August 2006 Issue

Featured case study:
Six-year-old, spayed West Highland white terrier, just not herself for the past two weeks
by Fred Metzger, DVM, DABVP (canine/feline), Metzger Animal Hospital, State College, PA, and Peter Kintzer, DVM, DACVIM, Boston Road Animal Hospital, Springfield, MA

Physical exam
Alert, but seems painful upon palpation of the thoracolumbar area

Plan
Bloodwork, urinalysis and survey radiographs of the abdomen/spine

Erythron—Normal

Leukon—There is a mild leukocytosis characterized by neutrophilia with left shift and monocytosis consistent with an inflammatory leukogram.

Thrombon—Normal

Protein panel—Unremarkable

Liver panel—Moderate elevations in ALT indicate hepatocellular injury and mild to moderate increases in ALKP and GGT support cholestasis. Total bilirubin is elevated without evidence of hemolysis, which is additional support for cholestasis.

Electrolytes—Hyperchloremia with decreased TCO2 suggests metabolic acidosis (normal anion gap, hyperchloremic). Loss of bicarbonate through duodenal vomiting or sequestration of bicarbonate are most likely mechanisms. Hypokalemia is most likely a consequence of vomiting. Mild hypocalcemia was present in the absence of hypoalbuminemia and ionized calcium measurement is indicated.

Lipase—Mild elevations of lipase may be associated with pancreatitis, however, mild elevations in lipase can also occur with other conditions (gastrointestinal disease, prednisolone therapy, etc.)

Renal—Unremarkable

Glucose—Mild hyperglycemia was present without glucosuria.

Diagnostic imaging
Abdominal/Spinal radiographs were unremarkable.

Ultrasound evaluation
Mild dilation of intrahepatic bile ducts was noted.

Presumptive diagnosis
Hepatic disease and/or pancreatitis was suspected.

Additional diagnositcs
Spec cPL® (canine pancreas-specific lipase) activity 440 µg/L (normal <200 µg/L) consistent with canine pancreatitis

Final diagnosis
Acute pancreatitis with cholestasis

Clinical case outcome
Treatment included intravenous lactated Ringer’s supplemented with potassium. Metoclopramide was administered as an antiemetic and a constant rate infusion of lidocaine (without epinephrine) was initiated for pain management. Intravenous cephalexin was administered because of possible bacterial involvement in the apparent inflammatory process (left shift, monocytosis).

Hematology performed the following morning was characterized by decreasing numbers of immature neutrophils and monocytes consistent with resolving inflammation. Normokalemia and normochloremia indicated that our fluid therapy program was improving the patient’s electrolyte status. Total bilirubin increased to 2.1. A follow-up Spec cPL® three days later corresponded with the patient’s improved clinical condition and the patient was discharged with a low-fat, easily digestible diet and instructions to recheck the laboratory profile in one week and a Spec cPL® Test in two to four weeks.

Possible sequel to pancreatitis includes recurring and chronic pancreatitis, diabetes mellitus, exocrine pancreatitic insufficiency, and biliary duct obstruction.

The recommendations contained in Diagnostic Edge educational materials are intended to provide general guidance only. As with any diagnosis or treatment, you should use clinical discretion with each patient based on a complete evaluation of the patient, including history, physical presentation and complete laboratory data. With respect to any drug therapy or monitoring program, you should refer to product inserts for a complete description of dosages, indications, interactions and cautions.

Do you have a case that you would like to submit? E-mail us at diagnosticedge@idexx.com.

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Plasma ammonia concentration shows better sensitivity to shunt presence,
by Dave Fisher, DVM, DACVP, IDEXX Reference Laboratories

Routine chemistry panel analytes are not sensitive or specific at detecting liver dysfunction, so other testing is often advised. There are many potential causes for dysfunction, including inflammatory disease, degenerative disease and neoplasia, as well as portosystemic shunts. Most commonly, bile acid concentration and ammonia concentration have been used as tools to evaluate for liver dysfunction. A recent paper by Gerritzen-Bruning, van den Ingh and Rothuizen (J Vet Intern Med. 2006;20:13–19.) compares the diagnostic value of fasting ammonia and bile acid concentrations to aid in diagnosing portosystemic shunts in dogs as one cause of liver dysfunction.

