Diseases #21
The larynx (voice box) is just the beginning of the respiratory or airway system in the body. It opens up when air comes in and relaxes when carbon dioxide is expired. It allows air to pass to and from the lungs. It also protects against food entering the lungs. Each time an animal swallows, the epiglottis (primary opening valve of the voice box) closes inhibiting the passage of food or water into the lungs. There is one big problem and this is why animals and people often choke. In mammals the beginning of the airways (nostrils) is at the top and slides to the bottom. The beginning of the digestive system (mouth) is at the bottom and slides to the top. When these two cross, it forms the pharyngeal isthmus. At that point food and water can go in either direction. If that direction is the respiratory tract, coughing begins.
Laryngeal Paralysis can be either genetic or acquired. I have seen genetic laryngeal paralysis in Doberman Pinscher dogs over the years. It is usually seen in young animals. Acquired laryngeal paralysis is often associated with excessive heat or stress and is seen most commonly in giant breeds of dogs such as Newfoundlands and St. Bernards.
In dogs with either type of larnygeal paralysis, the muscles causing the larynx to open during inspiration fail to function properly. Instead of opening the larynx, the walls of the larynx are sucked into the lumen of the airway causing a partial or total obstruction to airflow.
Clinical signs noted are panting and a different sounding bark. The most common sign is a whistling like sound on respiratory inspiration due to a narrowing (stenosis) of the laryngeal opening. Expiration may produce a rattling like sound.
A CBC and Chemistry profile are performed to assess the animal's condition. An ultrasound of the larynx may be performed as well as an examination of the organ under a sedative.
Diagnosis is made by the association of clinical signs in a large breed dog. The history in these cases is probably the most important. It is crucial to understand what set off the laryngeal attack in the first place. Was it heat related? Did the dog just finish romping in the yard? All those are give aways. If signs are noticed in young animals a genetic base of the disease is suggested. Exams of the larynx also help in the diagnosis.
Initial treatment of laryngeal paralysis involves calming and or cooling the animal to decrease oxygen demand. Oxygen is given to the animal and some have to be sedated and intubated to provide oxygen to the lung tissues. There are surgical procedures performed by board certified surgeons that open one side of the larynx with stay sutures to make it easier for air to enter and leave the larynx. As with any laryngeal issue, dog owners should use a harness to walk the animal rather than a collar. The collar will irritate that anatomical area and make breathing more difficult.
With the current level of medical technology, the majority of animals live a quality life; particularly after surgery. Oxygen is the basis of life along with water. Animals that have their laryngeal opening increased are going to breath better. Breathing better means more oxygen reaching tissues making the animal feel much better. Dogs are also more active. The only issues with surgery are those cases where the suture line breaks down or with occasional cases of inspiration pneumonia. Those are usually treated successfully.
Laryngitis is defined as inflammation of the larynx. This is commonly known as the voice box and serves as a conduit for air entering and leaving the lungs plus preventing inhaled food and water into the lungs.
Laryngitis is often secondary to a respiratory infection. It can also be caused by the inhalation of toxic fumes and smoke. Trauma to the area can cause laryngitis. Improper removal of endotracheal tubes after a surgical procedure can also cause the problem.
Laryngitis is the most severe in bracheocephalic dogs that have a short tortuous sinus cavity and a scrunched up flat head like an English Bulldog. With any cause of laryngitis, the mucosal tissues lining the larynx become reddened, thickened and inflamed. This leads to the production of mucous. In severe cases, it can actually inhibit air from entering the lungs or at the least, a stenosis (narrowing) of the larynx.
The most commonly seen signs associated with laryngitis in the dog or cat is a dry, hacky cough. Some animals may regurgitate some mucous or phlegm. Dogs may have have a weird sounding bark. This is seen all the time with cats where they squeak like a mouse.
A CBC and Chemistry Profile are performed in most cases to check the white cell count and organ functions. Endoscopy is performed in severe cases to visualize the anatomy of the larynx.
A diagnosis of laryngitis is made on history and a physical exam. Just touching the laryngeal area will elicit a severe cough in most animals. Clinical signs and lab work will guide the veterinarian to a diagnosis.
Treatment varies with the severity and causal agent. If it is secondary to a bacterial or viral infection, antibiotics, cough suppressants and nebulization will be provided. That will take care of not only the primary cause but the associated laryngitis. Animals are than put on a soft diet that is easy to swallow such as warmed up chicken and rice. In more severe cases, diuretics may be given to dry out the laryngeal area making it easier to breathe. Some animals warrant corticosteroids when a strong anti-inflammatory effect is needed. In extreme cases where the larynx is closed a tracheostomy tube is inserted in the trachea just distal to the larynx. As with any laryngeal disease, a harness should be used instead of a collar when walking the animal.
