DMN: practice questions (week 10)

colic, equine small bowel disease, variety of PA GI diseases

What is the most likely affected anatomic structure that is causing an abdominal distention pattern in this picture?

Rumen

What is the most likely affected anatomic structure that is causing an abdominal distention pattern in this picture?

Uterus

What is the normal position of the abomasum in a healthy adult cow?

Ventral on the abdominal floor to the right of midline beneath the rumen

A 5yo Holstein cow is presented with: 

• Progressive abdominal enlargement

• Weight loss despite eating

• Reduced fecal output

• Rumen contractions decreased

• Normal temperature and heart rate

• Serum chloride decreased

• Rumen chloride increased

Based on the information above, is the lesion more consistent with omasal transport failure (OTF) or pyloric outflow failure (POF)? 

POF → elevated rumen chloride + metabolic alkalosis

What structures are controlled by the vagus nerve in the bovine gastrointestinal tract?

Regulates motility and function of the esophagus, reticulum, rumen, omasum, abomasum, & pylorus

-coordinates movement of ingesta + eructation 

What clinical signs would be observed in a bovine patient if ingesta could not move normally through the forestomachs?

Progressive abdominal distension, decreased fecal output, weight loss despite eating, reduced appetite, recurrent bloat, decreased rumen motility

How quickly does feed material pass through the small intestine in horses?

1 foot a minute

What are the primary functions of the small intestine?

Enzymatic digestion + nutrient absorption (CHO/fats/proteins)

What part of the small intestine is prone to impaction in horses?

Ileum (ileo-cecal junction)

What is the hallmark sign of malabsorption in animals?

Weight loss

What are the clinical signs of acute small intestinal disease in horses?

Moderate/severe colic, copious gastric reflux, dilated SI loops on US

What are the clinical signs of chronic small intestinal disease in horses?

Weight loss, intermittent mild colic, thickened SI walls on US

What are the clinical signs specific to Inflammatory Bowel Disease (IBD) in horses?

Progressive weight loss despite good appetite, PLE (hypoalbuminemia + peripheral edema), lethargy, performance loss, intermittent mild colic, diarrhea

What is the only way to obtain a definitive diagnosis for any category of IBD in horses?

Histopathology (biopsy)

Which category of IBD in horses mainly affects young Standardbreds, marked by macrophages on histopathology & thought to be caused by Mycobacterium avium or an abnormal host inflammatory response to bacterial antigens?

Granulomatous enteritis

Which category of IBD in horses mainly affects young horses, marked by eosinophils, lymphocytes, & macrophages, & is thought to be a hypersensitivity response, leading to dermatitis, diarrhea, & tissue eosinophilia?

Multisystemic Eosinophilic Epitheliotropic Disease (MEED)

Which category of IBD in horses is characterized by Inflammatory eosinophilic cell infiltration at the level of the intestinal mucosa (diffuse in the SI/LI + focal)?

Eosinophilic enteritis (enterocolitis)

Which category of IBD in horses is most commonly marked by acute severe colic, but no weight or protein loss?

Idiopathic focal eosinophilic enteritis (IFEE)

Which category of IBD in horses is a rare disease with a grave prognosis marked by lymphocytes + plasma cells present in the lamina propria with villous atrophy upon histopathology as well as malabsorption?

Lymphocytic-plasmacytic entercolitis

When performing a glucose absorption test on a horse you suspect may have IBD, you would expect the glucose to elevate how much over the baseline between 60-120 minutes if the horse does NOT have IBD?

>85%

What therapeutics or management changes are used in IBD cases in horses?

-Corticosteroids (dexamethasone) → immunosuppressive doses (0.2mg/kg IM or IV)

-Decrease exposure to possible dietary, parasitic, or environmental antigens

What are some of the potential causes for spasmodic colic, which causes intestinal hypermotility + parasympathetic tone?

Lush pastures, drinking cold water after exercise, heavy GI parasite load, poor feed quality

-trx with Buscopan + NSAIDs

What is the most commonly used NSAID for colic cases in equine practice?

Flunixin meglumine

What is the proliferative enteropathy in weanling foals leading to “ill thrift” clinical signs is caused by an obligate gram negative intracellular bacterium ?

Lawsonia intracellularis

What is the suggested treatment for Lawsonia intracellularis in horses?

-Supportive care → NSAIDs, Omeprazole, Fluids

-Antimicrobials → Tetracyclines/Macrolides/Rifampin

What are the typical important parameters for a presumed diagnosis of Lawsonia intracellularis in horses?

Low total protein + Age

What is a typical age for a weanling?

4-6 months

Why do some foals exhibit diarrhea with a Lawsonia intracellularis infection?

