Urinary tract infections are relatively common in CKD cats
because the dilute urine seen in CKD allows bacteria to thrive.
In the worst case, the bacteria may travel up to the kidneys and cause
infection there.
It is extremely important to treat these infections because they may make
the CKD progress faster (in some cases, they may even cause CKD), and may
make the cat feel very uncomfortable or downright ill.
What Are Pyelonephritis
and Urinary Tract Infections?
Most people have heard of or experienced an infection of the urinary tract, but
may not be entirely clear exactly where it happens.
The urinary
tract consists of:
two kidneys
two ureters:
thin tubes, each of which leads from a kidney to the bladder
the bladder
the urethra:
a tube which carries urine from the bladder to outside the body
The bladder and
urethra are considered to be the lower urinary tract.
The kidneys and
ureters are considered to be the upper urinary tract.
The expression
"urinary tract infection" or "UTI" is normally (but not always) used to
refer to infections in the lower urinary tract.
Inflammation in
the upper urinary tract, particularly in the form of bacterial infections
in the kidneys themselves, is often referred to as pyelonephritis or a kidney infection.
Cats are very
prone to an inflammatory condition commonly known as
FLUTD (Feline
Lower Urinary Tract Disease, or feline idiopathic cystitis), which can have a variety of causes. FLUTD is not
normally caused by
bacterial infection (which is what this page addresses), and therefore
cats with FLUTD do not normally benefit from antibiotic therapy.
Importance
It is extremely important to treat infections in the urinary tract because they may
make the CKD progress faster, and may make the cat feel very
uncomfortable or downright ill.
In some cases, these infections may even cause CKD. Bacterial urinary tract infections
(2016) Dowling PM Merck
Veterinary Manual says "The consequences of untreated UTI include
lower urinary tract dysfunction, urolithiasis, prostatitis, infertility,
septicemia, and pyelonephritis with scarring and eventual kidney failure."
Frequency
Urinary tract
infections are relatively common in CKD cats.
Problem urinary tract infections
(2012) Chew DJ & Westropp JL American College of Veterinary
Surgeons Proceedings state "UTI occurs in approximately
30% of all cats with chronic renal failure (CRF), many within one year of
diagnosis of CRF."
Age is also a factor.
Managing
the Ecoli
UTI
(2011) KuKanich KS NAVC Clinician's BriefAug 2011 pp61-66
says "cats older than ten years of age are predisposed and usually have
concurrent illness."
Since most cats with CKD are older, they are at additional risk.
Causes
Lower Urinary Tract Infections
These are usually caused by bacteria gaining access to the bladder.
Urinary tract infections are relatively common in CKD cats
because the dilute urine seen in CKD allows bacteria to thrive.
Around 40-60% of UTIs in cats are caused by e Coli.
Managing
the Ecoli
UTI
(2011) KuKanich KS NAVC Clinician's BriefAug 2011 pp61-66
says "Other bacteria associated with UTI include
Staphylococcus, Streptococcus, Enterococcus,
Proteus, and Klebsiella."
In some cases, the bacteria involved rise further into the upper
urinary tract and cause kidney inflammation, also known as pyelonephritis.
Chronic Renal Failure
(2001) Polzin DJ
Delaware Valley Academy of Veterinary Medicine
states that
"infection at one location potentially places the entire urinary tract
at risk for infection."
Sometimes pyelonephritis has other causes. Kidney stones can cause
pyelonephritis, as may
polycystic
kidney disease (PKD). It may also be caused by bacteria carried via
the bloodstream.
Veterinary Partner
says
pyelonephritis is "caused
by a bacterial invasion. The kidney infection may have come from the
bladder through the ureters, the bloodstream, or have invaded via other
organs. Infection via the bladder/ureters is the most common route... The bloodstream route
of infection may be caused by bacterial endocarditis, diskospondylitis,
abscesses, and dental disease."
The Feline Patient (4th Ed.)
(2010) Norsworthy GD (ed.) Wiley-Blackwell
states "Pyelonephritis is inflammation of the renal pelvis and
parenchyma. The etiology in cats is typically bacterial…The infection may arise hematogenously (i.e., bacterial
endocarditis, abscesses, or dental disease); however, experimental
evidence favors ascension of bacteria from the lower urinary tract in most
cases."
Classification
of Urinary Tract Infections
Previously UTIs
were commonly classified on the basis of complicated or uncomplicated.
Uncomplicated
Uncomplicated
or simple urinary tract infections meant that the cat is normally healthy, and there
are no problems with the cat's bodily defence mechanisms or any structural
problems, so the infection should respond fully and usually quickly to antibiotic therapy.
Complicated
Kidney infections were always deemed to be
complicated, even in otherwise healthy cats.
Complicated
lower urinary tract infections were described as infections where there were other factors which increased
the likelihood of an infection arising,
persisting or recurring.
Antimicrobial
use guidelines for treatment of urinary tract disease in dogs and cats:
antimicrobial guidelines working group of the international society for
companion animal infectious diseases (2011) Weese JS,
Blondeau JM, Boothe D, Breitschwerdt EB, Guardabassi L, Hillier A, Lloyd
DH, Papich MG, Rankin SC, Turnidge JD & Sykes JE Veterinary Medicine
International2011 pp1-9 state "A
complicated UTI is an infection that occurs in the presence of an anatomic
or functional abnormality or a comorbidity that predisposes the patient to
persistent infection, recurrent infection, or treatment failure.”
