December 2005 Issue

Featured Case Study: Four-year-old spayed female Yorkshire terrier, Madison
by Lisa C. Paull, DVM, DACVIM, Internal Medicine Consultant, IDEXX Reference Laboratories

Special thanks to Steve Pirkey, DVM, of Sachse Veterinary Hospital, Sachse, Texas, for submitting this case.

Interpretive Summary
Day 1

There is minimal normocytic, normochromic anemia that appears nonregenerative (absence of polychromasia). This anemia is likely due to inflammatory disease, which is evidenced by the mild mature neutrophilia and minimal monocytosis, with no evidence of glucocorticoid influence/stress (no lymphopenia is observed). Other possible interpretations for the anemia include low-grade blood loss, as well as underlying hypothyroidism, however, in the absence of clinical signs consistent with hypothyroidism, the low T₄ in this patient is thought to be due to illness. The minimal thrombocytosis is insignificant.

There is marked panhypoproteinemia consistent with either gastrointestinal loss or hemorrhage. Since the anemia is both minimal and nonregenerative, blood loss is an unlikely cause. Renal loss and hepatic insufficiency can also contribute to hypoalbuminemia, however, the panhypoproteinemia is most compatible with gastrointestinal loss of all proteins. A urinalysis is not available.

The minimal increase in ALT is insignificant; this may represent either a normal result for this patient or minimal hepatocellular injury. The increased AST could be related to either muscle or hepatocellular injury; changes are minimal and insignificant. The slight increase in CK is not significant.

In this patient, minimal hypocholesterolemia may be associated with the documented hepatic dysfunction and/or the suspected protein-losing enteropathy.

The acid-base status of this animal is difficult to accurately assess without blood gas data. Typically, in the absence of significant acid-base disturbances, severe hypoalbuminemia results in increased TCO² (bicarbonate). Increased TCO² maintains electroneutrality in the face of the loss of negatively charged albumin. In this case, when the effect of hypoalbuminemia on TCO² is considered, the high chloride concentration relative to sodium in conjunction with a high normal TCO² suggests a simple metabolic acidosis due to loss of TCO². Blood-gas analysis and urinalysis would be useful to clarify the acid-base status of this patient.

Day 2

Serum bile acids results are consistent with hepatic dysfunction.

Assessment
Dr. Pirkey, Madison’s veterinarian, consulted with an IDEXX Reference Laboratories internal medicine consultant regarding the case.

Based on clinical presentation, hematology and biochemical analyses, a protein-losing enteropathy (PLE) was strongly suspected. Differentials for PLE include inflammatory bowel disease, lymphangiectasia, neoplasia and parasitism, among others. Detection of alpha protease inhibitor in the feces could further confirm protein loss via the gastrointestinal tract. Biopsy of the liver and small intestines was suggested as further diagnostics.

Day 3

Surgical exploration and biopsy
Intestinal and hepatic biopsies were acquired via abdominal exploratory surgery. Oncotic pressure is reduced with severe panhypoproteinemia, therefore, increased risk of hypotension during general anesthesia is a concern. Plasma transfusion or other colloid support (hetastarch, dextrans) prior to general anesthesia is advisable to minimize this risk.

Histopathology Report
Source: Samples were obtained from the liver and small intestine of a four-year-old dog with panhypoproteinemia.

Histologic description: Not requested

Morphologic

• Minimal lymphoplasmacytic portal hepatitis with extramedullary myelopoiesis and mild portal vascular proliferation
• Moderate diffuse lymphoplasmacytic enteritis with moderate diffuse lymphangiectasia

Comment: The presence of intestinal inflammation and dilated lymphatics may be consistent with protein-losing enteropathy, although the intensity of inflammation overall was somewhat less than generally expected. However, diffuse dilatation of lymphatics (lymphangiectasia) does correlate well with the clinical history of hypoproteinemia. Hepatic changes were minimal; there was no evidence of primary liver disease. Mild portal vascular proliferation was seen, as can be encountered in some cases of vascular anomaly, including microvascular dysplasia and shunts. Correlation with clinical findings would be required for definitive diagnosis.

