How common is it to have an asymptomatic UTI?

Here is My Question:
I had a urinalysis done this week prior to my scheduled infusion of Ofatumumab. My urine culture came back positive for a UTI. I have no UTI symptoms, but have had flare ups of past MS related symptoms and headaches for the last week. My question is, how common is it to have an asymptomatic UTI?

I have never had one (that I know of) before. I’m 33, diagnosed with RRMS in October, take no other medications and have no other medical conditions. Would it be helpful to take any supplements (cranberry) to help prevent future UTIs?

Answer:
Your can categorize bacteriuria (i.e bacteria in the urine) into four categories for people with Multiple Sclerosis :

1. Contamination: this is usually obvious and caused by normal skin bacteria getting into the urine when the subject does not clean themselves well and do a mid-stream collection. This can also be caused by sampling urine that has been sitting too long in a collection bag
2. Colonization: This usually occurs in people with neurogenic bladder dysfunction and is far more common in disabled people with indwelling catheters or those performing intermittent self catheterization.  Colonization is defined as a positive urine culture but without definite signs of a urinary tract infection on urinalysis (see below) or symptomatically. We do not usually treat colonization for a variety of reasons; first, it is very difficult to eradicate colonization and second, trying to treat with antibiotics often causes resistant infections to develop
3. Asymptomatic urinary tract infection (UTI): This is defined as an individual with both an abnormal urinalysis (leukocyte esterace positive with many WBCs and bacteria) and an abnormal urine culture (> 100,000 bacteria) who does not clearly present with symptoms of a urinary tract infection. This is very common in MS patients (more common than a symptomatic UTI) . People with MS with asymptomatic UTIs often present with increased fatigue or other worsening neurological symptoms but without typical symptoms of a UTI, such as increased urinary frequency, pain on urination, malodorous urine or fever. We usually treat these individual with appropriate antibiotics and, if their worsening symptoms are significant, we will simultaneously treat them with intravenous corticosteroids. The worsening symptoms in these individuals are often not definable as a relapse.
4. Symptomatic UTI: These individuals have typical signs of a UTI with a positive urinalysis and urine culture. 

Overall, risk factors for asymptomatic or symptomatic UTIs in people with MS include being female, older, more disabled (at least walking with assistance), prior UTIs and using catheters.

In your case, I do not have enough information to determine if your positive results were caused by contamination or an asymptomatic urinary tract infection. If both your urinalysis and urine culture showed signs of an acute infection then this likely represents an asymptomatic UTI. 

​Revere P (Rip) Kinkel, MDProfessor of Clinical Neurosciences
Director of the Multiple Sclerosis Program
Clinical Neurosciences Director
University of California San Diego