This case report was written by NJVTA member Tina DeVictoria, BS, CVT. She is employed by The Animal Hospital at Kingston and Blawenburg.
This was previously printed in the May/June 2012 NAVTA Journal.
SIGNALMENT
Charlie: 8 week old male
mix-breed dog, 2.9kg, June 1, 2011, from log #3.
PRESENTING COMPLAINT/HISTORY
Charlie was a new pet
and was brought home 2 days prior to presentation. He presented with a 24 hour
history of vomiting, watery diarrhea, and lethargy. He received a DA2PP
vaccine 7 days prior as well as a deworming treatment with pyrantel pamoate.
PHYSICAL EXAM FINDINGS/OBSERVATIONS
On physical exam his
abdomen was uncomfortable with fluid-filled small bowel loops, his muscle mass
was poor, he was dehydrated, and there was a small amount of flea dirt present.
PROBLEM LIST/DIFFERENTIAL DIAGNOSIS
Charlie’s problem list
includes dehydration, lethargy, vomiting, and diarrhea. His differentials were
intestinal parasitism, viral disease such as parvovirus, dietary indiscretion,
or foreign body obstruction.
DIAGNOSTIC APPROACH
The diagnostics began
with an in-house ELISA test for parvovirus. The test indicated a strong
positive, although at the time we could not rule out a false positive due to his
vaccination 7 days prior. We proceeded with in-house bloodwork, including a
12-panel chemistry, CBC/differential and electrolytes. Charlie’s chemistry
panel was normal, but his CBC showed leukocytosis with a white blood cell count
of 19.26 K/µL (normal 5.5 – 16.9) and neutrophils at 16.52K/µL (normal 3.0 –
12.0). His electrolytes were normal with low normal potassium.
TREATMENT PLAN
Charlie was treated
aggressively with hospitalization for several days on IV fluids. He was
maintained in isolation with strict isolation protocols due to the likelihood
of contagious disease. He was initially started on 120ml/kg/day of Plasmalyte
IV fluids that was supplemented with potassium using Scott’s Sliding Scale
(16mEq/L). On day 1 he was given a topical flea treatment, but we postponed
oral deworming medications due to his history of vomiting, and 1 episode of
vomiting a few hours after admission. He was given ampicillin 22mg/kg IV slowly
q8hrs, metronidazole 15mg/kg IV slowly q12hrs, famotidine 0.5mg/kg IV slowly q12hrs
and maropitant citrate 1mg/kg SQ q24hrs. He was NPO for the first 24 hours in
the hospital.
On
day 2, Charlie seemed better hydrated, although his gums were paler. His
abdomen was more comfortable as well. We checked his PCV/TP, and his PCV did
drop by 10% and TP by 1.0g/dL. We also checked his electrolytes, and his
potassium level was improved. We continued with his prescribed plan from the
previous day but also gave praziquantel/pyrantel pamoate/febantel (Drontal)
orally as a dewormer and collected a sample of feces to screen for
ova/parasites and giardia. His PCV/TP was repeated 12 hours later and was
stable. We started offering small amounts of bland food as well, and while not
interested at first, he did start to eat later in the day. Charlie had several
episodes of diarrhea through the day, including one sample with adult
roundworms in it. His fecal sample did come back positive for roundworm eggs,
but negative for other ova and giardia cysts.
Charlie
had 2 episodes of vomiting overnight into day 3. We pursued radiographs at this
point to rule out an obstruction or other cause of the vomiting. The x-rays
showed a small amount of effusion that was consistent with his age, gas in his
colon, and mild dilated small bowel loops likely from ileus. No obvious
obstruction was seen. His ampicillin was discontinued in the event it was
contributing to the vomiting, and he was transitioned onto PO famotidine. He
was continued on metronidazole and maropitant citrate and also received a dose
of pyrantel pamoate and prochlorperazine/isopropamide as a motility-modifying
drug. His electrolytes remained normal, and his PCV was slightly improved.
