Pathology of the Alimentary System. Lecture 4 Diseases of esophagus & forestomachs

Transcription

1 Systemic Pathology I - VPM 221 Pathology of the Alimentary System Lecture 4 Diseases of esophagus & forestomachs Enrique Aburto Fall 2014

2 IV. Diseases of esophagus Infections extending from mouth Megaesophagus Esophageal rupture Esophageal obstruction (choke) Reflux esophagitis Parasitic lesions Neoplasms

3 IV. Diseases of esophagus (Clinical consequences) Manifested by regurgitation, dysphagia, odynophagia, multiple swallowing attempts & excessive salivation May lead to respiratory disease (aspiration pneumonia)

4 Ulcerative esophagitis, BVD, cow Noah s arkive Ulcerative esophagitis, Bovine papular stomatitis virus, calves

5 1. Megaesophagus Dilation due to insufficient / uncoordinated peristalsis Often no microscopic lesions (achalasia) Congenital form Vascular ring Idiopathic Congenital megaesophagus, dogs. The dilated portion is cranial to the heart and is due to persistent right 4 th aortic arch. Pathologic Basis of Veterinary Disease, 4 th ed., Mosby-Elsevier

6 1. Megaesophagus Acquired form Idiopathic Muscle disease Myasthenia gravis Chagas disease Hypothyroidism Polymyositis Lead & thallium poisoning Idiopathic megaesophagus, dogs. Dilation starts just cranial to the stomach (top) or diaphragm (bottom).

7 2 & 3. Esophageal obstruction (choke) and rupture Obstruction sites: Larynx Thoracic inlet Base of the heart Diaphragmatic hiatus Sequelae: Pathologic Basis of Veterinary Disease, 4 th ed., Mosby-Elsevier Perforation Cellulitis Pleuritis / pyothorax Bloat Stenosis Pneumonia Examples of foreign bodies causing choke, ulceration (left), and perforation right top), dogs. If the animal survives, healing is by fibrosis, which may lead to stenosis, horse (bottom right)

8 Chemical damage of the squamous epithelium due to repeated gastric acid reflux. 4. Reflux esophagitis N Barret esophagus M N M Acid reflux esophagitis, horse. The dark red streaks are areas of epithelial loss. The white streaks are areas of unaffected mucosal epithelium. Barret esophagus (M= intestinal metaplasia human), right. Lesions are most severe on the esophageal mucosa adjacent to the cardia (arrows). N= Normal. Robbins and Cotran Pathologic Basis of Disease (2010), 8 th ed., Elsevier, Inc.

9 Sarcocystosis (Sarcocystis sp) Spirocerca lupi Gongylonema spp Gasterophilus & Hypoderma spp Fly larvae 5. Parasitic lesions Gongylonemiasis, esophagus, cow. Note The serpentine nematodes underneath the mucosa Sarcocystosis, esophagus, duck. Note the pale elongated nodules within the esophageal muscle (arrows). Pathologic Basis of Veterinary Disease, 4 th ed., Mosby-Elsevier

10 5.1 Spirocerca lupi n Indigenous scavenger dogs & wild canids Dung beetles & paratenic hosts Stomach aortic wall distal esophagus granulomatous inflammation and fibroplasia Sequelae: Dysphagia Hypertrophic osteoarthropathy Spondylosis deformans Aortic aneurisms Hemothorax Fibrosarcomas/osteosarcomas n Spirocercosis, dog. Note the presence of granulomatous nodules (n). A single adult nematode is projecting into the lumen of the esophagus (bottom).

11 Hypertrophic osteoarthropathy, dog. Note the periosteal proliferation of the scapula associated with the granulomatous esophagitis due to Spirocerca lupi. Noah s arkive Spondylosis deformans, dog. Note the fusion of vertebral bodies (bridging) due to periosteal proliferation. This can be a sequel of spirocercosis due to the extension of aortic granulomas to the overlying vertebrae.

12 Pathologic Basis of Veterinary Disease, 4 th ed., Mosby-Elsevier A Spirocercosis, dog. Submucosal nodules can transform to become malignant tumors e.g fibrosarcoma (arrow heads). A section of the parasite is shown by the arrows. Spirocercosis. Aortic aneurism & aortitis. Note the focal dilation (arrows) of the aorta (A) and the irregular surface of the intimal layer due to larval migration. Fibrosarcoma, distal esophagus, dog.