A comorbidity
means the presence of other illnesses. As you might expect (particularly
so since the kidneys are part of the urinary tract), chronic kidney
disease means that UTIs in CKD cats might be considered complicated, but cats with other diseases
such as diabetes would also qualify.
Other factors
would include anatomic or functional problems, for example a cat with
polycystic
kidney disease (PKD) forms cysts in the kidneys which can be a breeding
ground for infection.
Cats with
kidney stones or dental problems may also be at increased
risk, and if they were to develop an infection, that would also be considered complicated.
However, later
guidelines,
International Society for Companion Animal
Infectious Diseases (ISCAID) guidelines for the diagnosis and management
of bacterial urinary tract infections in dogs and cats (2019)
Weese JS, Blondeau J, Boothe D, Guardabassi LG, Gumley N, Papich M, Jessen
LR, Lappin M, Rankin S, Westropp JL, Sykes J Veterinary Journal 247 pp8-25,
concede that cats with conditions such as CKD may be at increased risk of
recurrent UTIs, but state "animals with urinary tract abnormalities or comorbidities can
develop sporadic cystitis and not necessarily be at substantially
increased risk for complications or recurrence or have infections that are
more difficult to treat."
Therefore the
2019 guidelines propose a different classification system, as follows
(there are a couple of other categories, which are not relevant to CKD
cats with a UTI or kidney infection):
Sporadic Bacterial Cystitis
A one off lower
urinary tract bacterial infection.
Recurrent
Bacterial Cystitis
Three or more
lower urinary tract infections in the last twelve months or two in the last six
months.
Subclinical
Bacteriuria (SBU)
A urine culture indicates the presence of bacteria, and often there is
evidence of inflammation in the urine such as blood or an increased number
of white blood cells, but the cat is not showing any
signs or symptoms. This is
not unknown in CKD cats (see
below).
Upper Urinary Tract Infection
(Pylonephritis)
An infection of
the kidneys, which may be present with or without a lower urinary tract
infection.
Symptoms
Urinary Tract Infections
Cats with a UTI often do not show
any symptoms.
Bacterial urinary tract infections Dowling PM Merck
Veterinary Manual says "Unlike humans, veterinary patients are often
asymptomatic, and the UTI may be an incidental finding."
However, if
signs are present, they may include visiting the litter tray more
frequently but perhaps producing little or no urine, lying in the litter
box, or urinating other than in the litter box.
Humans with urinary tract infections are often confused, and some people
believe their cats may show similar problems.
Pyelonephritis
Cats with acute pyelonephritis will often be obviously ill, e.g. not
eating, sensitive to the touch in the lower back or abdomen (which your
vet may detect during
palpation), and/or have a fever.
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says "Animals with acute
pyelonephritis may exhibit kidney or flank pain, fever, malaise, and
sometimes vomiting, polyuria, and polydipsia."
Unfortunately, cats with chronic pyelonephritis may not be obviously ill
or the signs may be subtle, such as increased urination, increased
drinking, or vomiting, all of which are not uncommon in CKD
cats anyway.
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says "Chronic
pyelonephritis is more difficult to recognize, because clinical signs may
be subtle or absent. Polyuria and polydipsia are frequent. In many cases,
the disease goes unrecognized until kidney failure occurs."
One of our cats was prone to pyelonephritis,
maybe because he had PKD (in PKD cats, the bacteria can enter the cysts in
the kidneys and cause a deep-rooted infection),
and initially he would simply be a little subdued.
Fortunately, within a day or so he would also become incontinent, so we were able to
recognise the problem and get treatment started promptly.
Diagnosis
The usual method of diagnosis is a urine test, but for pyelonephritis in
particular other tests may also be appropriate.
The usual method to check for UTIs initially is via a urine sample.
Cystocentesis is the
best way to obtain a urine sample if you want to check for infection
because the sample is sterile.
International Society for Companion Animal
Infectious Diseases (ISCAID) guidelines for the diagnosis and management
of bacterial urinary tract infections in dogs and cats (2019)
Weese JS, Blondeau J, Boothe D, Guardabassi LG, Gumley N, Papich M, Jessen
LR, Lappin M, Rankin S, Westropp JL, Sykes J Veterinary Journal 247
pp8-25, state
"specimens for culture
should be collected by cystocentesis...Culture
of voided samples should only be performed when cystocentesis is
contraindicated because of the potential for both false positive and false
negative cultures."
Urinary tract infection: how to diagnose and treat
correctly (2003) Brovida C
Presentation to the
World Small Animal Veterinary Association World Congress explains why cystocentesis is the ideal method of urine collection, but not
always possible.
Once the urine sample has been obtained, usually the vet will test it by dipping a test strip into the urine
sample or by looking at a few drops of urine under a microscope.
If bacteria are present
in a clean urine sample, this is indicative of an infection. If no
bacteria are seen, the result will usually say "none seen" or "negative"
or "NSF" (an abbreviation for "no significant findings").
A negative test for bacteria does not mean no infection is present.
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says
of chronic pyelonephritis "Although abnormalities in the urinalysis
are present, they are often less dramatic than with acute kidney
infection. A single urine culture can be negative if bacterial numbers are
low."
