Hypothyroidism is defined as the clinical and biochemical syndrome resulting from decreased thyroid hormone production. Overt hypothyroidism occurs in 1.5 to 2 percent of women, and 0.2 percent of men, and its incidence increases with age. The vast majority of hypothyroid patients have primary hypothyroidism, or thyroid gland failure. Less common causes include pituitary failure (secondary hypothyroidism) or even more rarely, generalized resistance to thyroid hormone. Thyroid hormone is essential for normal growth and development during embryonic life. Thyroid hormone deficiency during fetal and neonatal development results in mental retardation.

Common duct stones known as choledocholithiasis pose a high risk for complications and nearly always warrant treatment. The common bile duct carries bile from the liver and gallbladder to the small intestine. Bile helps digest fats. The stones form from bile. Most gallstones and duct stones are made of cholesterol in the bile. Usually acids in bile keep cholesterol from forming into stones. If the amount of cholesterol in the bile increases beyond the ability of acids to maintain a balance, the cholesterol crystallizes and forms a stone. Some common duct stones result from infection in the bile duct or liver.

Pressure from stones blocking the duct makes it hard for the liver and gallbladder to function. As a result the stones in the bile ducts may cause sudden pain in the upper right side of the abdomen which could last for hours, jaundice, light colored bowel movements, dark urine, chills, fever, nausea and vomiting. Possible treatments for bile duct stones would be medicine, endoscopy or surgery.

Since patients with common bile duct stones (CBDS) have higher rates of clinical and subclinical hypothyroidism, a recent study sought to investigate the prevalence of CBDS in patients with diagnosed hypothyroidism compared to age, sex and living area control patients. The study included a total of 14,334 patients who between 1987 and 2001 were approved for Special Medical Coverage for hypothyroidism or glaucoma (control group). The results revealed that 33 patients in the hypothyroidism cohort and 23 in the control group had been treated for CBDS. The researchers found that the groups did not differ in the number of CBDS treatments before the diagnosis of hypothyroidism or glaucoma. However, after the diagnosis of hypothyroidism or glaucoma there were significantly more CBD stone patients in the hypothyroid cohort (25 patients) than in the glaucoma cohort (14 patients). The researchers conclude that diagnosed hypothyroidism is a significant risk factor for CBDS.¹ 

¹ Laukkarinen J, Sand J, Autio V, et al. Bile duct stone procedures are more frequent in patients with hypothyroidism. A large, registry-based, cohort study in Finland. Scand J Gastroenterol. Jan2010;45(1):70-4.