Through the day, though, Charlie continued to decline. He vomited a total of 5
times through the day, his energy level was down and his hydration was worse at
his evening physical exam.
Into
day 4 Charlie had no episodes of vomiting or diarrhea. He was continued through
the day on PO famotidine, IV metronidazole, prochlorperazine/isopropamide, and
another dose of pyrantel. He had his IV catheter replaced since his first
catheter had been placed 72 hours prior. He was syringe fed bland food as his
appetite was poor. He had good progression from day 3 to 4, with only one
episode of vomiting mid-day on day 4.
On
day 5 he had no episodes of vomiting or diarrhea. We repeated his
CBC/differential, and his white blood cell counts had plummeted to 1.46K/µL
(neutrophils, monocytes and eosinophils were all low). His anemia was stable.
We resumed treatment with ampicillin and added gentamicin as an additional
antibiotic. We continued IV metronidazole, prochlorperazine/isopropamide, and
PO famotidine. He was syringe fed through the day, and his IV fluids were also
supplemented with 2% dextrose (50%).
On
day 6, Charlie was eating and drinking well and had no episodes of vomiting and
diarrhea. He did develop a fever of 104.8ºF that fluctuated up to 106.8, clear
nasal discharge, an oral ulcer on his tongue, and a cough. His white blood
cells had dropped to 1.14K/µL. His medication regimen was continued. Carafate
was added for the oral ulcer and azithromycin as a macrolide antibiotic to
treat for possible pneumonia/CIV/bordetella. To ensure that the catheter was
not contributing to his fever, his IV catheter was removed and he received SQ
fluids.
On
day 7, Charlie had his IV catheter replaced and was re-started on fluids due to
his persistent fever. His GI signs and appetite were improved. He was
transitioned onto all PO medications; famotidine 0.5mg/kg PO q24hrs, carafate ¼
gram in slurry to tongue q6hrs, enrofloxacin 10mg/kg PO q24hrs, azithromycin
10mg/kg PO q24hrs and metronidazole 10mg/kg PO q 12hrs. His plan included
nebulizing and coupaging lightly, and he did have productive coughs after
coupage. His fever did break mid-day and came down to 100.7ºF.
On
day 8 Charlie’s white blood cell count was dramatically improved at 6.95K/µL.
His temperature was normal, his appetite was good, and he had a normal bowel
movement. His temperature fluctuated mildly through the day, but was normal
before discharge. Charlie was discharged with his regimen of PO medications and
bland diet.
FINAL DIAGNOSIS
Canine parvovirus (CPV) and
pneumonia versus CIV versus bordetella.
OUTCOME
Charlie had very
waxing/waning clinical signs throughout his hospital stay. He also developed an
upper respiratory infection that may have been due to immunosuppression,
aspiration pneumonia, or he may have contracted CIV or bordetella prior to
admission. All of his clinical signs improved well with appropriate treatments,
and his recheck appointment 5 days and 11 days after discharge showed him to be
doing well. At the 11 day recheck, his white blood cell count was elevated, but
at recheck 3 weeks later showed they were normal.
CONCLUSION
CPV is a contagious
virus causing enteritis in dogs. Signs usually begin 5-12 days after infection
via oral-fecal route and hallmark signs involve destruction of intestinal
crypts. The virus invades and destroys rapidly dividing cells, such as bone
marrow progenitors and intestinal epithelium, causing villus collapse,
vomiting, diarrhea, intestinal bleeding, and bacterial invasion.1
CPV is generally seen in puppies under 6 months of age, and commonly between 6
and 20 weeks.2 It has been reported that Doberman Pinschers,
Rottweilers, Pit Bulls and Labrador Retrievers may be more susceptible than
other breeds.1
Common
clinical presentation includes lethargy, anorexia and vomiting. Diarrhea often
develops later in the course of the disease, between 24 and 48 hours. The
diagnostic approach should begin with a parvovirus ELISA. The ELISA can be
affected by vaccination within 5-15 of testing, but a positive ELISA paired
with appropriate clinical signs can still give the presumptive diagnosis.
