CPV infection is primarily treated with aggressive supportive care with fluid therapy, antibiotics, antiemetics, and nutritional support. Thus, hospitalization is required for most dogs with CPV infection, although recent evidence suggests that patients may be considered for outpatient therapy after fluid resuscitation has been performed.15
Dogs with signs of intravascular fluid deficit (ie, hypovolemia [tachycardia, weak peripheral pulses, prolonged capillary refill time, pale mucous membranes, altered mentation, hypotension, and elevated lactate concentration]) should be fluid resuscitated. Fluid resuscitation involves restoring oxygen delivery by providing 20 to 25 mL/kg of a balanced isotonic crystalloid (eg, lactated Ringer’s solution, 0.9% NaCl) over 10 to 15 minutes.16 This dose can be repeated up to 90 mL/kg/hr if physical examination findings of hypovolemia do not resolve.
Although their use is controversial, synthetic colloids (hydroxyethyl starch [5 mL/kg over 15 minutes]) may also be used in hypovolemic and/or hypoalbuminemic dogs with CPV. Recent concerns about acute kidney injury, coagulopathy, and increased risk for death associated with the use of synthetic colloids in humans and veterinary patients should be carefully considered on a case-by-case basis.17-19 Animals with signs of hypovolemia should be treated with IV fluids, as subcutaneous or oral fluids are not efficient. Intraosseous catheters may be used in patients in which IV access is difficult. In some cases, vasopressors (eg, norepinephrine, dopamine, vasopressin) may be required if there is little to no response to fluid therapy.
Once perfusion is restored, interstitial fluid deficit should be corrected by rehydrating the patient. Physical examination findings of dehydration may include dry mucous membranes, skin tenting, sunken eyes, and/or a doughy abdomen on palpation. Dehydration should be roughly estimated based on physical examination findings and the fluid deficit replaced with a balanced isotonic crystalloid over 4 to 12 hours (up to 24 hours if congenital heart disease is present) using the following equation:
Fluid deficit (L) = Weight in kg × % dehydration
An hourly maintenance rate should be added to the rehydration rate, and potassium supplementation should be considered in patients with hypokalemia. Ongoing losses should be replaced in patients with significant vomiting and/or diarrhea. Many patients with CPV require dextrose supplementation in their fluids (1.25%-5%) to treat hypoglycemia.
Antibiotic therapy should be initiated because of sepsis that results primarily from bacterial translocation from the GI tract.
A broad-spectrum antibiotic with gram-positive, gram-negative, and anaerobic coverage should be provided. Examples of potential combinations include:
- A potentiated aminopenicillin (eg, ampicillin–sulbactam [30 mg/kg IV q6-8h]) with a fluoroquinolone (10 mg/kg IV or IM q24h)
- Cartilage developmental abnormalities should be considered when using a fluoroquinolone in young dogs.20,21
- A second-generation cephalosporin (eg, cefoxitin [30 mg/kg IV q6-8h22]) with an aminoglycoside (eg, amikacin [20 mg/kg IV q24h23])
- Clindamycin (15 mg/kg IV q12h24) with a fluoroquinolone
Aminoglycosides should not be used in patients with compromised renal blood flow (ie, patients with ongoing hypotension). However, if used, daily urine monitoring is necessary to assess for proteinuria, glucosuria, or development of casts, which can indicate tubular damage.
Nausea should be treated with an antiemetic (eg, maropitant [1 mg/kg IV or SC q24h25], dolasetron [0.6 mg/kg PO, IV, or SC q24h26], ondansetron [0.5-1 mg/kg IV or PO q12h27], metoclopramide [0.2-0.5 mg/kg SC, IM, or PO q8h28 or 0.01-0.09 mg/kg/hr as a continuous IV infusion]). Nutritional support should be considered early, as it decreases the length of hospitalization in dogs with CPV.29 Feeding tubes (nasogastric or nasoesophageal) should be considered in the first 24 hours for inappetent patients. Dogs should be allowed to eat as soon as they show interest in food.
Analgesia should be considered in all dogs with abdominal pain. Buprenorphine (10-30 μg/kg IV or IM q6-8h) is effective for most dogs with mild or moderate pain.30 Dogs with severe pain should be treated with a pure μ-receptor agonist (eg, fentanyl [3-6 μg/kg/hr], hydromorphone [0.1-0.2 mg/kg IV q4-6h], methadone [0.1-0.5 mg/kg IV q4h]).31
Other therapies that may be considered include acid suppressants for dogs with suspected esophagitis (eg, pantoprazole or omeprazole [1 mg/kg IV or PO q12h32]), prokinetics in dogs with regurgitation or ileus (eg, metoclopramide [0.2-0.5 mg/kg SC, IM, or PO q8h or 0.01-0.09 mg/kg/hr as a continuous IV infusion], erythromycin [0.5-1 mg/kg PO or IV q8h33]). A broad-spectrum dewormer (eg, fenbendazole [50 mg/kg PO q24h for 3 days34], pyrantel pamoate [10 mg/kg PO once35]) should be used in all puppies.
Although hospitalization should be recommended for all CPV cases, some owners may not be able to afford hospitalization. One recent study found that outpatient therapy was a reasonable alternative for dogs that could not be hospitalized for standard treatment.15 There was no significant difference in survival between dogs that received inpatient therapy versus outpatient therapy.15 Of importance, all dogs were initially resuscitated with IV fluids before outpatient therapy with subcutaneous fluid. Hypoglycemia was also corrected using IV dextrose, and all dogs that appeared to be critically ill were excluded from outpatient therapy.15
Outpatient therapy typically consists of subcutaneous fluids with a balanced isotonic crystalloid, subcutaneous antibiotic therapy (eg, cefovecin), subcutaneous antiemetic therapy (eg, maropitant, dolasetron), and oral potassium supplementation as needed. It is important that the client returns for inpatient therapy if the patient does not respond well at home.