The prognosis for most basic cases of laryngitis is excellent. If there are complications such as laryngeal stenosis or collapse, the prognosis is guarded until the airway issues are resolved.
Leptospirosis is a disease caused by a bacterial spirochete that lives in areas with high rainfall and in the soil. The most common pathogens causing the disease in dogs are: Leptospira grippotyphosa and Leptospira pomona. It is seen in dogs throughout the world but rarely seen in cats. It is a zoonotic disease, meaning there is a possibility of it being transmitted to humans. A spirochete looks like a corkscrew. Another disease causing spirochete is the one causing syphilis in humans; Treponema pallidum.
Dogs that hunt and or spend the majority of their time outdoors are at a higher risk of getting leptospirosis. The corkscrew shaped organism penetrates a scrape, cut or any other mucosal surface and reproduces in the kidney, nervous system and liver. Where the infection goes from there, depends upon the animal's individual immune system. In many cases the animal self resolves by producing antibodies to the spirochete hence eliminating it from the blood. If the liver is affected it can produce several hepatitis. If the animal clears the bacteria, it can be a dangerous carrier of the disease. Even though the fever and infection have cleared, the leptospira organism can still reproduce in the kidneys and be passed in the urine to another susceptible animal (dog).
Leptospirosis has a wide variety of clinical signs that can be associated with many diseases in the dog. Fever, anorexia, lameness, weakness, hematuria, vomiting, diarrhea and depression can be seen amongst others.
A CBC and Chemistry profile are ordered since many body systems can be damaged by the organism. A fluorescent antibody urine test is the lab test usually used to diagnose the disease.
If a veterinarian suspects leptospirosis in your pet, it is extremely important that he and or other veterinary personnel are protected from coming into contact with ANY secretion and that means: urine, feces, vomit or diarrhea. All exams are performed with gloves. A diagnosis is made by obtaining a history of a dog exposed to the outdoors on a regular basis. A little Maltese sitting on a couch all day is not going to get leptospirosis. Clinical signs plus a positive titer to leptospirosis is diagnostic of the disease.
Animals that are severely ill are hospitalized and given intravenous fluids and other supportive care. Dogs that are not severely ill are put on antibiotics for a minimum of 4-8 weeks. The most commonly used antibiotics to treat leptospirosis are the quinolones: Baytril® or Zeniquin®. As long as there is no major organ involvement, most animals do well.
Prevention is the best bet. Vaccination has been available for the most common causes (strains) of leptospirosis for years. They are combined with other vaccines such as distemper or adenovirus or administered separately on a case by case basis. All large dogs, hunting dogs or others that spend a lot of time in the outdoors should be vaccinated and boostered in a year, if an adult. If it is a puppy, the animal is vaccinated for it monthly until a minimum age of 16 weeks has been reached; than vaccinated annually. Even if a dog is vaccinated, keep it away from areas of standing water and wash your hands as a preventative. Never come in contact with an animal's urine.
The prognosis for most cases of leptospirosis is very good as long as there is no major organ involvement. The dangerous part of this disease is the presence of untreated dogs that are carriers of the spirochete. They can cause massive infections in susceptible animals that have not been vaccinated or those with a compromised immune system.
Lick granulomas may seem to be a simple thing to treat but they are not. A lick granuloma is composed of scar tissue. This is what a granuloma is. It is a condition that produces scar tissue that is exacerbated by licking the area. Suspected causes of lick granuloma are boredom, a persistent itch or separation anxiety produced by whatever stimuli.
A lick granuloma starts out as a small sore. If the animal would leave it alone, it would heal in two seconds! It does not! Instead of healing in a primary way, it is never allowed to heal correctly due to the constant licking of the lesion. This produces scar tissue that is extremely THICK. It is always seen over the wrist joint of the animal on either forelimb or over the hock (tarsus) of the hindlimbs. They seem to appear figuratively and literally overnight.
Clinical signs seen are the rapid presentation of a circular or oblong, inflamed lesion over the wrist or hock joint of the dog. It is usually moist due to the constant licking of the lesion by the animal. It is a psychological issue with the dog but it drives clients nuts particularly if the animal sleeps in bed with the owners. All they hear all night is....slurp, slurp, slurp. These lesions can become infected.
Most dogs with lick granulomas are not really sick. If the lesion is infected a CBC may be drawn to check the white cell count.
Diagnosis of a lick granuloma is by the presentation of a dog with characteristic lesions over the hock or wrist joint that suddenly appeared.
