Horse- Diarrhea Flashcards
How can you tell if a foal is not nursing? (three observations)
- Watch foal for nursing activity
- Examine mare’s udder - if a foal is not nursing, the udder will become very full, and the mare may stream milk spontaneously
- Look to see if the foal has milk on its face - sick foals will often go to the udder to nurse, which will result in the mare letting down. However, the foal will not nurse, and the milk will run onto its face.
Diagnostics for Aetiology of the Diarrhea in a Foal
- Faecal culture - selective culture for Salmonella spp, and anaerobic culture for Clostridium spp
- Faecal toxin assay for toxins produced by Clostridium spp
- Testing of faeces for Rotavirus (eg ELISA)
Signs of hypovolemia in a foal
- Tachycardia, sunken eyes and depression
- The cool distal extremities and poor pulse quality suggest hypoperfusion and hypovolaemia.
Why is it important to take a blood culture in a foal with diarrhoea?
- Approximately half of foals with diarrhoea that are referred for intensive management of diarrhoea are bacteraemic.
- Bacteraemia can only be diagnosed by obtaining a blood culture.
- The sensitivity pattern of the cultured organism can be used to guide treatment
Why did you repeat the IgG level if it was normal at 24 hours of age
- Foal that are sick will tend to utilise their immunoglobulins quicker than a normal foal.
- These foals will often benefit from supplemental immuoglobulin
How can you monitor the effectiveness of your fluid therapy?
- After each fluid bolus, you should re-assess the foal.
- If the fluids are being effective the foal should look brighter, the heart rate should decrease, and the other signs of poor perfusion should improve
- (eg the distal extremities should feel warmer and pulses stronger)
What is a reason that the foal is azotaemic
(showing diarrhea)
Azotaemia can be due to pre-renal, renal or post renal causes.
- The most common cause of post-renal azotaemia in a foal would be ruptured bladder, however there is no evidence to suggest this is the case in this foal.
- Renal azotaemia suggests kidney dysfunction, and although there is no way to disprove this at them moment, it is more likely that the azotaemia is due to pre-renal causes (ie hypovolaemia, dehydration leading to decreased renal perfusion)
Azotemia
- pre-renal
- renal
- post renal
should you treat low IgG in a foal that is over 24hrs old? how?
- The foal is likely to benefit from additional immunoglobulins to improve its ability to ‘fight’ infection.
- Plasma is the treatment of choice in this case, as the foal is older than 24 hours.
- The immunoglobulins contained in oral colostrum would not be absorbed in this foal, although it may have some local protective effect in the GIT
Possible Antimicrobials you could give a foal with suspected sepsis (from bacterial infection):
- cephalosporin such as cefquinome
- Metranidazole
- limited nursing time while healing (muzzle) - may require parenteral nutrition (IV) if not nursing
Septic Arthritis
- Septic arthritis, also known as joint infection or infectious arthritis, is the invasion of a joint by an infectious agent resulting in joint inflammation
- ex: foal may develop infection at other sites, such as umbilicus, lungs or joints. If the foal develops septic arthritis or osteomyelitis, this may impact on its ability to function as an athlete.
Borborygmi
- a rumbling or gurgling noise made by the movement of fluid and gas in the intestines
- example: hypermotile borborygmi
What contagious causes of diarrhoea are you concerned about with equine diarrhea?
- The primary contagious cause of diarrhoea would be Salmonellosis.
- Infection with Clostridium difficile/perfringens is less likely to be transmitted to other horses, but would also be a concern.
- Other differentials would include larval cyathostominosis, dietary induced diarrhoea, right dorsal colitis, sand enteropathy and antimicrobial associated diarrhoea.
Flunixin
Flunixin is a nonsteroidal anti-inflammatory drug, analgesic (relieve pain), and antipyretic used in horses, cattle and pigs.
How can you rule out Salmonella as a cause of the diarrhoea??
Due to the intermittent shedding of Salmonella bacteria in faeces, 3-5 samples are required to rule out Salmonellosis
Why would a pitting oedema (ventral) develop in a horse with diarrhea?
- Horses with diarrhoea typically develop a protein losing enteropathy. The resultant hypoproteinaemia can result in peripheral oedema.
- The hypoproteinaemia can be confirmed by measuring the total protein (ideally measure the albumin and globulin individually)
TP on blood work
Total Protein
Albumin/Globulin
-in horses more likely to be protein loss from GIT or renal
What can be a cause of protein losing enteropathy in an adult horse?
- Encysted larval cyathostomins
- trying to kill the larval stages may result in severe damage to the GI, resulting in diarrhoea (using anti-parasitics)
Catheter placement in horses (for fluids)
- Jugular is the most accessible and used in emergency situations (hypovolemic shock)
- you can also use lateral thoracic, cephalic and saphenous veins, but these vessels are smaller, less accessible, and not as robust, so more prone to damage
- Catheters can also be placed in the cephalic and lateral thoracic vein in horses, although they can be difficult to place and maintain, and to give the large volume of IV fluids that this filly is likely to need.
Formulating a fluid plan for treatment
- The fluid plan should include calculations for deficit, maintenance and ongoing losses.
- The deficit calculation is an estimate, based on clinical and laboratory data, and is usually described as a percentage of body weight.
- As a rough guide, horses that are less than 5% dehydrated cannot be identified on PE findings.
- Horses that are greater than 12% dehydrated are close to death.
- Maintenance requirements are between 2 and 4ml/kg/hr
- Ongoing losses is again and estimate, and can be very difficult to quantify in horses with diarrhoea.
- As you can see, fluid plans are estimates that should be implemented but then continually readdressed to ensure they are appropriate for the patient.
Treating Endotoxaemia
Polymixin B and flunixin can be used to treat endotoxaemia
Salmonella
- Gram-negative facultative rod-shaped bacterium in the same proteobacterial family as Escherichia coli, the family Enterobacteriaceae, trivially known as “enteric” bacteria.
- Could result in endotoxemia
Right Dorsal Colitis
(RDC)
- Right Dorsal Colitis (RDC) is a term given to ulceration found specifically in the upper right section of the colon of a horse.
- RDC has been specifically linked to the use of non-steroidal anti-inflammatory drugs (NSAIDs), such as phenylbutazone.
- Unfortunately, like most medicines, there are side effects to NSAIDs.
Differences between foals and adults
D+ in Neonates (less than 10 days)
D+ in Older Foals
(up to about 10-12 months)
D+ in Adult Horses
Duration of Clinical Signs
- Acute D+
- Chronic D+
-Acute/Chronic D+
Differential Diagnosis
(Presence of Risk Factors)
Principles of Therapy
(1. Addressing Fluid Loss)
Principles of Therapy
(2. Address Inflammation and Endotoxaemia)
Foals & Endotoxaemia
Treat or Refer?
