What Is Tetany

Introduction

Tetany is a medical condition characterised by involuntary muscle contractions and spasms due to overactive (hyperexcitable) nerves, usually secondary to abnormalities in electrolytes.¹ These contractions can be painful and affect various muscles, causing muscle stiffness and twitching.  

Recognising the signs and symptoms allows for prompt medical intervention. Furthermore, knowing what the causes and risk factors are will allow people to adopt preventive measures to reduce the likelihood of developing tetany or managing it effectively once diagnosed. 

Overview of tetany

Although the names may seem similar, it's important to note that tetany is a different problem from tetanus. Tetanus is a bacterial infection that occurs through contaminated cuts, resulting in severe nerve stimulation throughout the entire body. Tetany, on the other hand, is a symptom triggered by the hyperexcitability of the nerves due to an underlying issue. 

The most common symptoms experienced are: 

• Muscle cramps or spasms
• Tingling or numbness of hands, feet, and face
• Muscle weakness 
• Convulsions or seizures in severe cases

Causes of tetany

Calcium deficiency  

Calcium deficiency is the most common cause of tetany. When the body lacks enough calcium because of insufficient intake through diet or problems with absorption, it disrupts the delicate balance needed for muscle contraction and nerve function. Calcium is essential for transmitting nerve impulses and regulating muscle contractions. When calcium levels drop, the nerves become more excitable, leading to involuntary muscle contractions and spasms.² 

Therefore, ensuring a sufficient intake of calcium-rich foods or supplements is important in preventing tetany related to calcium deficiency. 

Hyperventilation and respiratory alkalosis

When a person breathes very quickly (hyperventilation), such as when anxious, they breathe off a large amount of carbon dioxide from the body. 

The body has a careful balance of acid and alkali. As carbon dioxide is acidotic, if you breathe off more than usual when hyperventilating, you become less acidotic (i.e. alkalotic). This is what we call respiratory alkalosis – where the blood has become alkalotic due to a change in breathing. 

Alkalosis can disrupt the body's calcium ion balance, making nerve cells hypersensitive and prone to triggering muscle spasms. This hyperventilation-induced alkalosis can lead to symptoms of tetany, such as muscle cramps, tingling sensations, and muscle weakness.³ 

Recognising the importance of proper breathing and managing stress to avoid hyperventilation is essential in preventing this form of tetany. 

Hypoparathyroidism

Hypoparathyroidism is a medical condition where there is an insufficiency in parathyroid hormone (PTH) production, a hormone produced by the parathyroid glands in the neck. PTH is responsible for maintaining the levels of calcium in the body. It can stimulate calcium release from bones and increase its absorption in the intestines.⁴ 

Therefore, when hypoparathyroidism occurs, there is a deficiency of PTH, resulting in decreased calcium levels in the blood, which, as we mentioned before, is vital in the conduction of nerve signals.

Other causes 

Tetany can also stem from various other potential factors.  

Vitamin D deficiency, which is essential for calcium absorption, can contribute to low calcium levels and subsequently induce tetany.  

Similarly, renal failure can disrupt calcium and phosphorus balance, impacting nerve and muscle function.⁵  

Magnesium deficiency is another potential cause, as magnesium is linked to how well calcium is used by the body.  

Certain medications, particularly diuretics and medications that interfere with calcium absorption, can also lead to tetany.  

Risk factors for tetany

Age and gender

Tetany is more prevalent in certain age groups, particularly children and the elderly. In children, rapid growth phases and inadequate calcium intake can make them more susceptible to calcium imbalances. On the other hand, the elderly are at risk due to age-related factors such as decreased calcium absorption and potential medical conditions affecting calcium regulation.⁶ Additionally, gender can be a factor, with postmenopausal people assigned female at birth (AFAB) facing an increased risk due to hormonal changes that affect bone health and calcium absorption.

Dietary factors

Insufficient dietary intake of calcium, vitamin D, and magnesium increases the risk of low calcium levels in the body, a significant predisposing factor for tetany. Individuals with diets lacking dairy products, leafy greens, nuts, and fortified foods may be particularly at risk. Additionally, poor dietary habits and restrictive diets can contribute to nutritional deficiencies, further elevating the risk of tetany.

Medical conditions

Various medical conditions can increase the risk of tetany. Conditions that affect the parathyroid glands, kidneys, or digestive system can disrupt calcium regulation in the body.⁷ For instance, individuals with chronic kidney disease may experience impaired calcium metabolism, potentially leading to tetany. Disorders such as coeliac disease, Crohn's disease, or gastrointestinal surgery can affect proper nutrient absorption, including calcium, exacerbating the risk of tetany.

Medications

Certain medications can also increase the risk of tetany. For example, medications that affect calcium metabolism, such as diuretics or certain antiepileptic drugs (to prevent seizures), may lead to lower calcium levels in the blood, predisposing individuals to tetany. 

