Thursday, January 17, 2013

Pancreatitis... medical challenge & enigma.




Pancreatitis.   Much more common  in cats then we realize. 









The pancreas performs two important and different jobs

  1. The exocrine pancreas produces digestive enzymes to break down and aid digestion of  fat, protein, and carbohydrates. These chemicals are very caustic to normal tissues and cause tremendous damage if they leak out into the belly in the course of pancreatitis,  literally causing digestion of organs.  They are secreted inside the small intestine ( duodenum) through a tube known as the pancreatic duct, which in cats joins the common bile duct from the liver. 
  2. The endocrine part of the pancreas makes hormones such as insulin ( the absence of which causes diabetes ),  as well as glucagon and somatostatin. 

Pancreatitis means inflammation or infection of the pancreas.

Cats unlike people and dogs can have very subtle and vague signs

 In dogs and people the disease produces extreme abdominal pain and nausea but these signs are absent in cats. Often cats with pancreatitis are presented with symptoms we like to call ADR ( ain't doing right).


Dogs

 

Causes


  • toxins and drugs: potassium bromide, L-aspraginase, sulfa drugs, azathioprine
  • obesity
  • hyperlipidemia -familial in miniature Schnauzer
  • high fat or spicy meals--- getting in the garbage
  • high calcium levels
  • hypothyroidism
  • Cushing's disease
  • blunt force trauma


Symptoms:

  • abdominal pain
  • loss of appetite
  • nausea, diarrhea
  • weakness
  • dehydration
  • shock

 

Cats:

 

Causes


  • blunt force trauma- rare
  • high calcium-rare
  • viral infections : FIP, calici, herpes
  • parasitic: Toxoplasma, flukes
  • high fat meals not implicated

concurrent diseases:
  • inflammatory bowel disease
  • hepatic lipidosis-  can be seen since pancreatitis can lead to loss of appetite and mobilization of fat
  • cholangitis/ cholangiohepatitis
  • diabetes

Symptoms
  • lethargy
  • depressed appetite
  • weight loss
Less commonly seen,  unlike dogs are: abdominal pain in less than a quarter of cats and vomiting in  less than half of cases. 

  •  diarrhea, jaundice, abdominal mass felt on examination, fever

Diagnosis:

Blood Count changes are non specific.
anemia ( low red blood cell counts), elevation and decrease of white blood  cells in less than 1/4 of cases
depressed platelet counts especially in the more severe cases leaning to D.I.C. ( disseminated intra-vascular coagulation)

Biochemistry
  • elevated bilirubin
  • elevated liver enzymes
  • electrolyte abnormalities
  • azotemia: elevated BUN due to dehydration
  • low calcium due to saponification of fat in severe cases
  • glucose can be elevated due to stress/ concurrent diabetes- or- depressed
  • amylase is of no utility in cats
  • Lipase of 2-3 times normal range is specific for pancreatitis in dogs, but not in cats
  • Pancreas Specific Lipases:
spec cPL is a  sensitive test (93%) of pancreatitis in dogs , while spec fPL is slightly less sensitive  test of pancreatitis for cats. While when elevated these tests help diagnose pancreatitis, absence  of elevation  doesn't rule it out completely.


Radiographs (X-rays) are helpful in diagnosing pancreatitis about 25% of the time, but they are often performed to rule out  other causes of vomiting such as obstructions and foreign bodies. 

Abdominal ultrasound is a very useful tool in diagnosing pancreatitis if performed by a skilled, experienced ultrasonographer using newer and more sensitive equipment.


As the symptoms  of pancreatitis can be  vague and nonspecific in cats: lethargy, loss of appetite and dehydration- the disorder is easy to miss and is believed to be under-diagnosed in cats.


Treatment


There is no specific treatment for pancreatitis, and the patients are typically hospitalized for supportive symptomatic care, and it consists of: 
  1. Intravenous fluids to correct dehydration, improve blood flow to the pancreas and correct acid-base and  electrolyte abnormalities
  2. Anti-emetics to control nausea
  3. Analgesics  to control pain, which can be extremely severe requiring opioid pain relievers.
  4. Plasma transfusions in some cases to provide anti-proteases, clotting factors and macroglobulins and/ or synthetic colloids to improve pancreatic perfusion ( blood supply).
  5. Antacids if there is evidence of gastrointestinal bleeding
  6. Dogs are fed small amounts of  bland fat-restricted diets, while in cats fat- restriction is not needed and is not effective. Cats sometimes required feeding tubes to prevent or treat coexisting hepatic lipidosis ( fatty liver disease).
  7. B12 vitamin deficiency is common in cats with intestinal disease, so it is often supplemented
  8. Corticosteroids which used to be thought of as a cause of pancreatitis are now being used to treat chronic pancreatitis in cats due to high frequency of coexisting inflammatory bowel disease and inflammatory liver diseases.  
  9. Insulin is administered if  pancreatitis has progressed to diabetes mellitus. 
References:
Treatment Recommendations for Feline Pancreatitis

Take-away: 

In most dogs and cats where dietary indiscretion, such as ingestion of garbage or a fatty/spicy meal has been ruled out, the cause is unknown.

recent study found evidence of pancreatitis  in 67% of the cats  admitted to a teaching hospital for various unrelated causes on autopsy, though remarkably in the 90's the disorder was diagnosed in  less than 1% of cats.   So either we are much better at diagnosing this illness,  or there has been a profound environmental change since the 1990s predisposing cats to pancreatitis.


I tend to believe it is the latter, and so feel  it is important to evaluate the  changes occurring  in the cats' diets in the last several decades. This brings us back  to genetic modification of soy, which is commonly included in pet foods and was demonstrated to induce alteration in  pancreatic zymogen granules in rodents. http://www.ncbi.nlm.nih.gov/pubmed/12448776.  Therefore, until thorough studies are performed, the precautionary principle dictates not feeding cats soy.