Lung Lobe Twisting in Dogs

Dogs have a considerably different lung configuration that humans. Each lobe is separate from the others, with four located on the right side of the body and three on the left. The lobes are connected to the trachea via a bronchial tube, and blood supply comes to each lobe through separate veins and arteries leading to the heart. The individual nature of the lung lobes in dogs means there is less attachment holding them in place and it is easier for them to become twisted. This is called lung lobe torsion (LLT). It occurs also in humans, but it is more common in dogs. LLT cause serious respiratory problems. The lobe usually twists around the bronchial tube and arterial connection. Its air intake is minimal, but it will continue to fill with blood. Fluid and blood will start to accumulate in the chest cavity, limiting the function of the other healthy lobes, and reducing your dog’s entire oxygen supply. LLT is more common in large, deep-chested breeds; studies have found that the Afghan Hound is 133 times more likely to develop LLT, however, many smaller breeds have also been known to be affected and the condition could occur in any dog. Many cases of LLT are spontaneous, with no known triggering factor, although it’s believed that reduced ligament connections in the chest may be at the root of the problem. Other instances of LLT occur secondary to another disease. Conditions that cause fluid or air to accumulate in the chest cavity put more pressure on the lung lobes and increase the risk of torsion. Pneumonia can contribute to lobe torsion, as well as cancer and Chylothorax, a disease in which intestinal lymphatic fluid is diverted into the chest. LLT can be treated with surgical removal of the affected lobe, and primary, spontaneous conditions have a fairly good outlook. If the lobe torsion is secondary to another disease that is difficult to treat, the prognosis is not as good.

When a lung lobe becomes twisted around the bronchial tube and arterial connection this is defined as lung lobe torsion. It is more common in dogs than it is in humans due to the separate nature of each lung lobe. Lung lobe torsion can be a serious and life-threatening condition.

Some dogs can have acute, sudden, respiratory distress, while others will have milder chronic symptoms that are less noticeable. Early treatment is more effective, so see a veterinarian as soon as you notice a difference in your dog’s breathing or exercise level.

• Difficult or labored breathing (dyspnea)
• Rapid breathing (tachypnea)
• Cough
• Coughing of blood (hemoptysis)
• Intolerance to exercise
• Lack of appetite
• Lethargy
• Weight loss
• Vomiting
• Fever (pyrexia)
• Pale or bluish mucous membranes
• Abdominal pain
• Diarrhea

Types

There are two types of LLT.

Spontaneous

• A primary condition with no identified cause except possibly genetic factors

Secondary

• Secondary to another disease such as cancer or a respiratory problem that causes fluid in the lungs

These are some of the factors that may be related to LLT.

• More common in large, deep-chested breeds of dogs, especially Afghan Hounds
• Smaller breeds that can also be affected include Pugs, Miniature Poodles, Dachshunds, Shih Tzu, Yorkshire Terriers, Pekinese, Beagles, and mixed breeds

Conditions that may cause secondary LLT

• Trauma
• Error during surgery
• Pleural effusion – fluid accumulation in the lungs
• Severe pneumonia with fluid in the lungs
• Chylothorax – a type of pleural effusion in which chyle, a milky lymphatic fluid from the intestine, accumulates in the chest
• Pneumothorax – accumulation of air in the lungs 
• Cancer

LLT may be suspected based on the symptoms, especially if your dog belongs to a breed that is commonly affected. The veterinarian will evaluate your dog’s symptoms and listen to the lungs through a stethoscope. With LLT, breathing sounds are often absent over the affected lung. Chest x-rays will show fluid in the lungs as well as a darkened, more opaque looking lung, sometimes with an abnormal gas pattern. Severe acute cases will be more obvious and may even show tracheal displacement. If the x-ray is not clear, a CT scan may be ordered for a more definitive diagnosis. Analyzation of a lung fluid sample can help to determine primary conditions, like Chylothorax or cancer. It will also help to detect the presence of bacterial infections that may be causing pneumonia. If you already know your dog has cancer or another condition that causes pleural effusion this may help to explain the reason for LLT.

Immediate treatment will focus on stabilizing your dog’s symptoms. Additional oxygen may be necessary for dogs with severe respiratory difficulty. Thoracentesis is an invasive procedure that can help eliminate fluid from the chest so that the non-twisted lung lobes can function more normally. Antibiotics may be given for bacterial pneumonia.

Surgical treatment involves removing the lung lobe and securing the bronchial and arterial connections. A stapling device is often used for the lung, while sutures will tie up the connections. Thoracoscopy, a version of endoscopy, may allow for a smaller incision, however, lung lobectomy is still an invasive surgical procedure. A tube to syphon off excess fluid will remain in your dog’s chest for a few days after surgery, and the veterinarian will not send him home until the lungs have stabilized and are functioning normally.

If LLT is a secondary condition, the original disease will need to be treated also. Chylothorax can sometimes be ameliorated by surgically redirecting chyle back into gastrointestinal tract, but this is difficult and risky. Cancerous pleural effusion may be treated with chemotherapy or radiation in the early stages. Other treatments will depend on the condition that is causing fluid accumulation. If your dog is not healthy enough for surgery, or the primary condition is untreatable, the veterinarian may recommend euthanasia.

Your dog’s chances of recovery will be evaluated by a veterinarian upon diagnosis. Many dogs with primary LLT do make a complete recovery. One study of close to one hundred dogs found that about 50% achieved long-term survival after lobectomy. Conditions that are caught and treated early have a better prognosis. Recovery from secondary LLT will depend on the primary condition.