Page 1283 - Cote clinical veterinary advisor dogs and cats 4th

646 Melena

Melena Client Education
Sheet
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• If hemostatic disorder, may see petechiae and
BASIC INFORMATION
ecchymosis; less often, epistaxis, hematuria, • Abdominal radiographs/ultrasound
○ Thickened GI wall
Definition intracavitary hemorrhage ○ Lesions suggesting infection or neoplasia
Black, tarry stool containing partially digested • If respiratory disease, may find tachypnea, (lymphadenopathy, hepatosplenomegaly,
blood dyspnea, epistaxis, stertor, adventitial lung masses)
sounds ○ Abdominal effusion (severe hypoalbumin-
Epidemiology emia, portal hypertension)
SPECIES, AGE, SEX Etiology and Pathophysiology ○ GI foreign bodies
• More common in dogs than cats • Most commonly caused by bleeding ○ GI ulceration
• Neoplastic causes more common in older originating from the oropharynx or upper • Coagulation profile for suspected hemostatic
animals GI tract due to local disease or hemostatic disorder (p. 1325)
defects. Less often, swallowed blood from • Primary hemostatic defects more likely to
RISK FACTORS the respiratory tract or ingestion of blood cause melena than secondary defects (i.e.,
• Ulcerogenic drugs (e.g., nonsteroidal anti- causes melena. thrombocytopenia/thrombocytopathy)
inflammatory drugs [NSAIDs], high-dose • Further discussion of causes provided on
corticosteroid, tyrosine kinase inhibitors) p. 1252. Advanced or Confirmatory Testing
• Anticoagulant exposure • Thoracic imaging
DIAGNOSIS ○ Include in initial diagnostics if neoplastic
ASSOCIATED DISORDERS or respiratory disease suspected
Anemia, panhypoproteinemia, increased blood Diagnostic Overview • Fecal sedimentation, wet mount, and Baer-
urea nitrogen (BUN), and increased BUN/ The history, physical exam, and initial database mann fecal flotation test performed on fresh
serum creatinine ratio guide additional testing. feces to evaluate for GI and respiratory parasites
• Esophagogastroduodenoscopy: to identify
Clinical Presentation Differential Diagnosis the source of GI bleeding ± biopsy. Capsule
DISEASE FORMS/SUBTYPES • Bismuth-containing products, iron, or char- endoscopy can be used in dogs but cannot
• Commonly due to upper gastrointestinal coal can change fecal color and be confused sample lesion.
(GI) disease that causes bleeding or with melena. • Imaging studies as appropriate for sus-
hemostatic disorders or, less often, due • Stool exposed to air may appear dark; the pected respiratory bleeding (e.g., CT scan,
to swallowed blood from respiratory tract presence of melena should be judged on fresh pharyngoscopy/bronchoscopy)
disease stool. • Specific disease testing may be recommended,
• Presentation may be chronic or acute, depending on history, physical exam findings,
and the animal may be stable or Initial Database results of initial tests, and the prevalence in
critically ill. • CBC the area.
○ Acute bleeding: normal or regenerative ○ Gastrinoma (p. 1346)
HISTORY, CHIEF COMPLAINT anemia (i.e., reticulocytosis) ○ Hypoadrenocorticism (pp. 512 and 1300)
Pet owners may or may not recognize melena in ○ Nonregenerative anemia with microcytosis ○ Heartworm disease (pp. 415, 418, and
their pet’s stool. Other signs depend on severity and hypochromasia, thrombocytosis, 1350)
and cause of bleeding. suggest chronic GI bleeding ○ Folate/cobalamin (pp. 1325 and 1344)
• Lethargy, weakness may be caused by anemia ○ Thrombocytopenia (<30,000 platelets/
or hypovolemia. mcL) may explain cause of bleeding. TREATMENT
• GI disease: anorexia, regurgitation, vomiting, ○ Neutrophil count > 50,000 neutrophils/
diarrhea, weight loss, hematemesis (raises mcL should raise suspicion for infectious Treatment Overview
suspicion for GI ulcers) disease or GI perforation. Successful treatment depends on the ability to
○ Include questions about ulcerogenic ○ Lack of stress leukogram compatible with resolve the cause, stabilize patient hemodynam-
drugs hypoadrenocorticism ics, and restore the GI mucosal barrier.
• Hemostatic disorder: other evidence of bleed- • Biochemical profile
ing (e.g., ecchymosis, epistaxis, hematuria) ○ BUN/creatinine ratio: often high end/ Acute General Treatment
• Respiratory disease: epistaxis, stertor, above reference range (unless liver failure) • Severe anemia or shock: administer intrave-
coughing, exercise intolerance, dyspnea, ○ Total protein: often low end/below nous crystalloids, colloids, or blood products.
hemoptysis reference range due to loss of globulin • Supportive therapy for proximal GI bleeding
and albumin, but if underlying disease includes
PHYSICAL EXAM FINDINGS (e.g., neoplasia, fungal infection) causes ○ Proton pump inhibitors (PPIs [e.g.,
• Rectal exam: tarry stool hyperglobulinemia, total protein may be omeprazole]) 1.0 mg/kg PO or IV q
• If anemia and/or hypovolemia: pallor, within reference range 12h. Do not use in combination with
tachypnea, tachycardia, thready pulses, dull ○ Electrolyte disturbances: may suggest histamine-2 receptor antagonists (H2RAs)
mentation primary GI or metabolic (e.g., hypoad- when treating ulcerative disease.
• If GI disease, may find any of the following: renocorticism) ○ H2RAs (e.g., famotidine) are inferior to
○ Loose stool in rectum ○ Other abnormalities related to underlying PPIs for GI bleeding.
○ Pain on abdominal palpation disease (e.g., GI ulcers due to uremia or ○ Sucralfate 0.5-1.0 g (dogs) or 0.25 g
○ Abdominal mass effect liver failure) (cats) q 6-8h PO administered as liquid
○ Thickened intestines • Centrifugation fecal flotation: evaluate for or slurry is more effective for duodenal
○ Oral cavity bleeding helminths; sensitivity is low with single than gastric ulcers. Caution if concurrent
○ Occasionally, hematochezia testing kidney disease

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