You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Hemorrhagic gastroenteritis and explain in detail?
Hemorrhagic gastroenteritis (HGE) is a disease of dogs characterized by sudden vomiting and bloody diarrhea.  The symptoms are usually severe, and HGE can be fatal if not treated.  HGE is most common in young adult dogs of any breed, but especially small dogs such as the Toy Poodle and Miniature Schnauzer.  It is not contagious.

Cause
The cause is uncertain.  Suspected causes include abnormal responses to bacteria or bacterial endotoxin, or a hypersensitivity to food.  Pathologically there is an increase in the permeability of the intestinal lining and a leakage of blood and proteins into the bowel.  Clostridium perfringens has been found in large numbers in the intestines of many affected dogs.

Clinical signs
Profuse vomiting is usually the first symptom, followed by depression and bloody diarrhea with a foul odor.  Severe hypovolemia (low blood volume) is one of the hallmarks of the disease, and severe hemoconcentration (concentrated blood) is considered necessary for diagnosis.  The progression of HGE is so rapid that hypovolemic shock and death can occur within 24 hours.  Disseminated intravascular coagulation (DIC) is a possible sequela of HGE. As a result, this disease can cause severe damage.

Diagnosis
Clinical signs of HGE and canine parvovirus (CPV) are similar enough that they need to be differentiated