Small Animal Gastroenterology

Authors
Abbreviations
Preface
Part I Diagnosis of
Gastrointestinal Disorders
1 Diagnostic Tools
1.1 Clinical History
1.1.1 Introduction
1.1.2 History of specific gastrointestinal signs
1.1.2.1 Dysphagia and regurgitation
1.1.2.2 Gagging
1.1.2.3 Vomiting
1.1.2.4 Retching
1.1.2.5 Diarrhea
1.1.2.6 Other stool abnormalities
1.1.2.7 Flatulence and borborygmus
1.1.2.8 Dyschezia
1.1.2.9 Constipation
1.1.2.10 Fecal incontinence
1.1.2.11 Anal pruritus
1.1.2.12 Abdominal pain
1.1.3 Dietary history
1.2 Physical Examination
1.2.1 Introduction
1.2.2 General physical examination
1.2.2.1 Skeletal growth and development
1.2.2.2 Body condition
1.2.2.3 Mental status
1.2.2.4 Abnormalities in posture and locomotion
1.2.2.5 Mucous membranes
1.2.2.6 Peripheral lymph nodes
1.2.2.7 Skin and subcutaneous tissue
1.2.2.8 Body temperature
1.2.2.9 Pulse rate
1.2.2.10 Respiratory rate
1.2.3 Examination of the gastrointestinal tract
1.3 Diagnostic Imaging
1.3.1 Introduction
1.3.2 Oropharynx
1.3.2.1 Structural abnormalities
1.3.2.2 Functional Disorders
1.3.3 Esophagus
1.3.3.1 Generalized esophageal dilation
1.3.3.2 Segmental esophageal dilation
1.3.4 Stomach
1.3.4.1 Gastric dilation and volvulus
1.3.4.2 Gastric causes of chronic vomiting
1.3.4.3 Diagnosis of delayed gastric emptying
1.3.5 Small intestine
1.3.5.1 Ileus
1.3.5.2 Partial obstructions
1.3.5.3 Complete obstructions
1.3.5.4 Functional ileus
1.3.5.5 Detecting ileus with ultrasound
1.3.5.6 Complicated ileus
1.3.5.7 Chronic diarrhea
1.3.5.8 Diffuse bowel wall infiltration
1.3.5.9 Gastrointestinal hemodynamic assessment
with Doppler ultrasound
1.3.6 Large intestine
1.3.7 Liver and biliary tract
1.3.7.1 Hepatic parenchymal disease
1.3.7.2 Non-obstructive biliary tract disease
1.3.7.3 Obstructive disease
1.3.7.4 Interventional procedures of the liver
and biliary system
1.3.8 Pancreas
1.3.8.1 Pancreatitis
1.3.8.2 Pancreatic neoplasia
1.4 Laboratory Tests
1.4.1 Laboratory assessment of gastric disease
1.4.1.1 Introduction
1.4.1.2 Evaluation for parasitic infestation
1.4.1.3 Sucrose permeability testing
1.4.1.4 Minimally-invasive markers for gastric
disease
1.4.1.5 Analysis of gastric juice
1.4.1.6 Evaluation of gastric emptying time
1.4.2 Laboratory tests for the diagnosis of
intestinal disorders
1.4.2.1 Introduction
1.4.2.2 Assessment of serum cobalamin and
folate concentrations
1.4.2.3 Assessment of gastrointestinal protein loss
1.4.2.4 Assessment of intestinal absorptive
capacity and barrier function
1.4.3 Laboratory tests for the diagnosis of liver
disease
1.4.3.1 Introduction
1.4.3.2 Routine hematological testing, urinalysis,
and fecal examination
1.4.3.3 Analysis of ascites fluid
1.4.3.4 Classical serum parameters
1.4.3.5 Other serum markers
1.4.3.6 Abnormalities of coagulation parameters
1.4.3.7 Other hepatic function tests
