Lung Lobe Torsion in Dogs

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Article Written by Dr. Daniel A. Degner, Board-certified Veterinary Surgeon (DACVS)

Key Points

Lung lobe torsion results in fluid accumulation in the chest and breathing difficulty

Deep-chested dogs are most commonly affected, however, other breeds can develop the condition

Surgery is the treatment of choice

Prognosis is excellent, providing that no other chest-related diseases are present


Introduction

  • The lungs of the dogs and cats have separate lobes. There are 4 separate lobations of the right lung and 3 of the left lung field.
  • In a case of lung lobe torsion, the lobe typically twists at the level of the base of the heart, but may also twist in the mid section of the lung lobe
  • The right middle lung lobe is the most commonly affected in most breeds. Pugs most commonly develop lung lobe torsion of the left cranial lung lobe. The accessory lung lobe torsion ( right lung) also has been reported in a series of dogs.
  • The pathophysiology of lung lobe torsion starts with a physical twist of the lung lobe along its long axis, which results in collapse of the vein of the lung lobe, but the muscular artery continues to pump blood into the lobe. The lobe becomes distended with blood and weeps bloody fluid into the chest cavity. The fluid accumulation in the chest prevents the remaining lung lobes from expanding, thus causing breathing difficulty. With time, the torsed lung lobe dies off and releases toxins into the body.
  • In some cases, underlying disease in the chest such as cancer or chylothorax may predispose the patient to developing lung lobe torsion, thus the patient will have ongoing issues even though the lung lobe has been removed. If chylothorax is present prior to surgery, the prognosis is thought to be somewhat guarded, however, one study showed that 5 of 6 dogs had resolution of chylothorax after surgery (all had the torsed lung lobe removed and 2 of these had thoracic duct ligation).

Signs

  • Breeds reported to have develop this condition include deep-chested dogs such as Afghans and Borzois, however other susceptible breeds include miniature poodles, dachshunds, Shih Tzu, Yorkshire terrier, pekinese and pugs. Cats uncommonly develop lung lobe torsion.
  • Signs typically include progressive worsening breathing problems, coughing, loss of appetite, and in some cases vomiting and diarrhea
  • Signs that a veterinarian may also note when listening to the chest with a stethoscope includes decreased heart and lung sounds

Diagnostic testing

  • Testing may include a complete blood count, chemistry profile and urinalysis
  • A chest radiograph (x-ray) will typically show fluid accumulation in the chest cavity. The torsed lung lobe will typically appear white on the radiograph due to accumulation of fluid within the affected lobe.
  • If the diagnosis is not obvious on the initial radiographs, the chest fluid is removed and the chest radiographs are repeated.
  • A fluid sample taken from the chest fluid frequently will be quite bloody.
  • Other less common tests that can help confirm a diagnosis of lung lobe torsion include bronchoscopy, chest CT scan, chest MRI, and thoracoscopy.

Treatment

  • Surgery is recommended to treat lung lobe torsion. This involves making an incision on the affected side of the chest. to expose the affected lobe.
  • The lobe is not untwisted, as this could result in release of toxins into the body and make the patient very will. The lobe thus is stapled or tied off at the hilus and removed. The photo right demonstrates a torsed lung lobe.
  • A drain is placed in the chest to allow evacuation of fluid and air from the chest cavity.
  • After surgery pain medication is administered for 3 to 4 days.
  • Intravenous fluid are administered for 24 hours after surgery.
  • Antibiotics are administered around the time of surgery
  • The patient is monitored closely for signs of breathing difficulty and low oxygen level in the blood with a pulse oximeter.

Complications

  • accumulation of milky fluid in the chest (chylothorax)
  • recurrence of lung lobe torsion (in another lobe)
  • pneumonia
  • infection of the incision

References

  1. David B. Spranklin, Keven P. Gulikers, and Otto I. Lanz. Recurrence of Spontaneous Lung Lobe Torsion in a Pug
    J. Am. Anim. Hosp. Assoc., September/October 2003; 39: 446 - 451.
  2. Andrew D. Hofeling, Andrew H. Jackson, Joel C. Alsup, and Debi O’Keefe. Spontaneous Midlobar Lung Lobe Torsion in a 2-Year-Old Newfoundland. J. Am. Anim. Hosp. Assoc., May/June 2004; 40: 220 - 223.
  3. TL Dye, HD Teague, and ML Poundstone. Lung lobe torsion in a cat with chronic feline asthma. J. Am. Anim. Hosp. Assoc., November/December 1998; 34: 493 - 495.
  4. MB Rooney, O Lanz, and E Monnet. Spontaneous lung lobe torsion in two pugs. J. Am. Anim. Hosp. Assoc., March/April 2001; 37: 128 - 130.
  5. AR Gelzer, MO Downs, SM Newell, MB Mahaffey, J Fletcher, and KS Latimer. Accessory lung lobe torsion and chylothorax in an Afghan hound. J. Am. Anim. Hosp. Assoc., March/April 1997; 33: 171 - 176.
  6. Michaël Lora-Michiels, David S. Biller, Dennis Olsen, James J. Hoskinson, Susan L. Kraft, and Jeryl C. Jones. The Accessory Lung Lobe in Thoracic Disease: A Case Series and Anatomical Review. J. Am. Anim. Hosp. Assoc., September/October 2003; 39: 452 - 458.
  7. Larue SM, Withrow SJ, Wykes PM. Lung resection using surgical staples in dogs and cats. Vet Surg 1987;16(3):238-240

Frequently Asked Questions After Surgery

When should my dog have the first bowel movement after surgery?

