Oct 25, 2021 — Oral calcium therapy is used in asymptomatic patients and as follow-up to intravenous (IV) calcium therapy. IV treatment is usually indicated in ... [4] Oct 25, 2021 — Calcium therapy is the mainstay of treatment for hypocalcemia. Therapy with IV calcium is the most effective and rapid means of elevating serum calcium ... [6] Treatment of symptomatic hypocalcemia is by intravenous (IV) Ca infusion with a dosage of 30 to 75 mg/kg/day of elemental Ca, titrated to clinical and ... [7] by J Fong · 2012 · Cited by 251 — Treatment focuses on oral calcium and vitamin D supplements, as well as magnesium if deficiency is present. Treatment can be further intensified with thiazide ... [8] by SA Abrams · Cited by 8 — Hypomagnesemia · Late hypocalcemia ... The etiology, definition, evaluation, and management of neonatal hypocalcemia are reviewed here. [9] by SS Pillai · Cited by 4 — Treatment can be further intensified with thiazide diuretics (increasing distal renal tubular calcium reabsorption) and a low salt (dietary sodium restriction).