Week 11: Horses (Mudge) Flashcards
(68 cards)
1
Q
Colitis & Enteritis in Horses
A
Colitis & Enteritis in Horses
2
Q
- Rapid onset of diarrhea
- Usually High-volume
Etiology- Infectious
- Non-infectious
A
Acute Colitis
3
Q
List the Infectious causes of Acute Colitis:
A
Bacterial
- Salmonella
- Clostridium perfringens
- Clostridium difficile
- Neorickettsia risticii
Viral
- Coronavirus
Parasitic
- Cyathostomiasis
- Strongylosis
4
Q
- May be associated with stress of transportation, feed changes, antibiotics
- Contagious and zoonotic potential
- Fecal cultures (5) or PCR!
- Can have active shedding without diarrhea
- Affected horses often have low WBC, signs of endotoxemia
- Always on our list of differentials
A
Salmonella
5
Q
(T/F) Horses are very sensitive to small amounts of gram-negative endotoxin
A
True
6
Q
Systemic Inflammatory Response Syndrome
- Fever
- Tachycardia
- Tachypnea
- Low or high WBC (or left shift/toxic changes)
A
Endotoxemia
7
Q
- Type C and A
- Severe, peracute cases in adult horses have been called “Colitis X”
- Salmonella would be the other top differential
- More common in neonatal foals
- Acute, often hemorrhagic, enterocolitis - may be typhlocolitis (involves the cecum)
A
Clostridium perfringens
8
Q
- May be antibiotic-associated (common in humans)
- Enterotoxin (A) and Cytotoxin (B) act synergistically
- Leading to mucosal damage - May be isolated in hospitalized horses
A
Clostridium difficile
9
Q
- Infects intestinal epithelial cells (SI and LI)
- Horses are infected via primary or secondary intermediate hosts
- Peak incidence June-September
- Dull, anorexic, variable diarrhea
- Fever
- Initial leukopenia +/- monocytosis
- Serology (IFA) and PCR of whole blood or feces
A
Potomac Horse Fever (Neorickettsia risticii)
10
Q
- Small intestine – sloughing of enterocytes, inflammation
- Diarrhea in only 20% of reported cases
- Anorexia, fever, lethargy = most common
- Encephalopathy possible
- PCR of feces
A
Equine Coronavirus
- Main viral diarrhea cause
11
Q
- Large Strongyles
- Well-controlled by macrocyclic lactones (e.g. ivermectin)
- Small Strongyles - Cyathosomes
- Late winter-spring -> emergence from hypobiotic state
- Encysted cyathostomes often associated with weight loss, chronic diarrhea
A
Gastrointestinal Parasites
12
Q
List the Non-Infectious causes of Acute Colitis
A
- Carbohydrate overload
- Accidental or Intentional
- Acidification of the large intestine
- Intestinal inflammation, death of normal GI flora, endotoxemia
- Cantharidin
- Blister beetles in alfalfa hay
- Oral ulcerations, colic, hypocalcemia, diarrhea
13
Q
List Colitis Complications:
A
- Laminitis
- 40% of PHF cases
- Jugular thrombosis
- Intestinal ischemia/infarction
- Septicemia
14
Q
What may you need to treat hypoproteinemia?
A
Colloids
15
Q
List some Anti-inflammatories for the treatment of Colitis:
A
- Flunixin meglumine for systemic inflammation
- Bismuth subsalicylate to control GI inflammation
16
Q
Treatment of Colitis - Antibiotics:
- ABs indicated with severe neutropenia
A
Salmonella
- Enrofloxacin
- Gentamicin
17
Q
Treatment of Colitis - Antibiotic:
Clostridium perfringens
A
Metronidazole (10-15 mg/kg PO q8h)
18
Q
Treatment of Colitis - Antibiotic:
Clostridium difficile
A
- Stop ABs if you suspect antibiotic-induced colitis
- Metronidazole (some resistance)
19
Q
Treatment of Colitis - Antibiotic:
Potomac Horse Fever
A
Oxytetracycline (6.6 mg/kg IV q12h)
20
Q
Treatment of Colitis:
- Polymyxin B (IV)
- Bind endotoxin
- Antiserum (e.g. salmonella typhimurium)
- Di-tri-octahedral smectite (PO)
- Binds clostridial toxins
A
Anti-toxin treatments
21
Q
- Hypersecretion from small intestine
- Functional ileus 2 to inflammation
- Leakage of protein
- AKA Proximal Duodenitis-Jejunitis
A
Anterior Enteritis
22
Q
List the Clinical Signs of Anterior Enteritis:
A
- Colic
- Mild to severe
- Often improves after refluxing
- Nasogastric reflux
- Large volumes (often >60L/day)
- Fever
- Leukopenia /Leukocytosis
- Hemoconcentration
23
Q
(T/F) Ultrasound is very useful for diagnosing anterior enteritis
A
True
24
Q
Anterior enteritis vs SI Strangulation
