HOW TO APPROACH…
AHDS (Acute Hemorrhagic Diarrhoea Syndrome) in dogs
Acute hemorrhagic diarrhoea syndrome (AHDS) is defined as sudden onset of severe bloody diarrhoea with significant loss of fluid into the intestinal lumen.
Frequently, vomiting is the first clinical sign seen by the family.
There is strong evidence that clostridial overgrowth and toxin release may be responsible for the intestinal epithelial necrosis, but 
faecal culture for Clostridium spp. or other potential enteric pathogens is not diagnostic, because man of these bacteria can be found in feces of healthy dogs.
( About 30% of dogs develop chronic diarrhea later in life.
DDX
- Drugs/toxins causing mucosal irritation (eg, doxycycline, NSAIDs)
- Previous event causing intestinal damage (eg, hypovolemia, blood loss, hypotension, heat stroke)
- Acute liver or kidney failure
- Acute pancreatitis
- Hypoadrenocorticism
- Intestinal foreign body, intussusception or mesenteric volvulus
- Intestinal infection (eg, canine parvovirus, Salmonella spp., Campylobacter spp.)
Clinical signs
- Acute to peracute
- VOMITING: first clinical sign 50% of cases followed by watery hemorrhagic diarrhea
- Usually hypovolemia (lethargy, weakness, tachycardia, > CRT, weak pulse)
Lab
- PCV either normal range or increased, but never low
- If low = true intestinal bleeding (eg hemostatic disorders, ulceration, int. neoplasia).
Stress leucogram. Usually mild left shift. If ++ segmented neutrophils > 20,000/mL or band neutrophils
>2500/mL: look for bacterial infection, translocation, sepsis
- If no stress leucogram, look for Addison’s
- Prerenal azotemia not common, if azot. seen check urine SG before fluids
- Low ALB (<10% cases): re assess after hydration as might need additional treatment (eg FFP)
There is no noninvasive test to diagnose
AHDS = diagnosis mainly based on the
typical clinical presentation and clinical course + exclusion of other known causes of acute intestinal s× associated with damage of the intestinal mucosa
DIAGNOSIS
*Confirming the presence of Clostridium perfringens NetF suggests AHDS as it has been assoc. with the disease, but a few healthy dogs can harbor these strains in their large intestine.
TREATMENT
- Depending on severity of the signs, rapid replacement with balanced solutions, given as shock bolus as fast as 30 mL/kg in 10 minutes repeated up to 3 times if needed or as CRI with the rate of up to 40 to 60 mL/kg/h IV until PCV is in the mid-normal range.
- Re-assess response to IVFT every hour, the clinical goal will be:
- HR< 120/min in small breed dogs and < 100/min in large breed dogs
- CRT <2s and normal pulse pressure
- Normal mental status
- After a few hours of adequate IVFT, dogs should be able to urinate when walked outside.
Maintenance
requirements (about 50 mL/kg/24 h) and ongoing losses (up to 10 mL/kg/h in severely affected dogs) have to be continued until the dog is able eat/drink
Symptomatic t× (as maropitant or buprenorphine) is important. NSAIDs and pure mu receptor agonists should be avoided!!!
*Usually very rapid improvement over the first 24 to 48 hours
If not, REEVALUATE: look for other causes of hemorrhagic diarrhea (eg, acute pancreatitis) or for possible complications (eg ++
hypoalbuminemia, bacterial translocation/sepsis, DIC)
