VetInfo Digest        September 2001

This Month:

Symptoms and Possible Causes

Polyuria/Polydipsia

Coughing

Itching

Acute Blindness

Acute Vomiting

Chronic Vomiting

Acute Diarrhea

Chronic Diarrhea

New Generics

Why we only accept written questions

 

Editor's Note:

This month I am going to provide lists of symptoms and diseases that are associated with them. One approach to making a diagnosis is to write down a list of all symptoms that a pet has, then to check these symptoms against a list of possible diagnoses. If a pet has several symptoms and all of the symptoms occur in the presence of one disease, it makes the likelihood of this disease higher. Unfortunately, this is not a sure way to reach a diagnosis. It does help a lot by insuring that a disease or disorder is less likely to be overlooked, though.

It is important to think about the symptoms, the history, the species and sex of the patient and all the other things that contribute to the overall picture. Some disease only occur in young animals or are much more common in older pets than in younger pets. Other diseases only occur in cats, even if a dog has all the symptoms. There are times when a pet has all the clinical symptoms of a disease, is the right species, the right sex and the right age, but still does not have it. This is where the experience of your veterinarian is especially helpful, since veterinarians see many variations of disease processes, as well as seeing many normal animals to compare them with.

One of our worries has always been that we would provide information that would allow people to mislead themselves without also making it clear that the best way to avoid this is to work well with your veterinarian. There are times when knowing all the possibilities is helpful, though. Sometimes it really does help to have a list of things that might be wrong, just to make sure that everything gets considered. These lists may help if you are dealing with a chronic problem that just doesn't seem to be responding properly to treatment.

Lists of Symptoms and Possible Diagnoses (Differential Diagnoses)

Increased Drinking and Urinating

Increased drinking is referred to as polydipsia. An increased volume of urine, usually resulting in an increased frequency of urination, but not always, is referred to as polyuria. It is important to differentiate between increased urination because more urine is being produced (polyruria) and increased frequency of urination without an increase in the volume of urine being produced (pollakiuria). Pollakiuria is more typical of disorders such as cystitis or bladder stones, in which there is a frequent urge to urinate that is due to pain or discomfort rather than an increase in urine volume. Often, on medical records an increase in drinking and urinating is abbreviated PU/PD or something close to that.

These are some of the causes of polyuria and polydipsia:

Disease or Disorder Species Affected Age/Breed/Sex Predilections Notes
 
Diabetes mellitus Both Usually middle aged or older, females affected a little more commonly Cats can have high blood sugar levels from stess, including drawing blood
Hyperadrenocorticism

(Cushing's disease)

 Both, usually dogs Uncommon in cats. Average age of onset 9 yr.  
Hypoadrenocorticism Dogs Primary occurs in young dogs, secondary at any age Only 25% of cases have PU/PD
Kidney Failure Both Can be any age, but more likely as pets get older More likely to be chronic in cats
Pyelonephritis Both   Can be very difficult to detect
Hypercalcemia Both   Cancer is the most common cause in dogs, cats have several causes
Intestinal Obstruction Both   Absorption of toxins from the intestine is most likely cause
Pyometra Dogs Pyometra = uterine infection, so females only  
Diabetes Insipidus Both   May be primary (brain related) or secondary (nephrogenic or related to the kidneys
Pyschogenic Causes Both More often a cause of this problem in young pets Difficult to prove, often must rule out all other causes
Hyperparathyroidism Both Usually older pets PU/PD behavior may be due to hypercalcemia associated with this condition
Liver Disease Both    
Leptospirosis Both Infectious, so may occur in outbreaks Causes liver disease and/or kidney disease
Hyperthyroidism Cats Most cats are over 9 years of age when this occurs  
Hypothyroidism Dogs Most dogs are over 5 years of age  
Fanconi's Syndrome (Renal glycosuria) Dogs Basenjis most commonly affected  
Urinary tract obstruction (may be partial)   Very young and very old pets most commonly Anatomic defects in young pets, cancer in older pets
Medication Reactions Both   Prednisone, phenobarbital, sulfa antibiotics, others
Pheochromocytomas Usually older dogs    
Polycythemia Both    
Acromegaly Both Unspayed female dogs due to mammary hyperplasia One cause of difficult to regulate diabetes in cats
Paraneoplastic Syndrome Both Older pets Some metastatic cancers produce active hormonal compounds
Pericardial Effusion Both    

Coughing

Some clinical signs are markedly different from one species to another. Coughing is one of those signs and it is easiest to produce two tables for this symptom, one for cats and one for dogs.

