Diseases #25
Otitis interna is not that common in dogs or cats. Also known as an internal ear infection, it is an inflammation of the semicircular canals of the inner ear. This inflammation can be caused by bacteria, yeast or fungal infections.
When inflammation occurs at the semicircular canal area, problems of balance will occur. This balance is what causes the majority of clinical signs associated with an internal ear infection.
Clinical signs noted will vary with the severity of the infection. Some animals may just shake their heads or paw at the ear. In severely affected animals, the dog or cat may lose hearing in the ear plus have signs of vestibular disease; which include circling to the side of the infection, nytagmus (darting of the eyes) with the fast phase to the affected ear and ataxia. Some animals may vomit due to balance issues.
Damage to the ear is difficult to visualize outside of CT or MRI imaging. Cultures will be performed as deep as possible to note any bacterial or yeast growth. A CBC and Chemistry profile will be performed to rule other causes of vestibular disease; particularly in the cat!
If advanced imaging is available, a diagnosis can be arrived at. In most cases, a tentative diagnosis can be reached by ruling out other causes of vestibular disease. A fine needle aspirate of middle ear secretions can lead to potential cause of the infection.
Treatment is long term antibiotic therapy. The ear canal may need to be surgically drained. Many animals that are showing signs of vestibular disease are hospitalized to observe and prevent self inflicted trauma. Some vestibular issues can be controlled by the use of oral Meclizine®.
The prognosis for otitis interna varies with the severity of the condition. A key prognosis is the response to medical therapy. Some animals will spontaneously resolve while others will show permanent vestibular signs. Animals have a fantastic built in survivor instinct. Dogs or cats with permanent vestibular disease secondary to otitis interna will often circle and fall down. Over time, the majority will compensate and walk with their head tilted at a certain angle to walk straight! It is great to see and animals can lead a happy life!
Otitis media is also known as a middle ear infection and is commonly caused by a variety of bacterial, yeast or fungal infections. An untreated external ear infection may creep down to form a middle ear infection. In older animals cysts and other growths can impede middle ear circulation hence setting up an external or middle ear infection.
Regardless of the cause of a middle ear infection, inflammation of the anatomical area is what causes the majority of clinical signs.
Clinical signs often involve a hybrid between external and internal ear infections. Some animals may shake their heads and find it painful to open their mouths or cry out when stroked over the ears. A foul smelling ear may be present. Others may actually show signs of ataxia or in coordination due to mild vestibular signs. Hearing loss may be present since the middle ear contains the ossicles; three small bones that physically vibrate and carry sound from the tympanic membrane to the inner ear.
The most common lab test is a fine needle aspirate of the middle ear that collects secretions from the ear for culture of fungal, bacterial and yeast organisms. A culture of the external ear canal may be done since many external ear infections will drop into the middle ear.
Diagnosis of a middle ear infection may be difficult to differentiate from a pure external or internal ear infection. A collection of clinical signs may suggest one or the other. If there are vestibular signs, that would lead one to think a middle or internal ear infection. In a middle ear infection, signs of nystagmus and extreme circling or ataxia may be absent. Culturing the organism from the middle ear is also diagnostic.
Treatment of the condition is associated with treating the primary cause of the infection. Long term antibiotic therapy is used for bacterial infections. Ketoconazole is used for fungal and yeast infections. Other supportive care such as ataxia or balance issues may be taken care of by prescribing Meclizine®. The external ear canal must be kept dry and acidic with prescription ear cleaners.
The prognosis for otitis media depends upon the severity and clinical signs present. Those associated with an external ear canal have a good prognosis if treated promptly while those animals that have vestibular disease may be more difficult to treat and have a guarded prognosis.
The fact is that the majority of cats and dogs do not wear shoes! Shoes protect human feet from cuts, abrasions and the like. If a cat or dog steps on something sharp, a laceration or damage to one of its foot pads is very likely. Pad injuries can be caused by car accidents, being dragged on asphalt while an owner is driving a pickup (Yup, I have treated those!), cats jumping up on to a stove element that is on, burns, exposure to corrosive chemicals and getting caught in a chain link fence. There are probably more but these will give you a good idea.
