malaborption and maldigestion in dogs and cats

exocrine pancreas function

and what are secreted by epithelial cells of ductules

• production of enzymes

• bicarbonate and water are secreted by epithelial cells of ductules

• bicarbonate neutralises the HCl coming from the stomach

• thus providing a suitable environment for pancreatic enzymes to work

effects of pancreatic dysfunction

• protein maldigestion

• carbohydrate maldigestion

• fat maldigestion

• impaired assimilation of fat soluble vitamins

• impaired absorption of cobalamin- vitamin B12

• increased bacterial growth in small intestine

what are the fat soluble vitamins

• A- retina and eyesight

• d- calcium metabolism

• e- protection form toxins, especially liver

• k- clotting factors to be activators

why is there increased bacterial growth in the gut

• chyme lies undigested in the upper gi tract

• provides growth media for bacteria

• leads to SIBO

• sometimes antibiotics are necessary

impared cobalamin absorption in EPI

• intrinsic factor essential to permit cobalamin absorption from gut is synthesised by pancreas

• thus absent in exocrine pancreatic insufficiency (although there is some secreted in stomach)

• also increased uptake of cobalamin by increased numbers of bacterias in gut- overgrowth

EPI

• what is it

• causes

• insufficient production of pancreatic enzymes

• insufficient bicarbonate to neutralised HCl

• large reserve capacity

• need loss of 90 percent pancreatic function before clinical signs occur

• causes : pancreatic acinar arophy, pancreatitis, pancreatic hypoplasia (uncommon), pancreatic neoplasia (rare cuase of total loss of function)

causes of maldigestion

• exocrine pancreatic insufficiency

• secondary enzyme deficiency- lumenal conditions not optimal for pancreatic enzyme function

• deficiency of bile acid

• loss of brush border enzyme

pancreatic acinar atrophy

• selective destruction of digestive enzyme producing acinar cells

• endocrine function usually unaffective

• progressive due to autoimmune disease

• STAGE ONE : subclinical. inflammation-mT lymphocyte infiltration. partial acinar atrophy

• STAGE 2 : clinical. severe endstage atrophy

breeds

• increased prevalence and believed to be inherited in german shepherds and rough coated collies

• suspected to be inherited in english setters

• in uk chow chow over represented

chronic pancreatitis

• what does it lead to

• most common cause of epi in cats- uncommon

• also occurs in dogs but PAA most common. middle aged to olde small medium dogs

• progressive destruction of both exocrine and endocrine pancreas with fibrosis

• can develop clinical signs of epi and diabetes mellitus

clinical signs of epi

• weight loss but normal or increased appetite

• increased faecal volume

• abnormal faeces- grey/yellow, increased water due to maldigested carbs, greasy

• flatulence

• coprophagia

diagnosis of epi

• not pathognomic and can occur with small bowel disease

• specific blood test for trypsin like immunoreactivity- small amount of trysin and other digestive enzymes always leak into bloodstream, can be detected in species specific assay, low levels of epi

• faeces may contain fat and starch seen micoscopically

treatment of epi

• avoid high fat but very fat restricted also not good

• high caloric density

• highly digestible and low fibre as this impairs pancreatic enzyme activity and soluble fibre can absorb enzymes

• feed two or more meals a ay

• can often be maintained on a normal diet

• epi due to pancreatitis in dogs do benefit from ow fat diets. in cats it does not matter

• lifelong pancreatic enzyme replacement on food. must have a high lipase level

• antimicrobial therapy 1-3 weeks

• supplementation of fat soluble vitamin a and b12- weekly injection, initially 6-8 weeks, may need to be lifelong. oral supplementation may be fine due to gasri secertion of intrinsic factor

phases of absorption

• luminal

• mucosal

• transport

pathology affecting the luminal phase

• involves digestion as well

• dysmotiliy- hyperthyroidism

• pancreatic enzyme deficiency or inactivation due to gastric acid hypersecretion

• fat maldigestion- epi, loss of or impaired bile salts actitivty due to ileal or liver disease

• brush border enzyme deifcieny- congenital, trehalase in cats. aquired- relative lactose deficiency

• brush border protein transport deficiency- congeital- intrinsic facto deifciency,.aquired- diffuse small intestinal disease

• enterocyte defects eg ibd

• lymphatic obstruction- primary lymphagiectasia, secondary (obrution due to neoplasia, infection or inflammation, most common)

• vascular compromise- vasculitis, infection, immune mediated. portal hyerptaension, hepatopathy, right sided heart failire

malabsorption- primary GI

infiltrative diseases of the gut wall

• parasitic

• inflammatory bowel disease

• lymphagiectasia

• GI lymphoma or other diffuse neoplasia

• severe SIBO

• dry feline infectious peritonitis

• deep mycoses (endemic areas)

clinical signs of malabsorption

weight loss

• often despite normal or increased appetite

• but can have decreased or capricious appetite

diarrhoea

• from slight to severe

coprophagia

• sometimes

malabsorption- secondary GI

hepatic disease

• bile acids imporantfor assisting in digestiona and absorption especially of fats

right sided cardiac disease

hyperthyroidism

• gut transit time of food decreased so less time for absorption

• weight loss also due to increased metabolic rate

treatment- hepatic disease

depends on pathology

• inflammatory

• infectious

• neoplasic

• toxic

• fibrosis

treatment- right sided cardiac disease

depends on cause

• valvular disease

• cardiac muscle disease

• pericardial disease

treatment- hypeerthyroidism

• anti thyroid drugs- tablets, oral liquid or transdermal cream

• diet

• surgery

• radioactive iodine I 131

treatment of malabsorption

depends on cause

• inflammatory

• infectious

• parasitic

• neoplastic

dogs or cats that develop epi due to chronic pancreatic inflammation will also often have…

diabetes mellitus