Tetany: Symptoms, Causes and Treatment

Tetany is a potentially life-threatening condition marked by heightened neuromuscular excitability, often manifesting as painful muscle cramps and spasms. While many people may associate muscle cramps with ordinary dehydration or exertion, tetany is driven by deeper imbalances within the body—primarily those involving minerals such as calcium and magnesium. Understanding the full spectrum of symptoms, underlying causes, and best treatment practices is essential for both clinicians and individuals at risk. In this article, we’ll take a detailed look at tetany, exploring its clinical presentation, root causes, and the latest evidence-based approaches to treatment.

Symptoms of Tetany

Tetany can present dramatically, but its symptoms often start subtly. Recognizing the early signs is vital to prompt diagnosis and intervention. The following section provides an overview of the typical symptoms and their progression.

Symptom	Description	Frequency/Severity	Source(s)
Muscle Cramps	Painful, involuntary contractions (e.g., hands/feet)	Very common, often severe	4 5
Paresthesia	Tingling/numbness in hands, feet, and face	Common early symptom	1 5
Carpopedal Spasm	Spasm of hands and feet (clawed appearance)	Characteristic sign	4 5
Laryngeal Spasm	Spasm of the larynx; can cause breathing problems	Emergency, life-threatening	4 5
Circumoral Numbness	Numbness around the mouth	Frequent and early sign	1 5
Muscle Twitching	Small, visible muscle twitches	Often precedes cramps	1 5
Chvostek/Trousseau Signs	Provoked facial/hand spasms by tapping/tourniquet	Diagnostic indicators	4
Generalized Seizure	Widespread muscle contraction	Severe, less common	4

Table 1: Key Symptoms of Tetany

Early Sensory Disturbances

The earliest symptoms of tetany often involve sensory changes, such as tingling (paresthesia) in the hands, feet, and around the mouth. These sensations may start subtly but can quickly progress to more pronounced numbness and discomfort. The tingling is thought to originate from abnormal spontaneous discharges in the nerve fibers, especially tactile fibers, which is why the sensation is so prominent and characteristic 1 5.

Muscular Manifestations

Tetany is best known for its painful muscle cramps and spasms. The classic presentation is the carpopedal spasm, where the hands and feet become tightly clenched in a characteristic posture. Other muscles, including those of the face and the larynx, can also be affected. Muscle twitching may occur as a warning sign before full-blown cramps develop. In severe cases, spasms can spread to the arms, legs, and trunk, sometimes leading to generalized seizures 4 5.

Life-Threatening Symptoms

Some symptoms of tetany can be life-threatening:

• Laryngeal spasm can obstruct the airway, causing stridor or even respiratory failure.
• Generalized seizure activity may occur in the most severe cases, representing uncontrolled, widespread muscle contraction 4 5.

Diagnostic Signs

Two classic clinical signs are used to diagnose latent (hidden) tetany:

• Chvostek sign: Facial muscle twitching when the facial nerve is tapped.
• Trousseau sign: Carpopedal spasm induced by inflating a blood pressure cuff on the arm 4.

These signs are useful in detecting neuromuscular irritability even before overt spasms occur.

Causes of Tetany

Understanding the causes of tetany is essential for both prevention and effective treatment. The condition is fundamentally linked to changes in the body’s electrolyte balance or pH, but a range of specific disorders can underlie these changes.

Cause	Mechanism/Description	Prevalence/Notes	Source(s)
Hypocalcemia	Low blood calcium increases nerve/muscle excitability	Most common cause	4 5
Hypomagnesemia	Low magnesium contributes to neuromuscular instability	Frequent, especially in malnutrition	4 5
Alkalosis	High blood pH (e.g., hyperventilation) promotes tetany	Can be acute (anxiety, vomiting)	1 4 5
Hypoparathyroidism	Low parathyroid hormone leads to hypocalcemia	Chronic or post-surgical	4 5
Vitamin D Deficiency	Impaired calcium absorption from gut	Often subtle/long-term	5
Acute Pancreatitis	Calcium sequestration during inflammation	Acute episodes	5
Recurrent Vomiting	Electrolyte loss, alkalosis, and hypocalcemia	Not uncommon	5
Bartter Syndrome	Renal wasting of potassium/calcium/magnesium	Rare inherited disorder	5
Anxiety/Hyperventilation	Rapid breathing reduces ionized calcium	Often acute, reversible	1 5

Table 2: Common Causes of Tetany

Electrolyte Disturbances

The most frequent underlying cause of tetany is hypocalcemia, a condition in which the level of free (ionized) calcium in the blood falls too low. Calcium is essential for stabilizing nerve and muscle cell membranes; when it’s lacking, nerves fire spontaneously, leading to the symptoms of tetany. Hypomagnesemia (low magnesium) can also trigger or worsen tetany, as magnesium is required for proper calcium handling and parathyroid function 4 5.

