“Asymptomatic” – Depends on Your Definition
I am constantly reminded that medicine is an art as well as a science. Definitions and guidelines are relied upon to help us practice in the best way possible for our patients. Sometimes, however, the choice of a specific word can take on a life of its own and influence clinical decision-making in ways that were never intended. In clinical practice, patients are considered to be asymptomatic if they are a carrier of a disease or infection, but have none of the symptoms associated with that disease or infection. Asymptomatic infections are also often referred to as subclinical infections, with some using the descriptor clinically silent. The trick when caring for elders, however, is to recognize that diseases often present in a nonspecific or atypical manner in this population, and some symptoms may even be opposite to what one has grown to expect. Waiting for the classic symptoms of a disease or infection to manifest in older adults may increase their risk of developing significant morbidity or even dying.
The term asymptomatic bacteriuria continues to confuse clinicians, who usually like to have a concrete understanding of what to do in a given circumstance. Most healthcare providers agree that the mere presence of bacteria in a urine specimen does not mandate treatment with antibiotics nor constitute an infection. Even when the culture demonstrates at least 100,000 colony-forming units (CFUs) per milliliter of urine in a voided midstream clean-catch specimen, or at least 100 CFUs per milliliter of urine from a catheterized specimen, the presence of a significant number of white blood cells (WBCs) in the urine is necessary before making a diagnosis of a urinary tract infection requiring treatment. In the absence of WBCs in the urine, a diagnosis of asymptomatic bacteriuria can be made and no treatment provided.
Unfortunately, with regard to urinary tract infections, many clinicians assume that the term asymptomatic refers to clinical symptomatology only affecting the urinary tract, such as increased frequency of urination, burning upon urination, and incontinence. When caring for older patients, however, atypical presentations are commonly the norm. Many elderly persons with a urinary tract infection based on a urine culture and the presence of significant WBCs in their urine initially report no urinary tract symptoms. Only when re-questioning them and pressing for more details may a possible symptom surface. At times, difficulties with cognition or communication may also impair elders’ ability to provide an accurate account of new signs and symptoms. In addition, the presence of incontinence due to detrusor instability or some other mechanism may make it more difficult to identify new urinary tract symptoms.
I continue to be concerned over the considerable number of older adults who present with symptoms such as an unexplained fall, change in mental status, decline in functional ability, and/or decreased appetite, but have no urinary symptoms other than an abnormal urinalysis with significant WBCs and a positive urine culture. While we are never certain of a cause and effect in medicine, I believe a likely relationship must be considered in these cases, despite a lack of specific urinary tract symptoms. Although these individuals meet the criteria for a urinary tract infection, without specific symptoms related to their urinary tract, they are considered by many guidelines to have asymptomatic bacteriuria and may not be considered candidates for treatment. I agree that even the presence of pyuria does not confirm a diagnosis of a symptomatic urinary tract infection, as WBCs in the urine can result from any number of other inflammatory disorders involving the genitourinary tract, such as vaginitis. Clearly, the entire patient must be considered, not just his or her urine specimen.
The Infectious Diseases Society of America1 does not recommend screening for or treatment of asymptomatic bacteriuria, which is a recommendation I concur with. When caring for the elderly, however, we need to consider exactly what the term asymptomatic means. In this case, I believe that we should not limit symptoms to those of the urinary tract, but rather recognize one of the hallmark principles in geriatric medicine: Elderly persons with unexplained symptoms, such as falls, functional decline, and confusion, should never be considered asymptomatic. All possible etiologies for these nonspecific findings must and should be searched for, and, if possible, eliminated. These atypical and nonspecific presentations are often the first warning sign that a serious illness, infection, or medication side effect is manifesting. At times, they are the only symptoms we will observe. Therefore, I will continue to advocate treating elderly patients with unexplained symptoms, such as those previously noted, for a urinary tract infection if they meet the criteria for this condition, even if there are no specific urinary tract symptoms. Asymptomatic? I guess it depends on who is doing the looking!
Reference
- Nicolle LE, Bradley S, Colgan R, et al; Infectious Diseases Society of America; American Society of Nephrology; American Geriatrics Society. Infectious Diseases Society of America guidelines for the diagnosis and treatment of aymptomatic bacteriuia in adults [published correction appears in Clin Infect Dis. 2005;40(10):1556]. Clin Infect Dis. 2005;40(5):643-654.