Apatite stones in dogs

Apatite or calcium phosphorous stones are the least common type of stone I see in practice. These rare stones form from the same risk factors responsible for calcium oxalate stones. These include increased amounts of calcium and/or phosphate in the urine. The one big difference is pH. While calcium oxalate stones precipitate out of acidic urine, calcium phosphate stones form in urine with an increased or basic pH. This increased pH may be caused by urease producing bacterial infections.
The same breeds that show an increased incidence of calcium oxalate are also prone to calcium phosphate stones. In addition to miniature schnauzers, Yorkshire terriers, shih tzu and miniature poodles, cocker spaniels are also on this list. Since females are more prone to urinary tract infections, they tend to have more calcium phosphate stones.

Treating calcium phosphate stones is tough because they often form in the kidney. Since surgical extraction will damage the kidney, I usually recommend lithotripsy for this condition. More information on lithotripsy may be found at my blog post; Removing Urinary Stones With Lithotripsy in Dogs. Once the stones are gone, prevention is based on keeping the urine dilute to flush the crystals out before they can form stones. Giving urinary acidifiers is not recommended as it might cause the formation of calcium oxalate stones.  


-Shell, Linda. Urolithiasis, Calcium Phosphate. Canine Partner, VIN 3/1/2010.

Santa Cruz County Arizona Under Rabies Quarantine

The Arizona Department of Health Services has placed Santa Cruz County, Arizona under a rabies quarantine due to an increase in wild animal cases.  From November 2013 to March 2014, there have been 28 cases, 4 in bats and 24 skunks. All dogs and cats who live in Santa Cruz County must be vaccinated for rabies. The Arizona Department of Health recommends avoiding contact with wild animals, especially ones that are acting abnormally, during the quarantine.

Here are some other suggestions for keeping your family safe:

1) Do not feed wildlife. This activity puts the humans as well as the animals at risk. Wild animals do best on their natural diets anyway.
2) Keep pet food in a secure location so as not to attract wildlife. I was visiting a ranch in Colorado when I surprised a skunk who was eating the dog’s leftovers. Thankfully, the skunk took off instead of spraying or biting me.
3) Keep pets under control at all times. That means a leash for dogs and a carrier for cats when away from home.
4) Vaccinate your pets for rabies. This is a federal requirement.
5) Secure garbage and compost bins to prevent entry of rodents and/or skunks.
6) Avoid animals that are acting abnormally. The rabies virus infects the central nervous system leading to salivation, aggression and a drunken gait in carnivores and omnivores. Herbivores get the ‘dumb’ form characterized by salivation, dropping food when trying to eat, extreme lethargy and head pressing.

More information may be found at the Center for Disease Control. Here is the link

-Rabies Quarantine Declared for Santa Cruz County, Arizona Veterinary News, Arizona Veterinary Medical Association, April 2014.

Removing Urinary Stones With Lithotripsy In Dogs

Lithotripsy is an alternative to surgery for removing urinary stones (uroliths) in dogs. For this procedure, the dog is placed under general anesthesia. Next, an endoscope is passed up the urethra to the stone. Once it is in the correct area, a laser is fed through the scope into contact with the stone. Energy from the laser causes the stone to crumble into small pieces. This procedure is repeated until all the stones or pieces of stones are small enough to be retrieved with the endoscope. Since there are no incisions, the advantage to this procedure is shorter healing time and a much lower chance of stricture formation. Disadvantages include thermal burns, difficultly reaching and removing all stones and risks commonly associated with general anesthesia.

Here are the guidelines often used by Virginia-Maryland Regional College of Veterinary Medicine to select dogs for this procedure:

-Small male dogs <15 pounds
-Male dogs with 2 or more large stones
-Female dogs with the entire bladder full of stones
-Dogs with uncontrolled urinary tract infections 

-Laser Lithotripsy of Canine Bladder and Urethral Stones, Virginia-Maryland Regional College of Veterinary Medicine, https://www.vetmed.vt.edu/vth/sa/clin/litho.asp.
-Lulich, J et al, Efficacy and safety of laser lithotripsy in fragmentation of urocystoliths and urethroliths for removal in dogs, J Vet Med Assoc. May 2009;234(10):1279-1285.


