What is the relationship between Parathyroid Hormone (PTH) and gastrointestinal (GI) issues?

From the Guidelines

Parathyroid Hormone (PTH) plays a crucial role in regulating calcium levels in the body, and its relationship with gastrointestinal (GI) issues is significant. The evidence suggests that PTH increases calcium concentration in the body by stimulating intestinal absorption of calcium, increasing calcium absorption in the kidneys, and releasing phosphate and calcium from bones into the circulation 1.

PTH and GI Issues

• Hypocalcemia, which can occur due to impaired calcium absorption in the GI tract, is sensed by the calcium-sensing receptor on the parathyroid glands, resulting in the release of PTH 1.
• Net calcium absorption is reduced in chronic renal failure, as a consequence of both decreased calcium intake and decreased fraction of calcium absorbed by the intestine 1.
• Dietary calcium intake is low in patients with CKD, and intake of calcium in adults with advanced CKD ranged between 300 and 700 mg/day 1.
• PTH stimulates the enzyme 1-a-hydroxylase to hydroxylate 25-hydroxyvitamin D into 1,25-dihydroxyvitamin D, which in turn increases intestinal absorption of calcium 1.

Clinical Implications

• Hypercalcemia poses a risk for CKD patients, as it would increase the Ca-P product index in blood, and severe hypercalcemia with clinical symptoms must be treated appropriately 1.
• Transient mild hypercalcemia has no detrimental effects on morbidity in patients with CKD, but isolated hypercalcemia is not associated with increased morbidity in the hemodialysis population 1.
• Calcitriol, which is used to treat hypocalcemia, has a direct effect on gut absorption of calcium, and its use can help maintain a high normal serum calcium level and maximize PTH suppression 1.

Overall, the relationship between PTH and GI issues is complex, and understanding the role of PTH in regulating calcium levels is essential for managing patients with CKD and GI disorders.

From the Research

Relationship between Parathyroid Hormone (PTH) and Gastrointestinal (GI) Issues

The relationship between Parathyroid Hormone (PTH) and gastrointestinal (GI) issues is complex, with PTH playing a crucial role in regulating calcium homeostasis in the body, which in turn affects the GI tract 2.

GI Manifestations of Parathyroid Disorders

Studies have shown that parathyroid disorders, including hypoparathyroidism and hyperparathyroidism, can cause various GI symptoms, such as:

• Steatorrhea in hypoparathyroidism due to a deficit in exocrine pancreas secretion 3, 4
• Constipation, nausea, and vomiting in hyperparathyroidism due to smooth-muscle atony 3, 4
• Peptic ulcer disease (PUD) in hyperparathyroidism, although the association is less clear in modern times due to early detection and treatment of hyperparathyroidism 3
• Pancreatitis in hyperparathyroidism, which may be caused by high calcium levels 3, 4

Prevalence of GI Symptoms in Primary Hyperparathyroidism

A study found that GI symptoms are the fourth most common presentation in patients with primary hyperparathyroidism (PHPT), with an incidence of 18.67% 5. Another study found that nearly 80% of PHPT patients had at least one symptom or sign related to the gastrointestinal system, with the most common symptoms being abdominal pain, constipation, and nausea/or vomiting 6.

Effect of Parathyroid Surgery on GI Symptoms

Parathyroid surgery has been shown to resolve GI symptoms in most patients with PHPT, with one study finding that GI manifestations resolved within three months of curative parathyroidectomy in the majority of patients 6.

Association between Biochemical Parameters and GI Symptoms

Studies have found that serum calcium levels are associated with an increased risk of developing pancreatitis in PHPT patients, but not with an increased risk of gallstone disease 6. However, another study found that biochemical parameters, including serum calcium, phosphate, and PTH levels, were not associated with a high risk for gallstone disease or pancreatitis in PHPT patients 6.

Key Findings

• PTH plays a crucial role in regulating calcium homeostasis, which affects the GI tract 2
• Parathyroid disorders can cause various GI symptoms, including steatorrhea, constipation, nausea, vomiting, PUD, and pancreatitis 3, 4
• GI symptoms are common in patients with PHPT, with an incidence of 18.67% 5
• Parathyroid surgery can resolve GI symptoms in most patients with PHPT 6
• Serum calcium levels are associated with an increased risk of developing pancreatitis in PHPT patients 6