13 6. Esophageal neoplasms Sarcomas associated with S. lupi Papilloma BPV-4 Squamous cell carcinoma Pteridium aquilinum (Bracken fern) Lymphoma Papilloma, bovine papilloma virus, esophagus, bull. Lymphoma, esophagus, dog. Pathologic Basis of Veterinary Disease, 4 th ed., Mosby-Elsevier

14 6. Esophageal neoplasms Bracken fern (Pteridium aquilinum) consumption. Squamous cell carcinoma, esophagus (left) and pharynx (right, bottom), bovines. Noah s arkive

15 Diseases of forestomach Most are related to management practices Ruminal tympany (bloat) Foreign bodies Inflammation

16 1. Ruminal tympany (Bloat) Over-distension of the rumen & reticulum with gases of fermentation 1.1 Primary Pasture bloat Feedlot bloat 1.2 Secondary Physical obstruction or stenosis of the esophagus Bloat. Note the distension of the paralumbar fossa and abdomen.

17 Primary bloat Pasture bloat Legumes release of chloroplast particles (containing soluble proteins) rumen microbes colonize particles & degrade proteins (insoluble proteins) gas bubbles get trapped among the particles & do not coalesce stable foam Organic acids (from legumes) + salivary bicarbonates CO 2 Feedlot bloat CHO s (fine particles) & microbes which produce slime it entraps gasses stable foam CHO s growth of encapsulated bacteria ( polysaccharides) viscosity of rumen contents stable foam

18 Pathophysiology of primary bloat Ruminal fermentation & acid production low ph (5-6) Legumes & CHO s salivary secretion viscosity of rumen contents foam physical blockage of the cardia Accumulation of gases intra-abdominal pressure diaphragmatic & abdominal vein compression respiratory & circulatory failure death

19 Signs & lesions in bloat Abdominal distension Animal found dead & rolled on back Large volume of frothy rumen content Marked congestion of head & neck Low rumen ph (<6) Bloat line on esophagus at thoracic inlet

20 Bloat line (arrow), esophagus, sheep Bloat line, esophagus and trachea at the thoracic inlet, cow. There is a sharp demarcation between the caudal (white) and the cranial (congested) mucosa of the esophagus (arrow). Pathologic Basis of Veterinary Disease, 4 th ed., Mosby-Elsevier

21 2. Foreign bodies 2.1 Trichobezoar (hair balls) 2.2 Phytobezoars (plant balls) 2.3 Lead substances poisoning 2.4 Sharp metals hardware disease (traumatic reticuloperitonitis or reticulopericarditis) Trichobezoar, from stomach and duodenum, human. Hardware disease, reticulum, cows. Lead particles, reticulum, cow.

22 4. Inflammation of forestomach Two main causes Extension from oral & esophageal infections Grain overload (ruminal lactic acidosis, engorgement toxemia, rumen overload, chemical rumenitis)

23 Pathogenesis of grain overload Sudden change to high CHO diet overgrowth of gram + bacteria lactic & dissociated fatty acids ph < 5 & ruminal atony: Acidic ph eliminates normal gram-negative bacteria Acidic ph damages mucosa microvesicles Organic acids osmotic effect fluids into rumen Sudden death from dehydration, acidosis & endotoxemia Survivors often have grave sequelae

24 Lesions of grain overload v Grain overload, ovine: Marked hyperemia, erosion and multiple confluent vesicles of ruminal mucosa (top left); moderate cellular infiltration (arrows) and vesiculation (v) of the mucosa (histo). Noah s arkive

25 Sequelae of grain overload Bacterial rumenitis Trueperella (Arcanobacterium) pyogenes Fusobacterium necrophorum Healed ulcers ( stellate scars ) Necrobacillary rumenitis, an ulcer is covered with fibrinonecrotic exudate, lamb. Resolved rumenitis, cow. Ruminal mucosa with stellate scars (s). s s

26 Sequelae of grain overload Liver abscesses Often subclinical May rupture into vena cava fatal septic embolism Noah s arkive Multifocal liver abscesses due to grain overload, ox. v a Liver abscess (a) with rupture into the caudal vena cava (v), cow Schematic diagram of pulmonary emboli (red dots) arising from: (1) rupture of a hepatic abscess into the caudal vena cava; (2) vegetative valvular endocarditis (tricuspid valve); and (3) jugular thrombosis. Pathologic Basis of Veterinary Disease, 4 th ed., Mosby-Elsevier

27 Sequelae of grain overload Mycotic rumenitis Well demarcated, circular hemorrhagic infarcts Can become systemic placentitis & abortion Mycotic rumenitis, calf. Note the well-demarcated, confluent areas of necrosis and hemorrhage (infarcts) in the ruminal mucosa that can be caused by angioinvasive fungi such as Aspergillus, Mucor, Rhizopus, Absidia, and Mortierella spp. Noah s arkive