View source for Pancreatic Atrophy, Exocrine

AKA Pancreatic Acinar Athropy (PAA)


[[Image:Pancreatic atrophy.jpg|right|thumb|100px|<small><center>Pancreatic atrophy (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]

*Degeneration of acinar cells ccurs as a sequel to
**Starvation - loss of zymogen granules
**Maldigestion
**Obstruction of the pancreatic ducts by
***Neoplasm
***Chronic inflammation and associated fibrosis
***Foreign bodies (parasites, pancreoliths
**Specific nutritional deficiencies include: essential amino acids, zinc, copper, selenium

===Clinical signs===
*By the time clinical signs of [[EPI|'''exocrine pancreatic insufficiency (EPI)''']] appear, the [[Pancreas - Anatomy & Physiology|pancreas]] is usually almost totally destroyed
*Chronic [[Diarrhoea|diarrhoea]] with steatorrhoea and undigested muscle fibres. Large quantities of pale faeces are passed (due to dilution of bile pigment and the presence of undigested fats). The faeces have a characteristic rancid or cheesy odour.
*Loss of condition despite marked increase in appetite
===Macroscopic appearance===
*The [[Pancreas - Anatomy & Physiology|pancreas]] is extremely thin and almost lace-like
*Primarily acinar tissue affected; the ducts and [[Pancreas - Anatomy & Physiology#Endocrine|Islets of Langerhans]] are relatively normal

===Microscopic appearance===
*In these cases the parenchyma is replaced by atypical parenchyma and adipose tissue
*Irregular, shrunken acini composed of cells with little cytoplasm
*Some cases show a few areas of apparently normal glandular tissue or foci of cellular infiltraton which have been interpreted as suggesting degenerative changes
===Aetiology===
*The underlying cause is not known, possibly due to nutritional imbalances
*Chronic pancreatitis is a rare cause of EPI
*Possible hereditary EPI in GSDs and rough coated collies
===Diagnosis===
*Low serum trypsin-like immunoreactivity is an early, preclinical diagnostic test for EPI




<big>Extra information for Exocrine Pancreatic Atrophy

Exocrine pancreatic atrophy in GSDs and rough coated collies: an end result of lymphocytic pancreatitis. Wiberg ME et al. Vet Path (1999) 36 530-41</big>

*Histological changes in EPI dogs
*Histological changes in the subclinical pancreas (ie; just TLI):
*Patchy areas of normal and abnormal exocrine parenchyma
*Consistently a marked lymphoid infiltrate (lesser numbers of plasma cells seen, occasional eosinophils), starting in the border zone with gradual loss of the pancreatic parenchyma
*Mainly CD3+ T cells, with fewer CD3+ lymphocytes. 
*Some lymphoid follicles (mainly B cells) scattered throughout.
*No associated increase in fibrous connective tissue
*Some intra-acinar lymphocytes seen
*As tissue destruction continued, ductal structures became more obvious
*Apoptosis seen in the acini often in normal looking acini.
*Ultrastructure
**Degenerative changes in acinar cells – dilation of rER, swelling of mitochondria, nuclear pyknosis, aptotitic bodies
*Histology of clinical EPI:
**Totally atrophied exocrine pancreas
**Some dogs had areas of normal acinar structures
**Little inflammation in the border zone
**Most of the remaining exocrine pancreas was disorganized, prominent ducts, increased amounts of adipose tissue.
**Slight increase in fibrous tissue compared to subclinical phase, but replacement with fat was more prominent than fibrosis.
**No ductular epithelial hyperplasia evident
*Ultrastructure
**Often no remaining acinar cells
*Suggests and immune-mediated destruction - ?hereditary
*Islet cells usually well preserved in the atrophied pancreas.



[[Category:Pancreas - Degenerative Pathology ]]
[[Category:Pancreatic Diseases - Dog]]
[[Category:To_Do_-_Clinical]]