Therefore even if the initial result is negative, it is important to run a culture and sensitivity test (see
below),
especially in a
CKD cat, in whom these infections do not always show in standard urine
tests (see below).
Elevated white blood cells are sometimes a sign of infection, but you cannot rely on checking white blood cells in the urine:
FLUTD: a diagnostic approach
(2011) Bovens C
Feline Update(Langford Veterinary Centre University of Bristol) states
"Urine dipstick is frequently positive for leukocytes [white
blood cells] in cats; this is
unreliable and does not indicate the presence of inflammation or
infection."
Urine tests may also find blood in the
urine. Blood in urine may be a sign of infection, but there are other
possible causes as discussed
here.
Culture
and Sensitivity (C&S) Test
A culture and sensitivity (or
susceptibility) test means that the laboratory tries to grow the bacteria
obtained from the urine sample over a few days (3-4).
If they are successful in
growing the bacteria, they then treat each batch with a different
antibiotic to ascertain to which antibiotic the bacteria are most
sensitive (i.e. which antibiotic is most likely to kill the bacteria).
Veterinary Partner
explains more about
these tests.
It is particularly important to run a C&S test for a CKD cat because the
dilute urine typically seen in CKD can make it hard to detect infections
in other types of urine test.
Cat Hospital of Chicago says
"Performing urine cultures on cats with CKD is important. Since the urine
is dilute, it can make identification of bacterial in the urine difficult.
Thus, bacterial urinary tract infections can be missed by running just a
simple analysis of the urine. A culture is the ‘gold standard’ test for
determining if a kidney infection is a cause or complicating factor in the
kidney failure."
A C&S test measures colony forming units (CFUs).
Diagnostic caveats for difficult bacterial urinary
tract infections (2005) Osborne CA DVM News Magazine
discusses UTIs and includes a table (Table 7) which shows what the levels of
bacteria found in a urine sample obtained by various methods probably
indicate.
Problem urinary tract infections
(2012) Chew DJ & Westropp JL American College of Veterinary
Surgeons Proceedings has a similar table, though the values given
differ somewhat.
Overview of the urinary system (2016)
Sanderson SL Merck Veterinary Manual states "If the sample is
collected by spontaneous micturition [urination] or manual compression,
significant numbers of bacteria are present if ≥10,000 CFU/mL of urine in cats are detected. Samples with
>1,000–10,000 CFU/mL in cats are
suspicious for a UTI. If the sample is collected by catheterization,
≥1,000 CFU/mL in cats is significant, whereas
samples containing 100–1,000 CFU/mL in
cats are suspicious for a UTI."
Generally speaking, for a cat whose urine was obtained by
cystocentesis, a level over 1000 cfu/ml indicates probable infection,
whereas for a mid-stream urine sample, the level would probably need to be
over 100,000 cfu/ml. A level below 20000 cfu/ml from a mid-stream urine
sample is probably contaminated.
Cultures are also often performed after a cat has been
treated with antibiotics to check that the infection has gone. You
normally have to wait seven days after stopping antibiotics before you can do
this (to give any surviving bacteria time to grow). Some vets also run C&S
tests during treatment for cats on
lengthy courses of antibiotics, or a cat with
recurring or resistant infections, to make sure the treatment is working. IDEXX Laboratories
offer a Urine Culture and MIC Susceptibility, Low Colony Count (test code
is 4033) which is "Recommended for patients with recent or current
antibiotic therapy or when a low level of infection is suspected." This
may also be of use for CKD cats where low levels of bacteria may be
present.
RapidBac Vet is a new test that takes only 20 minutes
to perform and
costs a lot less than a culture.
Diagnostic accuracy of a rapidimmunoassay for
point-of-care detection of canine urinary tract infection
(2016) Jacob ME, Crowell MD, Fauls MB,
Griffith EH, and Ferris K American Journal
Veterinary Research77 pp162
reports that it was 95% accurate in tests
with dogs. The manufacturer says recent tests in cats indicate sensitivity
of 100% and a negative predictive value of 99%. I do not know of anyone
who has used this test in a cat yet but the manufacturers are interested
in any feedback.
Cats with pyelonephritis may experience a worsening of their kidney
bloodwork. In the worst case, this may be so severe that it leads to
acute kidney
injury. One member of Tanya's CKD Support Group had
a cat who was diagnosed with pyelonephritis whose creatinine level was 26
mg/dl at diagnosis. Your cat's case will hopefully not be as severe, but
if your cat's bloodwork worsens suddenly, speak to your vet about the
possibility of your cat having an infection.
The presence of an infection is
sometimes indicated in the white blood cell
readings of a blood test, particularly if pyelonephritis is present.
CKD cats with chronic infections may also have
anaemia.
Ultrasound
For cases of pyelonephritis, your vet may also wish to
have an
ultrasound performed to look at the renal pelvis. The renal pelvis
is the top of the ureters (the tubes that lead to the bladder) and it may
be dilated if pyelonephritis is present (this is known as pyelectasis),
which should be visible on ultrasound (though this may not occur in the
case of acute infections).
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says "Other useful
diagnostic tests include abdominal ultrasonography and
IV pyelography. Both studies may show dilation of one or both renal
pelvises secondary to inflammation and partial obstruction."
