GI Labs Flashcards
History: This young stray dog was brought to your clinic as a “hit by car” case and was dead on arrival. Routine necropsy of this dog revealed this lesion.
Describe the lesion.
The enamel surface from the apex to 1/2 or more of the length of several teeth (mandibular canines, incisors) is irregular and pitted, lacks smooth white surface enamel and there is exposure of the underlying dentin which is stained a light brown color.
History: This young stray dog was brought to your clinic as a “hit by car” case and was dead on arrival. Routine necropsy of this dog revealed this lesion.
What is your morphologic diagnosis?
Oral cavity: Severe, chronic, multifocal enamel hypoplasia
History: This young stray dog was brought to your clinic as a “hit by car” case and was dead on arrival. Routine necropsy of this dog revealed this lesion.
What is the most likely pathogenesis of this lesion in dogs?
Systemic disease such as canine distemper or generalized fever due to septicemia, canine infectious hepatitis, etc. while the tooth is still forming→ degeneration of ameloblasts (which are differentiated and actively forming enamel)→lack of enamel formation. Once inactivated, the ameloblasts remain functionless and the defect cannot be repaired.
History: This young stray dog was brought to your clinic as a “hit by car” case and was dead on arrival. Routine necropsy of this dog revealed this lesion.
List an agent that would have the potential to cause this lesion in a dog and broadly outline the critical time period for this problem to occur.
Canine distemper
Critical time period: This problem only occurs during tooth development (ie. in utero and < 6 month of age).
History: Rocky, is an 8-year-old, neutered, male boxer that was presented for evaluation of gingival masses.
Describe the lesion.
Diffusely, there is bilateral outgrowth of the gingiva involving both the upper and lower arcades. The gingival multifocally forms masses which vary from 1-3 cm in diameter, are pink to red in color, and focally envelop portions of the teeth, especially the incisors. The lower jaw extends approximately 1.5 cm beyond the upper jaw.
History: Rocky, is an 8-year-old, neutered, male boxer that was presented for evaluation of gingival masses.
Provide a morphological diagnosis.
Oral Cavity: Chronic, diffuse gingival hyperplasia Chronic mandibular prognathism
History: Rocky, is an 8-year-old, neutered, male boxer that was presented for evaluation of gingival masses.
What are the two potential causes of this lesion?
Since this lesion is diffuse, it is likely either due to Drug administration (ex: Amlodipine, cyclosporine, diphenylhydantoin, nitrendipine, nifedipine) or it may be familial (inherited), where it is most commonly observed in large and giant breed dogs. (Boxer, Great Dane, Collie, Doberman, Dalmatian). This is a Boxer who is not on any meds – so this case is familial.
History: Rocky, is an 8-year-old, neutered, male boxer that was presented for evaluation of gingival masses.
If the lesion was focal, what might be the underlying cause?
If focal, it can be due to chronic irritation (periodontal disease or malocclusion).
History: Tissue from an 11 year old spayed female Golden Retriever with a 3 month history of progressive anorexia, some weight loss, excessive salivation, and halitosis.
Describe the lesion.
Head: Involving the caudal hard palate and soft palate there is an infiltrative, black mass measuring approximately 2 x 6 x 2 cm. This mass is firm and homogeneous, has infiltrated through the hard palate, which is palpably soft in this region, and extends into the nasal cavity (1.5 cm mass extending into the nasal cavity).
Lungs: Randomly scattered throughout all lung lobes are low to moderate numbers of firm, round black masses which vary in size from 0.5 – 1.0 cm in diameter.
History: Tissue from an 11 year old spayed female Golden Retriever with a 3 month history of progressive anorexia, some weight loss, excessive salivation, and halitosis.
Give an appropriate morphologic diagnosis.
Caudal oropharynx: chronic, locally extensive invasive pigmented mass Lung: chronic, multifocal pigmented masses
History: Tissue from an 11 year old spayed female Golden Retriever with a 3 month history of progressive anorexia, some weight loss, excessive salivation, and halitosis.
What is your most likely diagnosis for these lesions?
