00:00 / 00:00
Conductive hearing loss
Eustachian tube dysfunction
Tympanic membrane perforation
Age-related macular degeneration
Retinopathy of prematurity
Temporomandibular joint dysfunction
Gastroesophageal reflux disease (GERD)
Retropharyngeal and peritonsillar abscesses
Thyroglossal duct cyst
Acoustic neuroma (schwannoma)
Eye conditions: Inflammation, infections and trauma: Pathology review
Eye conditions: Refractive errors, lens disorders and glaucoma: Pathology review
Eye conditions: Retinal disorders: Pathology review
Nasal, oral and pharyngeal diseases: Pathology review
Parathyroid disorders and calcium imbalance: Pathology review
Thyroid nodules and thyroid cancer: Pathology review
Vertigo: Pathology review
0 / 8 complete
0 / 3 complete
TGH Hyperparathyroidism Patient Story
Parathyroid Gland Disorders
hyperparathyroidism p. 342
hyperparathyroidism and p. 342
associations p. 734
calcium pyrophosphate deposition disease p. 473
cinacalcet for p. 361
lab findings p. 730
lab values in p. 467
osteoporosis p. 467
renal osteodystrophy and p. 624
hyperparathyroidism (secondary) p. 342
hyperparathyroidism as cause p. 342
hyperparathyroidism caused by p. 342
in hyperparathyroidism p. 342
hyperparathyroidism p. 469
With hyperparathyroidism, “hyper” refers to over, and “parathyroid” refers to the parathyroid glands, so hyperparathyroidism refers to a condition where there is an overproduction of parathyroid hormone.
Parathyroid hormone comes from the parathyroid glands which are buried within the thyroid gland, and their main job is to keep blood calcium levels stable.
Now, the majority of the extracellular calcium, the calcium in the blood and interstitium, is split almost equally between two groups - calcium that is diffusible and calcium that is not diffusible.
Diffusible calcium is small enough to diffuse across cell membranes and is separated into two subcategories.
The first is free-ionized calcium, which is involved in all sorts of cellular processes like neuronal action potentials, contraction of skeletal, smooth, and cardiac muscle, hormone secretion, and blood coagulation, all of which are tightly regulated by enzymes and hormones.
The second category is complexed calcium, which is where the positively charged calcium is ionically linked to tiny negatively charged molecules like oxalate, which is a small anion that are normally found in our blood in small amounts.
The complexed calcium forms a molecule that’s electrically neutral but unlike free-ionized calcium it’s not useful for cellular processes.
Both of these are called diffusible because they’re small enough to diffuse across cell membranes.
Finally there’s the non-diffusible calcium which is bound to negatively charged proteins like albumin.
The resulting protein-calcium complex is too large and charged to cross membranes, leaving this calcium also uninvolved in cellular processes.
Changes in the body’s levels of extracellular calcium are detected by a surface receptor in parathyroid cells that’s called the calcium-sensing receptor.
These changes affect the amount of parathyroid hormone that’s released by the parathyroid gland.
Hyperparathyroidism is a condition in which the parathyroid glands produce too much parathyroid hormone (PTH), which regulates calcium levels in the blood. Hyperparathyroidism can be primary, secondary, or even tertiary.
Primary hyperparathyroidism usually results from PTH secretion by a parathyroid adenoma. It is characterized by excess PTH that leads to high blood calcium levels (hypercalcemia), bone mass loss, kidney stones, and other health problems, such as psychiatric issues.
Secondary hyperparathyroidism develops when there are conditions like chronic kidney disease, which can lead to low calcium, high phosphate, and low vitamin D levels. It is mainly characterized by osteodystrophy, in which there is bone weakening associated with bone pain and deformation.
Finally, there is tertiary hyperparathyroidism, which occurs because of chronic secondary hyperparathyroidism from kidney disease. This leads to hypercalcemia and phosphate imbalances.
Latest on COVID-19
Nurse Practitioner (NP)
Physician Assistant (PA)
Create custom content
Raise the Line Podcast
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
Terms and Conditions
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.