- Continued, severe pain
- Serosanguinous abdominal fluid with high lactate
A
SI Strangulation
25
Anterior enteritis vs SI Strangulation
- Less pain after refluxing
- Normal to orange/hazy abdominal fluid
Anterior Enteritis
26
List the Treatment for Anterior Enteritis:
- Gastric Decompression
- Intravenous Fluids
27
List the reasons you would Refer colitis and enteritis:
- Hypovolemic shock
- need very large volumes of IV fluids
- Unable to control pain
- Continued nasogastric reflux
- Need to isolate
- Faster test results
- Unresponsive to treatment
28
- Wide range of severity and symptoms
- Weight loss frequently reported
- Hypoproteinemia
- Etiologies
- Infectious
- Inflammatory/IBD
- NSAID toxicity
- Sand
- Idiopathic
Chronic Diarrhea in the Adult Horse
29
List the Infectious etiologies for Chronic Diarrhea in the Adult Horse:
- Salmonella
- Lawsonia intracellularis aka "Proliferative enteropathy"
- Rhodococcus equi
- Peritonitis
30
(T/F) Chronic Parasitism (Cyathostomes) can cause Chronic Diarrhea in the Adult Horse
True
- Small strongyles -- most common parasite of horses
- Encyst in winter (LI), emerge in spring
- Damage to intestinal mucosa
- Colic, diarrhea, low albumin
31
- Malabsorption & Malgigestion
- *Most often small intestinal* inflammatory bowel disease
- Hypoalbuminemia
- Dependent edema
- Weight loss
- Diarrhea (not always)
Inflammatory Bowel disease / Protein Losing Enteropathy
32
- Idiopathic Granulomatous enteritis
- Multisystemic Eosinophilic epitheliotrophic disease (MEED)
- Lymphocytic-Plasmacytic Enterocolitis
- Lymphosarcoma
Inflammatory Bowel Disease
33
Other etiologies:
Right Dorsal Colitis seems to be linked with ...
NSAID toxicity
34
- Colic, ventral edema, low-volume diarrhea
- Excessive *phenylbutazone* administration
- Decreased prostaglandin production -> decreased blood flow, decreased mucous and bicarbonate secretion -> ulceration RDC
Right Dorsal Colitis
35
Chronic Diarrhea in the Adult Horse
List Anthelmintics used:
- Fenbendazole
- Moxidectin
36
Diarrhea in Neonatal and Older Foals
Diarrhea in Neonatal and Older Foals
37
List the common causes of diarrhea in neonatal foals and older foals:
*Non-Infectious Neonatal diarrhea*
- "Foal heat" diarrhea
- 5-15 days
- changes in GI flora
- Usually still bright and nursing
- Self-limiting
- Perinatal asphyxia
- May lead to intestinal ischemia, maldigestion, ileus
- Necrotizing enterocolitis
- Lactose intolerance
- May be primary
- Most commonly 2 to rotavirus or C difficile
*Infectious Causes* - Bacterial
- C. perfringens
- Type C associated with severe hemorrhagic diarrhea
- C. difficile
- May be *asymptomatic carriers*
- Salmonella
- Often have neutropenia with a *left shift*
- 5 serial fecal cultures
- Fecal PCR
- Actinobacillus
- Blood culture positive
*Infectious Causes* - Viral
- Rotavirus**
- Highly contagious
- Coronavirus ?
- Adenovirus ?
*Infectious Causes* - Parasitic and Protozoal (uncommon)
- Parasitic
- Strongyoides westeri **
- Protozoal
- Cryptosporidium patvum
- Zoonotic
38
Describe the steps in a diagnostic workup for a foal with diarrhea:
- Physical exam
- CBC
- Chem profile
- IgG
- Blood Culture
- Ultrasound
- Radiographs
- +/- Abdominocentesis
- Collect feces
- Real-time PCR screening in healthy and sick foals 1-20 weeks of age
*Infectious Causes* - Bacterial
- Culture
- PCR
- Toxin assays
- Fecal smear gram stain
- Suspect in sick foals with Hemorrhagic diarrhea
39
Create a treatment plan for a foal with diarrhea, including adjunctive and supportive treatment:
- Supportive care
- Specific therapies
- Broad-spectrum parental *antibiotics for bacteremia*
- Metronidazole for Clostridial spp
- Withhold milk/provide parental nutrition
- Lactase tablets
- Di-tri-octahedral smectite
- NO probiotics
40
(T/F) E. coli is not a direct GI pathogen in foals, but diarrhea can occur in septic foals
True
41
(T/F) Older foals with diarrhea are less likely to become septic
True
42
(T/F) *ALL* horses can be affected by Salmonella spp and Clostridium spp
True
43
Rhodococcus equi (lung) & Lawsonia intracellularis are ...
