- Secondary hyperparathyroidism
Infobox_Disease
Name = Secondary hyperparathyroidism
Caption = Thyroid and parathyroid.
DiseasesDB = 6301
ICD10 = ICD10|E|21|1|e|20
ICD9 = ICD9|252.02, ICD9|588.81
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj =
eMedicineTopic =
MeshID = D006962Secondary hyperparathyroidism refers to the excessive secretion of
parathyroid hormone (PTH) by theparathyroid gland s in response tohypocalcemia (lowblood calcium levels) and associated hypertrophy of the glands. This disorder is especially seen in patients with chronic renal failure. It is often—although not consistently—abbreviated as SHPT in medical literature.igns and Symptoms
Bone and joint pain are common, as are limb deformities. The elevated PTH has also pleiotropic effects on blood, immune system and neurological system.
Diagnosis
The PTH is elevated due to decreased levels of calcium or 1,25-dihydroxy-vitamin D3. It is usually seen in cases of chronic renal disease or defective calcium receptors on the surface of parathyroid glands.
Causes
Chronic renal failure is the most common cause of secondary hyperparathyroidism. Failingkidneys do not convert enoughvitamin D to its active form, and they do not adequately excretephosphorus . When this happens, insolublecalcium phosphate forms in the body and removes calcium from the circulation. Both processes leads to hypocalcemia and hence secondary hyperparathyroidism. Secondary hyperparathyroidism can also result from malabsorption (chronic pancreatitis, small bowel disease) in that the fat soluble vitamin D can not get reabsorbed. This leads to hypocalcemia and a subsequent increase in parathyroid hormone secretion in an attempt to increase the serum calcium levels.Treatment
If the underlying cause of the hypocalcemia can be addressed, the hyperparathyroidism will resolve. In patients with chronic renal failure, older treatments consists of dietary restriction of phosphorus, supplements with the active form of
vitamin D (calcitriol ), andphosphate binders . In recent years, a newer class of medications, calcimimeticscinacalcet , have achieved amazing response rates and has reduced the number of patients who eventually require surgery. Some of these patients may also see resolution of their sHPT following kidney transplantation.Prognosis
If left untreated, the disease will progress to
tertiary hyperparathyroidism , where correction of the underlying cause will not stop excess PTH secretion, i.e. parathyroid gland hypertrophy becomes irreversible.ee also
*
Primary hyperparathyroidism
*Tertiary hyperparathyroidism External links
* [http://www.crescentcme.org CRESCENTcme.org - The Critical RolE of Serum Calcium: An Educational Network for Secondary HyperparaThyroidism]
Wikimedia Foundation. 2010.