Oral Malignant melanoma with multifocal pulmonary metastases
History: Tissue from an 11 year old spayed female Golden Retriever with a 3 month history of progressive anorexia, some weight loss, excessive salivation, and halitosis.
What is the typical behavior of this oral tumor in dogs?
Locally invasive, frequently recur, may invade bone (57% of gingival tumors)
Metastasis is common: 70% to regional lymph nodes 67% to distant sites.
History: Esophagus from a 2-year old cow with diarrhea & esophagus from a 2 year old cow with anorexia
Describe the lesion in esophagus A.
Esophagus A– There are multifocal to coalescing, shallow, linear ulcers that are 1-2 mm in width and vary from 2-3 cm in length. The ulcers are multifocally covered by a pale tan friable material. If the tan friable material is removed, the underlying tissue is depressed and reddened.
History: Esophagus from a 2-year old cow with diarrhea & esophagus from a 2 year old cow with anorexia
Describe the lesion in esophagus B.
Esophagus B-There are numerous multifocal to coalescing papillary to cauliflower-like grows 0.5 – 1.0cm in diameter extending from the mucosal surface of the esophagus. These growths are tan in color and have numerous papillary fronds.
History: Esophagus from a 2-year old cow with diarrhea & esophagus from a 2 year old cow with anorexia
Give a morphologic diagnosis for esophagus A.
Esophagus A: esophagitis, ulcerative & fibrinous (fibrinonecrotic) multifocal to coalescing, acute
History: Esophagus from a 2-year old cow with diarrhea & esophagus from a 2 year old cow with anorexia
Give a morphologic diagnosis for esophagus B.
Esophagus B: chronic, multifocal to coalescing papillary masses
History: Esophagus from a 2-year old cow with diarrhea & esophagus from a 2 year old cow with anorexia Both these lesions are multifocal and caused by viral infection.
List a potential disease differential for each lesion.
- BVDV (mucosal disease) →most likely cause for the ulcerative lesions
- Bovine papilloma virus infection.
History: Esophagus from a 6 year old male neutered Bull Terrier. On Monday he ate a toy bone. Now he is regurgitating and cannot keep anything down.
Describe the lesion.
Segmentally, the esophagus was markedly distended. The serosal surface of the distended segment (6.0 x 3.5 x 2.5 cm) was diffusely dark red to black. Within the lumen of the distended segment, was a roughly rectangular to wedge-shaped foreign body measuring 8.0x 5.0 x 3.5 cm, which was white to tan and firm and had a tapered edge at the distal end. The mucosal surface of the distended segment was extensively thinned and depressed (ulcerated), pale, green to black and covered by a thin layer of tan, friable material (fibrin).
History: Esophagus from a 6 year old male neutered Bull Terrier. On Monday he ate a toy bone. Now he is regurgitating and cannot keep anything down
Provide a morphologic diagnosis.
Esophagus: Luminal foreign body with obstruction and associated fibrinous and ulcerative esophagitis
History: Esophagus from a 6 year old male neutered Bull Terrier. On Monday he ate a toy bone. Now he is regurgitating and cannot keep anything down.
What process may have led to the mucosal ulceration and what might be a potential sequela to this lesion had the animal lived?
Pressure necrosis Esophageal perforation (acute sequela) Esophageal stricture (chronic sequela)
History: Esophagus from a 6 year old male neutered Bull Terrier. On Monday he ate a toy bone. Now he is regurgitating and cannot keep anything down.
If this lesion were in a bovine rather than a dog. What might this esophageal obstruction lead to?
Secondary bloat
History: Tissue from a feline with a history of halitosis
Describe the lesions.
There are multifocal raised tan plaques on the dorsal surface of the tongue and along both dorsal and ventral lips. The plaques are round to oval, about 0.5-1 cm in diameter, tan, firm, and focally ulcerated. There are also larger (about 1.5 cm) cauliflower-like plaques within the palatopharyngeal fossae.
History: Tissue from a feline with a history of halitosis
What are your differential diagnoses?
- Eosinophilic granulomas
- Plasma cell/lymphocyte ulcerative proliferative stomatitis
History: Tissue from a feline with a history of halitosis The owner had looked in the animal’s mouth and was worried her beloved cat had a tumor.
