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Also Known As: '''''HPT — Parathyroid Hyperplasia — Parathyroid Adenoma — Fibrous Osteodystrophy — Grain Overload — Bran Disease — Big Head Disease — Millers Disease — Rubber Jaw — [[Metabolic Bone Disease]]'''''

Also Known As: '''''HPT — Parathyroid Hyperplasia — Parathyroid Adenoma — Fibrous Osteodystrophy — Grain Overload — Bran Disease — Big Head Disease — Millers Disease — Rubber Jaw — [[Metabolic Bone Disease]]'''''

[[Image:Renal_osteodystrophy.jpg|thumb|right|200px|"Rubber jaw" in renal osteodystrophy. Image courtesy of Biomed Archive.]]

[[Image:Renal_osteodystrophy.jpg|thumb|right|200px|"Rubber jaw" in renal osteodystrophy. Image courtesy of Biomed Archive.]]

[[Image:parathyroidhyperplasia.jpg|thumb|right|200px|Parathyroid hyperplasia. Image courtesy of Biomed Archive.]]

[[Image:parathyroidhyperplasia.jpg|thumb|right|200px|Parathyroid hyperplasia. Image courtesy of Biomed Archive.]]

Hyperparathyroidism is an '''[[Endocrine System - Anatomy & Physiology|endocrine]] disease''' caused by overactivity of the [[Parathyroid Glands - Anatomy & Physiology|parathyroid gland]] and consequent '''raised body levels of [[Calcium#Parathyroid Hormone|parathyroid hormone (PTH)]]'''. It occurs in many veterinary species and can be primary or secondary.  

Hyperparathyroidism is an '''[[Endocrine System - Anatomy & Physiology|endocrine]] disease''' caused by overactivity of the [[Parathyroid Glands - Anatomy & Physiology|parathyroid gland]] and consequent '''raised body levels of [[Calcium#Parathyroid Hormone|parathyroid hormone (PTH)]]'''. This in turn results in chronic hypercalaemia. It occurs in many veterinary species and can be primary or secondary.  

'''Secondary hyperparathyroidism''' can be either renal or nutritional in origin:

<big>'''Primary hyperparathyroidism'''</big> originates within the parathyroid gland itself and can be due to '''glandular hyperplasia or [[Neoplasia - Pathology|neoplasia]]'''. It is most commonly due to a '''solitary benign [[Adenoma|adenoma]]''' of either the [[Parathyroid Glands - Anatomy & Physiology|internal or external parathyroid gland]].<ref>Merck Veterinary Manual, '''Primary Hyperparathyroidism''', accessed online 25/07/2011 at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/40407.htm</ref>

Secondary '''renal hyperparathyroidism''' is a complication of '''chronic renal failure'''. This is due to '''hyperphosphataemia developing as a result of impaired glomerular filtration rate'''. Renal production of [[Calcium#Calcitriol|calcitriol]] is also reduced, exacerbating the resulting [[hypercalcaemia]].  

 

 

Secondary '''renal hyperparathyroidism''' is a complication of '''chronic renal failure'''. This is due to relative '''hyperphosphataemia developing as a result of impaired glomerular filtration rate'''. '''Reduced vitamin D''' synthesis or absorbtion is also thought to contribute to low serum calcium levels and subsequent stimulation of the parathyroid gland. Renal production of [[Calcium#Calcitriol|calcitriol]] (active Vitamin D3) is also reduced, exacerbating the resulting [[hypercalcaemia]].  

Secondary '''nutritional''' hyperparathyroidism is caused by excessive '''phosphorus intake''' causing a total or relative calcium deficiency by '''binding calcium in the gut and decreasing its absorption'''.  This category encompasses '''bran disease in horses and also [[Metabolic Bone Disease|metabolic bone disease]] in reptiles'''.

Secondary '''nutritional''' hyperparathyroidism is caused by excessive '''phosphorus intake''' causing a total or relative calcium deficiency by '''binding calcium in the gut and decreasing its absorption'''.  This category encompasses '''bran disease in horses and also [[Metabolic Bone Disease|metabolic bone disease]] in reptiles'''.

'''Exploratory surgery''' of the cervical region may identify enlarged parathyroid glands if no other test is available or to confirm the diagnosis.  

'''Exploratory surgery''' of the cervical region may identify enlarged parathyroid glands if no other test is available or to confirm the diagnosis.  

In cases of '''nutritional hyperparathyroidism, serum calcium is normal or low''' compared to high in other pathogeneses. '''Urinary excretion of phosphorus is markedly increased''' and serum PTH high. Radiographs will identify bony resorption and pathological fractures with fibrous tissue calluses.  

In cases of '''nutritional hyperparathyroidism, serum calcium is normal or low''' compared to high in other pathogeneses. '''Urinary excretion of phosphorus is markedly increased''' and serum PTH high. Radiographs will identify bony resorption and pathological fractures with fibrous tissue calluses.  

{{Learning

{{Learning

|flashcards = [[Hyperparathyroidism Flashcards]]<br>[[Small Mammals Q&A 19]]

|flashcards = [[Hyperparathyroidism Flashcards]]<br>[[Small Mammals Q&A 19]]<br>[[Veterinary Dentistry Q&A 12]]

}}

}}

Merck Vet Manual, '''Nutritional Diseases''', accessed 25/07/2011 at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/182606.htm&word=nutritional%2csecondary

Merck Vet Manual, '''Nutritional Diseases''', accessed 25/07/2011 at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/182606.htm&word=nutritional%2csecondary

{{review}}

{{review}}

[[Category:Endocrine Diseases - Dog]] [[Category: Endocrine Diseases - Cat]] [[Category:Bones - Metabolic Pathology]] [[Category:Parathyroid Glands - Pathology]] [[Category:Colic in Horses]][[Category:Endocrine Diseases - Horse]]

[[Category:Endocrine Diseases - Dog]] [[Category: Endocrine Diseases - Cat]] [[Category:Bones - Metabolic Pathology]] [[Category:Parathyroid Glands - Pathology]] [[Category:Colic in Horses]][[Category:Endocrine Diseases - Horse]]