Urate Urinary Stones in Dogs

Ammonium urate or urate stones in dogs are common in Dalmations and bulldogs. Dalmations lack the enzyme needed to convert uric acid in the urine to allatoin. As a result, their urine contains high concentrations of uric acid leading to formation of uroliths (stones) in the urinary tract. Urate uroliths are also seen in dogs with portosystemic (liver) shunts due to increased levels of ammonium and uric acid. I have also seen urate stones form in dogs with other types of liver disease, especially cirrhosis.

Diagnosing these stones can be challenging, as they do not show up on routine x-rays. I usually recommend an abdominal ultrasound to visualize the urinary system as well as the liver. I also perform blood work, urinalysis and urine culture. Urate stones form in acidic to neutral urine and can on rare occasions be associated with bacterial infections that produce urease. Most of these patients have low levels of albumin and blood urea nitrogen as well as abnormal bile acids when tested.

Treatment will depend on where the stones are located and whether the dog has liver disease. If the stones are stuck in the urethra or ureters, surgery or lithotripsy is required to remove the obstruction as soon as possible. If the stones are in the urinary bladder and the dog does not have a shunt, medical dissolution can be tried. The dog is fed Hill’s UD which is formulated to reduce uric acid production. The dog is also placed on a drug called allopurinol to further reduce uric acid production. In my experience, this treatment protocol works in about 40% of the dogs.

After the stones are gone, the dog is placed on lifelong therapy to prevent recurrence. For dogs without liver problems, I use either Hill’s UD or Royal Canin UC. I check urine frequently for pH and urate crystals. If crystals recur, I add allopurinol back into the dog’s treatment until the crystals are gone. Dogs with liver disease including portosystemic shunts are more challenging. My patients have done the best when their liver disease is treated. I usually use HIll’s LD or Royal Canin Vegetarian Formula combined with lactulose and sam-e. For all dogs with any type of urinary stones, I recommend increasing the dog’s water consumption to produce a more dilute urine which helps prevent stone formation. This can be done in a variety of methods including adding water to the food, giving ice cubes as treats or flavoring the water.

-Grauer, Gregory. Urolithiasis, Clinician’s Brief, NAVC April 2014,  27-29.
-Shell, Linda. Urolithiasis, Ammonium Urate, VIN Canine Associated, 1/12/2009.

Struvite Urinary Stones in Dogs

Struvite is the common name for magnesium ammonium phosphate uroliths (stones) found in dogs. These stones may occur anywhere in the urinary tract including the kidneys, ureters, urinary bladder and urethra. Struvite stones often form when the dog has a urinary tract infection with bacteria that produce urease. This enzyme leads to over production of ammonia which in turn, increases urinary pH. Alkaline urine (high pH) causes struvite crystals to form. Since females are more prone to infection, they are also more prone to developing struvite stones. According to the Minnesota Urolith Center, magnesium ammonium phosphate uroliths may also be caused by chronic use of antacids due to the excess magnesium, chronic diuretic use, hypoxemia and dogs who cannot produce acidic urine.  I rarely see these causes in practice. Most of my patients develop struvite stones due to urinary tract infections.  

Because of the magnesium, this type of urinary stone shows up well on x-rays. Stone analysis done by the Minnesota Urolith Center provides the final diagnosis.  If the patient does not pass any stones in the urine, surgical removal may be necessary to obtain a sample. The urine is also cultured to find out what bacteria is present and its antibiotic sensitivity.  

