PANCREAS

36 PANCREAS



1 How is pancreatitis classified?


Pancreatitis is inflammation of the pancreas that may be classified as acute or chronic. Acute pancreatitis is marked by inflammatory episodes that often have a sudden onset. Chronic pancreatitis is defined as an ongoing inflammatory process that may lead to exocrine pancreatic insufficiency (EPI) and diabetes mellitus (DM) if not controlled.



2 What mechanisms lead to the development of pancreatitis?


The pancreas is rich in digestive enzymes that are essential for food digestion and absorption. To prevent pancreatic autodigestion, several of these enzymes are stored in an inactive form (zymogens) in the pancreas and are activated only when released in the intestine under physiologic conditions. Moreover, when synthesized, these zymogens are contained into granules that are physically segregated from lysosomal enzymes, preventing their accidental activation within the pancreas itself. In cases of pancreatitis, however, it is believed that abnormal fusion of zymogen granules and lysosomal enzymes results in the intrapancreatic activation of zymogens, most notably trypsinogen, which is converted to trypsin. Once trypsin has been activated, a domino effect ensues, resulting in more activation of pancreatic enzymes inside the gland. This results in autodigestion of the gland with secondary activation of inflammatory mediators, including tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-2, IL-6, IL-8, IL-10, interferon-α (IFN-α), INF-γ, nitrous oxide (NO), and platelet-activating factor (PAF). These mediators play an important role in the progression of the inflammation.



3 Is it true that only dogs can develop acute pancreatitis?


Until the early 1990s, acute feline pancreatitis was thought to be rare. With the development of more sophisticated tests (see Questions 9 to 13), however, feline pancreatitis is now more common than previously thought, although its prevalence is much lower than for canine pancreatitis.



4 What are the clinical signs that suggest acute pancreatitis in dogs and cats?


Most dogs with pancreatitis are overweight, middle-aged to older animals. Clinical signs may be related to recent ingestion of a large amount of fatty meals and may vary depending on whether the pancreatitis is acute or chronic. In cases of acute pancreatitis, clinical signs may include anorexia, depression, vomiting, and possibly marked abdominal pain. Diarrhea may occur but is not as common as vomiting. Some animals may even be in shock on presentation. Clinical signs of chronic pancreatitis, if present, are variable and frequently nonspecific, rendering the diagnosis more difficult.


In cats, clinical signs may be subtler. In some cases, cats show no clinical signs, and pancreatitis is diagnosed only at necropsy; others display signs that are not recognized by the owner. In cases of severe pancreatitis, lethargy is the most common clinical sign reported by owners, followed by anorexia. Vomiting, which is a common sign in dogs with pancreatitis, seems to be present in only about one third of feline cases. Abdominal pain is present in about one fourth of feline cases.



5 What hematologic changes are found in cases of acute canine pancreatitis?


Neutrophilic leukocytosis is a common finding in cases of acute canine pancreatitis. If pancreatitis is severe (usually reflected by more severe clinical signs), the neutrophilia may be associated with a left shift and toxic neutrophils. Erythrocytosis (increased hematocrit, hemoglobin, and red blood cell [RBC] count) is common and is secondary to clinical dehydration. If a hemorrhagic pancreatitis is present, a slight anemia (nonregenerative or regenerative depending on duration of condition) may be present, but the anemia may be masked by clinical dehydration, resulting in RBC parameters within reference limits. If pancreatitis is extremely severe, disseminated intravascular coagulation (DIC) may result, possibly causing a thrombocytopenia as well as RBC pathologies on the blood smear, including schizocytes (Figure 36-1), keratocytes (Figure 36-2), and acanthocytes (Figure 36-3).


image

Figure 36-1 Schizocyte (arrow), a red blood cell fragment, in a dog with acute pancreatitis.


(Modified Wright’s stain; 500×.)


image

Figure 36-2 Keratocyte (arrow) in a dog with acute pancreatitis. Note the projections resembling blunt horns.


(Modified Wright’s stain; 500×.)


image

Figure 36-3 Acanthocyte (arrow) in a dog with acute pancreatitis. This red blood cell pathology has projections varying in length and width, allowing its differentiation from an echinocyte.


(Modified Wright’s stain; 500×.)



6 What changes can be expected on a routine biochemistry panel in cases of acute canine pancreatitis?



a. Hyperglycemia is common in dogs with acute pancreatitis and is associated with a combination of stress and increased glucagon production in relation to insulin production. Glucose monitoring is important in cases of pancreatitis because DM may be a transient or permanent consequence.

Related posts:

  1. ERYTHROCYTE DISORDERS
  2. OVERVIEW: HEMOSTATIC COMPONENTS AND DISORDERS
  3. INTERPRETATION OF THE LEUKOGRAM
  4. AVIAN BIOCHEMICAL ANALYSIS

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Aug 26, 2016 | Posted by in INTERNAL MEDICINE | Comments Off on PANCREAS

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