Explain to her why this is unlikely to be a tumor.
It is rare for a tumor to cause multiple masses involving multiple different regions of the oral cavity, especially involving the tongue and lips, so these masses are unlikely to be tumors.
History: Tissue from a feline with a history of halitosis You made an impression smear of the lesions and noted numerous eosinophils and macrophages.
What is your diagnosis?
Eosinophilic granuloma
History: Tissue from a 750# steer found dead
Describe the lesion.
Approximately ½ of this section of esophagus is diffusely reddened and slightly thickened by clear glistening fluid (edema). The other 1/2 of the esophagus is pale (blanched) and there is a sharp demarcation between the blanched and congested segments of the esophagus.
History: Tissue from a 750# steer found dead
Name this lesion.
Bloat Line
History: Tissue from a 750# steer found dead
Give an explanation for the appearance of this lesion.
Gross distension of the rumen puts massive pressure on the diaphragm leading to increased intra-thoracic pressure. The increased intra-thoracic pressure compresses the veins of the intra-thoracic esophagus, leading to blanching of the intrathoracic esophagus. The increased intra-thoracic pressure leads to poor drainage of blood from the head and neck, resulting in congestion of the cervical esophagus, and a line of demarcation at the thoracic inlet.
History: Tissue from a 750# steer found dead
What other gross changes might be observed in this animal?
Congestion, edema and hemorrhage in the muscles and lymph nodes of the head and neck. The animal would also be markedly bloated. The lungs may be mildly collapsed (atelectasis) and there may be a stable foam in the rumen.
History: Tissue from a 4 year old female Boer goat that had developed anorexia and lethargy after she had a stillborn lamb. She was off feed for a few days, but improved following treatment, started to feel much better, developed a ravenous appetite, and gobbled down the high quality alfalfa hay and grain mixture and she had only previously picked at. A few days later, she developed diarrhea and died.
Describe the lesion(s).
Rumen: There is a large depression in which the mucosa (and ruminal papilla) are absent, measuring approximately 15 cm X 10 cm. The center was covered by grey-green, friable material and the periphery was intensely red in color (hyperemia) and slightly thickened. There were several additional similar ulcers ranging in size from 2-3 cm located in a multifocal pattern around this central ulcer. Variably sized (2-3 cm in diameter) dark red blotches can be observed from the serosal surface which correspond to the mucosal ulcers.
History: Tissue from a 4 year old female Boer goat that had developed anorexia and lethargy after she had a stillborn lamb. She was off feed for a few days, but improved following treatment, started to feel much better, developed a ravenous appetite, and gobbled down the high quality alfalfa hay and grain mixture and she had only previously picked at. A few days later, she developed diarrhea and died.
Provide an appropriate morphologic diagnosis.
Rumen: subacute, multifocal, ulcerative and fibrinonecrotic rumenitis with intense peripheral hyperemia.
History: Tissue from a 4 year old female Boer goat that had developed anorexia and lethargy after she had a stillborn lamb. She was off feed for a few days, but improved following treatment, started to feel much better, developed a ravenous appetite, and gobbled down the high quality alfalfa hay and grain mixture and she had only previously picked at. A few days later, she developed diarrhea and died.
Based on the history, propose a pathogenesis for the development of this lesion.
Anorexia felt better ate abundant grain without time for rumen to re-adapt rumen acidosis disruption of mucosa integrity fungus colonized mucosal defect mycotic rumenitis.
History: Tissue from a 4 year old female Boer goat that had developed anorexia and lethargy after she had a stillborn lamb. She was off feed for a few days, but improved following treatment, started to feel much better, developed a ravenous appetite, and gobbled down the high quality alfalfa hay and grain mixture and she had only previously picked at. A few days later, she developed diarrhea and died.
What additional lesions might you have observed in this animal?
Loss of mucosal integrity of the ruminal mucosa can lead to bacteria (or even fungi) gaining access to the portal blood supply leading to liver abscesses or irregular foci of hepatic necrosis (hepatic necrobacillosis)
History: Tissue from a race horse that was off feed.