Treatment of struvite stones focuses on curing the urinary tract infection as well as removing the stones.  After antibiotic therapy, I always recommend another culture of the urine to make sure the infection is gone. Existing stones are removed through surgery or dissolving them with diet. Hill’s SD is designed to dissolve the stone by having lower levels phosphorous and magnesium. It also lowers the pH to a slightly acidic level. I like to check a urine pH after a week of the diet to make sure the pH is around 6.0. If it goes too low (acidic), the patient is in danger of developing other types of stones including calcium oxalate. When the stones are shrinking, it is possible for them to flow out of the kidney and become trapped in the ureter or leave the urinary bladder and become trapped in the urethra. Owners must watch the dog closely for any signs of discomfort, straining or lethargy. If observed, the dog must be brought in for veterinary care immediately. Urinary obstruction is an emergency condition.  After the initial check, I take x-rays and check urine every month until the stones are gone. The length of treatment depends upon the size of the stones. In my experience, dogs with average size stones require about 10 weeks of therapy.   

To prevent the recurrence of struvite stones, dogs must be monitored closely for urinary tract infections. I recommend a urinalysis with culture every three months the first year then every six months thereafter.  As long as re-infection is prevented, the dog may return to their normal diet. The dissolution diet should only be used for a short period of time. Please note, this recommendation does not apply to cats or dogs who have ‘sterile‘ struvite uroliths which means that an infection is not present. Animals with this condition are placed on a maintenance diet, formulated to produce a slightly acidic urine with a pH around 6.0. These diets also produce a less concentrated urine which helps to wash crystals out before they become stones.   

If the struvite stones recur, further diagnostics are needed to find out what is causing re-infection. This includes a thorough vaginal exam looking for anything that might cause urine pooling.  Obesity and/or a deeply set vulva are two common causes. If this exam is normal, the next step is often an ultrasound of the abdomen followed by a contrast study of the bladder.  


-Minnesota Urolith Center, Canine Struvite Urolithiais, University of Minnesota, http://www.cvm.umn.edu/depts/minnesotaurolithcenter/prod/groups/cvm/@pub/@cvm/@urolith/documents/asset/cvm_asset_143354.pdf.
-Shell, Linda, Urolithiasis, Magnesium Ammonium Phosphate, VIN Canine Associate, March 15, 2010.

Hypoadrenocorticism (Addison’s Disease) in Dogs

Hypoadrenocorticism or Addison’s Disease is a serious health problem that can cause death if left untreated. In this disease, the adrenal glands fail to produce two very important hormones, cortisol and aldosterone. Cortisol is the stress hormone important for regulating heart rate and blood pressure. Aldosterone is the hormone that regulates electrolyte levels. Without aldosterone, levels of sodium plummet while potassium surges. Without treatment, the electrolyte derangements will slow the heart until it stops beating.  

Hypoadrenocorticism is more common in females than males. Dogs may display a variety of nonspecific signs. Early in the disease, I often see intermittent bouts of bloody diarrhea, vomiting, generalized weakness, lethargy, poor appetite and increased water consumption. Blood work at this stage often shows increase in BUN and creatinine that may be confused with simple dehydration, as well as, a decrease in blood sugar. As the disease progresses, the clinical signs listed above become more consistent. In addition to an increased BUN and creatinine, blood levels of sodium fall and potassium rises. To make the diagnosis, an ACTH stimulation test is performed. ACTH causes cortisol release from the adrenal glands. Blood is drawn for cortisol analysis before and after an injection of ACTH. Humans and animals with hypoadrenocorticism do not respond to the injection. Their cortisol levels do not increase as they should.

Treatment is based on replacing the missing cortisol and aldosterone. Replacing cortisol is easy. The dog is put on oral hydrocortisone or prednisone therapy. Replacing the aldosterone is another matter. Currently, there are two medications being used for this, fludrocortisone (Florinef) and DOCP (Percorten-V). Florinef is a tablet given orally. Percorten-V is an injectable medication that is given approximately every 30 days.  Please note there is a condition called atypical Addison’s disease that only requires cortisol replacement.  
Most dogs respond well to treatment and live normal lives. Unfortunately, problems arise when owners cut back on the dose or frequency of administration of Flurinef or Percorten-V in order to save money.  This can lead to disastrous results. Both medications must be given at the recommended dosages and frequency to control this disease. 

