People often have no clue about what might be important when an older individual, especially if they have dementia, develops a bladder infection. I often hear that the key indication is that the patient’s urine is “smelly” or “darker” and that a checking a urine culture for bacteria is sufficient for diagnosis. While both are good guidelines, this is not necessarily true.
First, what are the symptoms?
Is there a fever, urinary burning, frequent urination, or poor appetite? Those are the specific symptoms which clearly indicate the need to be treated. However, with my elders who have dementia, it is often not so straightforward. Sometimes the symptoms are behavioral, such that the person becomes more agitated, aggressive, or conversely, lethargic.
The person with dementia may not feel well, but be unable to communicate their distress. This is serious.
Studies show an elder with fairly advanced dementia has a 25% chance of dying from pneumonia, even when treated with antibiotics.  This is related to the fact that they are not aware that something bad is happening to their body and don’t communicate that need for evaluation. This is just as true with bladder infections as with lung infections.
It is very important to order a full urinalysis, with microscopy and urine cultures if needed. Nothing less is sufficient in my practice. However, just finding some bacteria or some white blood cells in the urine, or a “Positive” urine culture does not mean that there is a bladder infection that needs to be treated.
The difficulty is that it is often hard to get a good sample for a test. The elder may be incontinent or very private and not allow anyone near them in the bathroom. Getting a “hat” for urine collection in the toilet is a good start. There needs to be a discussion about goals of care before we forcibly stick a catheter into anyone’s bladder, let alone someone who does not understand what is being done, and may think they are being violated (that is another discussion).  (How to use a hat)
One we get the urine, just seeing white cells or bacteria is not an accurate diagnosis. I have seen patients in the ER diagnosed with urosepsis presenting with a fever of 102, but their urine labs show a count of 5-10 white blood cells (WBCs) per HPF. More likely in the case of urosespsis would be urine with more than 20 WBCs, even upwards of 100, if it was really an infection of the bladder making this person sick. 
Remember, an elder may have 100 WBC in the urine, but not show any symptoms. The new geriatric guidelines advise not to treat in such cases, but in such cases be aware and watch the patient carefully.
The bacterial culture alone does not indicate with certainty the presence of an infection. It may be positive from contamination, and the urine would not show more than a few WBCs. It is important to look at how many epithelial cells are found. If there are more than a few, the specimen is likely not a “clean catch” and there is likely contamination from outside sources. Redo the test with more care to cleaning the perineal area. Bacterial presence but low WBC count would not indicate an infection, unless the person has an immune problem.
Those are the diagnostic steps needed before treating any suspected bladder infection. Treatment with antibiotics is not benign, and should be used in elders only when clearly necessary. I have seen three frail people die from subsequent antibiotic-associated colitis, or from catching an antibiotic-resistant Clostridia Dificille infection after the antibiotics cause a disruption to their healthy gut bacteria.
Please share any questions you have related to bladder infections at our community chat.
Elizabeth Landsverk, MD