Alkalosis and Hyperventilation

Alkalosis—an increase in blood pH—shifts calcium from its active, ionized form to a protein-bound, inactive state. This can occur rapidly in people who hyperventilate due to anxiety or other causes. As a result, even people with normal total calcium levels can develop tetany if their blood becomes too alkaline 1 4 5.

Endocrine Disorders

Hypoparathyroidism—whether due to autoimmune destruction, surgical removal, or other causes—results in insufficient parathyroid hormone, which is vital for maintaining calcium levels. This chronic deficiency can lead to persistent tetany unless addressed 4 5.

Other Medical Conditions

• Vitamin D deficiency impairs calcium absorption from the gut, contributing to hypocalcemia and tetany, especially in populations with limited sunlight exposure or malnutrition 5.
• Acute pancreatitis can cause calcium to precipitate in inflamed tissues, leading to a sudden drop in blood calcium 5.
• Recurrent vomiting and certain inherited kidney disorders (e.g., Bartter syndrome) can lead to significant electrolyte losses, setting the stage for tetany 5.

Provoking Factors

Some people may develop tetany acutely during times of stress, anxiety, or after prolonged vomiting. In these scenarios, rapid changes in pH or electrolyte levels can overwhelm the body’s compensatory mechanisms 1 5.

Treatment of Tetany

Timely and effective treatment can be lifesaving in tetany. Management strategies depend on both the severity of symptoms and the underlying cause. Here’s a summary of the main treatment options and interventions.

Treatment Approach	Method/Goal	Notes/Indications	Source(s)
Intravenous Calcium	Rapidly restores blood calcium for acute relief	First-line for hypocalcemia	4 5
Magnesium Supplementation	Corrects hypomagnesemia, stabilizes neuromuscular activity	Essential for some cases	4 5 11
Address Underlying Cause	Treats root problem (e.g., vitamin D, parathyroid, etc.)	Prevents recurrence	4 5
Manage Alkalosis	Control breathing, treat vomiting, address pH	Supportive	1 4 5
Supportive Care	Airway management, oxygen, seizure control	For severe/life-threatening cases	4 5
Diagnostic Tests	Chvostek/Trousseau, laboratory evaluation	Confirms diagnosis	4 5

Table 3: Treatment Strategies for Tetany

Emergency Management

Acute tetany is a medical emergency. The immediate priority is to correct life-threatening symptoms:

• Airway protection: Laryngeal spasms can obstruct breathing; prepare for advanced airway management if needed.
• Rapid correction of hypocalcemia: Intravenous calcium (typically calcium gluconate) is administered to quickly restore blood calcium levels and relieve neuromuscular irritability 4 5.
• Magnesium sulfate may be given if hypomagnesemia is present or suspected, as correcting magnesium is often required to resolve persistent hypocalcemic tetany 4 11.

Treating the Underlying Cause

While acute management is critical, identifying and treating the root cause is essential for preventing recurrence:

• Hypoparathyroidism: Long-term calcium and vitamin D supplementation are needed, and sometimes synthetic parathyroid hormone analogs.
• Vitamin D deficiency: Supplementation with vitamin D and dietary counseling.
• Renal or gastrointestinal losses: Address underlying vomiting, diarrhea, or kidney disorders 4 5.

Managing Alkalosis

In cases where tetany is triggered by alkalosis, such as after hyperventilation or repeated vomiting, the underlying trigger must be treated. This may involve:

• Encouraging slow breathing or using a paper bag in cases of anxiety-induced hyperventilation.
• Treating underlying medical conditions causing metabolic alkalosis 1 4 5.

Monitoring and Support

Continuous monitoring is crucial, especially for patients with severe symptoms or those at risk of airway compromise. Supportive care may include:

• Oxygen therapy
• Intravenous fluids and electrolytes
• Seizure precautions

Diagnostic and Follow-Up Measures

Provocative tests such as Chvostek and Trousseau signs can help confirm the diagnosis, but laboratory tests (serum calcium, magnesium, and pH) are essential for identifying the cause and tailoring treatment 4 5.

Conclusion

Tetany is a dramatic and potentially dangerous condition that stems from disturbances in calcium, magnesium, or pH balance within the body. Its symptoms—ranging from tingling and muscle twitching to severe spasms and airway compromise—demand rapid recognition and intervention. Treatment focuses on immediate correction of biochemical disturbances, supportive care, and meticulous attention to underlying causes.

Key points covered:

• Symptoms: Early sensory changes, muscle cramps, carpopedal and laryngeal spasms, and diagnostic signs such as Chvostek and Trousseau 1 4 5.
• Causes: Most often due to hypocalcemia, but also hypomagnesemia, alkalosis, endocrine disorders (hypoparathyroidism), vitamin D deficiency, acute pancreatitis, and more 4 5.
• Treatment: Emergency correction of calcium/magnesium deficits, treating the root disorder, supportive care, and ongoing monitoring 4 5 11.

Recognizing tetany early and acting decisively can save lives and prevent long-term complications. For both healthcare professionals and patients, awareness and education are the first steps in effective prevention and management.