One difficulty with diagnosis is that cats do not always show any
symptoms, so you may not realise there is a problem.
Subclinical bacteriuria in cats: prevalence,
findings on contemporaneous urinalyses and clinical risk factors
(2017) Puchot ML, Cook AK & Pohlit C Journal of Feline Medicine and
Surgery19(12) pp1238-1244 looked at 500 urine samples from
cats with no clinical signs of infection and found that 6.2% did actually
have a urinary tract infection, as indicated by a positive urine culture. It states that the presence of subclinical
bacteriuria "was significantly associated with a lower urine
specific gravity and presence of chronic kidney disease."
Other studies support the increased likelihood of subclinical UTIs in cats
with CKD.
Urinary tract infections in cats with chronic kidney
disease (2013) White JD, Stevenson M, Malik R, Snow D &
Norris JM Journal of Feline Medicine & Surgery 15(6)
pp459-65 found that 72% of the cats in the study had occult (hidden) UTIs,
i.e. a positive urine culture but no clinical signs of infection.
Even if you suspect that your cat might have an infection, it is quite common for tests to indicate that
this
does not appear to be the case when in fact one is present. Unfortunately
not every vet accepts that this may happen.
One human study,
Establishment of a persistent Escherichia coli
reservoir during the acute phase of a bladder infection
(2001) Mulvey MA, Schilling JD & Hultgren SJ Infection and Immunity69(7) pp 4572-9,
found that in some cases the bacteria that cause urinary tract
infections can burrow so deep into the bladder lining that they cannot be
detected in the usual tests.
In a 2004 study reported by
Science Daily, researchers found that the
bacteria commonly involved in UTIs pass through four distinct
developmental stages, including a dormant stage in some cases, which may
help explain why UTIs often recur.
Urinary tract infection and subclinical bacteriuria
in cats, a clinical update (2019) Dorsch R, Teichmann-Knorrn &
Lund HS Journal of Feline Medicine and Surgery21
pp1023-1038 states "Some E
coli strains in humans and mice are able to invade deeper tissues,
persisting intracellularly, and may also form intracellular biofilm. Thus,
those pathogens cannot be isolated from urine and can escape antimicrobial
treatment."
It is also quite common for nothing to grow
in a culture if the cat has pyelonephritis rather than a lower urinary
tract infection,
particularly if the infection is chronic rather than acute. Some types of
bacteria do not grow in a culture, or levels are too low to measure easily.
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says
of chronic pyelonephritis "Although abnormalities in the urinalysis
are present, they are often less dramatic than with acute kidney
infection. A single urine culture can be negative if bacterial numbers are
low."
The Feline Patient (4th Ed.) (2010) Norsworthy GD (ed.) Wiley-Blackwell
states "The etiology in cats is typically bacterial (…) However, urine
cultures do not always recover an organism. Usually, the affected cat is
presented for chronic renal failure after many months or years of
subclinical pyelonephritis; by this time, it is abacteriuric."
(2005) Parry NMA UK Vet10(6) pp1-5
says "Absence of urinary changes does not rule out pyelonephritis as infection
can localise to the renal parenchyma, producing no abnormalities on
urinalysis and negative urine cultures. (...) The presence of urinary
leucocyte casts is consistent with renal inflammation. Positive bacterial
culture from urine obtained by cystocentesis is yielded in most acute
cases, although in chronic cases cultures are often negative, and multiple
cultures may be required to confirm UTI. Unfortunately, the leucocytosis
may resolve with chronicity, making chronic pyelonephritis difficult to
diagnose. Similarly serum chemistry profile is usually normal unless CRF
develops."
Ultrasound
may be helpful in diagnosing the existence of pyelonephritis,
though this can be of limited value in cats with
PKD, whose
kidneys already look abnormal. Ultrasound may also help with detecting
lower urinary tract infections, but only
if the bladder is full. In both cases you need an experienced operator.
Treatments
The main treatment for urinary tract infections is antibiotics.
D-mannose is a natural treatment which seems to help
many cats, though it should never be used instead of antibiotics. See below
for more information.
Infections may sometimes lead to
anaemia. If your cat has anaemia and an infection, and the
anaemia is not life-threatening, you may be able to wait before starting
treatment for the anaemia because often anaemia caused by infection or
inflammation will resolve once the infection has gone.
The British Medical Journalhas
information about a human study which showed that
lactulose (which is normally used for
constipation) may
help prevent urinary tract infections in humans. However, I would
only give lactulose if my cat needed it for constipation.
Humans with cystitis are sometimes advised to take
cranberries. However, cranberries are not appropriate for CKD cats (see
Holistic Treatments for more information on this).
Below I give the 2019 guidelines from ISCAID for
treating UTIs. The guidelines focus strongly on what has been shown to
work for humans, admitting there are limited data available regarding
cats, and on the issue of antibiotic resistance. The authors of the
guidelines stress that they are general guidelines, good for the majority
of cases but not for all.
They also
recommend managing any other illnesses or risk factors that may be
present.
