HISTORY / CLINICAL SIGNS: 1 week history of lethargy and decreased appetite. No reported changes in diet or medications. UTD on routine vaccines (though no recent vaccination within the past several months). On monthly HW/flea/tick prevention. 3 year unchanged Hx of mitral valve degeneration (no CHF).
PHYSICAL EXAM FINDINGS: BCS 7/9. QAR. Pale mucous membranes. CRT 2.5 sec. T 103ยฐF (39.4ยฐC). HR 150 bpm. RR 50 brpm. Grade III left-sided systolic heart murmur. Clear lung sounds. Bilateral grade 1 patellar luxation. Moderate periodontal disease.
What is on your differential diagnosis list? What diagnostic tests would you order? Any other questions?
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DIFFERENTIALS: (In addition to the differentials for the pale gums, CHF was also a consideration based on the increased HR/RR and Hx of heart murmur.)
- Blood Loss: internal hemorrhage (ulceration, neoplasia), external hemorrhage (GI/urinary), coagulopathy/thrombocytopenia, intestinal parasites
- Hemolysis (intravascular vs. extravascular): idiopathic IMHA, infectious (Mycoplasma, Ehrlichia, Anaplasma, Babesia), oxidative damage (onion/garlic/zinc toxicity), neoplastic
- Decreased RBC production: chronic disease (neoplasia, renal/liver disease, etc.), bone marrow suppression (infectious vs. neoplastic)
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DIAGNOSTIC TESTS & RESULTS:
- CBC: RBC 3.91M/uL. HGB 10.0g/dL. PCV 28.6%. MCV 74.6fL. MCHC 31.8g/dL. nRBCs 12/100WBCs. Reticulocyte # 195.1K/uL. Reticulocyte 4.99%. WBC 20.3K/uL (Seg Neut 16.24X10^3/uL, Band Neut 0.000; otherwise, within reference range). Platelets 522K/uL. Plasma Protein 7.0g/dL. Plasma appearance = slight pink tinge.
- Blood smear: decreased RBC, anisocytosis +1, poikilocytosis +2, spherocytes, schistocytes +1, echinocytes +2, autoagglutination of RBCs, no organisms noted
- Blood Chemistry: Glu 171mg/dL. ALT 229U/L. AST 21U/L. ALKP 2652U/L. GGT 48U/L. Otherwise, within reference range (including: TBil 0.2mg/dL. DBil 0.01mg/dL. IBil 0.2mg/dL).
- SNAP 4Dx: negative
- Thoracic Radiographs: moderate left-sided enlargement of the cardiac silhouette; otherwise, unremarkable
- Abdominal Ultrasound: unremarkable
- Urinalysis: USG 1.038. Trace bilirubin. Blood +1. No RBCs noted in sediment.
- Fecal float: NOPS
What other tests would you recommend?
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- Direct Antiglobulin Test (Coombs Test): positive agglutination
- Tick titers: negative
Based on this patientโs signalment, clinical signs, physical exam findings, and test results, what is your diagnosis, recommended treatment, and prognostic outlook?
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DIAGNOSIS: Immune-mediated hemolytic anemia (IMHA) โ primary/idiopathic, seemingly intra- & extravascular co-occurrence
(How is intravascular vs. extravascular hemolysis differentiated?)
This patientโs IMHA is idiopathic, as tests for an infectious etiology were ruled out, and a neoplastic cause was not detected on imaging.
TREATMENT & PROGNOSIS: An immunosuppressant dose of oral prednisone (1mg/kg q12hr) was started as well as gastroprotectant oral famotidine and a low-dose oral aspirin. This patientโs RBC count improved upon subsequent weekly rechecks over the next month. However, she developed signs of iatrogenic Cushingโs disease due to the high steroid use, so it was tapered. However, her IMHA relapsed slightly, so the prednisone dose was increased again temporarily, and oral azathioprine (2mg/kg q24hr) was introduced. The cushinoid signs developed again, and after several more weeks, a prednisone taper was attempted again (the azathioprine dose was kept the same). The patientโs RBC count remained stable and continued to improve. With sequential tapers over several months, both immunosuppresants and other drugs were able to be stopped, and the IMHA fortunately resolved in this patientโs case.
Any other questions, comments, or suggestions?
Unless otherwise stated, these clinical cases are real-life cases that I have managed as a veterinarian in general small animal veterinary practice or else assisted with as a student in vet school. These cases are a great real-world learning tool for vet students and other veterinary professionals. They shall be used for learning purposes and collaboration of knowledge only. These cases are not intended to diagnose or treat any disease by pet owners. – Maranda Elswick, DVM