Describe the lesion.
Involving the squamous (non-glandular) portion of the stomach along the margo plicatus, there is an irregular dark red to black focus of mucosal depression that is approximately 12cm in length and 3-4 cm in width. This region is significantly depressed (ulcer) compared to the adjacent mucosa and the margins of the lesion are not thickened.
History: Tissue from a race horse that was off feed.
Give a morphologic diagnosis.
Non-glandular stomach: acute focally extensive gastric ulcer (ulcerative gastritis)
History: Tissue from a race horse that was off feed.
Do you think this lesion is acute or chronic and provide rationale?
This is acute. The periphery of chronic ulcers are generally thickened by dense fibrous connective tissue and inflammation and are firm and less pliable.
History: Tissue from a race horse that was off feed.
Name several predisposing factors that may contribute to the development of this lesion in the horse.
a. Infrequent, high carbohydrate meals b. Inadequate access to hay or pasture c. Heavy training schedules d. High stress environments e. Excessive use of drugs, especially non-steroidal anti-inflammatories
History: Tissue from a pig that had respiratory signs a couple of days ago and was recently found dead. A few other pigs are pale and a few have melena.
Describe the lesion(s).
There is an irregularly shaped, sharply-demarcated, depressed (ulcer), firm area approximately 5 cm in diameter that occupies nearly the entire pars esophagea. The margins of this ulcer are markedly thickened (3X thicker than adjacent normal mucosa), firm and less pliable than the adjacent tissue. When sectioned, the stomach wall at the margins of this defect is markedly thickened by firm dense white tissue (fibrosis). The adjacent gastric lymph nodes are moderately enlarged.
History: Tissue from a pig that had respiratory signs a couple of days ago and was recently found dead. A few other pigs are pale and a few have melena.
Give an appropriate morphalogic diagnosis.
Stomach: severe focal chronic ulceration of the pars esophagea (or, severe locally extensive chronic ulcerative gastritis of the pars esophagea) with associated lymphadenomegally
History: Tissue from a pig that had respiratory signs a couple of days ago and was recently found dead. A few other pigs are pale and a few have melena.
Do you think this lesion is acute or chronic and provide rationale?
This is chronic. The periphery of the ulcer is markedly thickened by dense fibrous connective tissue and is firm and less pliable.
History: Tissue from a pig that had respiratory signs a couple of days ago and was recently found dead. A few other pigs are pale and a few have melena.
What are risk factors that contribute to the formation of this lesion?
Feed: Feed properties that contribute to ulceration include: Small feed particle size, pelleting feeds, diets with high levels of unsaturated fats, low fiber, high energy diets.
Irregular feeding patterns (Note: disease may lead to irregular feeding patterns)
Stress (transportation, overstocking)
Respiratory tract infection: Pneumonia may lead to irregular feeding patterns, lead to stress of intercurrent disease, and in response to infection, the body releases histamine, which stimulates gastric acid secretion. Death was due to hemorrhage associated with the ulcer, resulting in severe anemia (hence the pallor).
History: Tissue from a 27 year old female giraffe with a history of chronic progressive anemia and hypoproteinemia.
Describe the lesion.
Uniformly disseminated throughout the majority of the abomasal mucosa are multifocal to coalescing 1-3 mm in diameter, slightly raised, firm, tan nodules. The mucosa has a micronodular appearance; it looks like “Morroccan leather.”
History: Tissue from a 27 year old female giraffe with a history of chronic progressive anemia and hypoproteinemia. Provide a morphologic diagnosis.
Abomasum: Severe, chronic, disseminated, multifocal to coalescing nodular abomasitis
History: Tissue from a 27 year old female giraffe with a history of chronic progressive anemia and hypoproteinemia.
What is the likely cause?
Ostertagia ostertagii
History: Tissue from a 27 year old female giraffe with a history of chronic progressive anemia and hypoproteinemia.
Outline the pathogenesis of this disease, including why it would lead to the development of bottle jaw.