Subclinical
Bacteriuria
International Society for Companion Animal
Infectious Diseases (ISCAID) guidelines for the diagnosis and management
of bacterial urinary tract infections in dogs and cats (2019)
Weese JS, Blondeau J, Boothe D, Guardabassi LG, Gumley N, Papich M, Jessen
LR, Lappin M, Rankin S, Westropp JL, Sykes J
Veterinary Journal247 pp8-25
state "Treatment of subclinical bacteriuria with antimicrobials is
rarely indicated and is discouraged. In animals where it is unclear
whether clinical signs are attributable to cystitis, a short course (e.g.
3–5 days duration) of antimicrobials as recommended for sporadic cystitis
could be considered. If there is no clinical response, antimicrobials
should be discontinued, as an infectious process is unlikely."
When to Start Treatment
for CKD Cats
The 2011 guidelines advised starting treatment
immediately for CKD cats with a UTI,
because of the fact that
infections do not always show (see
above) and
the risks of leaving possible infections untreated. The 2019 guidelines
are much vaguer, making no specific reference to CKD cats. However,
Urinary tract infection and subclinical bacteriuria
in cats, a clinical update (2019) Dorsch R, Teichmann-Knorrn &
Lund HS Journal of Feline Medicine and Surgery21
pp1023-1038 state "The decision to treat with antimicrobials should be
based on the presence of clinical signs, and/or concurrent diseases, and
the results of urine culture and susceptibility testing."
Personally, I would want to treat any urinary tract
infection in a CKD cat because of the risk of the infection rising into
the kidneys.
Renal dysfunction in small animals (2016)
Brown SA Merck Veterinary Manual states that even for cats in Stage
1 CKD, "The identification and supportive treatment of developing
complications (eg,...bacterial urinary tract infection) should be
aggressively pursued."
This is particularly important if your cat's kidney values have recently
worsened, because an infection may be the cause.
Management and treatment of chronic kidney disease
in cats (2016)
Caney S In PracticeOct 2016 pp10-13 says of lower urinary
tract infections "Current recommendations are that these should be
treated if the patient shows clinical signs (systemic and/or lower
urinary), if pyuria is present, where ultrasound evidence of
pyelonephritis is present and/or if renal function has recently
deteriorated."
Treatment recommendations for CKD in cats
(2019) International Renal Interest Society
says that for CKD cats "any urinary tract infection should be regarded as
a potential pyelonephritis and treated appropriately."
Pyelonephritis
Pyelonephritis should be treated immediately, according
to
Treatment of urinary tract infection (UTI):
guidelines for sporadic and recurrent UTI
(2020) Adams LG Presentation to the Michigan Veterinary Medical
Association, which says "For treatment of
animals with pyelonephritis, empirical antibiotic therapy should be
initiated pending urine culture results rather than waiting for culture
results."
Intravenous fluid therapy may also be necessary, particularly for cats who
have a fever or who are not eating, or whose kidney values have worsened.
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says "Animals that are febrile,
anorectic, dehydrated, or azotemic should be hospitalized to provide IV
antibiotics and fluid therapy. Fluid therapy may prevent acute
pyelonephritis from progressing to azotemic acute kidney injury and will
improve renal perfusion and uremic signs in animals already experiencing
uremia."
Antibiotics
UTIs and pyelonephritis are usually treated with
antibiotics.
Lower urinary tract infections are usually relatively easy to
treat, but pyelonephritis can be trickier:
Managing complicated urinary tract infections
(2008) Grauer GF CVC in San Diego Proceedings says
"Most bacterial infections of the lower urinary tract respond quickly to
antimicrobial treatment; however, urinary tract infections (UTI)
associated with defects in the host immune system (complicated UTI) often
fail to respond or recur after antibiotic withdrawal and can be a
therapeutic challenge."
Managing complicated urinary tract infections
(2008) Grauer GF CVC in San Diego Proceedings says with
regard to simple UTIs "Without benefit of
bacterial sensitivity testing, the following are the drugs of choice for
the bacteria listed: E. coli - enrofloxacin; Proteus -
amoxicillin-clavulanic acid; Staph - amoxicillin-clavulanic acid; Strep -
amoxicillin-clavulanic acid; Enterobacter - tetracyclines; Klebsiella -
enrofloxacin; Pseudomonas - tetracycline. If bacterial identification is
unknown, treatment is best based on the gram-staining characteristics,
i.e., ampicillin/amoxicillin or amoxicillin-clavulanic acid for
gram-positive bacteria and trimethoprim-sulfa or enrofloxacin for
gram-negative bacteria."
In the UK you may be offered
cefovecin (Convenia), because this is approved in Europe for the
treatment of UTIs in cats. However, bacteria can develop resistance to
cefovecin over time, so it should normally only be used a maximum of
around three times.
The manufacturer actually recommends only using cefovecin once.
UTIs caused by Enteroccocus may not need to be
treated immediately.
Diagnosing and treating urinary tract infection in
cats
(2015) Kovalik D
Veterinary Medicine says "Treatment
is not currently recommended for asymptomatic cats with isolates of
Enterococcus species, as this infection commonly resolves without
intervention." However, pyelonephritis must be treated immediately,
whatever the cause.
Pyelonephritis
Treatment recommendations for CKD in cats
(2019)International Renal Interest Society says "any urinary tract infection should be regarded as a potential
pyelonephritis and treated appropriately."
