PTH deficiency causes hypocalcemia and hyperphosphatemia.
Before you read
Test yourself first: 1 question
Question 1 of 1
A client with hyperparathyroidism is most likely to have which electrolyte abnormality?
Answer: B. Hyperparathyroidism raises calcium (hypercalcemia) and lowers phosphate — monitor for bone pain, kidney stones, muscle weakness, and constipation. (Hypoparathyroidism causes hypocalcemia.)
Keep the streak going with more questions like these, each with a full rationale.
What is hypoparathyroidism?
The most common cause is accidental damage to or removal of the parathyroid glands during thyroid or neck surgery. Low calcium increases nerve and muscle excitability, producing tetany. Memory aid: it is the opposite of hyperparathyroidism, so think low calcium, high phosphorus, and twitchy, irritable muscles.
Key points to remember
- PTH deficiency causes hypocalcemia and hyperphosphatemia.
- Low calcium increases neuromuscular excitability, producing numbness and tingling around the mouth and in the fingers.
- Muscle cramps, spasms, and tetany occur, and severe cases cause laryngospasm and seizures.
- Positive Trousseau sign (carpal spasm with BP cuff inflation) and Chvostek sign (facial twitch when tapping the cheek) are classic.
- It is most commonly caused by inadvertent injury or removal of parathyroid tissue during neck/thyroid surgery.
Common causes
- Thyroidectomy removed parathyroids
- Neck surgery/radiation damage
Signs & symptoms
- Trousseau + Chvostek signs
- Tetany, tingling, muscle cramps
- Laryngospasm, seizures = severe
Nursing priorities
- Administer calcium and vitamin D as ordered, and keep IV calcium gluconate available for acute, severe hypocalcemia.
- Monitor for tetany, assess Trousseau and Chvostek signs, and institute seizure precautions.
- Continuously monitor airway and respiratory status for laryngospasm and stridor.
- Monitor cardiac rhythm, as hypocalcemia can prolong the QT interval and cause dysrhythmias.
- Provide a high-calcium, low-phosphorus diet as ordered.
Labs & values
Patient teaching
- Take calcium and vitamin D supplements for life as prescribed.
- Eat a high-calcium, low-phosphorus diet, limiting dairy excess and high-phosphorus foods as directed.
- Report numbness, tingling, muscle cramps, or spasms promptly.
Red flags: report now
- Laryngospasm, stridor, or respiratory difficulty is a life-threatening airway emergency requiring immediate intervention.
- Report seizures, severe tetany, or carpopedal spasm immediately.
- Report prolonged QT interval or dysrhythmias on cardiac monitoring.
References
Clinical references for this topic