Destruction of parietal cells by the presence of young adults in the mucosal glands → damaged abomasal glands are lined by immature cells which do not produce adequate HCL or pepsinogen → increase in abomasal pH from 2 to 7 → inability to convert what pepsinogen that was produced to pepsin → Inability to digest protein & massive numbers of bacteria enter small intestine due to decreased abomasal pH → diarrhea, hypoproteinemia, weight loss
History: Tissue from a 4 week old M German Shepherd. Approximately a week and a half ago the owner noticed that the pup was regurgitating his food frequently and now has raspy sounding breathing
Describe the tissue.
The diameter of the esophagus was greatly and diffusely dilated ranging from the 3 cm in the cervical region to 3.5 cm in thoracic portions. The tissue was soft and beige pink externally.
History: Tissue from a 4 week old M German Shepherd. Approximately a week and a half ago the owner noticed that the pup was regurgitating his food frequently and now has raspy sounding breathing
Provide a morphological diagnosis.
Chronic, diffuse megaesophagus
History: Tissue from a 4 week old M German Shepherd. Approximately a week and a half ago the owner noticed that the pup was regurgitating his food frequently and now has raspy sounding breathing
Is this likely a congenital or acquired lesion? If congenital, why did clinical signs not appear until it was 2.5 - 3 weeks old.
Congenital
Clinical signs generally do not become apparent until the animal begins to eat solid food
History: Tissue from a 4 week old M German Shepherd. Approximately a week and a half ago the owner noticed that the pup was regurgitating his food frequently and now has raspy sounding breathing
If this were an older animal, what types of conditions could cause an acquired megaesophagus.
Neuromuscular disease leading to weakness of the esophageal musculature 1. Primary Idiopathic acquired megaesophagus 2. Secondary acquired megaesophagus: results from another disease causing neuromuscular weakness Ex: Myasthenia gravis (most common), hypoadrenocorticism, polymyositis, polyradiculoneuritis, lead poisoning, systemic lupus erythematosus (SLE), dysautonomia idiopathic.
History: Tissue from a canine with vomiting (sometimes containing blood), weight loss, and inappetence.
Describe the lesion.
This section of canine stomach is extensively thickened (up to 4 cm thick) by an irregular firm, uniform, red to tan-colored mass which is affecting approximately 50-60% of the gastric mucosa leading to flattening of the gastric rugae. There is a focal 3 cm in diameter region where the involved mucosa is markedly depressed forming a crater-like lesion (ulcer).
History: Tissue from a canine with vomiting (sometimes containing blood), weight loss, and inappetence.
Provide a morphological diagnosis.
. Stomach – locally extensive, ulcerated, mural mass, chronic severe.
History: Tissue from a canine with vomiting (sometimes containing blood), weight loss, and inappetence.
What is your likely diagnosis?
Gastric adenocarcinoma.
History: Tissue from a canine with vomiting (sometimes containing blood), weight loss, and inappetence.
Based on the lesion and your tentative diagnosis, what additional clinical sign might have been observed in this animal?
Melena
History: Tissue from a canine with vomiting (sometimes containing blood), weight loss, and inappetence.
Based on your tentative diagnosis, what is the anticipated biologic typical behavior?
Biologic Behavior: Locally invasive Disease is usually advanced at presentation. Metastasis is expected: Regional lymph nodes (gastric, gastroduodenal, splenic) Intraperitoneal – peritoneal implantation (omentum, mesentery, and peritoneal cacinomatosis) Liver and spleen
History: Tissue from a 4 yr old mixed breed beef cow with a history of weight loss, hair loss, and submandibular swelling. On PE clinicians were unable to hear the heart on the right side. There were jugular pulses and submandibular edema.
Describe the lesion.
Heart: The epicardial surface of the heart and internal surface of the pericardial sac are covered by a thick (1-3 cm in thickness) layer of tan fieable material which can be readily removed. The pericardium and adjacent mediastinum are moderately thickened by firm, dense white fibrous connective tissue. There was a 10 cm long and 0.1 cm diameter linear metal foreign body penetrating through the pericardial sac. Reticulum: The serosal surface of the section of reticulum is diffusely adhered to the adjacent diaphragm by dense, white/grey (fibrous) tissue and the reticulum and diaphragm cannot be separated by manual manipulation. The diaphragm is multifocally thickened and less pliable due to the presence of dense, firm white fibrous connective tissue.