Your vet will
choose the most appropriate antibiotic based on the results of the culture
and sensitivity test. Normally a broad spectrum antibiotic will be chosen
because although
one bacterium may dominate, it is not uncommon for more than one to be
present (which may also be the case with recurrent bacterial cystitis).
Hyperthyroidism: a view from the urinary tract
(2010) Grauer GF CVC in Kansas City Proceedings says "Urine cultures should be obtained as part of the workup of
both hyperthyroidism and CKD. In either case, a concurrent UTI should be
managed as a complicated UTI with long-term antibiotic treatment based
on culture and sensitivity results."
My cat with repeated pyelonephritis did not respond to amoxicillin but
enrofloxacin (Baytril) worked every time.
Chronic Renal Failure
(2001) Polzin DJ
Delaware Valley Academy of Veterinary Medicine
states "Enrofloxacin's excellent in vitro activity combined
with good serum, renal tissue, and urine concentrations following
oral or parenteral administration make it an excellent choice for
these patients. Further, fluoroquinolones may ultimately supplant use
of aminoglycosides for managing pyelonephritis in most patients
because of their effectiveness in achieving both renal and urine
concentrations with minimal toxicity."
Length of Treatment:
Recurrent Bacterial Cystitis or Pyelonephritis
Since cats with CKD are not healthy, it was felt that they usually need a longer course of
treatment
in order to be sure that the bacteria are completely eradicated and the
infection completely cured.
Cats
with pyelonephritis in particular were
usually given a prolonged course of antibiotics.
The course of treatment was usually for at least four weeks and could be
as long as eight weeks, or occasionally even longer.
Chronic Renal Failure
(2001) Polzin DJ
Delaware Valley Academy of Veterinary Medicine
states "It is recommended that acute, uncomplicated UTIs and some
reinfections be treated for a period of 10 to 14 days whereas most
recurrent UTI, complicated infections, pyelonephritis, and prostatitis
should be treated for at least 4 to 6 weeks. Infections involving the
kidney(s) and prostate gland may require even more prolonged therapy."
Urinary tract infection (UTI): how to diagnose
correctly and treat (2003),
Brovida C Presentation to
the28th World Congress of the World Small Animal Veterinary Association
mentions that antibiotic treatment should continue for 4-8 weeks in the
case of kidney infections.
More recent papers make similar recommendations.
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says "Pyelonephritis should
be treated aggressively with broad-spectrum antibiotics, based on urine
culture and antimicrobial susceptibility testing, for 4–8 wk."
Management and treatment of chronic kidney disease
in cats (2016)
Caney S In PracticeOct 2016 pp10-13
says "Typically
a prolonged course of treatment (eg, four to six weeks) is needed to
eliminate the infection."
However, in 2019 ISCAID issued new guidelines,
International Society for Companion Animal
Infectious Diseases (ISCAID) guidelines for the diagnosis and management
of bacterial urinary tract infections in dogs and cats (2019)
Weese JS, Blondeau J, Boothe D, Guardabassi LG, Gumley N, Papich M, Jessen
LR, Lappin M, Rankin S, Westropp JL, Sykes J Veterinary Journal
247 pp8-25, which state "Treatment
for 4–6 weeks has previously been recommended for veterinary patients
(Weese et al., 2011). However, the recommended duration of therapy for
acute bacterial pyelonephritis in humans is 7–14 days... There is no
reason to suspect that a longer duration would be necessary for dogs and
cats. In the absence of veterinary-specific data, the Working Group
recommends 10–14 days of treatment."
The authors of the new guidelines are rightly concerned about the risk of
antibiotic resistance.
However, one reason why a longer course of treatment was previously recommended was
because blood flow to the site of most kidney infections is poor, so it
can take a while for the antibiotics to reach and kill the bacteria; and
based on what I have seen over the twenty years I have been running this
website, some CKD cats do indeed need a longer course of treatment,
particularly in cases of chronic pyelonephritis.
Diagnosing and treating urinary tract infection in
cats (2015) Kovalik D
Veterinary Medicine states "Antimicrobials
should be given not just for seven to 14 days, but until a
bacteriologically sterile urine can be confirmed both during
administration of medication and for a protracted time after cessation of
treatment."
In cases of pyelonephritis, the dose may also need to be increased or
given more frequently:
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says "The infection may
respond to the same antibiotics recommended for cystitis, but more
frequent administration (eg,
amoxicillin tid rather than bid [three times a day rather than
twice a day]) and/or higher dosages are
indicated."
If Your Vet Refuses to Assist
Some vets will refuse to prescribe antibiotics for infections where no
bacteria have been cultured.
Vets may act in this way because of concerns about
antibiotic resistance. Whilst this is a valid concern, giving too
short a course of treatment actually increases the chance of antibiotic
resistance.
Not treating pyelonephritis appropriately in particular may be dangerous
according to
International Society for Companion Animal
Infectious Diseases (ISCAID) guidelines for the diagnosis and management
of bacterial urinary tract infections in dogs and cats (2019)
Weese JS, Blondeau J, Boothe D, Guardabassi LG, Gumley N, Papich M, Jessen
LR, Lappin M, Rankin S, Westropp JL, Sykes J Veterinary Journal
247 pp8-25,
which say "As opposed to bacterial cystitis, where patient morbidity is
relatively low, pyelonephritis can result in severe and rapid kidney
injury. Thus, rapid diagnosis and treatment is important, and the
implications of initial treatment failure are higher as compared with
bacterial cystitis."