Coughing in cats:

Vomiting Vomiting doesn't really cause coughing in cats but it is almost impossible to distinguish vomiting from coughing in many cats and so cats that are vomiting are often brought to the vet's for coughing
Asthma Siamese cats might be predisposed
Heartworm disease  
Roundworm migration  
Lungworms  
Chronic Bronchitis  
Cardiomyopathy  
Bordetellosis Not very common in cats, but if there is upper respiratory disease with coughing it should be considered

Coughing in dogs:

Tracheobronchitis (Bordetellosis) Very common in dogs, honking cough
Heartworm Disease  
Chronic heart failure Common cause of coughing in older dogs
Distemper Not very common anymore, but easily confused with bordetellosis in dogs from shelters or similar situations
Lungworms  
Pneumonia Not a common cause of coughing
Chronic (allergic) bronchitis Cocker spaniels are predisposed to this problem
Collapsing Trachea Very common cause of persistent coughing in older dogs, especially small breeds
Laryngeal paralysis Older Labrador retrievers are the most common breed affected in our practice, usually causes a "roaring" sound associated with breathing

 

Itchiness (Pruritis)

Itchiness is one of the most frustrating conditions for pet owners. People relate to itchiness since almost everyone has experienced it and they seek instant relief for their pets since they know how awful itchiness can be. Itching used to be extraordinarily difficult for pet owners because we didn't have very good flea control measures. Now, with fipronil (Frontline, Frontline Topspot tm), imidocloprid (Advantage tm), selamectin (Revolution tm), lufenuron (Program tm) and nitenpyram (Capstar tm), it is usually possible to control fleas. In fact, the majority of the severe skin disease we see in our practice now occurs in pets of people who refuse to use one of these products, for one reason or another.

Itching in dogs and cats:

Cause of Itching Dogs Cats
 
Fleas Most common cause of itching in dogs. Fleas must be eliminated to really differentiate well between the other skin diseases.

 

 Most common cause of itching in cats. Often can not be found on flea allergic cats

 

Mosquitos Not a common cause of itchiness in dogs May be fairly common in cats
Sarcoptic Mange Fairly common, hard to find on skin scrapings, may cause itching in dog owners, intense itching in affected dogs Not found in cats
Notedric mange Uncommon in dogs Similar to sarcoptic mange of dogs but less common
Cheyletiella mites (mange) Common in some areas of the country Same for cats
Lice Uncommon Uncommon
Demodecosis Initially not itchy, often itchy as secondary infections occur More likely to be itchy in cats
Intestinal parasite hypersensitivity Roundworm and hookworm migrations lead to itchiness, usually in young dogs  
Atopy (inhalant allergies) Common in dogs  
Food allergies Occasional problem, usually to one or more food ingredients, rather than to a type of dog food Occasional problem, same as dogs
Contact allergies Not especially common, cedar chips, poison ivy, wool, plastic food or water bowls Same as dogs
Primary bacterial infections Common in short coated dog breeds Rare in cats
Secondary bacterial infections Very common with any other skin disease Uncommon in cats
Eosinophilic granuloma complex Rare in dogs Fairly common in cats, may be a manifestation of food or flea allergy
Cushing's disease If calcinosis cutis skin sores are present and from secondary bacterial infections Uncommon in cats
Dermatophytosis (Ringworm) Often not itchy but can be A little more likely to be itchy in cats
Mast cell tumors Skin sores or lumps that are itchy should raise suspicions for this tumor  
Malassezia (yeast) infection Fairly common in dogs, may have a yeasty odor, often a lot of dander, skin oils or thickened skin  

 

Blindness (sudden acute blindness)

Cause of Blindness Dog Cat
 
Sudden Acquired Retinal Degeneration Syndrome (SARDS) Usually middle aged dogs, loss of vision over the course of 1 to 2 weeks Not known to occur in cats
Acute glaucoma The eye is usually painful and excessive tearing or eye discharges are common, loss of vision in a few days to a few weeks Eye pain is less obvious in cats, as are the other symptoms
Eye trauma Look for blood inside the eye Same
Retinal detachment sudden blindness, can be treated in some cases if caught early Less common in cats
Hypertension Less common in dogs Most common cause of acute blindness in older cats
Toxins (central) Ivermectin toxicity in dogs will cause temporary blindness  