History: Tissue from a 4 yr old mixed breed beef cow with a history of weight loss, hair loss, and submandibular swelling. On PE clinicians were unable to hear the heart on the right side. There were jugular pulses and submandibular edema.
Provide a morphological diagnosis.
Heart: Severe, chronic diffuse fibrinous and fibrosing pericarditis/epicarditis with a penetrating metallic foreign body Reticulum: Focally extensive, chronic, fibrous adhesions.
History: Tissue from a 4 yr old mixed breed beef cow with a history of weight loss, hair loss, and submandibular swelling. On PE clinicians were unable to hear the heart on the right side. There were jugular pulses and submandibular edema.
What is the common name for this condition?
Hardware disease:
History: Tissue from a 4 yr old mixed breed beef cow with a history of weight loss, hair loss, and submandibular swelling. On PE clinicians were unable to hear the heart on the right side. There were jugular pulses and submandibular edema.
What additional lesions might be observed with this condition?
Pleural cavity: Severe fibrinous pleuritis Peritoneal cavity: Severe, extensive fibrinous peritonitis with multifocal abscessation The adhesions may lead to free gas bloat.
History: Tissue from a 2.36 year old female pony with a 3 day history a fever and severe watery foul-smelling diarrhea which was occasionally bloody.
Describe the lesion.
Small Intestine: There are numerous multifocal to coalescing, often circular regions of the mucosa that are slightly raised, have a central region of tan, friable material (fibrin) surrounded by an encircling rim of firm, pale white tissue. These vary in size from 0.5-1 cm in diameter.
History: Tissue from a 2.36 year old female pony with a 3 day history a fever and severe watery foul-smelling diarrhea which was occasionally bloody.
Give a morphologic diagnosis.
Small Intestine: Subacute to chronic, multifocal to coalescing fibrinous (fibrinonecrotic) and ulcerative enteritis
History: Tissue from a 2.36 year old female pony with a 3 day history a fever and severe watery foul-smelling diarrhea which was occasionally bloody.
List a potential cause.
Salmonella typhimurium
History: Tissue from a 2.36 year old female pony with a 3 day history a fever and severe watery foul-smelling diarrhea which was occasionally bloody.
What other lesion might be present in the abdominal cavity?
Enlarged mesenteric lymph nodes
History: Tissue from two different 100 lb pigs. Both have diarrhea and reduced weight gain.
Describe the lesion for specimen A.
Specimen A (74): The serosal surface appears convoluted (cerebriform) with varying areas of thin and thick tissue. The mucosa was thickened with accentuation and corrugation of intestinal folds. Diffusely, the mucosal surface is covered by a thick layer of tan to greenish friable material which could be readily separated from the mucosa.
History: Tissue from two different 100 lb pigs. Both have diarrhea and reduced weight gain.
Describe the lesion for specimen B.
Specimen B (59): The mucosa of ileum and spiral colon has an irregularly thickened and folded surface which could be observed through the serosa and in cross section. The mucosa was thickened with accentuation and corrugation of intestinal folds.
History: Tissue from two different 100 lb pigs. Both have diarrhea and reduced weight gain.
Provide a morphologic diagnosis for specimen A.
Specimen A: Small intestine. Severe, chronic, diffuse, proliferative and fibrinonecrotic enteritis
History: Tissue from two different 100 lb pigs. Both have diarrhea and reduced weight gain.
Provide a morphologic diagnosis for specimen B.
Specimen B: Small intestine and colon. Severe, chronic, diffuse, proliferative enterocolitis
History: Tissue from two different 100 lb pigs. Both have diarrhea and reduced weight gain. These pigs have different forms of the same disease.
What is the likely cause and what is the pathogenesis of the diarrhea?