Alternatively, vets may prescribe antibiotics but only for a short period,
which may not be sufficient for a CKD cat. This is likely to become more
common in light of the latest (2019) ISCAID guidelines. If your cat is
only given a short course and after finishing it, you think your cat is
still not right, ask for a longer course. Also ask for repeat culturing
(see Monitoring immediately below).
For short courses of antibiotics (3-14
days),
many vets liked to check the urine again and run
another culture 7-14 days after stopping the antibiotic to make sure the
infection was completely gone. With a 14 day course, some vets also liked
to check the urine about three days before the end of the course.
If, as is possible with a CKD cat, you are giving a lengthy course of four weeks
or more,
your cat's progress may be monitored via urine culture once or twice a
week during the first month of therapy and checked again after completion
of the treatment course.
Management and treatment of chronic kidney disease
in cats (2016)
Caney S In PracticeOct 2016 pp10-13 says "Repeat
urine culture is recommended during the treatment period and seven to 10
days after treatment has concluded to confirm treatment success."
The purpose of monitoring during treatment is to make sure there is a response, in case you need to change to a
different antibiotic.
If the antibiotics seem to be working (i.e. culture counts are reducing),
you do not normally stop the antibiotics, but give the complete course to
be sure you are eradicating the infection.
Unfortunately since there is often poor antibiotic
penetration into the renal medullary parenchyma, chronic
pyelonephritis may be difficult to treat. A urine sample may
be cultured seven to ten days after treatment initiation, and
then repeated one week post-antibiotic therapy, and
monthly thereafter until three consecutive negative cultures are
obtained."
Pyelonephritis in small animals (2016)
Brown SA Merck Veterinary Manual says "A urinalysis and culture should be repeated 3–7 days after therapy,
and then monthly for 3 consecutive months. If all of these cultures are
negative, the interval between urine cultures may be gradually lengthened.
Animals with pyelonephritis are at high risk of persistence or recurrence
of infection and for secondary infections at other sites (eg, bacterial
endocarditis and discospondylitis)."
Recurrence: Relapses and Reinfection
Unfortunately it is not uncommon for urinary tract infections to relapse
or recur, especially if too short a course of antibiotics has been given.
A recurring urinary tract infection is often classified as:
Relapsing
The infection returns, usually a few days after stopping treatment, and it
is caused by the same bacteria that caused the first infection.
Reinfection
The cat develops another infection but this time it is caused by a
different bacterium. This will usually happen some time after the
antibiotics used to treat the initial infection were stopped. This can
occur because often the cat is infected with more than one infective
agent.
Bacterial urinary tract infections
(2016) Dowling PM Merck
Veterinary Manual says
"In dogs and cats, UTI are caused by more
than one pathogen 30% of the time.
In immunocompromised patients, funguria from
Candida spp may be seen."
It can be difficult to tell if an infection is relapsing or recurring. I
am guessing with my cat who had repeated infections that it was relapsing,
because the antibiotic we used did always do the trick, and the period
between his infections was usually quite long.
"Recurrence of UTI with the same organism warrants further
investigation of potential problems with antimicrobial treatment and/or
reevaluation for a source of the infection (uroliths or neoplasia).
Recurrence of UTI with a different organism warrants further investigation
for a cause of immunosuppression."
Refractory Infections
This means that the infection does not resolve despite
giving antibiotics to which the bacteria causing the infection are
susceptible. This may happen for a number of reasons, e.g. if the cat is
not given the full course of antibiotics (perhaps spitting them out behind
the sofa when you are not looking).
Focus on pharmacology: use of antibiotics for the
urinary tract (2017) Foster JD
Today's Veterinary Practice 7(2) pp119-127 mentions that
another possible cause is "Decreased renal drug elimination (results in
lower than expected urine drug concentration)." The paper goes on to
discuss choosing antibiotics.
For
animals with frequent infections, which cannot be cured, low dose (1/3 to
1/2 of the conventional daily dose) antimicrobial administration at
bedtime may be recommended after the urinary tract has been sterilized
with standard dose antibiotic treatment. This allows the drug to be
present in the bladder overnight supplementing the animal's defense
mechanisms. Low (sub therapeutic) dosages of antibiotic may reduce
infections by interfering with bacterial fimbria production and therefore
uroepithelial attachment. For recurrences due to gram-positive bacteria,
penicillins are recommended; while for recurrences caused by gram-negative
bacteria, trimethoprim-sulfa or enrofloxacin is recommended."
There may be risks in
doing this because it can increase the chance of antibiotic resistance,
but if your vet wishes to do this, discuss it and decide whether
you think it is a reasonable treatment for your cat: infections can be
hard for the weakened immune system of a CKD cat to cope with and to
recover from, so in some cases this is not an unreasonable option.
I did not try pulse
dosing for my cat, but since he used to let us know whenever he had a
kidney infection by becoming incontinent, my vet gave me an emergency
supply of enrofloxacin (Baytril) so I could start antibiotics immediately
whenever the problem arose.
