Diaphragmatic hernia in dogs – symptoms, surgery and recovery

Overview

The diaphragm separates the chest and abdomen

The diaphragm is a muscular partition separating the abdominal and chest cavities and helping with breathing. An accident can tear this muscle. Organs such as the liver, stomach or intestines can move through the tear into the chest. They then occupy space needed by the lungs and hinder lung expansion.

Signs vary from a slight breathing change to a life-threatening situation. A small or congenital hernia may cause no obvious signs. An old injury may therefore be identified only later.

Normally, diaphragm contraction makes the lungs expand and fill with air during inhalation.

Causes

Traumatic rupture of the diaphragm

The most common cause is blunt trauma, such as being struck by a car, falling or receiving a blow to the abdomen. Rib fractures, lung bruising and lung rupture may occur in the same accident. A diaphragmatic hernia is therefore assessed as part of all the dog's injuries.

Among 63 operated dogs, a road accident was responsible in 42, or 66.7%. A bite was recorded as the cause in 7 dogs, or 11.1%. The cause was unknown in 13 dogs, or 20.6%. These figures describe surgical patients brought for treatment.

A congenital connection to the sac around the heart

PPDH is a congenital peritoneopericardial diaphragmatic hernia. It involves abnormal diaphragm development before birth. An opening remains between the abdominal cavity and the pericardial sac surrounding the heart. This differs anatomically from a traumatic tear.

Herniation through the oesophageal opening is a separate form

In a hiatus hernia, abdominal contents protrude through the diaphragm's oesophageal opening into the chest. This may involve weakness of the muscle tissue around the opening, for example. Treatment of a hiatus hernia is therefore not directly equated with treatment of a large traumatic diaphragm rupture.

Risk factors

Accidents predispose to diaphragmatic hernia, making escape into traffic and falls from a height relevant hazards. Congenital diaphragmatic hernia is recognised in breeds including Weimaraners and Cocker Spaniels. PPDH is often diagnosed in a puppy. A congenital hernia can nevertheless remain without signs. Short-nosed dogs have an increased hiatus hernia risk because of their anatomy.

Traumatic diaphragmatic hernia is not confined to puppies: the median age of operated dogs was 3 years. Ages ranged from 2 months to 18.3 years. Scarring in an old hernia can later complicate surgery.

The operated dogs had a median weight of 8 kg. Weights ranged from 1.5–33.5 kg, so patients included different-sized dogs.

Typical symptoms

In acute diaphragmatic hernia, breathing signs often predominate, whereas general signs may become more prominent in a long-standing condition. At home, you may notice:

• Faster, shallower breathing than usual even at rest.
• A breathing posture with the head and neck extended.
• Breathing difficulty more pronounced during exertion or stress.
• Vomiting and recurrent digestive signs.
• Loss of appetite, potentially associated with dysfunction of displaced organs.
• Weight loss, particularly with a long-standing diaphragmatic hernia.

Congenital PPDH can be found incidentally without clear previous signs. An absence of signs therefore does not define the hernia's anatomical form.

A hiatus hernia can also cause regurgitation, meaning food returns from the oesophagus to the mouth. Excessive drooling is another possible sign of this form.

Complications and consequences

Impaired blood supply to organs

Blood flow to a herniated organ can be reduced. Part of a severely damaged organ may need removal during surgery. A stomach displaced into the chest can fill with gas and rapidly prevent lung function. Stomach twisting is also possible.

Other chest problems

Lung damage can cause pneumothorax, with air collecting in the chest cavity outside the lungs. Blood can also collect in the chest, causing haemothorax. Displaced abdominal tissue can irritate the heart and cause arrhythmias. Fluid moving from the abdomen into the chest can also worsen breathing and circulatory problems.

PPDH can additionally reduce venous blood returning to the heart. Adhesions are scar tissue attachments between organs or between organs and chest tissues.

Pulmonary oedema after surgery

As a long-collapsed lung expands, fluid can accumulate within it, causing re-expansion pulmonary oedema. Risk is particularly relevant after repair of a chronic diaphragm rupture. The prognosis is therefore assessed cautiously for at least the first 24 hours after surgery.

Diagnosis at the vet

History and clinical examination

Your vet asks about a possible accident and combines this with examination findings. Lung sounds may be reduced or absent over part of the chest. Bowel sounds can sometimes be heard in the chest when intestine has moved through the diaphragm. Heart sounds may also be quieter than usual. The abdomen may feel unusually empty on palpation. These findings guide imaging rather than replace it.

X-rays and additional imaging

A diaphragmatic hernia is usually diagnosed on chest X-rays. The diaphragm's normal outline may no longer be visible. Abdominal organs may be seen in the chest where they do not belong. Displaced organs can also obscure the heart's outline. Lung position and the space available for expansion can change.

Fluid in the chest can make X-rays harder to interpret. Ultrasound can complement examination of the chest and abdomen. Some situations require a contrast study or CT. If diagnosis remains uncertain, surgical exploration of the abdomen may be necessary.

General condition and other injuries

A blood count and biochemical blood tests provide information about disturbances in the patient's general condition. Blood gas analysis can add to assessment of a dog with breathing difficulties. An electrocardiogram, or ECG, helps investigate possible arrhythmias. Lung and rib injuries sustained in the same accident are investigated separately. Imaging therefore also indicates which other treatments your dog needs.