Additionally, medications that interfere with the absorption or utilisation of calcium, such as proton pump inhibitors (PPIs) or corticosteroids, can contribute to calcium deficiencies and subsequently elevate the risk of developing tetany. It is essential for individuals taking such medications to be monitored regularly for any signs of tetany and to maintain appropriate calcium and vitamin D supplementation as needed.

Diagnosis of tetany

Clinical examination 

If you’re concerned that you are experiencing tetany, the first step of diagnosis is through a thorough clinical examination by a doctor. The examination involves assessing your medical history and symptoms and conducting a physical examination to evaluate muscle strength, reflexes, and any signs of muscle spasms or cramping. The doctor will also consider your diet, other medical conditions, medications, and potential exposure to risk factors associated with tetany.  

Blood tests and calcium levels  

Blood tests are also important parts of diagnosing tetany. Looking at calcium levels is key to identifying any issues with calcium imbalances, which is the most common cause of tetany. Serum calcium levels, along with other relevant electrolytes such as magnesium and phosphorus, are measured to determine if there is a deficiency or excess. Moreover, evaluating blood pH and bicarbonate levels helps in understanding the acid-base balance, which will identify if respiratory alkalosis is a possible cause of tetany.  

Electrocardiography (ECG) and other diagnostic tests  

Electrocardiography (ECG) and other diagnostic tests may be conducted to assess cardiac function and its potential relationship with tetany. Electrocardiograms can reveal abnormalities in heart rhythms and electrical activity that may be associated with low calcium levels affecting cardiac muscle function. Additional diagnostic tests, such as nerve conduction studies or electromyography (EMG), may be performed to evaluate nerve and muscle function, helping to confirm if tetany is present and assess how severe it is. 

Treatment and management of tetany

Calcium supplementation 

Given that a lack of calcium is the most common cause of tetany, supplementing calcium is an important possible treatment. Administering calcium in various forms, such as calcium carbonate or calcium gluconate, helps restore normal calcium levels in the body. The dosage and type of calcium supplement prescribed will depend on the severity of the tetany and the underlying cause. Regular monitoring of blood calcium levels is crucial to adjust the dosage effectively and ensure optimal supplementation. 

Vitamin D supplementation  

Vitamin D often goes hand-in-hand with calcium supplementation. Vitamin D is essential for proper calcium absorption from the digestive system, making it a vital component in managing tetany caused by calcium deficiency.⁸ Supplements such as Vitamin D3 are commonly prescribed to individuals with tetany to enhance calcium absorption, support bone health, and aid in preventing future calcium deficiencies.    

Lifestyle modifications  

Adopting a diet rich in calcium and vitamin D is vital to support the supplementation and aid in maintaining appropriate calcium levels. Incorporating dairy products, leafy greens, nuts, and fortified foods into the diet is encouraged. Moreover, regular physical activity and weight-bearing exercises contribute to bone health and calcium utilisation. Lifestyle changes that promote a well-balanced diet and an active, healthy lifestyle play a significant role in preventing recurrent tetany. 

Treatment of underlying causes 

Addressing and treating the underlying causes of tetany is a critical aspect of its management. Whether it's addressing calcium and vitamin D deficiencies, treating hypoparathyroidism, managing respiratory alkalosis through breathing exercises, or stopping medications that contribute to calcium imbalances, targeting the root cause is essential. Regular follow-ups and monitoring are essential to track progress and make necessary adjustments to the treatment regimen. 

Prevention of tetany

Adequate calcium and vitamin D intake 

Adequate calcium and vitamin D intake is fundamental for the prevention of tetany. Incorporating calcium-rich foods and supplements and maintaining sufficient levels of vitamin D through a balanced diet and safe sun exposure are crucial steps. The recommended daily allowances for both calcium and vitamin D should be met to ensure optimal bone health and to minimise the risk of calcium deficiencies, a leading cause of tetany.   

Regular exercise 

Physical activity, especially weight-bearing and muscle-strengthening exercises, supports bone health and calcium absorption.⁹ Engaging in regular exercise routines helps maintain muscle strength and flexibility, reducing the likelihood of muscle spasms and cramps associated with tetany. It is important to design an exercise regimen suitable for your particular fitness levels and to consult a healthcare professional before starting any new exercise program. 

Monitoring and managing chronic conditions  

Monitoring and managing chronic conditions play a crucial role in tetany prevention. Chronic conditions such as kidney disease, gastrointestinal disorders, and hormonal imbalances can disrupt calcium metabolism, leading to an increased risk of tetany.¹⁰ Regular medical check-ups, monitoring blood calcium levels, and managing these underlying conditions effectively are essential preventive measures.  

Summary

In summary, tetany is a medical condition characterised by involuntary muscle contractions and spasms due to disturbances in calcium levels. Recognising its symptoms and understanding its importance for overall health is crucial. Adequate calcium intake, vitamin D supplementation, regular exercise, and proactive management of chronic conditions are essential in preventing tetany and promoting optimal musculoskeletal health.