Lawsonia: both have a proliferative component and A also has a necrotizing or fibrinonecrotic component. Lawsonia enters cell –> Infected cells continue to undergo mitosis → Organism inhibits enterocyte differentiation → Decreased expression of apical membrane transporters involved in absorption → Nonabsorbed solutes cause osmotic/malabsorptive diarrhea
History: Tissue from two different 100 lb pigs. Both have diarrhea and reduced weight gain.
What would be an important differential for Pig A?
Salmonella
History: Tissue from a 4 month old puppy with severe diarrhea and dehydration.
Describe this lesion.
The wall of the small intestine is diffusely dark red in color (hemorrhage) and the serosa has a slightly granular appearance. There are locally extensive regions in which the mucosa is covered by a thin layer of tan friable material (fibrin). The mesenteric lymph nodes are moderately enlarged measuring approximately 2.5 x 2 x 2 cm and are dark red in color.
History: Tissue from a 4 month old puppy with severe diarrhea and dehydration.
Give a morphologic diagnosis.
Small intestine: severe acute locally extensive fibrinonecrotic and hemorrhagic enteritis
Mesenteric lymph nodes: Moderate lymphadenomegally with congestion.
History: Tissue from a 4 month old puppy with severe diarrhea and dehydration.
Given the history and gross findings, name the most likely etiologic agent and briefly describe the likely pathogenesis of this animal’s death.
Virus destroys rapidly dividing crypt epithelial cells → apical enterocytes are continually sloughed normally but cannot be replaced (necrosis of crypt cells) → Villus atrophy → malabsorptive / maldigestive diarrhea →if severe, there will be a completed loss of surface epithelium and an exudative diarrhea
The loss of epithelium leads to malabsorption, maldigestion, fluid loss into the lumen, and dehydration. Hypovolemia, electrolyte imbalances, and often secondary sepsis (due to loss of the mucosal barrier) ultimately caused the animal’s demise.
History: Tissue from a 4 month old puppy with severe diarrhea and dehydration.
You also ran a CBC on this puppy. What would be the expected change?
Leukopenia (< 2000). Parvovirus also attacks rapidly dividing cells in the bone marrow leading to leukopenia
History: Tissue from a 4 month old puppy with severe diarrhea and dehydration.
Cats can become infected by a similar virus as well. What is the disease called and are the clinical signs, lesions, and pathogenesis different than in dogs?
The feline version of parvo is called panleukopenia. The clinical signs, lesions and pathogenesis are the same as in the dog.
History: Tissue from a 10 day old pig with diarrhea
Describe the lesion.
From the serosal surface, the intestinal wall appears thickened and rugated (ropy). The mucosal surface is extensively covered by an adherent, shaggy, tan, friable material.
History: Tissue from a 10 day old pig with diarrhea
Give a morphologic diagnosis.
Small intestine: acute, diffuse, fibrinonecrotic enteritis.
History: Tissue from a 10 day old pig with diarrhea
Differentials are based on both the age of the animal and the type of gross lesion. What are the two top differentials in this case?
Chronic clostridium perfringens type C, or necrotic coccidiosis (this was necrotic coccidiosis). (Salmonella would be a differential in older pigs, but suckling pigs almost never get salmonella)
History: Tissue from a 10 day old pig with diarrhea
An apicomplexan parasite caused the diarrhea. By what mechanisms can this parasite cause diarrhea?
Destruction of villus epithelial cells → Villus atrophy → malabsorption / maldigestion
Intracellular organism → decreased enterocyte function → malabsorption / maldigestion
Inflammation ± ulceration → increased vascular permeability.
History: Small intestine from a 3 year-old cow with profuse watery diarrhea and progressive emaciation
Describe the (gross) lesions.
Small intestine. The intestinal mucosa is diffusely and severely thickened, folded (corrugated), and the surface has a granular appearance.
History: Small intestine from a 3 year-old cow with profuse watery diarrhea and progressive emaciation
Microscopic examination of small intestine reveals numerous macrophages, epithelioid macrophages, and occasional giant cells within the lamina propria and submucosa. Give an appropriate morphologic diagnosis.
Small intestine: Severe, diffuse, chronic granulomatous enteritis
History: Small intestine from a 3 year-old cow with profuse watery diarrhea and progressive emaciation
What is the most likely etiologic diagnosis?