Fluid obtained through thoracocentesis can also undergo laboratory testing. PPDH is sometimes found incidentally during a female dog's spay surgery.

Investigating a hiatus hernia

A hiatus hernia may require fluoroscopy, which follows the movement of contrast material using moving X-ray images. Endoscopy of the oesophagus and stomach can also investigate this hernia type.

Treatment

Supporting breathing and circulation first

A dog with breathing difficulties is stabilised before other treatment. Initial care may include supplemental oxygen, pain relief and intravenous fluids. If air or fluid has accumulated in the chest, a vet can remove it using a needle or catheter. This procedure is called thoracocentesis. Your vet selects measures according to breathing and circulation.

A stomach displaced into the chest and dilated with gas may require emergency surgery. The stomach can first be decompressed at the clinic to ease breathing. In some severely affected dogs, breathing does not improve sufficiently until the displaced organs are returned.

Surgical repair of diaphragm rupture

Surgery is the definitive corrective treatment for traumatic diaphragm rupture. It is performed when your dog is stable enough for general anaesthesia. Through an abdominal approach, organs are returned from the chest to the abdomen. The diaphragm tear is sutured closed. The organs' blood supply can determine whether a damaged portion also needs removal.

Adhesions in a chronic hernia can cause bleeding during surgery. They can form as early as around 7 days after an accident. They may hinder lung expansion even before repair. Surgical timing is determined by the dog's condition; no single delay is considered safe for every patient.

In a study of 189 dogs and cats, surgery within the first 24 hours was not associated with increased mortality.

Treating congenital forms

An asymptomatic PPDH or a patient with a high surgical risk may sometimes be managed without surgery. When repair is indicated, however, it should not be unnecessarily delayed. Mild signs from a small hiatus hernia may initially be managed with medicines reducing reflux and oesophagitis. The hernia type therefore affects the possible treatment plan.

Surgery may be recommended for a severely symptomatic or chronic hiatus hernia.

Hospital monitoring and recovery

Diaphragmatic hernia surgery requires subsequent hospital monitoring. A chest drain may be left in place to remove air, blood or fluid. Pain management is essential to surgical recovery. Other traumatic injuries may prolong the need for hospital care.

A feeding tube is used where necessary to maintain nutrition after surgery.

After surgery, your dog may quickly seem brighter and keen to move. Rest and activity restriction are nevertheless needed during recovery. Among 63 dogs treated at a Thai hospital, 52, or 82.5%, survived to discharge. This figure concerns operated traumatic hernia patients, rather than every form of diaphragmatic hernia.

Prevention

Accident risk is reduced by keeping your dog on a short lead near traffic. Fencing around an off-lead exercise area must prevent access to a road. Reflective equipment helps motorists see your dog in the dark.

In a car, transport your dog on the rear seat in a seat-belt harness or an appropriately sized crate secured to the vehicle structure. A deploying front-seat airbag can injure a dog. These measures reduce exposure to accidents; they do not correct a diaphragm developmental abnormality formed before birth.

A retractable lead does not provide enough control if a dog suddenly lunges into the road.

Important for dog owners

Travel to treatment and home observations

Keep an injured dog's movement to a minimum while arranging transport. A rigid supporting surface can help move a large dog. Call the practice and report the accident and breathing changes. Also mention an older accident because a diaphragmatic hernia may be found only later.

After discharge, monitor breathing effort and your surgical patient's willingness to move. Follow prescribed rest even when your dog seems bright again. Record vomiting, appetite changes and weight trends. New breathing difficulty requires prompt veterinary contact. Agree increases in exercise and follow-up timing according to discharge instructions.

Frequently asked questions

Can a dog have a diaphragmatic hernia without obvious breathing difficulty?

Yes. Small tears and congenital hernias may cause few signs. In a long-standing diaphragmatic hernia, weight loss may predominate over breathing signs. An asymptomatic PPDH may be found incidentally. Diagnosis relies on examination and imaging, rather than the severity of a sign.

Can medication alone heal a traumatic diaphragm rupture?

Surgery is the corrective treatment for a diaphragm tear. Supplemental oxygen, pain relief and circulatory support stabilise the dog before the procedure. Surgery returns displaced organs to the abdomen and sutures the diaphragm closed. An asymptomatic congenital PPDH may, however, sometimes be suitable for monitoring without surgery.

Why is surgery not always performed immediately on arrival?

Breathing and circulation are stabilised first, particularly with severe respiratory difficulty. Surgery is performed when the dog is stable enough for anaesthesia. Gas dilation of the stomach within the chest may nevertheless require emergency surgery. Timing therefore depends on findings and vital functions.

What is the outlook after surgery?

The prognosis for a traumatic hernia is affected by other injuries from the same accident. Among 63 operated dogs, 52, or 82.5%, survived to discharge. The outlook for return to normal function after congenital PPDH repair is generally good. Outcomes for different hernia forms are assessed separately.

Why monitor breathing after successful surgery?

Lung re-expansion can be associated with pulmonary oedema. Monitoring is particularly important when repairing an old diaphragm rupture. The postoperative prognosis is assessed cautiously for at least 24 hours. Other traumatic injuries may also require hospital care even after the diaphragm tear has been closed.