Blood in the stool can be from various causes. It is important to identify the color of the blood. Bright red blood in the feces is hermatchezia. This is an indication of bleeding in the lower intestines. If the blood color is dark, or the feces is black, this is melena and is an indication of problems in the upper digestion system and is potentially much more serious.
The presence of hematochezia may be a symptomatic of either a minor problem, or a potentially serious problem in your dachshund. One occurrence of hematochezia may be a minor and transient event. Repeated or persistent hematochezia is more serious and should not be ignored.
Infectious agents, such as bacteria, protozoa, viruses, and intestinal parasites
Dietary intolerance/allergy/indiscretion
Cancer (neoplasia) of the lower bowel
Polyps (benign masses) in the colon or rectum
Inflammatory bowel diseases, such as colitis
Trauma to the lower bowel or anal area
Clotting disorders (coagulopathy)
Intussusception (the telescoping of one part of the bowel into another)
Bright red blood in the feces
Possible straining to defecate as if constipated
Increased number of bowel movements
Possible other systemic signs of illness, such as excessive drinking, urinating, vomiting and diarrhea, lethargy, poor appetite, weight loss
Your dachshund may not have any other clinical signs
If your dachshund has symptoms of hematochezia the following diagnostic tests may be required by a vet: rectal examination, complete blood count (CBC— requires a blood withdrawal), completion of a biochemical profile, urinalysis, examination of fecal matter, coagulation profile, abdominal X-rays (radiographs), abdominal ultrasound, or a colonoscopy.
Melena usually indicates the presence of a significant upper gastrointestinal problems, although occasionally other diseases (such as clotting disorders, ingestion of blood, etc.) unrelated to the gastrointestinal tract may present with melena.
Melena is usually the result of bleeding in the upper gastrointestinal tract (esophagus, stomach, or small intestine). As the blood moves through the gastrointestinal tract, it is digested by normal digestive juices. The digested blood appears black or tarry in the bowel movements. Melena also can be caused by digestion of blood from other sources such as swallowing blood from the mouth or blood coughed up from the lungs and licking blood from a wound.
The classic appearance of melena is black, shiny, sticky, foul-smelling feces with a tarry consistency. Melena may be seen as the only clinical sign, although other systemic signs often accompany it.
A careful history and thorough physical examination of dachshunds exhibiting this disease is essential. The presence of melena generally warrants hospitalization, extensive diagnostic testing, and supportive care. It is best to determine the underlying cause and treat the specific problem.
Ulcers of the stomach or upper small intestine (bleeding ulcers)
Inflammation of the stomach or intestinal tract
Cancer
Infections (usually fungal or parasitic infections)
Foreign body in the gastrointestinal tract
Ingestion of certain medications, especially steroids or NSAIDs (non-steroidal anti-inflammatory drugs) used to treat arthritis; some human or veterinary NSAIDs include aspirin, carprofen, etodolac, or ibuprofen Note: animals are very sensitive to human, "over the counter" nonprescription NSAIDS (such as ibuprofen); always check with your veterinarian prior to giving your pet any human medications
Kidney failure
Liver disease
Inflammation of the pancreas
Lesions of the nose or mouth cavities
Abnormalities in blood clotting