Mycobacterium avium subspecies paratuberculosis (Map)
History: Small intestine from a 3 year-old cow with profuse watery diarrhea and progressive emaciation
What are the most appropriate samples to collect for histologic diagnosis of this disease?
Ileum and draining lymph node
History: Small intestine from a 3 year-old cow with profuse watery diarrhea and progressive emaciation
Do we need to do a necropsy to diagnose this disease or can it be diagnosed with antemortem tests?
All three of the following tests tend to be positive in CLINICALLY affected animals (animals with diarrhea and weight loss). When positive, serology (fast) is very useful. Alternatively, the causative organism can be detected with PCR (fast) or by culture methods (takes a long time - 2 to 4 months) on feces
History: Tissue from a very large, 6 month old dog that was anorexic and not passing feces
Describe the lesions.
There is approximately 5 cm long section of distal ileum telescoped upon itself that extends into the colon. The internal segment (intussusceptum) appears dark red in color, the wall in cross section is expanded by clear glistening fluid, and the intussusceptum cannot be removed from the outer segment (intussuscipiens).
History: Tissue from a very large, 6 month old dog that was anorexic and not passing feces
Name the lesion.
intussusception (acute focally extensive with congestion and edema)
History: Tissue from a very large, 6 month old dog that was anorexic and not passing feces
In a thin and/or cooperative animal, you can often make a tentative diagnosis via abdominal palpation. How would you imagine this lesion would feel on abdominal palpation?
The segmentally thickened bowel would feel as if the dog/cat had a whole sausage or hot dog within the intestinal lumen.
History: Tissue from a very large, 6 month old dog that was anorexic and not passing feces
Are there any factors that could predispose this animal to developing this condition?
May be due to a) enteritis, b) parasites, c) intestinal surgery, d) linear foreign bodies
History: Tissue from a 5 year old dog with a 1/2 day history of lethargy, inappetance, painful abdomen, and vomiting. His abdomen was subjectively distended, and a diagnostic abdominocentesis yielded a straw-colored fluid with a lactate of 7.
Describe the lesion.
Small Intestine: The small intestine is segmentally diffusely dark purple to black in color, the wall is moderately thickened, and the lumen moderate to markedly distended.
History: Tissue from a 5 year old dog with a 1/2 day history of lethargy, inappetance, painful abdomen, and vomiting. His abdomen was subjectively distended, and a diagnostic abdominocentesis yielded a straw-colored fluid with a lactate of 7.
Give the appropriate morphologic diagnosis.
Small Intestine: severe, acute, segmental, venous infarction (due to an intestinal volvulus).
History: Tissue from a 5 year old dog with a 1/2 day history of lethargy, inappetance, painful abdomen, and vomiting. His abdomen was subjectively distended, and a diagnostic abdominocentesis yielded a straw-colored fluid with a lactate of 7.
Propose a pathogenesis for the development of this lesion.
twisting around the mesenteric root (volvulus) → artery continues to pump blood into the segment but venous return is inhibited → venous congestion → edema (hence mucosal thickening) → hypoxia and subsequent necrosis of the bowel wall (venous infarction).
History: Tissue from a 5 year old dog with a 1/2 day history of lethargy, inappetance, painful abdomen, and vomiting. His abdomen was subjectively distended, and a diagnostic abdominocentesis yielded a straw-colored fluid with a lactate of 7.
What might the intestine proximal and distal to this lesion look like?
This lesion could act as an intestinal obstruction. Proximal intestine would be dilated with fluid and ingesta. At necropsy, you will immediately suspect small intestinal obstructive disease as some loops of bowel are distended with fluid (proximal to lesion) and others appear relatedly empty (distal to lesion). The cause will be where these two areas intersect.
History: Tissue from a 5 year old dog with a 1/2 day history of lethargy, inappetance, painful abdomen, and vomiting. His abdomen was subjectively distended, and a diagnostic abdominocentesis yielded a straw-colored fluid with a lactate of 7.
If this had been a horse, what process may have caused this lesion?
Strangulating lipoma