Neutropenia on bloodwork is often suggestive, but not diagnostic of parvovirus,
and is seen in less than 50% of infected dogs.2 Other bloodwork
abnormalities that can be seen with both general enteritis cases and parvovirus
include; hypoproteinemia secondary to fluid loss from vomiting/diarrhea and
electrolyte derangements such as hypokalemia, hypernatremia, and
hyperchloremia. In advanced cases, hypoglycemia can be seen secondary to
inappetance and/or sepsis. Hypercoagulability has also been noted due to
hyperfibrinogenemia. Radiographs are often pursued to rule out other causes of
gastrointestinal upset, such as foreign body obstruction, surgical ileus, or
intussusception.
Like
most other enteritis cases, treatment involves symptomatic supportive care with
fluids, antibiotics, and antiemetics. Fluid therapy should begin with an
isotonic crystalloid such as Plasmalyte, although colloid therapy may be
required for patients with hypoproteinemia or septic shock. Whole blood may be
necessary as well if the enteritis progresses to hemorrhagic and severe anemia
is present. Potassium chloride is often required to counter hypokalemia, and
glucose supplementation may be added as well due to inappetance or sepsis.
Antibiotic therapy is indicated in patients with
evidence of pyrexia, neutropenia, or sepsis. Aminopenicillins and
aminoglycoside penicillins such as ampicillin and gentamicin are often used.
Proper hydration/perfusion are necessary when using aminoglycosides due to potential
nephrotoxic side-effects.3 Metronidazole is a good antibacterial and
antiprotozoal agent as well. Flourquinolones such as enrofloxacin can be used
with ampicillin, although adverse effects can be seen on growing puppies.2
Antiemetics are also an important therapy as vomiting contributes to
dehydration and esophagitis. H2 receptor antagonists such as
famotidine and neurokinin receptor antagonists such as maropitant citrate are a
good combination for treatment.3 Prognosis is generally good if
treatment is initiated quickly, especially if patients survive the first 4 days
of clinical signs.1 CPV can, though, be fatal, particularly if
treatment is not initiated quickly before the patient becomes hypovolemic from
fluid loss.
CPV
patients should be isolated to avoid transmission to other patients in the
hospital. After discharge, CPV-infected dogs should be kept away from other
dogs initially, as they have been shown to shed the virus for up to 39 days
post infection.2 Bleach is one of the only known disinfectants to
properly disinfect hard surfaces and bedding. Patients with CPV are also
severely immunocompromised, and the isolation serves to protect them as well.
DISCUSSION
Charlie’s case
management was complex and prolonged, but his clinical signs all improved
before discharge and he recovered well. His symptoms waxed and waned over the
first several days which lead to other diagnostic testing to ensure his disease
was not complicated by other processes. His immunocompromised state made him
susceptible to upper respiratory infection, which could have been due to viral
pneumonia, aspiration pneumonia, or CIV/bordetella. These signs began at day 5,
which would be consistent with when the clinical signs of viral/bacterial
tracheobronchitis usually commence. Some of Charlie’s treatments were
controversial, such as maropitant citrate use before the age of 16 weeks as
well as early use of enrofloxacin. In his case, the doctors felt the benefits
outweighed the risks.
REFERENCES
1. Nelson RW, Couto CG,
eds. Infectious Diarrhea: Canine Parvoviral Enteritis. Small Animal Internal
Medicine.
3rd ed. St. Louis: Mosby Inc, 2003; 433-435.
2.
Hopper
K, Silverstein DC, eds. Canine Parvovirus Infection. Small Animal Critical
Care Medicine.
1st ed. St. Lous: Saunders, 2009; 482-485.
3.
Plumb
DC, ed. Plumb’s Veterinary Drug Handbook. 6th ed. Ames, IA:
Wiley-Blackwell; 2008: 122, 77, 457, 562, 751, and 819.