ReliOn N Insulin For Dogs

Now that Walmart is offering an NPH insulin (RelinOn) for approximately $25.00 a vial, I am getting questions from some people wanting to switch their pets to save money. Unfortunately, not all insulin is the same which means switching may not save money. Let me explain:

There are many types of insulin used in human and veterinary medicine. Insulin is classified based on its duration of action into short, intermediate and long-acting. In veterinary medicine, short-acting insulin is used primarily to bring down blood sugar levels quickly in patients with diabetic ketoacidosis.  Short-acting insulin is called regular and usually has an R after the trade name. It only lasts a few hours and requires careful monitoring while the animal is hospitalized. NPH (isophane) insulins have an intermediate length of action that is often used twice a day to control blood sugar levels. Intermediate-acting insulin has an N after the trade name. Glargine and PZI insulin are long-acting insulin which in some patients, may be dosed once a day. 

Most diabetic dogs are controlled with twice daily injections of either NPH or Vetsulin insulin. Vetsulin made by Intervet is a combination of amorphous and crystalline zinc insulin derived from pigs. NPH is a human product that is used off label in dogs. Since dogs are genetically closer to pigs than humans, it is believed there is less chance of dogs developing antibodies with Vetsulin versus NPH. In my experience, dogs who are on NPH insulin most often are on the brand Humulin N produced by Eli Lilly. ReliOn N is also NPH insulin but produced by Novo Nordisk.  For Walmart’s distribution the company renamed its product Novolin N as ReliOn N.

Unfortunately, the two different brands of NPH insulin are not interchangeable.
According to veterinary endocrinologist, Dr. Mark Peterson, each firm uses different manufacturing techniques and ingredients to create their product. That means the two types of insulin do not react the same when injected into the patient. Therefore, a patient who changes from one brand to another must be re-regulated to find the proper dose of the new insulin. In my experience, the cost of doing blood glucose curves, urinalysis and/or fructosamine level far outweigh any potential savings. Also, use the proper syringe to match the concentration of the insulin.    

WARNING! Before changing the type, brand, dose or frequency of insulin for your pet, please check with your veterinarian. NPH of any brand is not used in cats.  

-Peterson, Mark. Humulin Versus Novolin NPH Insulin: Are They Bioeqivalent?, Insight into Veterinary Medicine (Blog), April 3, 2014.

Weight Loss and Poor Appetite in Elderly Cats

Weight loss and/or poor appetite is a common problem in elderly cats. A cat who used to be a good eater suddenly becomes selective, refusing to eat any food consistently. Concerned owners try all kinds of foods including a variety of canned and dry food, human baby food and home cooking. Unfortunately, the results are disappointing, the cat will eat it for a few days then refuse. It is one of the most frustrating syndromes veterinarians and owners face.

Here are some of the common causes of weight loss and decreased appetite in older cats and how they are diagnosed:
1)  Kidney disease – When uremic toxins build up in the bloodstream from poorly functioning kidneys, the condition often leads to gastric ulcers, anorexia and vomiting. Kidney disease can be diagnosed with blood work, a urinalysis and sometimes x-rays or an ultrasound.
2) Diabetes mellitus – In my experience, the most common cause of weight loss in obese cats is diabetes. The blood sugar in cats with diabetes skyrockets leading to weight loss, excessive thirst, frequent urination and lethargy. Diagnosis is based on finding a high blood sugar level in combination with glucose in the urine.
3) Pancreatitis – Inflammation of the pancreas or pancreatitis causes abdominal pain, anorexia and weight loss in middle to older aged cats. Diagnosis requires a special blood test called an fPLI.
4) Liver Disease – Many older cats suffer from either primary liver disease such as cholangiohepatitis or secondary liver disease like hepatic lipidosis. A presumptive diagnosis is made with blood work and ultrasound. A biopsy is required for the final diagnosis.   
5) Inflammatory bowel disease – Inflammation of the lining of the intestine causes anorexia, vomiting, diarrhea and weight loss in cats. Diagnosis requires a biopsy of the intestines.
6) Combination of the above conditions – Some of these conditions often occur together such as diabetes is often found with pancreatitis and inflammatory bowel disease.   
Although the conditions listed above are the most common, I have seen a few cats that are never diagnosed. In these frustrating cats, the lab results and ultrasound are all within the normal range. To help these cats out, I have had good luck putting them on an anti-nausea medication.
Please Note: Even though cats with hyperthyroidism will lose weight, I did not include that condition on this list because most of these cats have voracious appetites.