  • Many dogs will not have a bowel movement for the first 4 to 5 days after surgery
  • Reasons that a dog will not have regular bowel movements after surgery include:
    • The dog has been fasted prior to surgery
    • Dogs do not eat well during the hospital stay
    • They frequently do not eat well when they go home
    • They are fed highly digestible food that produces little stool
    • Pain medication that contain narcotics (such as morphine, fentanyl patches, and tramadol) can be constipating
  • If a pet does not have a bowel movement on the 5th day of being home, a stool softener such as metamucil can be fed
    • Dose of metamucil is 1 tsp per 25 Kg mixed in with each meal (canned dog food); feed immediately after mixing, as the metamucil will gel the food and may make it less palatable

My pet had surgery and will not eat.  What can be done?

  • Dogs
    • Most pets will not eat their regular dog food after surgery, especially if it is kibble.
    • Offer a cooked diet having a 1:1 ratio of a protein source and carbohydrate source.  The protein source can be any meat (example: chicken breast, turkey breast, lean hamburger) that is low in fat and should be cooked (drain off all fat after the meat has been cooked).   The carbohydrate can be pasta, potato or white rice.
    • Try canned dog food; to enhance the flavor sprinkle a very small amount of garlic powder or chicken or beef broth (Chicken-in-a- MugTM or Beef-in-a-MugTM products)
    • Try Gerber strained meats for babies such as the chicken, beef, turkey, or veal
    • Try Hill's A/D diet available at most veterinary hospitals
    • Hand feeding: place a small amount of food in the mouth so that your dog gets the flavor
    • Warm the food slightly in a microwave, as the food will be more aromatic; stir the food before feeding and test the temperature on the bottom side of your wrist; it should only be luke warm.
    • Remember that most pets will not eat the first day or two after they get home from surgery
  • Cats
    • Offer smelly foods that contain fish such as tuna or smelly cat foods
    • Try Gerber strained meats for babies such as the chicken, beef, turkey or veal
    • Hand feeding:  with your finger place a small amount of food on the roof of your cat's mouth; use a syringe to get soft food into the mouth
    • Warm the food slightly in a microwave as the food will be more aromatic; remember to stir the food before feeding and test the temperature; it should be only luke-warm
    • Some cats will only eat dry food, try kibble if your cat normally has been fed that food
    • Petting and stroking your cat frequently will help to stimulate appetite
    • Remember that most pets will not eat the first day or two after they get home from surgery
    • Appetite stimulants such as cyproheptadine may be helpful
    • If your cat refuses to eat anything for 7 days a stomach tube or nasogastric tube should be placed to provide nutrition so that a serious liver problem (hepatic lipidosis) does not develop

My pet is vomiting.  What can be done?

