Hypocalcaemia: Causes, Symptoms and Management

Hypocalcaemia, also known as low blood calcium, is a medical condition that results from decreased levels of calcium in the blood serum. Calcium is a vital mineral, essential for many bodily functions including nerve conduction, muscle contraction, hormone release, and blood clotting. The importance of calcium in maintaining bone health and structural integrity of teeth is well-established. When calcium levels fall below the normal range, typically less than 8.5 mg/dL, various physiological disturbances begin to emerge. Understanding the causes, clinical signs, consequences, treatment options, and the role of medications like Alfacip is crucial for both medical professionals and patients.

What Causes Hypocalcaemia?

Hypocalcaemia can be triggered by a range of conditions and physiological imbalances. One of the primary causes is hypoparathyroidism, a condition in which the parathyroid glands produce insufficient amounts of parathyroid hormone (PTH). This hormone is responsible for maintaining calcium levels in the blood by increasing calcium absorption from the gut, reabsorption from the kidneys, and mobilization from bones. In cases where PTH is lacking or ineffective, calcium levels can drop significantly.

Vitamin D deficiency is another leading cause. Vitamin D is essential for calcium absorption in the intestines. Without enough vitamin D, even a calcium-rich diet may not be sufficient to maintain healthy levels in the bloodstream. Conditions such as chronic kidney disease also impair the body’s ability to activate vitamin D, further contributing to hypocalcaemia.

Magnesium deficiency can indirectly lead to hypocalcaemia as it interferes with PTH secretion. Similarly, acute pancreatitis, sepsis, and certain medications such as bisphosphonates, diuretics, or chemotherapy drugs can disturb calcium homeostasis. Transfusion of citrated blood products may also cause a transient drop in calcium, especially in critically ill patients.

What Is the Most Specific Sign of Hypocalcaemia?

While hypocalcaemia presents with a variety of symptoms, the most specific and recognizable signs include Chvostek's sign and Trousseau's sign, both indicating neuromuscular excitability due to low calcium.

Chvostek’s sign is elicited by tapping on the facial nerve in front of the ear. A positive response — twitching of the facial muscles — indicates increased neuromuscular irritability. This is not exclusive to hypocalcaemia but is considered highly suggestive when seen in conjunction with other signs.

Trousseau’s sign is another hallmark of hypocalcaemia. It is demonstrated by inflating a blood pressure cuff on the arm to a pressure above systolic for several minutes, which can induce carpal spasm (involuntary contraction of the hand muscles). This is considered a more specific and reliable clinical indicator of low serum calcium levels.

What Happens When Your Calcium Is Low?

Low calcium levels can have widespread effects on various systems in the body. Early symptoms often include numbness or tingling in the fingers, toes, or around the mouth. Muscle cramps, spasms, and twitching are common. If left untreated, these neuromuscular symptoms can progress to more serious manifestations such as seizures, laryngospasm (causing difficulty breathing), or cardiac arrhythmias.

Neurological symptoms might include confusion, irritability, or depression. Prolonged hypocalcaemia can also affect skin and hair, causing dry skin, brittle nails, and coarse hair. Dental issues like enamel hypoplasia or delayed tooth eruption may occur, particularly in children.

Cardiac manifestations can be life-threatening. Calcium plays a key role in the electrical conduction system of the heart. Severe hypocalcaemia can cause a prolonged QT interval on electrocardiogram (ECG), increasing the risk for arrhythmias.

In chronic cases, particularly those linked to chronic kidney disease, patients may develop secondary hyperparathyroidism as the body attempts to compensate for persistent low calcium levels. This can result in bone demineralization and skeletal deformities over time.

How Do You Fix Hypocalcaemia?

Treatment of hypocalcaemia depends on the severity and underlying cause. For acute, symptomatic cases, intravenous calcium gluconate or calcium chloride may be administered to rapidly correct levels and alleviate symptoms. Close monitoring is necessary during infusion to avoid complications such as cardiac arrhythmias.

Oral calcium supplements are typically used for chronic or less severe cases. These are often combined with vitamin D supplementation to improve intestinal absorption of calcium. It’s essential to determine whether the underlying problem lies in vitamin D deficiency, hypoparathyroidism, or renal dysfunction, as this will guide the choice of therapy.

In cases where hypocalcaemia is caused by low PTH levels, treatment may include active forms of vitamin D, such as calcitriol, or analogs like Alfacalcidol (marketed as Alfacip), along with calcium supplements. Monitoring magnesium levels is also important, as magnesium repletion may be necessary before calcium levels can normalize.

For patients with chronic kidney disease, dietary modifications, phosphate binders, and active vitamin D analogs form the cornerstone of long-term management. The goal is to maintain calcium, phosphate, and PTH within acceptable ranges to avoid both hypocalcaemia and secondary complications like vascular calcification or bone disease.

The Role of Alfacip in the Treatment of Hypocalcaemia

Alfacip, a brand name for Alfacalcidol, is a synthetic analog of vitamin D used to treat and prevent hypocalcaemia in various conditions, particularly those related to impaired kidney function and hypoparathyroidism. Unlike regular vitamin D (cholecalciferol), which needs to be hydroxylated in the liver and kidneys to become active, Alfacalcidol is already hydroxylated at the liver stage and can be quickly converted to the active form of vitamin D (1,25-dihydroxyvitamin D3) in the body.

This makes Alfacip especially useful for patients with chronic kidney disease, where renal conversion is impaired. It helps increase calcium absorption from the gut, enhances calcium reabsorption in the kidneys, and promotes the release of calcium from bones, thereby helping to restore serum calcium levels.

Alfacip is often prescribed as part of a broader treatment regimen for conditions like renal osteodystrophy, secondary hyperparathyroidism, and vitamin D-resistant rickets, as well as hypocalcaemia due to various other causes. It is available in oral capsule or drop formulations, and dosage is carefully adjusted based on serum calcium and phosphate levels.

Patients on Alfacip require regular monitoring of calcium, phosphate, and parathyroid hormone levels to avoid overcorrection, which could lead to hypercalcaemia and associated complications. The goal of therapy is to maintain calcium within the normal range while minimizing fluctuations that could cause symptoms or long-term tissue damage.

Final Thoughts

In summary, hypocalcaemia is a condition with serious clinical implications if left untreated. It arises from a wide variety of causes, most notably hypoparathyroidism, vitamin D deficiency, and renal dysfunction. The most specific signs, such as Trousseau’s sign and Chvostek’s sign, offer valuable clues for diagnosis. The effects of low calcium on the body are extensive, affecting the nervous system, muscles, heart, and even the skin and hair.

Management requires a thorough understanding of the underlying cause, with treatment strategies ranging from intravenous calcium administration in emergencies to long-term maintenance with oral supplements and vitamin D analogs. Among these, Alfacip (Alfacalcidol) stands out as a critical option for managing hypocalcaemia in patients with kidney-related disorders or impaired parathyroid function. With appropriate treatment and monitoring, patients can achieve stable calcium levels and avoid the complications associated with this potentially life-threatening condition.

Medically Reviewed by Dr. Rabeea Aboufakher, MD