 

Acute Vomiting (Sudden onset, short duration)

Cause of vomiting Dogs Cats
 
Internal parasites - esp. roundworms, hookworms, whipworms, tapeworms Occasional cause of vomiting Occasional, cats very rarely have whipworms
Acute Pancreatitis Usually middle aged or older dogs, can occur at any age Acute pancreatitis is not very common in cats
Parvovirus Parvovirus is most common in puppies between 8 weeks and 1 year of age Panleukopenia (feline distemper) virus in cats is a parvovirus. It is uncommon at this time
Intussusception Young dogs, usually less than one year of age Rare in cats
Foreign bodies (objects that shouldn't be eaten) Rocks, peach pits and corn cobs seem common String (a "linear" foreign body) is most common in cats
Dietary indiscretion: (sometimes called "garbage can enteritis") Overeating, chocolate or other high fat meals, spoiled foods. Dietary changes can also cause this (changing foods) Occurs in cats when type of food is changed, sometimes.
Medication Reactions common causes: erythromycin, morphine, tetracyclines, theophylline, chloramphenical, digitalis doxycycline, morphine (not used very commonly in cats), xylazine (an injectable medication
Toxins ethylene glycol based antifreeze ethylene glycol, permethrin and organophosphate flea products
Peripheral vestibular syndrome Acute onset loss of balance, often with vomiting Less common in cats than in dogs

Chronic Vomiting

Cause of vomiting Dogs Cats
 
Inflammatory bowel disease occasional in dogs common in cats
Food allergies Usually cause itching, rarely vomiting associated with inflammatory bowel disease in cats
chronic pancreatitis schnauzers especially prone very common in older cats, part of the "triad syndrome" in cats
chronic gastritis/ulcers medication induced, parasites, cancers, pyloric obstruction  
Cancers Several have this effect Intestinal lymphoma in cats is the most common cancer to cause chronic vomiting
Liver disease   Especially hepatic lipidosis
Kidney failure Young dogs with congenital illness, older dogs Many older cats
hypercalcemia most commonly due to cancer in dogs occurs due to cancer and also for no apparent reason in cats
coughing Not likely in a dog Coughing doesn't really cause vomiting but coughing and vomiting are hard to tell apart in cats
Hyperthyroidism rare in dogs common in older cats
Heartworm disease unusual symptom in dogs Occurs as real vomiting in cats and also as coughing disguised as vomiting
Central nervous system disease Especially if vestibular system (balance) is disturbed Especially if vestibular system (balance) is disturbed
Parasites Whipworms sometimes cause chronic vomiting Roundworms sometimes cause chronic vomiting
Helicobacter Occurs in dogs, arguable cause of GI disease as it may be a normal resident Occurs in cats, arguable cause of GI disease as it may be a normal resident
Partial intestinal obstructions Usually foreign bodies and cancers, slight intussusceptions can do this, too Usually string and cancers
Persistent Right Aortic Arch Vomiting starts as soon as solid food is given  
Megaesophagus Usually actually regurgitation but most clients think of this as vomiting, associated with myasthenia gravis Rare in cats
Colitis Some dogs with chronic colitis also have vomiting Cats with megacolon often vomit
Pharyngitis   Mostly a problem in cats with chronic upper respiratory disease
hypoadrenocorticism (Addison's disease) Young dogs that just don't seem right, older dogs as an acquired problem Rare in cats
Diabetes with diabetic ketosis Serious diabetes complication Less common in cats

 

Acute Diarrhea

Cause of Diarrhea Dog Cat
 
Internal parasites (both large and small intestinal can occur) Roundworms, hookworms, whipworms, tapeworms, coccidia, giardia Same list plus toxoplasmosis, whipworms rare

 