1.4.3.8 Species differences
1.4.4 Laboratory tests for the diagnosis of
exocrine pancreatic disorders
1.4.4.1 Introduction
1.4.4.2 Pancreatitis
1.4.4.3 Exocrine pancreatic insufficiency (EPI)
1.4.5 Molecular-genetics-based laboratory tests
1.4.5.1 Introduction
1.4.5.2 Test Development
1.4.5.3 Diseases of the esophagus and stomach
1.4.5.4 Intestinal diseases
1.4.5.5 Pancreatic disease
1.4.5.6 Liver disease
1.5 Endoscopy
1.5.1 Introduction
1.5.2 Indications
1.5.3 Basic principles of endoscopy
1.5.3.1 Choice of endoscopes
1.5.4 Esophagogastroduodenoscopy
1.5.4.1 Preparation and anesthesia
1.5.4.2 Technique
1.5.4.3 Gastroduodenoscopy
1.5.5 Colonoileoscopy
1.5.5.1 Preparation and anesthesia
1.5.5.2 Technique
1.5.6 Proctoscopy
1.5.7 Diagnostic procedures
1.5.7.1 Biopsy
1.5.7.2 Mounting and handling tissue samples
1.5.8 Appearance of the upper gastrointestinal
tract
1.5.8.1 Abnormal findings
1.5.9 Interventional procedures
1.5.9.1 Foreign body removal
1.5.9.2 Percutaneous gastrostomy tube
1.5.9.3 Dilation of esophageal strictures
1.5.9.4 Electrocautery techniques
1.6 Diagnostic Laparoscopy
1.6.1 Introduction
1.6.2 Indications
1.6.3 Laparoscopic equipment and technique
1.6.3.1 Basic equipment
1.6.3.2 Procedural considerations
1.6.4 Biopsy techniques
1.6.4.1 Liver biopsy
1.6.4.2 Pancreatic Biopsy
1.6.4.3 Intestinal biopsy
1.6.4.4 Other biopsy techniques
1.6.5 Ancillary procedures
1.6.5.1 Cholecystocentesis and cholecystography
1.6.5.2 Portography
1.6.5.3 Other procedures
1.6.6 Complications of laparoscopy
1.7 Cytology
1.7.1 Introduction
1.7.2 Technique
1.7.3 Liver
1.7.3.1 Normal liver cells
1.7.3.2 Hyperplasia
1.7.3.3 Inflammation
1.7.3.4 Neoplasia
1.7.3.5 Other abnormalities of the liver
1.7.3.6 Bile
1.7.4 Pancreas
1.7.5 Stomach and intestines
1.8 Histopathology
1.8.1 Introduction
1.8.2 Types of gastrointestinal biopsies
1.8.2.1 Endoscopic biopsies
1.8.2.2 Full-thickness biopsies
1.8.2.3 Needle biopsies
1.8.2.4 Brushing and curettage samples
1.8.3 Advantages and disadvantages of different
biopsy techniques
1.8.4 Tissue handling and processing
1.8.5 Interpretation and misinterpretation of
GI tract biopsies
1.9 Assessment of Gastrointestinal
Motility
1.9.1 Disorders of gastrointestinal motility
1.9.2 Methods for assessing gastrointestinal
motility
1.9.2.1 Survey radiography
1.9.2.2 Contrast radiography - liquid barium
1.9.2.3 Contrast radiography - barium meal
1.9.2.4 Contrast radiography - BIPS
1.9.2.5 Ultrasonography
1.9.2.6 Nuclear scintigraphy
1.9.2.7 Tracer studies
1.9.2.8 Manometry
1.9.2.9 Functional MRI
2 Clinical Evaluation of Dogs and Cats
with Specific Clinical Signs
2.1 Clinical Evaluation of Patients with
Acute Signs of Gastrointestinal
Disease
2.1.1 Introduction
2.1.2 Diagnostic evaluation of vomiting
2.1.2.1 Vomiting versus regurgitation
2.1.2.2 The vomiting reflex