Diagnosis

Anomalous hepatic vasculature (consistent with portosystemic shunt (PSS) or microvascular dysplasia) and intestinal lymphangiectasia secondary to lymphoplasmacytic enteritis (LPE) is confirmed with histopathology. Intestinal inflammation is moderate and less than expected to cause lymphangiectasia. This suggests the possibility of congenital mildly compromised lymphatics further exacerbated by the onset of LPE.

Additional imaging (portogram, technetium scan) is necessary to differentiate PSS from microvascular dysplasia (MVD) as either vascular anomaly will result in these histopathological findings. The owners declined further diagnostic imaging.

Treatment/Plan

• Based on follow-up consultation with the same IDEXX consultant, treatment is focused on LPE and lymphangiectasia as few clinical signs of hepatic insufficiency are present.
• A novel, low-fiber, low-fat, highly digestible protein diet is recommended to address possible dietary antigenic stimulation causing LPE and to reduce stimulation of intestinal lymph flow. Addition of lactulose is advised if signs of protein intolerance (hepatic encephalopathy) occur.
• Metronidazole at a reduced dose of 7.5 mg/kg PO every 12 hours is recommended. Metronidazole has several potentially beneficial effects for the treatment of LPE, including inhibition of cell-mediated immunity, broad-spectrum activity against anaerobes, positive effects on brush-border enzyme levels and nutrient uptake (glucose, amino acids). Additionally, its activity against enteric anaerobes (e.g., Bacteroides spp) that may metabolize nitrogenous substances is beneficial for controlling signs of hepatic encephalopathy. The dose is reduced to account for diminished hepatic biotransformation and elimination.
• Dexamethasone at 0.1–0.2 mg/kg PO every 12 hours for 1–2 weeks followed by a gradual taper to every second or third day. Glucocorticoid therapy reduces inflammation, suppresses the immune system and promotes enterocyte function. Addition of a glucocorticoid is delayed following abdominal surgery, particularly in the face of marked hypoproteinemia, to allow for proper tissue healing. Although prednisone is preferred, dexamethasone, which is devoid of mineralocorticoid effects, is used in this case due to the presence of ascites. Caution is necessary when using glucocorticoids in states of hepatic insufficiency due to increased catabolism and the increased risk of gastroenteric hemorrhage, both of which can exacerbate hepatic encephalopathy.
• Long-term management of this patient will entail regular monitoring of body composition and weight, hepatic enzyme activity and protein concentrations.

Prognosis

The prognosis for protein-losing enteropathies due to inflammation is generally guarded. Specifically, lymphangiectasia has a guarded prognosis, and response to therapy is unpredictable. The hepatic vascular anomaly in this case appears mild and may not influence the dog’s overall response to therapy. Success with medical management of PSS and MVD is variable.

Follow-up

Madison has responded extremely well to therapy. Attitude and appetite are improved, ascites has visibly diminished on physical examination and there is weight gain of 0.4 kg. Evaluation of in-house diagnostics bloodwork, using the VetTest® Chemistry Analyzer and the LaserCyte® Hematology Analyzer, indicate that the anemia has resolved, inflammation has subsided and the total protein has returned to within reference-range values.

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.

We want to hear from you. Let us know what you think about this case and tell us about any other case topics that you would like to see. E-mail us at diagnosticedge@idexx.com.

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NEW NSAID Monitoring Panel for the IDEXX VetTest® Chemistry Analyzer

Now monitoring your patients on nonsteroidal anti-inflammatory drugs (NSAID) therapy is easy. The NSAID Monitoring Panel consists of five chemistries (ALKP, ALT, AST, BUN and CREA) targeted at the liver and kidneys, those organs most at risk for patients on NSAID therapy. The panel is conveniently packaged in a freezer tray with twelve panels per tray, making protocol implementation easy.

While a comprehensive baseline is recommended before initiation of NSAID therapy, the NSAID Monitoring Panel should be used during the 14-day trial period and every six months throughout the length of therapy. The panel provides a comprehensive, cost-effective screen that allows doctors to closely monitor the health status of their patients while following FDA recommendations. With the shift in vaccine requirements, medication monitoring gives you a solid medical reason to have your patients come in for annual visits.

For more information about the VetTest NSAID Monitoring Panel and other IDEXX products, call IDEXX at 1-800-355-2896 or e-mail diagnosticedge@idexx.com.

