A recent CMAJ article and commentary go against a lot of the principles for diagnosing and managing urinary tract infections in elderly people that those of us who work in long-term care institutions have been following for many years.1,2 I disagree with the definition Susan Walker and colleagues provide for asymptomatic bacteriuria: the presence of bacteria without urinary symptoms.1 Is a previously stable patient with dementia who exhibits acute delirium asymptomatic? I do not think so. My colleagues and I are unable to elicit information on lower urinary tract symptoms from many of our patients because of their dementia and incontinence.
The important question in the long-term care facility is, How does one assess the cause of an episode of acute delirium, especially if there is fever? Such cases are fairly common, yet Lindsay Nicolle suggests that acute changes in clinical status such as fever and delirium should not be attributed to urinary tract infection and that urine samples should not even be obtained. How then are we to tell if a urinary tract infection is indeed causing the delirium? How are we to manage residents with dementia who exhibit delirium with no other obvious cause, particularly if the resident is febrile?
I have seen many residents with dementia who suffer an acute worsening of confusional state, often with behavioural changes and agitation, who show a urine sample positive for white blood cells and are treated with antibiotics and promptly get better. We are now being told that this is strictly coincidence: the antibiotics were not of any help, the urinary tract infection was asymptomatic and there was some other cause for this acute delirium. I do not believe the point has been proven.
I do agree with Walker and colleagues that many elderly residents who have minimal symptoms are inappropriately treated for urinary tract infection. It is clear that a negative dipstick result for white blood cells reasonably excludes the diagnosis of a urinary tract infection but that a positive urine dipstick result or culture is not to be relied upon to diagnose significant infection. Our policy here is to discourage urine cultures and not to look for or treat truly asymptomatic urinary tract infections.
Signature
John Miller
Medical Coordinator Mount St. Mary Extended Care Hospital Victoria, BC
References
- 1.Walker S, McGeer A, Simor AE, Armstrong-Evans M, Loeb M. Why are antibiotics prescribed for asymptomatic bacteriuria in institutionalized elderly people? CMAJ 2000;163 (3): 273-7. [PMC free article] [PubMed]
- 2.Nicolle LE. Asymptomatic bacteriuria in institutionalized elderly people: evidence and practice [commentary]. CMAJ 2000;163(3):285-6. [PMC free article] [PubMed]