2.1.2.3 Etiology of vomiting
2.1.2.4 History and physical examination
2.1.2.5 Laboratory and ancillary testing
2.1.3 Diagnostic evaluation of acute diarrhea
2.1.3.1 Etiology of acute diarrhea
2.1.3.2 Pathophysiological changes with acute
diarrhea
2.1.3.3 History and physical examination
2.1.3.4 Laboratory and ancillary testing
2.2 Clinical Evaluation of Patients with
Chronic Vomiting
2.2.1 Introduction
2.2.2 Initial evaluation
2.2.3 Diagnostic approach
2.2.4 Secondary gastrointestinal disease
2.2.4.1 Hyperthyroidism
2.2.4.2 Hepatobiliary disease
2.2.4.3 Renal failure
2.2.4.4 Hypoadrenocorticism
2.2.4.5 Pancreatitis
2.2.4.6 Heartworm disease
2.2.5 Primary gastrointestinal disease
2.3 Clinical Evaluation of Patients with
Chronic Diarrhea
2.3.1 Introduction
2.3.2 General workup
2.3.2.1 Case history
2.3.2.2 Physical examination
2.3.2.3 Laboratory evaluation
2.3.3 Division of patients according to the
findings on initial evaluation
2.3.3.1 Patients with obvious abnormalities (A)
2.3.3.2 Patients with diarrhea without any
other obvious abnormalities (B)
2.3.4 Diagnostic imaging (C)
2.3.4.1 Abdominal ultrasonography
2.3.4.2 Endoscopy
2.3.4.3 Abdominal radiography
2.4 Clinical Evaluation of Patient with
Chronic Weight Loss
2.4.1 Introduction
2.4.2 Pathophysiology
2.4.3 Etiology
2.4.4 Diagnosis
Part II Diseases of the
Gastrointestinal Tract
3 Esophagus
3.1 Anatomy
3.2 Physiology
3.3 Diseases of the Esophagus
3.3.1 Cricopharyngeal achalasia
3.3.2 Esophagitis
3.3.3 Gastroesophageal reflux
3.3.4 Esophageal foreign bodies
3.3.5 Esophageal strictures
3.3.6 Esophageal diverticula
3.3.7 Airway-esophageal fistula
3.3.8 Megaesophagus
3.3.9 Hiatal hernia
3.3.10 Gastroesophageal intussusception
3.3.11 Vascular ring anomalies
3.3.12 Neoplastic conditions of the esophagus
4 Stomach
4.1 Introduction
4.2 Anatomy
4.3 Gastric physiology
4.3.1 Gastric glands
4.3.2 Gastric secretion
4.3.3 The gastric mucosal barrier
4.4 Diseases of the Stomach
4.4.1 Gastritis
4.4.1.1 Acute gastritis
4.4.1.2 Chronic gastritis
4.4.1.2.1 Lymphoplasmacytic gastritis
4.4.1.2.2 Eosinophilic gastritis
4.4.1.2.3 Hypertrophic gastritis
4.4.1.2.4 Atrophic gastritis
4.4.1.2.5 Helicobacter infection
4.4.1.2.6 Parasitic gastritis
4.4.1.2.7 Treatment of chronic gastritis
4.4.1.3 Gastric ulceration
4.4.2 Gastric dilation-volvulus
4.4.3 Motility disorders
4.4.4 Neoplastic conditions of the stomach
5 Small Intestine
5.1 Anatomy
5.1.1 Introduction
5.1.2 Gross anatomy of the intestinal tract
5.1.2.1 Anatomical features of the small intestine
5.1.2.1.1 Increasing available surface area
5.1.2.1.2 Microscopic anatomy of the intestinal
tract
5.1.2.1.3 Spatial variation in intestinal structure
5.2 Intestinal Physiology
5.2.1 Introduction
5.2.2 Secretion, digestion, and absorption:
function of the villus
5.2.3 Regulation of secretion, absorption, and
