Changes

==Description==

==Description==

Addison's disease occurs due to a failure to produce adequate amounts of glucocorticoid and mineralocorticoid hormones from the adrenal cortex.  The majority of cases are '''primary''' and occur due to an autoimmune response directed at the endocrine cells of the adrenal glands, resulting in adrenocortical atrophy.  This is an example of a [[Type IV Hypersensitivity - WikiBlood|type IV (delayed type) hypersensitivity response]].  Smaller numbers of primary cases are caused by haemorrhage, necrosis or neoplasia within the adrenal glands.  '''Secondary''' hypoadrenocorticism occurs due to a reduction in the secretion of ACTH from the anterior pituitary gland.  

Addison's disease occurs due to a failure to produce adequate amounts of glucocorticoid and mineralocorticoid hormones from the adrenal cortex.  The majority of cases are '''primary''' and occur due to an autoimmune response directed at the endocrine cells of the adrenal glands, resulting in adrenocortical atrophy.  This is an example of a [[Type IV Hypersensitivity - WikiBlood|type IV (delayed type) hypersensitivity response]].  Smaller numbers of primary cases are caused by haemorrhage, necrosis or neoplasia within the adrenal glands.  '''Secondary''' hypoadrenocorticism occurs due to a reduction in the secretion of ACTH from the anterior pituitary gland.  

===Primary Hypoadrenocorticism===

===Primary Hypoadrenocorticism===

==Diagnosis==

==Diagnosis==

===Clinical Signs===

===Clinical Signs===

Addison's disease may present acutely as an '''Addisonian crisis''' or it may cause chronic disease over several months before it is diagnosed.   

Addison's disease may present acutely as an '''Addisonian crisis''' or it may cause chronic disease over several months before it is diagnosed.  Acutely, affected animals present in hypovolaemic [[Shock|shock]] with severe dehydration and bradycardia (caused by hyperkalaemia).  This feature of the crisis is extremely suggestive of Addison's disease as hypovolaemic animals would usually be expected to be tachycardic.

 

*Acute necrosis will present as an acute syndrome with hypovolaemic shock, [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|vomiting]] and collapse.

*Acute necrosis will present as an acute syndrome with hypovolaemic shock, and collapse.

*Chronic damage to the adrenal gland will result in dehydration, [[Diarrhoea|diarrhoea]], anorexia and weakness.

*Chronic damage to the adrenal gland will result in dehydration, [[Diarrhoea|diarrhoea]], anorexia and weakness.