Page 1499 - Cote clinical veterinary advisor dogs and cats 4th

Parvoviral Enteritis 761

in the lymphoid tissues of the oropharynx, contribute to refractory hypokalemia. • If hypoglycemic (≤60 mg/dL), administer
thymus, and regional lymph nodes. Hypoglycemia occurs with a combination 50% dextrose (0.5-1 mL/kg) diluted 1 : 2
VetBooks.ir infection, allowing viral movement into the • Blood lactate concentration can be used to sterile water, and give IV over 3-5 minutes. Diseases and Disorders
(central line) or 1 : 4 (peripheral line) with
• Marked plasma viremia occurs 1-5 days after
of anorexia, sepsis, and/or decreased liver
function.
○ After the patient is normoglycemic, initiate
small intestinal crypt cells. Necrosis and col-
lapse of these cells impair intestinal function.
GI signs cause progressive dehydration, guide IV fluid resuscitation and should be dextrose by continuous-rate infusion (CRI)
by adding 50% dextrose (50 mL of 50%
used in conjunction with other perfusion
hypovolemia, and blood electrolyte distur- parameters, including arterial blood pressure. dextrose per 1 L bag = 2.5% solution;
bances. The compromised blood-gut barrier • Biochemical profile can be useful to assess 100 mL of 50% dextrose per 1 L bag = 5%
results in translocation of gram-negative and kidney and liver function and plasma solution) to a 1 L bag of isotonic crystalloids,
anaerobic bacteria from the intestinal lumen albumin concentration. provided at a maintenance fluid rate.
into systemic circulation. • Urinalysis or urine specific gravity is needed • If severely hypokalemic (≤2.0 mEq/L), begin
• Destruction of other rapidly dividing cells to confirm azotemia as prerenal in origin. an IV CRI of potassium chloride (KCl) up to
(i.e., hematopoietic progenitor cells in the • Abdominal imaging helps exclude other a maximum rate of 0.5 mEq/kg/h. Recheck
bone marrow) leads to leukopenia. Profound causes of GI signs (e.g., foreign body, serum potassium q 2h and continue CRI
neutropenia combined with bacteremia leads intussusception). until serum potassium is ≥ 2.5 mEq/L.
to sepsis, coagulation disorders, and possible • Fecal wet mount and flotation can identify ○ Mild to moderate hypokalemia may
death. co-infection with intestinal parasites. then be corrected by providing KCl
• If initial ELISA is negative and parvovirus in the maintenance fluids at a dose of
DIAGNOSIS still suspected, consider PCR of rectal swab 0.1-0.2 mEq/kg/h, as indicated by blood
or feces or repeat ELISA the next day. potassium concentrations.
Diagnostic Overview • Puppies that die peracutely should be • Administer parenteral, broad-spectrum
• Diagnosis is typically confirmed by point- necropsied. antimicrobials. Recommended drugs include
of-care enzyme-lined immunosorbent assay extended-spectrum penicillins, second-
(ELISA) from feces or rectal swabs, but false- TREATMENT generation cephalosporins, or a penicillin
negative results are common (up to 50%). paired with a fluoroquinolone. Examples:
In such cases, PCR has a higher sensitivity Treatment Overview ○ Ampicillin-sulbactam 50 mg/kg IV q 8h
for detecting CPV antigen in feces. Immediate cardiovascular stabilization with IV ○ Cefoxitin 30 mg/kg IV q 6-8h
• Maintain biosecurity precautions for any fluid resuscitation, correction of glucose and ○ Ampicillin 22 mg/kg IV q 6-8h plus
young dog displaying clinical signs consistent electrolyte derangements, initiation of antimi- enrofloxacin 10 mg/kg IV q 24h (dilute
with CPV. Use serial ELISA testing, PCR crobials, control of vomiting, and analgesia are and infuse slowly; concern for cartilage
testing, and/or exam of clinicopathologic paramount. damage in growing puppies)
data to verify diagnosis. • Add metronidazole 7-15 mg/kg IV q 12h to