motility: gastrointestinal hormones
5.2.4 Gut-associated lymphoid tissue and the
immune system
5.2.5 Intestinal bacteria
5.3 Small Intestinal Disease
5.3.1 Introduction
5.3.2 Infectious causes of small intestinal
disease
5.3.2.1 Viral infections
5.3.2.1.1 Canine parvovirus enteritis
5.3.2.1.2 Canine distemper virus infection
5.3.2.1.3 Feline coronavirus infection
5.3.2.1.4 Feline panleukopenia
5.3.2.1.5 Feline leukemia virus (FeLV) and
feline immunodeficiency virus (FIV)
5.3.2.2 Bacterial Infections
5.3.2.2.1 Campylobacter spp
5.3.2.2.2 Clostridium spp
5.3.2.2.3 Enterobacteriaceae
5.3.2.2.4 Pathogenic E. coli
5.3.2.2.5 Salmonellae
5.3.2.2.6 Other bacteria
5.3.2.3 Fungal and algae infections
5.3.2.3.1 Histoplasmosis
5.3.2.3.2 Pythiosis
5.3.2.4 Parasitic diseases
5.3.2.4.1 Helminths
5.3.2.4.2 Protozoal infections
5.3.2.4.3 Other protozoal parasites
5.3.3 Dietary indiscretion
(garbage can intoxication)
5.3.4 Intestinal obstruction - intestinal foreign
bodies, intussusception, and intestinal
torsion
5.3.5 Hemorrhagic gastroenteritis (HGE)
5.3.6 Short bowel syndrome
5.3.7 Motility disorders
5.3.8 Alterations in the small intestinal
microflora (Small intestinal bacterial
overgrowth)
5.3.9 Protein-losing enteropathies
5.3.10 Neoplastic diseases of the small intestines
6 Large Intestine
6.1 Introduction
6.2 Anatomy
6.3 Physiology
6.3.1 Motility
6.3.2 Water and electrolyte transport
6.3.3 Mucus secretion
6.3.4 Colonic microflora
6.3.5 Immune function
6.4 Diseases of the Large Intestine
6.4.1 Whipworms
6.4.2 Colitis
6.4.2.1 Histiocytic ulcerative colitis of Boxers
6.4.2.2 Clostridium perfringens enterotoxicosis
6.4.2.3 Tritrichomonas foetus infection
6.4.3 Irritable bowel syndrome
6.4.4 Fiber-responsive large bowel diarrhea
6.4.5 Feline megacolon
6.4.6 Neoplastic diseases of the large intestines
7 Liver
7.1 Anatomy
7.1.1 Biliary system
7.1.2 Blood supply
7.1.3 Microanatomy
7.2 Physiology
7.3 Diagnostic approach to patients with
suspected liver disease
7.3.1 Prevalence of liver disease
7.3.2 Symptoms associated with liver diseases
7.3.3 Physical examination
7.3.4 Diagnostic tests for liver disease
7.3.5 Liver biopsy
7.3.5.1 General considerations
7.3.5.2 Biopsy techniques
7.3.5.2.1 True-cut biopsy needle
7.3.5.2.2 The Menghini aspiration needle
7.3.5.2.3 Fine needle aspiration
7.3.5.3 Surgical wedge biopsy
7.3.5.4 Gall bladder aspiration
7.4 Complications of liver disease
7.4.1 Ascites
7.4.2 Jaundice
7.4.3 Hepatic encephalopathy
7.4.3.1 Management of hepatic encephalopathy
7.4.4 Coagulopathies
7.4.5 Polyuria and polydipsia
7.5 Liver diseases of the dog
7.5.1 Parenchymal liver diseases of the dog
7.5.1.1 Canine hepatitis
7.5.1.1.1 Acute Hepatitis
7.5.1.2 Leptospirosis
7.5.1.3 Chronic hepatitis and hepatic cirrhosis
7.5.1.4 Chronic hepatitis due to copper storage
in the liver
