Diaphragmatic hernia in dogs - Causes, symptoms and treatment

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When a dog has suffered a traumatic process such as a run over, a fall or a blow strong enough to cause a defect in the diaphragm that allows the abdominal viscera to pass into the thoracic cavity, a diaphragmatic hernia occurs. This disorder can also be congenital. In these cases, the puppy is born with the hernia and it should be resolved as soon as possible, although sometimes it takes time for the hernia to become apparent to the caregivers..

Keep reading this AnimalWised article to know exactly what is a diaphragmatic hernia in dogs, its causes, symptoms and treatment to learn more about this process that our dogs can suffer.

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  1. What is a diaphragmatic hernia?
  2. Symptoms of diaphragmatic hernia in dogs
  3. Diaphragmatic hernia diagnosis in dogs
  4. Canine diaphragmatic hernia treatment

What is a diaphragmatic hernia?

A diaphragmatic hernia occurs when a failure occurs in the diaphragm, which is the musculotendinous separation between the abdominal and thoracic cavity, that limits and separates the organs at the same time that it intervenes in the respiration of the animal. This failure consists of a hole that allows the passage between the two cavities, therefore, it consequently results in the passage of abdominal organs to the thoracic cavity..

There are two types of diaphragmatic hernia in dogs: congenital and traumatic..

Congenital diaphragmatic hernia

Dogs are born with hernia due to improper or defective development of the diaphragm during embryogenesis. Said hernia, in turn, can be:

  • Peritoneopericardial hernia: when the abdominal contents enter the pericardial sac of the heart.
  • Pleuroperitoneal hernia: when the content enters the pleural space of the lung.
  • Hiatal hernia: when the distal esophagus and part of the stomach cross the esophageal hiatus of the diaphragm and enter the thoracic cavity.

Traumatic diaphragmatic hernia

This hernia occurs when a traumatic external process, such as being run over, falling from a great height, or being crushed, causes a tear in the diaphragm.

Depending on the severity of the damage from the rupture of the diaphragm, the process will be more or less severe, allowing the passage of more abdominal content that will hinder the dog's vital functions, such as breathing..

Symptoms of diaphragmatic hernia in dogs

The clinical signs that a dog with diaphragmatic hernia presents are mostly respiratory due to the compression exerted by the abdominal viscera on the lungs, making it difficult to breathe correctly. It should also be considered that congenital hernias may not be apparent until the dog reaches an age, with less acute and often intermittent symptoms. Acute cases are those of traumatic hernias, where the dog usually shows tachycardia, tachypnea, cyanosis (bluish discoloration of the mucous membranes) and oliguria (decreased urine output).

Therefore, symptoms of a dog with diaphragmatic hernia are:

  • Dyspnea or shortness of breath.
  • Anaphylactic shock.
  • Chest wall dysfunction.
  • Air in thoracic cavity.
  • Reduction in lung distention.
  • Pulmonary edema.
  • Cardiovascular dysfunction.
  • Cardiac arrhythmias.
  • Tachypnea.
  • Silenced breath sounds.
  • Lethargy.
  • Thoracic rumbling.
  • Increased heart tip shock on one side of the thorax due to mobilization of the heart tip by herniated abdominal viscera.
  • Fluid or viscera in the pleural space.
  • Palpitation of the abdomen.
  • Vomiting.
  • Gastric dilation.
  • Oliguria.

Diaphragmatic hernia diagnosis in dogs

The first thing to do in the diagnosis of a diaphragmatic hernia is to perform x-rays, especially chest to assess damage. An incomplete diaphragm silhouette is seen in 97% of dogs, and gas-filled bowel loops in the thoracic cavity are found in 61%. Content may be seen in the pleural space, which may be a hydrothorax due to pleural effusion in recent cases or a haemothorax with hemorrhage in more chronic cases.

To assess the respiratory capacity, the blood gas analysis and noninvasive pulse oximetry to determine ventilation / perfusion imbalances with alveolar-arterial oxygen difference. Likewise, the ultrasound allows to identify abdominal structures in the thoracic cavity and can even sometimes determine the location of the diaphragm defect.

To confirm the presence or absence of hernia in dogs, they can be used contrast techniques such as administration of barium or pneumoperitoneography and positive contrast peritoneography with iodinated contrast. This is only used if the dog can tolerate it and if imaging tests have not been illuminating..

The gold standard for the diagnosis of diaphragmatic hernia in dogs is computed tomography, but due to its high price it is not usually considered.

Canine diaphragmatic hernia treatment

Diaphragmatic hernia correction in dogs is achieved with a surgery. Around 15% of dogs die before surgery, with treatment for shock before the operation being key to their survival. Those that are operated on immediately, that is, during the first day of the trauma, have a high mortality rate, hovering around 33%. If you can wait because its cardiorespiratory function allows it, it will be better to wait a little longer until the animal is stabilized and the anesthetic risk is reduced..

¿What is diaphragmatic hernia surgery in dogs??

The hernia resolution surgical operation consists of a celiotomy or ventral midline incision to visualize the abdominal cavity and access to the entire diaphragm. Subsequently, the strangulated viscera of the thoracic cavity must be rescued to restore their blood supply as soon as possible. They should also reposition herniated viscera in the abdominal cavity. Sometimes, if the irrigation has been very marked and they are very affected, the necrotic portion must be removed. Finally, the lesion of the diaphragm and the skin is closed by planes.

After surgery, drugs should be prescribed, especially to treat pain, such as opioids, and the dog should be in a safe and quiet place and be well fed and hydrated.


Death from diaphragmatic hernia in dogs is due to hypoventilation due to compression of the viscera into the lungs, shock, arrhythmias, and multi-organ failure. However, the majority of dogs that undergo diaphragm reconstruction survive and fully regain their quality of life prior to the development of the hernia.

This article is merely informative, at AnimalWised.com we do not have the power to prescribe veterinary treatments or make any type of diagnosis. We invite you to take your pet to the vet in the event that it presents any type of condition or discomfort.

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