diagnosis-h/o vomiting loose motions 1 yrs shih tzu dog
Reading File
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dog CBC interpretation neutrophilia lymphopenia vomiting diarrhea GI disease
Harrison's Principles of Internal Medicine, Twenty First Edition
Page 9010
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microcytic anemia dog MCV low iron deficiency GI blood loss
Harrison's Principles of Internal Medicine, Twenty First Edition
Page 13585
GradeResponse
GradeResponse
CBC Interpretation — Bruno (1yr Male Shih Tzu, h/o Vomiting & Loose Motions)
CBC Abnormalities Summary
| Parameter | Result | Reference | Interpretation |
|---|---|---|---|
| Lym % | 6.3% ↓ | 10.0–28.0% | Lymphopenia |
| Mon % | 1.6% ↑ | 0.3–0.9% | Monocytosis |
| Gran % | 86.6% ↑ | 60.0–85.0% | Relative neutrophilia |
| Lym # | 0.6 ↓ | 1.0–4.8 | Absolute lymphopenia |
| MCV | 59.9 fl ↓ | 66.0–78.0 fl | Microcytosis |
| MCHC | 38.2 ↑ | 30.0–36.9 g/dl | Hyperchromia (borderline) |
| MPV | 6.8 ↓ | 7.0–13.0 fl | Low mean platelet volume |
Key Interpretations
1. Neutrophilia + Monocytosis + Lymphopenia (Stress Leukogram)
- The combination of relative and absolute lymphopenia with elevated Gran% and elevated Mon% is classic for a corticosteroid stress response or an active inflammatory/infectious process.
- In a vomiting/diarrhea dog, this strongly suggests systemic stress from GI disease, or an underlying bacterial/parasitic infection or endotoxemia.
- Monocytosis specifically suggests chronic inflammation or tissue necrosis.
2. Microcytic RBCs (MCV 59.9 fl ↓) with Normal HGB/HCT
- Microcytosis in a young dog with GI symptoms is a significant finding. Key differentials:
- Chronic GI blood loss (e.g., hookworms, whipworms, ulceration) → iron deficiency
- Portosystemic shunt (PSS) — very common in Shih Tzus; classic cause of microcytosis without anemia in young small breeds
- Dietary iron deficiency (less likely)
- The normal HGB (17.0) and normal HCT (44.5%) with low MCV suggests either early/compensated iron deficiency or PSS (where microcytosis precedes anemia).
3. Borderline High MCHC (38.2)
- Can indicate lipemia, hemolysis in sample, or true hyperchromia. Verify with fresh sample if needed.
4. Low MPV (6.8)
- Suggests older platelet population or reduced platelet production stimulus. PLT count is normal (233), so thrombocytopenia is not a concern. May be incidental.
Top Differential Diagnoses
| Priority | Diagnosis | Supporting Evidence |
|---|---|---|
| ⭐⭐⭐ | Parasitic gastroenteritis (hookworm, Giardia, Coccidia) | Age, vomiting + diarrhea, stress leukogram, microcytosis |
| ⭐⭐⭐ | Portosystemic shunt (PSS) | Breed (Shih Tzu high risk), young age, microcytosis without anemia, GI signs |
| ⭐⭐ | Bacterial enteritis / Campylobacter / Salmonella | Neutrophilia, monocytosis, acute GI symptoms |
| ⭐⭐ | Parvoviral enteritis (if unvaccinated) | Age, vomiting, diarrhea — though WBC typically drops in parvo |
| ⭐⭐ | Dietary indiscretion / food sensitivity | Common in young Shih Tzus |
| ⭐ | Protein-losing enteropathy (PLE) | Lymphopenia can indicate GI protein/lymphocyte loss |
Recommended Workup
- Fecal flotation + direct smear — rule out parasites (Giardia Ag ELISA if available)
- Serum bile acids (pre & post-prandial) — critical to rule out portosystemic shunt given microcytosis in a young Shih Tzu
- Serum iron + TIBC / ferritin — differentiate iron deficiency from PSS
- Serum albumin, total protein, BUN — screen for PLE and liver dysfunction
- Parvo Ag test — if vaccination history incomplete
- Abdominal ultrasound — liver size/echogenicity, portal vasculature (for PSS), intestinal wall thickness
- Reticulocyte count — assess bone marrow response to microcytosis
Clinical Bottom Line
The CBC pattern of stress leukogram + microcytosis without anemia in a 1-year-old Shih Tzu with chronic vomiting and diarrhea makes portosystemic shunt and parasitic GI disease the top priorities to exclude. Serum bile acids and fecal examination should be the immediate next steps before initiating treatment.
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