Enterocytes in the SI are affected, decreasing enzymatic activity + absorption resulting in an overload in CHO in the LI (osmotic diarrhea)

What syndrome in horses leads to excessive fluids + electrolyte secretion in the proximal part of the small intestine, leading to a high volume of enterogastric reflux & SI distention with abdominal pain (colic)?

Duodenitis Proximal Jejunitis (DPJ)

What is the main differential diagnosis for Duodenitis Proximal Jejunitis (DPJ) in horses?

Small intestinal obstruction (simple or strangulating)

What is the recommended treatment for Duodenitis Proximal Jejunitis (DPJ) in horses?

-Anti-inflammatory → NSAIDs/2% lidocaine CRI

-IV fluids

-Nutritional support

-Frequent gastric emptying

-Laminitis prophylaxis

A 16yo pregnant Standardbred mare presents with an acute onset of colic. HR is 64bpm, RR is 32bpm, & she is pawing. CRT is 3sec, & MM are red. Her rectal temp is 101.3F. GI sounds are completely absent, & gastric reflux yielded 16L of brown-to-yellow colored fluid. What is the most likely diagnosis?

Small intestinal volvulus

What are the main clinical signs of a small intestinal obstruction in horses?

Mild-moderate pain, good response to analgesia ± gastric decompression, minimal CV compromise, WNL peritoneal fluid, sometimes gastric reflux

What are the main clinical signs of a small intestinal strangulation in horses?

Moderate to severe pain, brief/no response to analgesia ± gastric decompression, CV deterioration, peritoneal fluid abnormal, gastric reflux

A 3yo Standardbred gelding is presented with acute onset of moderate to severe colic + slight fever. On rectal exam, distended loops of small intestine are palpated + a NGT intubation results in 15L of reflux being obtained. The horse seems less painful after the NGT was passed. What would be the top differential in this case?

Proximal enteritis

What are some of the differential diagnoses for small intestinal obstruction in horses?

Ascarid impaction, ileal impaction, ileal hypertrophy

What are some of the differential diagnoses for small intestinal strangulation in horses?

Intussusception, SI volvulus, pedunculated lipoma, abdmoninal incarceration (hernia, rent, etc.)

What is the roundworm found in either older foals or weanlings with a history of poor deworming, leading to an unthrifty foal, colic, depression, tachycardia, & tachypnea?

Parascaris equorum (Ascarid impaction)

What is the recommended treatment for ascarid impaction in horses?

-Gastric decompression/lavage initially

-Anti-inflammatory

-Surgery often indicated → dead worms cause damage to SI wall, poor prognosis

What is the recommended prevention for ascarid impaction in horses?

-Proper deworming + FECRT yearly for foals (start at 4-6mos)

-Pasture rotation management

-Benzimidazoles (Fenben)

-If large worm burden = non-paralytic anthelcide + mineral oil

When is ileal impaction associated with Coastal Bermuda Grass most commonly seen in horses in the Southern US?

June-November

What is a possible complication following resolution of an ileal impaction in horses?

Post-operative ileus (distention/inflammation)

What pathogen is the most important cause of neonatal + post-weaning diarrhea in pigs due to fimbrial adhesins that allow attachment to enterocytes of the small intestine, leading to secretory diarrhea, dehydration, & eventually death?

Enteric Colibacillosis (Enterotoxigenic E. coli - ETEC)

How does ETEC present in neonatal pigs (0-4 days)?

Severe watery yellow-green diarrhea + rapid dehydration + hypothermia

How does ETEC present in post-weaning pigs (3-10 weeks)?

Post-weaning diarrhea + edema disease

What is the pathogen that primary affects piglets <7 days of age via fecal-oral transmission, leading to severe mucosal necrosis & rapid development of necrohemorrhagic enteritis due to production of a beta toxin?

Clostridium perfringens Type C

-100% mortality

How can we prevent + control diseases such as ETEC & Clostridium perfringens?

Vaccinate sows/gilts 2-6 weeks prior to farrowing

-ensure colostrum intake + thorough sanitation of facilities (all in/all out)

How is Clostridium perfringens Type A different from Type C?

-Type A → produces alpha toxin, affects piglets 1-14 days old, causes yellow to creamy pasty diarrhea w/ mild dehydration + reduced weight gain, mild catarrhal enteritis at necropsy, low mortality

-Type C → produces beta toxin, affects piglets <7 days old, causes dark red to hemorrhagic diarrhea w/ rapid dehydration, high mortality

What is the pathogen that is most common in piglets 5-14 days of age with high morbidity + low mortality that leads to yellow/gray pasty to watery diarrhea, dehydration, poor BCS, & rough hair coat?

