Acute Haemorrhagic Diarrhoea Syndrome

Canine Acute Haemorrhagic Diarrhoea Syndrome (AHD), previosuly known as haemorrhagic gastro enteritis, (HGE) is a very acute form of dysentery (bloody diarrhoea) usually combined with vomiting. Hypovolaemia (reduction in the amount of blood plasma) occurs due to the dramatic loss of water and electrolytes into the bowel.

What is the cause?

Many conditions can result in bloody diarrhoea. AHD syndrome, however, is always very rapid in onset. Dehydration and shock due to hypovolaemia are the main causes of the acute emergency situation. If you are concerned call your veterinarian right away, as this is an emergency. The cause is not fully understood but an allergic response to certain toxins produced by bacteria is suspected.

How is AHD diagnosed?

Since the cause is unknown, diagnosis is by exclusion of other possible causes of vomiting and dysentery. These include ulcers, trauma, tumours and obstructions. Parvovirus infection often shows similar signs to AHD and has to be initially excluded. Tests include blood and urine analyses, radiography, faecal examinations (e.g. for bacteria and parasites), ultrasound scans and sometimes endoscopic examination of the bowel.

Are some breeds more prone than others?

The condition can affect any dog but small breeds, particularly Miniature and Toy Poodles, Yorkshire Terriers, Miniature Schnauzers and Miniature Dachshunds appear to be most prone. It appears to affect young adults, often with previously completely healthy medical histories.

What is the treatment?

AHD is an acute emergency. Due to disruption in fluid balance within the body dehydration and death can rapidly occur. It is therefore important that fluid therapy is provided without delay. Once fluid balance is restored most dogs will start to improve. Hospitalisation and professional monitoring are often required.

What is the prognosis?

Since the condition often affects previously healthy dogs, provided severe shock can be avoided by the early use of intravenous fluids, most dogs will recover well. Unfortunately further attacks can occur and have to be treated equally speedily.