Tear Stains in Dogs

Tear stains are a common problem in toy breed dogs due to their confirmation. Once and awhile, a dog with normal confirmation will develop tear stains from a blocked tear duct. In either case, tears spill down the face usually between the inner corner of the eye and nose. I was taught in veterinary college that the stains are caused by porphyrins within the tears.  The chronic moisture also contributes to bacterial growth which may cause a skin infection.  

Over my career, I have seen many different treatments for tear stains. Here are some of the most common ones:
1) Lacrimal flush- Sterile saline is flushed through the lacrimal duct with an olive-tipped catheter to remove debris.
2) Topical shampoos and/or solutions- I have seen many different chemicals used on tear stains. I personally do not recommend them for fear of damaging the cornea if some of the chemical gets into the eye.
3) Probiotics- After attending a holistic veterinary course, I tried probiotics for tear stains in a few dogs. In this limited experience, it worked well for one dog but did nothing for the others.
4) Tetracycline and Tylosin- These two antibiotics are thought to decrease the amount of porphyrins in the tears. They also might decrease the viscosity of tears, allowing for better flow through the lacrimal ducts. A low dose of either of these antibiotics is given orally to the dog. Tylosin comes in a powder or in a flavored tablet marketed as Angels’ Eyes. I personally am not a fan of giving chronic antibiotics, even at a low dose, for fear of creating bacterial resistance.
***Please note: Tetracycline will stain developing teeth. Only use tetracycline in dogs with all of their adult teeth present.
5) Hypoallergenic diets- I have placed a few dogs on hypoallergenic diets for food allergies and noticed that their tear stains improved. I have also noticed improvement when dogs who suffer from atopy are treated with anti-inflammatory medications. 
6) Surgical correction- depending upon the confirmation of the dog, there are several different techniques that can be used. Procedures include ablation of hair that grows in the area, enlarging the opening of the lacrimal duct and relocating the entire duct. 

Personally, I rarely recommend the treatments listed above (and some of them I never recommend) because this is primarily a cosmetic problem.  If the dog’s face is kept clean, they rarely develop any problems. I recommend keeping the hair around the inner corner of the eye trimmed short and cleaning the face with a warm washcloth to keep it clean.

2014 Desert Dog K9 Police Trials

Next weekend, April 12th & 13th, 2014 is the Desert Dog K9 Police Trials. Spectators are allowed to watch the protection work held at Scottsdale Civic Stadium. Starting at 9am, watch dogs from the military, police, hospital and private security firms, show off their skills. My favorite part is a drill called the ‘recall’ (First Image) because it gives a glimpse into the dog’s personality. During this exercise, the dog is signaled to apprehend a bad guy (agitator) in a bite suite. When the dog is almost there, the trainer will call them off. Most dogs instantly return to their handler, but I have seen a few dogs have a little fun with the agitator. One dog jumped up and barked in the agitator’s face while another gave the agitator a hip check from behind. Who says dogs don’t have a sense of humor! More information at www.desertdogk9trials.com.
Here are some images from the 2012 trials. Enjoy!