Parvovirus (primarily small intestinal) Usually 8 weeks to 1 year of age, rare in older dogs Panleukopenia (feline distemper) is a parvovirus
Acute colitis (large intestinal) Very common in dogs, frequent small volume bowel movements Common in cats, same signs as dogs
Gastroenteritis from dietary indiscretion (often small intestinal, can be either) Common in dogs Less common in cats
Canine distemper Gastrointestinal signs may occur before all other signs  
Feline enteric coronovirus   Usually young kittens
Acute pancreatitis Usually occurs with vomiting, often middle aged or older dogs Not as common in cats
Bacterial enteritis (large or small intestine affected) Salmonella, E. coli, Yersinia, Bacillus piliformis, Campylobacter jejuni, Clostridium species (several) Same list
Canine hemorrhagic gastroenteritis acute hemorrhagic enteritis, most common in small breeds  
Systemic illnesses sometimes seen with liver disease or kidney disease same
lactose intolerance estimates of lactose intolerance vary but probably at least 50% of dogs are lactose intolerant estimates vary, up to 70% of cats may be lactose intolerant

Chronic Diarrhea

Cause of Diarrhea Dog Cat
 
Internal parasites same list as for acute diarrhea same list
Rotavirus Not as likely to be chronic in dogs Young cats with diarrhea not responsive to treatment
Protozoan infections Amebiasis, balantidiasis, probably rare balantidiasis doesn't occur in cats
Feline immunodeficiency virus   Sometimes associated with chronic non-responsive diarrhea in cats
     
Feline leukemia virus (FeLV)   FeLV pretty much has to be considered in almost any feline illness
Fungal infections (uncommon, small bowel) Histoplasmosis, aspirgillosis, candidiasis Same list
Lymphocytic-plasmacytic enteritis Can occur secondary to other disorders, both intestinal and systemic, may be primary similar to dogs
Eosinophilic gastroenteritis/colitis often assumed to be due to food allergies but this is not proven same as dogs, may also be due to toxoplasmosis
Chronic colitis Often secondary to other conditions in this table, sometimes occurs independently Not as common as in dogs, megacolon sometimes causes both constipation and diarrhea in cats
Exocrine pancreatic insufficiency (EPI) Insufficient production of digestive enzymes, prevalent in German shepherds Not too common in cats, sometimes associated with chronic pancreatitis
Small intestinal bacterial overgrowth (SIBO) usually secondary to other conditions or long term antibiotic use  
Intestinal cancers several in dogs lymphoma most common in cats but there are others
histiocytic ulcerative colitis Boxers, rare in other breeds, chronic mucoid diarrhea Rare reports of occurrence in cats
Irritable colon syndrome colitis that occurs for no discernible reason and may seem to be associated with stress doesn't seem common in cats
Pyschogenic diarrhea Dogs with thunderstorm anxiety for instance  

 

New Generics Now Available:

Enalapril, Enacard Rx, is available in most common sizes. Selegiline (Anipryl Rx) is available in 5mg size tablets, which is good for small breeds but loses cost effectiveness for bigger dogs due to the number of pills that must be administered. Ivermectin and pyrantel (Heartgard Plus Rx) will be available in September from at least one competitor.

 

Why We Insist on Written Communications

This month we have had a number of requests for phone consultations. This is not a service that we can offer and my hospital staff, who answer the phone, will not allow you to reach me for consultations. There are several reasons for this. The primary one is that I am simply not very good at thinking and talking on the phone at the same time, which limits the value of any phone consultation I would be willing to provide. I am much more comfortable with written communications. By receiving questions in writing and providing written answers we feel that there is less chance for confusion over the information provided, as well. We do not feel that it is appropriate, in most circumstances, to provide emergency advice online. For real emergencies, the pet needs to be at a veterinary facility that can deal with the crisis. Providing phone consultations in emergencies seems as likely to delay necessary care as to promote good quality care and is really impossible for us to provide emergency assistance on a consistent basis, in any case. Finally, I practice veterinary medicine full time, in addition to writing the VetInfo Digest and www.vetinfo.com web site. E-mail and written communication allows me to respond when there is time to do so. Telephone conversations are hard to put on hold for three or four hours when it is time to return to the examination room to deal with our "real world" clients. Actually practicing veterinary medicine is part of what makes our web site valuable and so I feel obligated to continue to practice but it also means I must put my practice patient first, when a choice must be made.

I hope that most of you can understand why we insist on a written questions only policy. Michal and I do appreciate your support for the site and hope that it is valuable even when we can't provide all the help you may need.

 

The VetInfo Digest is published by TierCom, Inc., P.O. Box 476, Cobbs Creek, VA 23035. The opinions expressed in this newsletter are those of Michael Richards, DVM., author.

Please send email for Dr. Richards to mervet@inna.net

Copyright 2001, TierCom, Inc.