A dog or cats foot pad sort of acts like a miniature shoe. It is composed of thick, leathery like skin that covers and protects a sweat gland under each pad. It does work in protecting the limb but can easily get injured. If torn, the lower paw area can get infected and even an abscess may form due to the presence of bacteria.
The most common clinical sign is licking at a lower limb. They are trying to remove something from their paw or respond to physical discomfort. This is what most owners see. In the medical office the pad injury is noticed. There may be just a small laceration or the entire pad may have been sheared off. Depending upon how long the animal waited for medical care, the lower limb or digits may be swollen due to an infection or abscess.
If an infection or abscess is present, a CBC is performed to check for the presence of a left shift neutrophilic leukocytosis.
Diagnosis is made by the visual appearance of an injured foot pad.
Treatment varies with the injury to the pad in question. In mild cases, the paw is cleaned, wrapped in a comfort bandage and the animal is placed on antibiotics for 14 days. To alleviate pain anti-inflammatory drugs may be prescribed. Rimadyl® for dogs and Torbutrol® drops for cats.
If the pad has been lacerated, the pad can be sutured back together or surgical glue applied to bring the wound edges together. This often has to be done with a light sedative since the animal is in pain.
Animals may have the entire pad sheared off or burned such as with car accidents or cats jumping up on hot stoves. All you can do is debribe (clean out) dead tissue and try to create a healthy wound so that granulation can take hold. The animal's limb is bandaged plus antibiotics are prescribed for several weeks.
Wounds that are produced by irritating chemicals are treated to preserve as much pad tissue as possible. If the pad is completely destroyed or sheared off, it will not regrow since the cell type is totally different from surrounding skin.
The prognosis for pad injuries is usually excellent. During the attacks of 9/11 many of the search and rescue dogs going up into the mangled Twin Towers in NYC had many pad injuries secondary to irritants and sharp objects.
The best approach is prevention. The animal should not be allowed to run free. There is a greater risk of pad problems if the animal is not confined. Check the exterior of your home to insure that sharp objects such as nails, metal and the like do not pose a threat to your pet. Cats are natural jumpers. When cooking, do not leave the stove area unattended if cats are present.
Pancreatic insulomas are malignant tumors of the beta cells of the pancreas. The cause of the insuloma is unknown but it is most commonly seen in upper middle aged dogs and up.
The pancreas is composed of two parts: one exocrine and the other endocrine. The exocrine part produce enzymes that are needed for initial digestion of fats and sugars in the small intestine. The endocrine component consists of two types of cells; the alpha cells and beta cells. Alpha cells are responsible for the production of a hormone known as glucagon. It is responsible for raising blood sugar. The beta cells are responsible for producing the hormone known as insulin. It is responsible for lowering blood sugar. A tumor in the beta cells is called an insuloma and is characterized by the excess production of insulin. This causes a persistent hypoglycemia (low blood sugar) in the dog and associated clinical signs. Pancreatic insulomas may metastasize to the lung tissue as the disease progresses.
The most common signs are ataxia, depression, disorientation, collapse and coma.
A CBC and Chemistry profile are performed. A low blood glucose level is detected. Animals must demonstrate a persistent low blood sugar. There are tests that will measure the insulin to blood glucose ratio. Animals are fasted and the lowest blood sugar is obtained. Over time, the animal eats which forces the production of even more insulin. This is a vicious cycle that leads to persistently low blood sugars and clinical signs.
An ultrasound or CT scan may delinate the margins of the pancreatic tumor.
A diagnosis is made by the historical findings and dogs that show a persistent low blood sugar along with associated clinical signs in an upper middle aged dog and up. A CT scan can confirm the presence of a pancreatic tumor.
There is no medical cure for pancreatic insuloma. The most immediate treatment at home for dogs that show clinical signs of hypoglycemia is to smear KaroSyrup® over the oral cavity of the animal. This will rapidly raise the blood sugar and reduce clinical signs. Next stop, is a medical facility. Surgery can excise the part of the pancreas containing the tumor but cellular metastasis has usually occurred to other parts of the gland. Medical care is geared towards alleviating signs of hypogylemia and to moderate the levels of circulating insulin.
