Treating Feline Urinary Problems: Cranberries

Cranberries

If you go to any alternative medicine site and look for natural treatments for bladder infections, cranberry in its many forms is touted as a cure or prevention.  But does it work?  And more importantly for me, does it work for a cat?

Cranberry seems to work because a proanthocyanidins (an antioxidant) prevents the E. Coli from attaching to the cell walls in the bladder.  In vitro studies have confirmed that proanthocyanins do cause deformation of the E. coli cells and thus suggests prevents them from adhering to the bladder walls.  The adhesion in one study was reduced by 75%

There are no studies in cats.

There is a study in beagles showing that the metabolites of the cranberry do appear to make it to the bladder and do reduce the adhesion of the E. coli.  The researchers administered 1 Crananidin tablet per day and the dose peaked at 7 days after which it remained steady.

There are human studies that show no significant improvement with the use of cranberries.  Several of the studies do comment that perhaps the potency of the cranberry used in the study was not sufficient.

So what does this all mean?  It does seem that cranberry can prevent UTIs in cell cultures, but there is no evidence that it does in cats.

There are however many anecdotal accounts by cat owners that cranberry pills, cranberry powder, and even cranberry juice has helped cats.  I know from personal expereience, I have used cranberry powder with cats exhibiting UTI symptoms and the symptoms disappeared in 2-3 days.  Was it coincidence?  Maybe, maybe not.  I do know that 1/2 a cranberry extract pill is a much larger dose for a cat than 1 pill 2x a day is for a person.  So maybe, the proanthocyanins did reach a therapeutic level in my cats.

There are also a couple of concerns about using cranberries with cats.  One is cranberries contain salicylic acid (aspirin).  Now, before people panic, cranberry juice contains 7mg/L of juice.  Presumably poders and extracts would contain more.  But.... for cats, the toxic level for aspirin begins at about 50mg/kg of body weight.  So an 11 lb cat (5 kgs) would need 250mg to reach a minimum toxic level, of about 37 quarts (35L) of juice.

The other concern is the presence of oxalates.  Oxalates have been tied to the formation of oxalate kidney stones in humans, but cats rarely develop kidney stones -- they are more likely to have bladder stones, so I am unclear if this is even a concern.  In any case, cranberries contain 5-7 mg of oxalates per 3.5oz of food.  This is the same level for pumpkin, which is wildly used for cats and regarded as beneficial.

Bottomline, if I have another cat with UTI symptoms, I will use it again.  If and when the researchers ever do a sound study on felines and show it does not work, then I may rethink my position.

Summary of scientific studies from "Complementary and Integrative Therapies" by Donna Raditic, in Vet. Clinics of N. Am.: Small Animal Practice,  July 2015

Urinary Tract Infection in Cats

When a cat repeatedly visits the litter box, like 5 times in 10 minutes, or begins to pee outside the litter box, with even a drop or two of blood, one likely cause is a urinary tract infection.

There are several related medical problems that are related and must be clearly distinguished if treatment is to be successful.  They are:  bladder stones, urethral plugs in males, idiopathic cystitis, plus some other causes.  The key to determining IF it is a UTI is a urinalysis.  The urine specific gravity will help determine if the help distinguish upper urinary tract infection, associated diseases (e.g. CRF), or lower urinary tract infection.  A urine culture will determine the bacteria involved.  In more complicated cases, bloodwork, xrays, thyroid tests, and even an ultrasound may be needed.

The likey cause of most UTI's is bacteria spreading from the external opening up into the bladder and then even on to the kidenys.  Few infections seem to begin from blood into the kidneys, except in cases of trauma or urinary tract obstruction.  33-50% of all bacteria is E. coli.  25-33% are one of the many strains of Staph or Enterococci.  The remaining are a mix of 8+ bacteria.  In about 75% of the cases, only one bacteria is responsible for the infection, with 20% of the cases having 2 different species involved.  There is also the slim chance that a fungal infection can be the cause.

The standard treatment is antibiotics.  The first-line options are amoxicillin are trimethoprim-sulfadiazine.  Second-line option is nitrofurantoin.  Other antibiotics can be used, but many seem to be resistent to Enterococci.  Interestingly, the article says about clavamox "not established where there is any advantage over amoxicillin alone", which is intersting because clavamox is often seen as the go-to antibiotic.  Also of interest is the comment on cefovecin (Convenia) "Should only be used in situations where oral treatment is problematic" and it goes on to explain that the long duration interfers then with any post-treatment cultures for over 21 days.

In simple cases, treatment with antibiotics is for 10-14 days, with symptoms lessening in 48 hrs.  Sadly, simple UTI's are rare.  More complicated cases involving CKD or diabetes should be treated for 4-6 weeks.  Reinfection and relapse can occur.

The article also mentions alternative treatments, including cranberry extracts, D-mannose, methenamine hippurate, and probiotics.  Sadly there are no feline studies on any of these products.  Do note that methenamine is "poorly tolerated by feline patients".

Summarized from "Urinary Tract Infections", Shelly Olin and Joseph W. Bartges, pp 509-517, in Consultations in Feline Internal Medicine, v.7, 2015.