E20-E35: Disorders of other endocrine glands

E21: Hyperparathyroidism and other disorders of parathyroid gland

Hyperparathyroidism and other disorders of the parathyroid gland refer to conditions related to overactive or underactive parathyroid glands. Located in the neck, these four small glands produce parathyroid hormone (PTH), which helps control the amount of calcium in your body. If these glands produce too much PTH, it's called hyperparathyroidism. This can result in high calcium levels in the blood and urine, causing kidney stones, bone disease, and other symptoms like fatigue, depression, and memory issues. Conversely, if they make too little PTH, it's called hypoparathyroidism, leading to low calcium and high phosphorus levels in the blood. This can result in muscle cramps, spasms, and tingling in the hands and feet. These conditions can be triggered by factors like gland tumors, neck surgery, radiation treatment, or certain genetic disorders. They typically progress gradually and affect the skeletal, renal, and nervous systems.