What is the most common sign of hyperparathyroidism?

The most common sign of hyperparathyroidism is hypercalcemia, which is an elevated level of calcium in the blood. In hyperparathyroidism, there is an overproduction of parathyroid hormone (PTH), which regulates calcium levels in the body. When there is excessive PTH, it leads to increased release of calcium from bones, increased absorption of calcium in the intestines, and increased renal tubular reabsorption of calcium. This results in high levels of calcium in the bloodstream, making hypercalcemia the hallmark manifestation of the condition.

The other signs listed, such as decreased body mass index, increased liver enzymes, and frequent vomiting, are not directly associated with hyperparathyroidism or are too nonspecific to be considered hallmark signs of the condition. Rather, hypercalcemia is a key biochemical abnormality that frequently indicates the presence of hyperparathyroidism, making it vital for diagnosis and subsequent management of the disorder.