Coccidiosis (Cystoisospora suis)

What is the pathogen in nursing + recently weaned piglets (1-8 weeks old) with high morbidity/low mortality that results in villous atrophy, malabsorption, & osmotic diarrhea (acute watery to creamy diarrhea)?

Rotavirus A

What are the diagnostic tests used in the diagnosis of Rotavirus A in piglets?

-Fecal PCR

-Antigen detection (ELISA)

-Necropsy → thin-walled/fluid-filled SI, villous atrophy of SI mucosa

What is the highly contagious pathogen with 100% morbidity/100% mortality seen most severely in piglets <2 weeks old that infects + destroys mature enterocytes lining the small intestinal villi (severe villous atrophy), leading to an acute onset profuse watery diarrhea, vomiting, sever dehydration, & huddling/reduced nursing behavior?

Transmissible Gastroenteritis (coronavirus)

How can we differentiate Porcine Epidemic Diarrhea (PED) from Transmissible Gastroenteritis (TGE)?

-TGE → severe disease, very high mortality, vomiting is common

-PED → moderate disease, lower mortality, vomiting is common

When does post-weaning diarrhea (E. coli) most commonly affect pigs, leading to a sudden onset of yellow to gray watery diarrhea, perineal fecal standing (scours), dehydration, anorexia, poor growth, & sudden deaths?

2-14 days after weaning → 3-8 weeks old

What is the pathogen that leads to edema disease in pigs, often induced by stress, allowing the toxin to enter the bloodstream + damage vascular endothelial cells which leads to vascular permeability & edema formation across the entire body, including the cerebrum?

Verotoxigenic E. coli (Shiga toxin-producing E. coli - STEC) → F18 fimbriae

What is the pathogen in pigs that presents as either an acute septic form (fever, depression, anorexia, cyanosis, dyspnea) or an enteric form (watery to mucoid diarrhea ± blood, dehydration, weight loss, reduced growth)?

Salmonella enterica serovar Choleraesuis (acute septic) + S. Typhimurium (enteric)

What is the large intestinal disease seen in growing pigs (6wks-adult) that causes mucosal destruction leading to mucohemorrhagic colitis, dehydration, metabolic acidosis, & weight loss?

Swine Dysentery (Brachyspira hyodysenteriae)

What are some of the other differential diagnoses that look similar to Swine Dysentery (Brachyspira hyodysenteriae) in the large intestine of growing pigs?

Salmonellosis, proliferative enteropathy (Lawsonia), whipworms, gastric ulcers

What are the two forms of Lawsonia intracellularis seen in grower pigs?

1. Proliferative enteropathy → 4-6 weeks post-weaning, poor growth, dull, poor appetite, ± pale diarrhea, thickened terminal ileum (‘hosepipe gut’), fail to thrive

2. Hemorrhagic enteropathy → 4-12mos old (young adults/gilts), sudden death, intestinal hemorrhage, pale MM

What are some of the other differential diagnoses that look similar to Proliferative Enteropathy in young pigs?

Swine Dysentery, Clostridium perfringens Type C, whipworms, gastric ulcers

What is the most common internal parasite of swine that causes poor growth, reduced feed efficiency, & “milk spots” in the liver?

Ascaris suum (large roundworm)

-trx with Fenbendazole or Macrocyclic lactones

What is the intestinal parasite seen post-weaning in pigs, leading to mild-moderate intermittent diarrhea, poor weight gain, & low mortality, but significant production losses?

Coccidia (Eimeria spp.)

-trx with Sulfonamides (Albon) or Amprolium

What is the intestinal parasite in pigs that resides in the cecum + colon, leading to mucoid to blood diarrhea, weight loss, & poor performance?

Trichuris suis (whipworms)

-trx with Fenbendazole or Macrocyclic lactones

What are the risk factors for developing gastric ulcers in pigs?

-Fine feed particle size

-Stress

-Concurrent GI dz

-Lack of roughage

-Pigs >6wks, adults

A producer reports that an entire litter of 5-day-old piglets has developed yellow, pasty diarrhea. Affected piglets remain active & continue nursing, although weight gain is reduced. Mortality has been minimal. Necropsy of one euthanized piglet reveals mild catarrhal enteritis without significant hemorrhage. What is the most likely cause of disease?

Clostridium perfringens Type A

A group of 10-week-old grower pigs from a commercial farrow-to-finish operation is presented for evaluation of diarrhea + poor performance. Over the past 7 days, several pigs within the same pen have developed progressive weight loss & reduced average daily gain. Affected pigs are depressed, have moderate pyrexia (40.5°C/104.9°F), & exhibit mucoid to bloody diarrhea with staining of the perineal region. Mortality has been low, but morbidity within the group is increasing. No vomiting has been observed. What is the most likely diagnosis?

Swine dysentery