This paper describes a retrospective study in dogs that presented with symptoms compatible with liver disease and/or hepatic encephalopathy that had both fasting plasma ammonia and fasting bile acids evaluated. The initial group of dogs was then divided into two groups—those with shunting and those without. The group with shunts was further subdivided into those with congenital shunts and those with acquired shunts. The total number of dogs included in the study was 337 (153 with shunts, 184 without). Ninety-eight percent of the dogs with shunts had increased fasting ammonia concentration, whereas 89% had increased fasting bile acid concentration. Eighty-nine percent of dogs without shunts had fasting ammonia concentration within normal limits, whereas 68% had fasting bile acid concentration within normal limits. The specificity for diagnosing a shunt when only looking at dogs with liver disease (+/- shunt) was 89% for fasting ammonia and 18% for fasting bile acids. In addition, the authors looked at several cutoff values for bile acids and ammonia, and how changing cutoffs affected sensitivity and specificity. The general finding was that fasting plasma ammonia concentrations have higher sensitivity and higher specificity in the detection of portosystemic shunts as compared to fasting bile acid concentrations.

The authors describe the reasons for the differences in specificity of these tests—most notably how cholestasis, regardless of cause, will affect bile acid circulation, but not necessarily ammonia metabolism. This difference likely explains the increased specificity of fasting ammonia in separating shunts from other liver disease. The authors note an important consideration for ammonia testing in the risk for artifactually increased results due to storage of sample, hemolysis or contamination with substances such as cigarette smoke, sweat or saliva. These factors heighten the need for rapid testing of this analyte and emphasize that patient-side testing should be strongly considered when evaluating ammonia concentration. The authors also note that evaluating both fasting and postprandial samples can increase the sensitivity of bile acid testing in detection of liver disease.

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Make the most of the IDEXX VetLab® Station’s parameter trending

Creating graphs of particular test results over a period of time can provide valuable information regarding a patient’s health, the efficacy of treatment or disease progression.

If you’re practice isn’t already using the trending feature for your in-house diagnostic results on your IDEXX VetLab Station, here’s how you can graph your hematology, chemistry, electrolyte and endocrinology results over time:

To graph test results:

1. Tap Records on the IDEXX VetLab Station Home screen, select the desired patient and tap View Records.
2. On the Select Results screen, select the desired test results and tap Trend.
3. On the Select Parameters screen, select two to six parameters to graph and tap Trend.
4. The selected parameters are then graphed from the earliest test to the most recent.

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Save counter space with sports water bottles

To save counter space, fill pop-up-topped sports water bottles with fecal floatation solutions to use when preparing samples. These are easier to handle than a pump jug. Be sure to label accordingly!

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Education and Events

We offer a variety of training events about emerging trends and best practices in veterinary diagnostics in a forum designed to involve, educate and motivate you and your staff. Here are some of the upcoming educational events.

Webinars

• The Most Commonly Misdiagnosed Diseases in Veterinary Medicine
  Fred Metzger, DVM, DABVP, and Peter Kintzer, DACIVM

Seminars

• Tick-Borne Diseases: Lyme Disease, Anaplasmosis and Co-infection
  Rick Alleman, DVM, PhD, DABVP, DACVP, and Matt Eberts, DVM

• A Practical Approach to Feline Retroviruses
  Erin Evans, DVM

Visit the education and events calendar to view a full list of current offerings, click the date to view the details, fill out and submit the form to register.

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Strategies to increase intestinal parasite screening and prevention
by Wendy S. Myers

Don’t ask clients, “Would you like a stool check today?” Instead, tell them, “Our hospital’s protocol is to do an intestinal parasite screen every six months to protect your pet and family from zoonotic disease.” Intestinal parasite screening is a key component of wellness exams and preventing zoonotic disease, especially in families with young children.