• Minimum diagnostics at presentation should Acute General Treatment the above for extended anaerobic coverage
include a CPV ELISA point-of-care test, • IV fluid resuscitation: administer one-fourth or profusely hemorrhagic diarrhea.
CBC with packed cell volume (PCV) and to one-half of the calculated blood volume • Treat nausea and vomiting using at least one
total solids (TS), and venous blood gas with (90 mL/kg) over 15 minutes using an of the following antiemetics:
lactate and electrolyte panel. isotonic crystalloid (i.e., Plasma-Lyte A, ○ Maropitant citrate 1 mg/kg IV q 24h
Normosol-R, lactated Ringer’s solution, ○ Ondansetron 0.3-0.5 mg/kg IV q 8h or
Differential Diagnosis or 0.9% NaCl) without additives. Smaller dolasetron 0.5-1 mg/kg IV q 24h
• Other GI infections (viral, bacterial, or aliquots (10-20 mL/kg) of volume can be ○ Metoclopramide 1-2 mg/kg/24 hours IV
parasitic) titrated until cardiovascular parameters CRI
• Gastroenteritis normalize. ○ Chlorpromazine 0.1-0.5 mg IM q 8h
• Mechanical obstruction ○ If response is poor, administer hypertonic • Provide analgesia using an opioid as a CRI
• Intussusception saline (7.2% NaCl) at a bolus dose of (i.e., fentanyl 2-5 mcg/kg/h, hydromor-
• Intoxication 4 mL/kg IV over 10 minutes. Avoid phone 0.01-0.05 mg/kg/h, or butorphanol
hypertonic saline in cases of severe 0.03-0.4 mg/kg/h). For mild cases, buprenor-
Initial Database dehydration. phine 0.01-0.02 IV q 6h is an acceptable
• CBC: neutropenia due to destruction of ○ Alternatively, a colloid (6% hetastarch or alternative.
myeloblasts and peripheral neutrophil VetStarch) can be administered at a bolus ○ Refractory abdominal pain should prompt
consumption; lymphopenia due to deple- dose of 2-5 mL/kg IV over 10 minutes. further investigation for CPV-related
tion of lymphoid tissue (may be a negative • After the patient is normovolemic, transition complications (e.g., intussusception).
prognostic indicator); anemia related to age, to maintenance fluid therapy using a balanced ○ Multimodal analgesia is helpful for
GI hemorrhage, and hemodilution after isotonic crystalloid. Daily fluid requirements enteritis-related discomfort. Add ketamine
fluid therapy; thrombocytopenia associated in juvenile dogs depend on age; an adult 2-4 mcg/kg/h or lidocaine 10-30 mcg/kg/
with platelet consumption and coagulation rate of 60 mL/kg/day is appropriate for pups min to opioid CRI.
disorders; hypoproteinemia > 16 weeks, and rates of 80-120 ml/kg/day ○ Avoid nonsteroidal antiinflammatories due
• Venous blood gas and electrolyte panel: are more appropriate for younger pups. In to adverse GI and renal effects.
mixed acid-base disturbances are common. addition to the baseline fluid rate, calculate • Ancillary treatments provided on an indi-
Metabolic acidosis may be secondary the following: vidual basis
to hyperlactatemia, pre-renal azotemia, ○ Correct for dehydration (mL to replace ○ Magnesium supplement as an IV CRI
or sodium/bicarbonate loss in diarrhea. = % dehydration × BW kg × 10); provide using MgCl or MgSO 4 in the mainte-
Metabolic alkalosis occurs with vomiting this volume over the first 24 hours of nance fluids: 0.75 mEq/kg q 24h for
of upper GI contents and loss of chloride hospitalization. hypokalemia that does not respond to
and/or hypoalbuminemia. Hypokalemia ○ Estimate ongoing losses (e.g., vomiting, KCl supplementation.
secondary to decreased intake and GI loss diarrhea), and replace the volume lost ○ Prokinetics: metoclopramide 1-2 mg/
can be profound and require aggressive (mL) every 6-12 hours. Continue replac- kg/day IV CRI for persistent regurgita-
supplementation. Hypomagnesemia can ing losses throughout hospitalization. tion; anecdotal concern for intestinal

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