specific weanling-age diarrhea
44
- Ages 1-6 months
- Respiratory signs are the most common
- Can cause abdominal abscesses
- Multiple foals are often affected
Rhodococcus equi
Treatment: Clarithromycin + Rifampin
45
- Most common at 4-7 months
- Clinical Signs
- Weight loss
- Diarrhea
- Edema
- *Severe hypoalbuminemia*
- Ultrasound: *THICK* small intestine
- Serology and Fecal PCR
Lawsonia intracellularis
Treatment: *Oxytetracycline*, Doxycyclin, Chloramphenicol, clarithromycin also options
46
Peritonitis
Peritonitis
47
Definition:
Is the *mesothelial lining* of the peritoneal cavity (parietal peritoneum) and the *viscera* (visceral peritoneum)
Peritoneum
48
Definition:
Is innervated by branches of spinal nerves
Parietal peritoneum
49
Definition:
Has no pain receptors
Visceral peritoneum
50
What is removing fluid and solutes from the peritoneal cavity?
Lymphatics
- Especially diaphragmatic lymphatics
51
What contains *macrophages, mast cells, mesothelial cells, and lymphocytes* which contribute to the immune response?
Peritoneum
52
Is defined as *infection of the peritoneal cavity* with *no identifiable intraperitoneal source of infection* (possible hematogenous or lymphatic origin)
Primary peritonitis
- Not common
- Most often *Monomicrobial*, such as infection with *Actinobacillus equuli* in horses
53
Is defined as infection from an underlying *primary disease* or *injury*
Secondary peritonitis
- Leakage of *gastrointestinal contents*
- Urogenital infection with leakage
- Abdominal trauma
- Abdominal abscess
- Iatrogenic
54
What is the most common source of peritonitis in horses and dogs?
Secondary peritonitis of *gastrointestinal origin*
55
What bacterium is most commonly associated with primary peritonitis in adult horses?
Actinobacillus equii
56
(T/F) Non-septic peritonitis can occur when there is chemical irritation from urine, lavage solutions, or talc powder from gloves
True
57
Fill in the blanks:
Animals with ______________ and ___________ often have a longer history of poor appetite, lethargy, and fever
primary peritonitis, abdominal abscess
58
How can you differentiate between GI rupture and enterocentesis?
- Both will have plant material and mixed bacterial populations, but *cytology* will show an *inflammatory response*, usually with *intracellular bacterial* and *degenerate neutrophils* with *rupture*. Also, *ruptured animals* will usually have a *large amount of peritoneal fluid* seen on ultrasound and will have *signs of septic shock*
- *GI rupture* cytology will show mixed bacterial population, plant debris, *degenerate neutrophils*
- *Enterocentesis* will have plant material and microorganisms, but *NO inflammatory response*
59
How do a cell count, total protein, lactate, and glucose change in peritoneal fluid with *septic
peritonitis* cases?
- Total Proteins: Increased
- Lactate: Increased
- Glucose: *Decreased* (relative to blood lactate & glucose)
- Cell count: Increased (usually > 10,000 & often > 100,000/ul)
60
- Is very sensitive for the detection of free peritoneal fluid
- Other findings:
- Thickened intestinal wall
- Ileus
- Abdominal abscess
Abdominal Ultrasound
61
What is your initial empirical antibiotic therapy in a dog with acute septic peritonitis? In a
horse?
- Dogs: Unasyn (ampicillin/sulbactam) or ampicillin/enrofloxacin +/- metronidazole
- *Horses*: Penicillin, Gentamicin (or enrofloxacin) +/- metronidazole
**Main idea is to use to use broad-spectrum antibiotics initially, and include something that will target anaerobes if you suspect GI leakage**
62
When is surgical exploration indicated for peritonitis?
Toxic/degenerate neutrophils, intracellular bacteria, especially if polymicrobial; suspicion of *GI leakage* (or uterine leakage, or intraabdominal abscess) based on cytology or imaging (ultrasound, CT)
63
Peritoneal Inflammation:
(T/F) Pain arises from *afferent nerve* endings in *parietal peritoneum*
True
64
- Usually *polymicrobial*
- E. coli is common
- Sources
- GI (50%)
- Urogenital
- Abdominal abcess
- Bile
- Iatrogenic
Secondary Peritonitis -- Most common source of peritonitis
65
Definition:
Relating to illness caused by medical examination or treatment
Iatrogenic
66
Definition:
A former name for a surgical procedure in which a hollow needle is pushed through the wall of the stomach or intestines to release an abnormal accumulation of gas or fluid or to introduce a catheter for feeding
Enterocentesis
67
What is Serum Amyloid A (SAA)?
Is an acute-phase protein that will increase rapidly in response to inflammation or infection
- It should also decrease quickly (in days) as the infection or inflammation resolves
- This test helps to have a baseline to determine if the antibiotic treatment is effective
68
- tachycardia
- fever
- hypovolemia
- bacterial peritonitis
Evidence of sepsis