Instead of “fecal test,” use the term “intestinal parasite screen” to more accurately describe the test and educate clients about the importance of regular testing. Consider these strategies:

Step 1: Set a protocol for intestinal parasite prevention and screening.
For adult pets, The Centers for Disease Control and Prevention (CDC) recommends intestinal parasite screens every six months and offers a brochure, Guidelines for Veterinarians: Prevention of Zoonotic Transmission of Ascarids and Hookworms of Dogs and Cats. The Companion Animal Parasite Council recommends:

• Administer year-round treatment with heartworm preventatives that have broad-spectrum activity against parasites with zoonotic potential.
• Administer flea and/or tick products year-round.
• Conduct annual physical exams with complete histories.
• Conduct annual heartworm testing in dogs and periodic testing in cats.
• Conduct fecal exams two to four times during the first year of life and one to two times per year in adults, depending upon patient health and lifestyle factors.
• Administer anthelmintic treatments to puppies at two, four, six and eight weeks of age, followed by administration of a monthly preventative.
• Administer biweekly anthelmintic treatments to kittens between three and nine weeks of age, followed by administration of a monthly preventative.

Set a protocol that pets must have a current intestinal parasite screen within 12 months to get a refill for preventatives. Also consider strategic deworming.

Step 2: Make appointment confirmation calls to remind clients to bring fecal samples.
“This is Wendy calling from Smith Veterinary Hospital to confirm your appointment for Kash with Dr. Johnson tomorrow, beginning at 10:30 a.m. Please remember to bring a teaspoon-sized fecal sample that is fresh within X hours. If you have questions or need to reschedule, please call us at 555-5000.”

Step 3: Make sure every staff member echoes the importance of intestinal parasite prevention.
Consumer research shows people need to hear a message three times before taking action. This 1–2–3 approach by a receptionist, technician and doctor clearly communicates your hospital’s emphasis on prevention.

Receptionists—Ask the client upon check-in, “Do you need any heartworm and intestinal parasite preventative refills while you’re here today?”

Technicians—Ask the client in the exam room, “Which heartworm and intestinal parasite preventative do you give your pet, and which day of the month do you give it?” A client questionnaire for wellness exams is in The Veterinary Practice Management Resource Book and CD.

Doctors—Say at the beginning of the exam, “We need to do an intestinal parasite screen today as part of your pet’s wellness exam.”

Step 4: Involve staff in monitoring compliance.
Assign a receptionist to pull and review patient records before the client’s arrival. In the medical record, note areas where the pet is out of compliance or requires follow-up. When the client arrives, the receptionist says, “I see Spike is due for his intestinal parasite screen. Our technician will collect a fecal sample before you see the doctor so you’ll have the test results before you leave.”

Did the client forget to bring a fecal sample? Use a fecal loop, or if you cannot get enough for a sample, have the client prepay for an intestinal parasite screen, leave with a fecalizer kit and drop it off at her convenience.

Step 5: Enter product reminders in your veterinary software.
For example, a 12-month supply of preventatives gets a postcard or phone call reminder in 11 months. A six-month dose is reminded in five months, and a single dose gets a callback in 20 days.

At your next staff meeting, talk about which of these proactive approaches you plan to implement. With protocols and reminders in place, you’ll protect pets and families from zoonotic diseases.

Wendy S. Myers owns Communication Solutions for Veterinarians in Denver, Colorado, and provides consulting services on client service, marketing and hospital management. She is the author of two books and four videos. You can reach her at 1-720-344-2347 or visit www.mycommunicationsolutions.com.

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NOW with FREE CE Credit!

Can you correctly identify the two leukocytes and the likely mechanism of the anemia presented in this monolayer region, 100x objective field of view peripheral blood film from a dog with moderate anemia (Wright’s stain)?

1. Identify the leukocyte indicated.
2. Identify the leukocyte indicated.
3. Identify the likely mechanism of the anemia.

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