  • The first thing for you to discern is whether your pet is vomiting or regurgitating.  Both will result in fluid or food being brought up.  Vomiting always will have heaving or retching of the abdomen prior to expulsion of the vomitus.  Regurgitation is not associated with heaving and the pet usually just opens the mouth and fluid or food will be expelled.  Usually the regurgited material will be clear or brown colored fluid. 
  • Next is to identify the cause of the vomiting or regurgitation.
  • Causes and treatment of vomiting after surgery
    • When some pets return home after a stay in the hospital they may drink excessive amounts of water at one time and then vomit; if this appears to be the case, the water should be limited to frequent smaller amounts.
    • Medications such as antibiotics, narcotics or nonsteroidal anti-inflammatory medication commonly cause vomiting after surgery.  In order to see which medication is causing the problem, the administration of each drug should be separated 2 hours apart.  Usually the pet will vomit or appear nauseated (drooling and sick look) within 1 hour of administration of the medication that they are sensitive to.  The antibiotic in some cases may be changed to a different one, or may be discontinued. 
    • Stomach upset from anesthesia is a potential cause of vomiting and will pass within a couple of days. 
    • An uncommon cause of vomiting after surgery is internal organ failure.  Blood testing will confirm this problem. For this reason vomiting should not be ignored if it persists for more than 24 hours.
    • If your pet had surgery of the bowels or stomach, vomiting is always a concern, as it may indicate that infection of the abdominal cavity, called peritonitis, is present.  Do not ignore this sign.
    • Symptomatic treatment of vomiting involves withholding food for 12 to 24 hours, then introducing small amounts of bland food such as rice and lean cooked hamburger, if your pet does not vomit after that then gradually wean him/her back onto the regular diet after 3 days.  In order to decrease the acidity of the stomach, Pepcid AC 0.5 mg/kg can be given by mouth twice daily for 5 days.  Metoclopramide and Cerenia are good anti-vomiting medications for dogs and cats.  You should always consult a veterinary healthcare professional before administering medication.
  • Causes and treatment of regurgitation after surgery
    • The most common cause of regurgitation is reflux of acid from the stomach into the esophagus while your pet is under anesthesia.  Acidic fluid from the stomach can cause a chemical burn of the esophagus and result in a bad case of heart burn, called esophagitis.  This results in poor motility of the esophagus, therefore water and food will accumulate in this structure.  In most cases, esphagitis is self-eliminating and will resolve within two or three days. 
    • If the esophagitis is severe the esophagus may develop one or more strictures.  A stricture is a narrowing or stenosis of the esophagus and does not allow passage of food down the esophagus, in regurgitation that lasts longer than one week.  This problem should be brought to the attention of your pet's doctor within the first two weeks so that it can be treated by ballooning the stricture (minimally invasive procedure, as it is done with the aide of an endoscope).  If an esophageal stricture is chronic surgery is needed.
    • Symptomatic treatment of regurgitation caused by esophagitis includes feeding bland food, and administering a coating agent (sucralfate) and an acid blocker (omeprazole or other).  Consult a veterinary health care professional if the regurgitation continues for more than a couple of days.

How do I know that my dog is in pain following surgery?

  • Signs of pain include
    • crying
    • biting if you get near the surgical site
    • grimacing (lips are pulled back and the the dog looks anxious)
    • tragic facial expression
    • panting
    • restlessness and unable to sleep; pacing
    • if abdominal surgery was done the pet will not lie down on the incision, or will continually sit up in spite of appearing very tired
    • the worst pain will be for the first 2 to 3 days after surgery

What can I do to control my dog's pain?

  • Narcotic medications that control pain: tramadol, butorphanol, Duragesic (fentanyl patch)
  • Anti-inflammatories used to control pain: Deramaxx, Rimadyl, Previcox, or Etogesic
  • If an orthopedic surgery has been done cold packing the surgical site may be helpful
    • A cold pack may be a pack of frozen peas, crushed ice in a Ziploc bag, or a cold gel pack; place a thin barrier between the skin and the cold pack.  An alternative to a cold pack is to freeze water in a styrofoam cup; after frozen cut the bottom of the styrofoam cup out. Cool the surgical site around the incision by rubbing the exposed ice directly on the skin in a circular pattern.  Cooling the surgical site helps to numb the area.

How do I know that my cat is in pain following surgery?

  • Pain is more difficult to assess in cats versus dogs, as signs can be more subtle and they usually do not vocalize when in pain
  • Signs of pain in a cat include the following:
    • biting if you get near the surgical site
    • growling or deep cry
    • not wanting to eat
    • hiding and not wanting to be near owner (remember that this could also be caused by the cat just being upset about leaving home and coming back)

What can be done for pain at home for my cat?

  • Pain medication such as buprenorphine or a Duragesic (fentanyl) patch
  • Tylenol will kill a cat as they lack abundant glutathione enzyme in the liver
  • Anti-inflammatories can be used, but the dose is much less than dogs

Is it okay for my pet to lick the incision?

  • If a dog licks the incision, the healing process may be delayed.
  • Licking can remove stitches and cause the incision to open
  • Licking can become a severe habit that is difficult to break
  • Licking can cause infection as the mouth has many bacteria
  • Dogs will frequently lick the incision when the owner is not watching such as at night time; if the skin looks red or excoriated the most common cause is from licking.
  • To stop your pet from licking the following can be tried:
    • Elizabethan collar can be placed on the neck; this will not help stop your pet from scratching at the region
    • Cervical collar (bite not collar) is a less awkward device and can be effective at stopping a pet from licking the surgical site
    • A tee shirt can be used to cover an incision on the chest or front part of the abdomen; gather the waist of the shirt up over the dog's back and wrap an elastic band around this part of the shirt.
    • A bandage or sock can be used to cover an incision on a limb; fasten the top of the sock to the dog's limb with tape.
    • Bitter apple can be applied around the incision; many dogs will continue to lick  after application of this topical
    • Bitter Apple and Liquid HeetTM (obtain this from a drugstore...it is used for sore muscles) mixed in a 2:1 ratio can be applied around the skin incision
    • Antipsychotic medication in some cases is needed

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What does it mean?

  • Four years of advanced training in surgery beyond the Doctor of Veterinary Medicine Degree

  • Experience in the development of new surgical treatments

  • Rigorous examination by the American College of Veterinary Surgeons to ensure competency in advanced surgical techniques

  • Assurance that a veterinarian is a surgical specialist

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