D-mannose
A human study at the Washington University in St Louis School of
Medicine,
Establishment of a persistent Escherichia coli
reservoir during the acute phase of a bladder infection
(2001) Mulvey MA, Schilling JD & Hultgren SJ Infection and Immunity69(7) pp 4572-9, found that in some cases the bacteria that cause
urinary tract infections can burrow so deep into the bladder lining that
they cannot be detected in the usual tests. D-mannose appears to be very helpful when dealing
with this sort of infection.
D-mannose is a simple sugar.
It does not kill the bacteria as an antibiotic does; rather, it works by
attracting the bacteria to bind with itself rather than with the bladder
wall; the bacteria can then be passed out of the body via urination.
D-mannose will only work for
urinary tract infections caused by E coli (and not all of them), and possibly
for infections caused by
Klebsiella bacteria.
Klebsiella infections are rare, but E coli accounts for around 67% of
urinary tract infections in cats.
Although D-mannose is a type of sugar, it does not get absorbed by the digestive tract.
Therefore it should be
safe for diabetic cats, but check with your vet before using if your cat
has diabetes.
Although
D-mannose appears to be effective, it seems to work best for cats with a
recurring UTI. If your CKD cat is
prone to persistent, ongoing or repeated UTIs, speak to your vet about
using
it.
D-mannose is not intended to take the place of antibiotics. If your vet prescribes
antibiotics, you must use them, because untreated urinary tract infections
can rise into the kidneys and cause permanent damage, which is the last
thing a CKD cat needs. See
above for more information on treating urinary tract infections.
D-mannose Dosage
A commonly used dose is 250-500mg twice a day.
Managing
the Ecoli
UTI
(2011) KuKanich KS NAVC Clinician's BriefAug 2011 pp61-66
mentions a dose of 250-1000mg twice daily.
With most (but not all) brands, a ¼ of a teaspoon of the powder is
500mg, so if you are giving 250-500mg, you would give ⅛-¼ teaspoon twice a day, but check with your
vet.
Some people find it works better if they divide the total amount over 3-4
doses a day.
Keep giving it for a week after the symptoms have disappeared.
Since it is a type of sugar, D-Mannose has a pleasant taste. It can be
easily mixed with wet food or mixed with water and syringed into the cat's
mouth.
Where to Buy D-mannose
D-mannose is widely available from health food shops such as Vitamin
Shoppe and Wholefoods (it is often in the
women's health section). You want pure D-mannose. It can also be bought
online:
sells 50g for £17.50. This
company will ship to other countries.
Prognosis
Urinary tract
infections can be very worrying, particularly so since they can trigger
CKD or acute kidney injury, or cause CKD to worsen. They can also be
challenging to treat.
Do not give up
hope. My cat did not have CKD but he had PKD and frequent kidney
infections, yet he never developed CKD.
One member of Tanya's CKD Support Group had
a cat whose
creatinine level was 26 mg/dl at diagnosis. He was diagnosed with
pyelonephritis, and although he needed a twelve week course of
antibiotics, he made a full recovery with no permanent kidney damage.
Although you may not see a full recovery in a cat who already has CKD,
the bloodwork may
improve once the infection is under control.
Urinary tract infections may sometimes lead to
anaemia, which
should also improve once the infection has gone.
For cats with
acute on
chronic kidney disease, it may be possible to resolve the AKI and
return to the status quo of CKD.
Tips for minimizing acute kidney injury in the older
pet(2012)
Ross SJ Presentation to the Australian Veterinary Association NSW Annual
Regional Conference says
"expedient treatment of factors causing acute decompensation of CKD (e.g.,
pyelonephritis, hypovolemia) may permit reversion to pre-crisis levels of
function."
Animals
with acute pyelonephritis may recover normal renal function, depending on
the amount of damage that occurred before treatment. In cases of chronic
pyelonephritis with a severely hydronephrotic, nonfunctional kidney, a
nephrectomy may be the treatment of choice once the animal has been
stabilized. This will remove the source of infection and hopefully save
the opposite kidney. IV pyelography and/or renal scintigraphy are useful
to assess the relative function of each kidney. If both kidneys are
severely affected, medical management alone is the only alternative.
Recovery to chronic, stable renal failure is possible in many cases."
TREATING YOUR CAT WITHOUT VETERINARY ADVICE CAN BE
EXTREMELY DANGEROUS.
I have
tried very hard to ensure that the information provided in this website is
accurate, but I am NOT a vet, just an ordinary person who has lived
through CKD with three cats. This website is for educational purposes
only, and is not intended to be used to diagnose or treat any cat. Before
trying any of the treatments described herein, you MUST consult a
qualified veterinarian and obtain professional advice on the correct
regimen for your cat and his or her particular requirements; and you
should only use any treatments described here with the full knowledge and
approval of your vet. No responsibility can be accepted.
If your cat
appears to be in pain or distress, do not waste time on the internet,
contact your vet immediately.
This site was
created using Microsoft software, and therefore it is best viewed in
Internet Explorer. I know it doesn't always display too well in other
browsers, but I'm not an IT expert so I'm afraid I don't know how to
change that. I would love it to display perfectly everywhere, but my focus
is on making the information available. When I get time, I'll try to
improve how it displays in other browsers.
This site is a labour of love, from which I do not make
a penny. Please do not steal from me by taking credit for my work.
If you wish to
link to this site, please feel free to do so. Please make it clear that
this is a link and not your own work. I would appreciate being informed of
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