Diazoxide may be used which inhibits insulin production but it is quite expensive.
The oral administration of prednisolone or prednisone will raise a dogs blood sugar. One of the side effects of glucocorticosteroids is a hyperglycemic state. This side effect comes in handy when trying to treat persistent hypoglycemia. Breaking up a dogs meal into multiple meals also causes insulin levels to stabilize. Dietary management may sometimes be successful. Successful enough to possibly cut back on the amount of oral prednisone.
The prognosis of pancreatic insuloma depends upon the successful management of the medical condition. A poorer prognosis is the development of metastatic lesions in the lungs or other tissues.
Pancreatitis is defined as inflammation of the pancreas. Common causes of pancreatitis are excessive levels of fat in the body. In dogs and cats a leading cause of pancreatitis is obesity. Others may have concurrent diseases such as Diabetes mellitus, cholangiohepatitis or Immune Mediated Hemolytic Anemia (IMHA). A common cause in many dogs is the ingestion of spicy foods and or garbage. Once pancreatitis starts in those cases, many will turn into true insulin dependent Diabetes Mellitus. This is always seen in Miniature Schnauzers.
The pancreas is situated in the initial angle formed by the duodenum, the first part of the small intestine. When pancreatic tissue is damaged digestive enzymes can not pass into the small intestine. Instead, they leach out into the abdominal cavity digesting the pancreas itself (autolysis) and other nearby organs such as the liver. This sets up clinical signs seen commonly in the disease.
In the dog, the most frequently seen signs are vomiting and diarrhea. The presentation is different in cats. The most commonly seen feline signs are anorexia and lethargy. That is why it is sometimes hard to diagnose in cats because the initial clinical signs are so vague. Further signs in the dog are more general. Anorexia, fever, depression and abdominal pain are typical. Those general signs are seen in cats. Because of initial digestive problems, animals will lose weight. In cats this occurs lightning fast!
All internal medical cases should have a CBC and Chemistry profile performed. Chemical levels of high lipases or amylases are not diagnostic of pancreatitis even though they are elevated. A CT scan or ultrasound will visualize the pancreatic tissue. The gold standard for diagnosis of pancreatitis in the dog and cat is the Idexx® fpl (Feline) Snap Test and the Idexx® cPL (Canine) Snap Test. The feline version has a 79% sensitivity when it comes to diagnosing feline pancreatitis. Exploratories can also be performed.
Diagnosis is is made by historical findings and clinical signs. A diagnosis can be confirmed by the appropriate Idexx® Snap Test.
All cases of canine and feline pancreatitis are hospitalized with intravenous fluids. Most of the treatment revolves around supportive care. This means drugs such as Cerenia® and famotidine to control vomiting. Animals may also be placed on a broad spectrum antibiotic to prevent secondary bacterial infections and bacterial gut translocation (E. coli and Enterococcus sp.). Pancreatitis is painful and drugs are administered to control it. Butorphanol is commonly given IV to control visceral pain. Vitamins and electrolyte deficiencies are administered through the catheter. It is important to rest the pancreas. Food should not be withheld for more than 1-2 days.
Dietary management is important but differs in the management of the disease in dogs and cats. Dogs should be put on a low fat diet such as Hill's® Prescription i/d canned or dry. In the cat, the amount of fat in the diet has nothing to do with the development of pancreatitis. Any high quality food may be administered to the animal. There is a big difference in the cat when it comes to food. Most patients are anorexic and often do not want to eat. If a cat does not eat in 3 days it will start to develop hepatic lipidosis (fatty liver). To insure that the cat eats, hospitalized patients will be syringe fed Hill's Prescription a/d food plus gobs of Nutrical® gel. Appetite stimulants such as mirtazapine and cyproheptadine are often used. Once animals are hydrated they are discharged on supportive care plus continued treatment of the primary cause.
The prognosis for pancreatitis depends upon the primary cause and management of the primary disease causing the pancreatitis. Bouts of pancreatitis can recur if the primary condition is not managed as well as maintaining a low fat diet in dogs.