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2006 IDEXX SNAP Up the Savings

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Helpful tips on running the new Quality Control Panel on your VetTest® Chemistry Analyzer

We all know the importance of quality-control testing—it’s the best way to independently verify and maintain the accuracy of your in-house results. Here are some helpful tips to keep in mind when running the new Quality Control Panel on your VetTest® analyzer.

When should you run quality control?

IDEXX recommends that a quality-control (QC) analysis be run preventively once per month. You should also run a QC analysis:

• When your analyzer is first installed
• When your analyzer has been moved or severely bumped
• If you think your results are incorrect
• If fluid has been spilled on your analyzer

Other Helpful Tips

• The Quality Control Panel must be stored in your freezer at or below -18ºC (0ºF).
• Run the entire panel (all six slides) for a complete QC test.
• Record your QC results on your Quality Control Log Sheet. (44 KB)
• Report any failing QC result immediately to IDEXX Customer Support at 1-800-248-2483 in the U.S. and Canada or visit www.idexx.com to find service numbers in other countries.
• Look for the new quality control reminder (available in VetTest software 8.05 and later) to appear once a month on your VetTest analyzer screen as a reminder to run your monthly QC test. (1.3 MB)
• Ensure that the VetTrol™ Control material is properly prepared.

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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. Click here to see a full listing.

Webinar

• Integrate UPC Ratios into Your Practice and Uncover Early Renal Disease
  by Fred Metzger, DVM, DABVP and Michelle Kahn, MS, DVM

Teleconference

• Diagnosing Canine Pancreatitis
  by Jörg M. Steiner, med.vet, Dr.med.vet, PhD, DAACVIM, DECVIM-CA

Seminars

• The Most Commonly Misdiagnosed Diseases in Veterinary Medicine
  by Fred Metzger, DVM, DABVP
• Practical Hematology
  by Robert Hawthorne, DVM

Visit the education and event calendar, click the date to view the details, fill out and submit the form to register.

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Surgery confirmation calls and callbacks show clients you care
by Wendy S. Meyers, Communication Solutions for Veterinarians, Denver, Colorado

Surgery confirmation calls help clients remember fasting instructions and help to allow ample time for check-in. For example, receptionists call clients the day before surgery and say, “This is Wendy calling from Myers Veterinary Hospital to remind you of Ollie’s surgery tomorrow. Please withhold food after 10 o’clock tonight. Your surgery admission appointment is scheduled for 7:45–7:55 a.m. with a technician who will spend 10 minutes reviewing the consent form, answering your questions and getting telephone numbers where we can reach you the day of surgery. Please allow at least 10 minutes for Ollie’s admission to the hospital. If you have questions, please call us at 1-555-555-5000.”

Remove “drop off” from your vocabulary and hospital forms. “Drop off” implies the surgery admission process takes seconds. Filling out paperwork at the front desk also reduces compliance for preanesthetic testing and elective services such as microchipping. When a patient is being admitted for surgery or dentistry, you need a minimum of 10 minutes to sign consent forms, collect telephone numbers, answer the client’s questions and explain when you will call following the procedure.

After any hospitalized patient is discharged, the client should be called within 24 to 48 hours. The 2003 AAHA study, “The Path to High-Quality Care,” found 75% of pet owners wanted their veterinarian or a staff member to call to follow up on the pet’s condition after a medical problem, but only 52% received a call.

Callbacks let you check on the patient’s recovery and reinforce home-care instructions and rechecks. With proper training, any staff member can make callbacks. To create callback protocols, list common categories such as dentistry, spays, neuters and other procedures, when to call and who should call. For example, technicians and receptionists can follow up on routine procedures while doctors may want to call clients about complex or chronic cases. Discuss callbacks as a team and decide what’s right for your practice. Use the recall report in your Cornerstone® practice management software to enter callbacks, along with the appropriate staff ID. Receptionists then print the recall report daily and distribute the list to specific individuals.

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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Can you identify these cells and structures?

Concentrated cellular preparation of a thoracic fluid from a dog with sudden onset dyspnea (Wright’s stain).

1. Identify the primary nucleated cell type present
2. Identify the cell indicated as “B”
3. Identify the structure indicated as “C”

Send your answer in an e-mail to: diagnosticedge@idexx.com. Please include your name, practice name, address and telephone number.

The first 10 respondents to correctly identify the cells and structure will appear in the next issue of the Diagnostic Edge.

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