7.5.1.5 Lobular dissecting hepatitis
7.5.1.6 Nonspecific reactive hepatitis
7.5.2 Parenchymal changes of the liver during
systemic disease
7.5.2.1 Steroid hepatopathy
7.5.2.2 Hepatic steatosis in diabetes mellitus
7.5.2.3 Hypoxic liver damage
7.5.2.4 Amyloidosis
7.5.3 Vascular diseases of the liver
7.5.3.1 Congenital portosystemic vascular
anomalies
7.5.3.2 Hepatic congestion
7.5.3.3 Primary portal vein hypoplasia
7.5.3.4 Portal vein thrombosis
7.5.3.5 Arteriovenous fistulas
7.5.4 Diseases of the biliary tract
7.5.4.1 Cholecystitis
7.5.4.2 Biliary duct or gall bladder rupture
7.5.4.3 Cystic liver disease
7.5.4.4 Extrahepatic bile duct obstruction
(EBDO)
7.5.5 Neoplastic conditions of the liver
7.5.5.1 Hepatocellular carcinoma and adenoma
7.5.5.2 Hemangiosarcoma
7.5.5.3 Malignant lymphoma
7.5.5.4 Bile duct carcinoma
7.6 Liver diseases in the cat
7.6.1 Parenchymal liver diseases in cats
7.6.1.1 Hepatic lipidosis
7.6.1.2 Acute toxic hepatopathy
7.6.1.3 Hepatopathy due to infectious peritonitis
(FIP)
7.6.1.4 Hepatic changes due to hyperthyroidism
7.6.1.5 Nonspecific reactive hepatitis and
amyloidosis
7.6.2 Vascular liver diseases in cats
7.6.2.1 Congenital portosystemic shunt
7.6.3 Diseases of the biliary system in cats
7.6.3.1 Neutrophilic cholangitis
7.6.3.2 Lymphocytic cholangitis
7.6.3.3 Extrahepatic bile duct obstruction
(EBDO)
7.6.4 Neoplasia
8 Exocrine Pancreas
8.1 Anatomy
8.2 Physiology
8.3 Diseases of the exocrine pancreas
8.3.1 Pancreatitis
8.3.2 Exocrine pancreatic insufficiency
8.3.3 Exocrine pancreatic neoplasia
8.3.4 Rare diseases of the exocrine pancreas
8.3.4.1 Pancreatic pseudocyst
8.3.4.2 Pancreatic abscess
8.3.4.3 Pancreatic parasites
8.3.4.4 Pancreatic bladder
8.3.4.5 Pancreatolithiasis
8.3.4.6 Pancreatic nodular hyperplasia
9 Diseases that affect more than one
Organ of the Gastrointestinal Tract
9.1 Adverse Reactions to Food -
Allergy versus Intolerance
9.1.1 Introduction
9.1.2 Terminology
9.1.3 Etiopathogenesis of food allergy
9.1.4 Food allergies
9.2 Inflammatory Bowel Disease
9.2.1 Introduction
9.2.2 Common principles of IBD
9.2.2.1 Etiology and pathogenesis
9.2.2.2 Clinical presentation
9.2.2.3 Diagnosis
9.2.2.4 Treatment
9.2.3 Lymphoplasmacytic enteritis (LPE)
9.2.4 Lymphoplasmacytic colitis (LPC)
9.2.5 Basenji enteropathy
9.2.6 Familial PLE and PLN in Soft-coated
Wheaten Terriers
9.2.7 Eosinophilic enteritis (EE)
9.2.8 Granulomatous enteritis
9.2.9 Histiocytic ulcerative colitis (HUC)
9.2.10 Proliferative enteritis
9.3 Gastrointestinal Lymphoma
9.3.1 Feline gastrointestinal lymphoma
9.3.2 Canine gastrointestinal lymphoma
9.4 Neuroendocrine Tumors of the
Gastrointestinal Tract
9.4.1 Introduction
9.4.2 Insulinoma
9.4.3 Gastrinoma
9.4.4 Glucagonoma
9.4.5 Pancreatic polypeptidoma
9.4.6 Carcinoids
9.4.7 Other neuroendocrine tumors of the
gastrointestinal tract
Subject Index