Over the years, I have heard of and tried many remedies to beat lick granulomas. I have tried injecting corticosteroids around the lesion. That helps a bit but does not get rid of the lesion. Owners have applied a sock and held it up with duct tape. The dog chews off the sock. Tabasco sauce, bitter apple, bitter orange have been applied with no luck. Dogs actually love the taste of tabasco sauce. Some owners, in jest, want the veterinarian to place the dog in a complete body cast. The best way to treat these lesions, from my own experience, is using laser surgery. This is called surgical ablation of the tissue. With the laser in hand, the doctor goes back and forth, back and forth over the entire lick granuloma over and over. The goal of this is to reach the nidus or irritating tissue way below the skin surface. It heals well and the dog stops licking. If the psychological issue is not resolved, the granuloma can pop up somewhere else in a month or so.
The prognosis for lick granulomas treated with laser surgery is quite good but they can occur elsewhere. Treating dogs with old remedies sometimes work. I feel those worked not because of the treatment employed but the psychological status of the dog improved. Improvement means it leaves the lesion alone to heal by itself.
The function of the digestive tract is to process food for nutritional support and rid the body of the digestive wastes. Dogs and cats love to ingest things that can play havoc in their digestive systems. Linear foreign bodies are those that basically form a line when the dots are connected. Examples are: string, yarn, tinsel from a Christmas tree, an electrical cord and thread are common examples.
When an animal swallows a linear foreign body, several things can happen. If the object swallowed is an irritant, it may make the animal regurgitate it up from the stomach or esophagus. Some cases that even make it down to the small intestine may actually pass in the feces if the object is balled up. Problems arise when it does not. The linear foreign body tries to snake through the small lumen of the small intestine. As this occurs, the intestine continues to work by its normal parastaltic motility. As this happens over and over the small intestine starts to look like an accordion and is literally all bunched up. Intestinal function can not continue and the normal functions stop. This is bad and is called ileus. When that happens, things stagnate and the blood supply to the area decreases. The intestine than sets up a bacterial infection with intestinal necrosis being the end result.
Clinical signs seen vary with the type of material and where it is lodged. Some animals may regurgitate up the offending material right in front of the owners or veterinarian. An object in the intestines leads to anorexia, vomiting and very little stool produced since digestive processes have come to a halt. In severe cases the animal runs a fever and becomes lethargic due to ileus. Sometimes the string cuts through the intestinal tract producing signs suggestive of peritonitis; characteristic radiograph "ground glass" appearance and extreme abdominal pain.
Cats are fascinating creatures but have an affinity and absolute attraction to linear foreign bodies. I have always asked clients if they sew or knit sweaters! If so, I have asked them to make sure the cat is kept out of the room to prevent not only yarn or thread from being swallowed but also preventing needles from being snarfed down by the creature.
Sometimes, the diagnosis is obvious. Such was the case when a small dog was presented with a balloon hanging out of its mouth by its string. That day, the owners held a birthday party for their young child. Surgery had to be done on that case. Cats are different from dogs. I made it a point in all vomiting cats to look at the base of the tongue (frenulum). If you are lucky, you may find string wrapped around there if the patient is cooperative. In most cases the string is already lodged in the intestines. The string is cut at the tongue base and removed through a gastrotomy or enterotomy.
Many animals presented with linear foreign bodies are ill; either from digestive signs or dehydration and electrolyte deficiencies. A CBC and Chemistry profile are done to assess those situations. It is very difficult to see a linear foreign body on radiographs since they are so small and narrow or radiolucent; meaning there is no surrounding contrast difference that would allow it to be seen. Once in a while I have been able to spot a linear foreign body after administering some barium to the animal. The barium coated the object making it easier to see.
Diagnosis can be tedious at times. The diagnosis is often made easier by a history of the owner seeing the dog or cat swallow the offending object. Many times that does not happen. If radiographs are negative, veterinarians will have a gut feeling inside them to make a tentative diagnosis based on physical findings and how the animal is feeling.
Initial treatment is geared towards stabilizing the patient's state of dehydration and electrolyte depletion to make the patient a better surgical risk. Antibiotics are always given at this time via intravenous administration.
Animals with a linear foreign body lodged in the esophagus or stomach may have it removed via an endoscope. If lodged in the small intestine, a laparotomy (exploratory) is performed. Going through the intestinal tract, loop by loop, will eventually lead you to the pleated accordion loops of the intestine. The object is removed by an enterotomy and the incision is closed. If the tissue is necrotic and the mesenteric blood supply to the intestinal loop is impaired, a resection and anastomosis is performed. Animals are managed post op and sent home on appropriate antibiotics and a bland chicken and rice diet. The goal is to feed the animal easily digestible foods that are easy for an injured intestine to digest.
The prognosis for linear foreign bodies is usually excellent. Complications such as sepsis or damaged blood supply to an intestinal loop need to be resolved before elevating the animal's prognosis.
Prevention is the key. Pets are like permanent toddlers. You literally have to pet proof your home continually! Look around the home and floors and pick up anything that a dog or cat can ingest. If you sew or knit, restrict access of that area to humans only!