What neurotransmitter changes are associated with a diagnosis of dementia and possible urinary tract infection (UTI) in an elderly patient presenting with confusion, disorientation, and impaired consciousness, along with symptoms of urgency to urinate and pain on urination, and a history of progressive memory loss and forgetfulness?

From the Guidelines

The likely diagnosis for this 78-year-old woman is delirium, possibly due to a urinary tract infection (UTI), rather than dementia, with significant neurotransmitter changes involving acetylcholine deficiency and dopamine excess. In delirium, acetylcholine, which is crucial for attention and memory, becomes depleted, disrupting normal cognitive function 1. Simultaneously, there is often an increase in dopamine levels, creating an imbalance that contributes to confusion, disorientation, and altered consciousness. Other neurotransmitter changes may include increased levels of norepinephrine, glutamate, and serotonin, as well as elevated inflammatory cytokines that affect brain function. These neurotransmitter imbalances explain the acute onset of confusion, disorientation, and reduced consciousness in this patient. The symptoms described by her husband (forgetfulness, leaving the stove on) may represent early dementia, but her current presentation of acute confusion, wandering at night, and urinary symptoms (urgency and pain) strongly suggest delirium secondary to a UTI, which is common in elderly patients and can cause dramatic changes in mental status even without significant fever or other typical infection symptoms.

Some key points to consider in this diagnosis include:

• The patient's age and presentation with acute confusion and urinary symptoms are consistent with delirium secondary to a UTI 1.
• The lack of clear evidence for a causal relationship between bacteriuria and delirium suggests that treatment of asymptomatic bacteriuria may not be beneficial in this case 1.
• The potential harm of antimicrobial treatment, including the risk of antibiotic-associated diarrhea and antimicrobial resistance, must be carefully considered 1.
• The patient's symptoms and presentation are more consistent with delirium than dementia, and treatment should be focused on addressing the underlying cause of the delirium rather than simply treating the symptoms 1.

Overall, the most appropriate course of action is to investigate and treat the underlying cause of the delirium, rather than simply treating the symptoms or prescribing antimicrobials without clear evidence of infection.

From the Research

Neurotransmitter Changes in Dementia

The patient's symptoms, such as forgetfulness, confusion, and disorientation, suggest a diagnosis of dementia, likely Alzheimer's disease 2. In Alzheimer's disease, there is a significant reduction in the levels of the neurotransmitter acetylcholine, which plays a crucial role in memory and learning.

Acetylcholine and Alzheimer's Disease

Acetylcholine is a key neurotransmitter involved in cognitive functions, and its depletion is a hallmark of Alzheimer's disease 3. The use of acetylcholinesterase inhibitors, such as donepezil, rivastigmine, and galantamine, can help increase acetylcholine levels in the brain, providing mild symptomatic relief for patients with Alzheimer's disease 2, 3.

Other Neurotransmitter Changes

In addition to acetylcholine, other neurotransmitters, such as dopamine, serotonin, and norepinephrine, may also be affected in Alzheimer's disease. However, the exact changes in these neurotransmitters are not as well understood as those in acetylcholine.

Urinary Tract Infections and Neurotransmitter Changes

The patient's symptoms of urgency to urinate and pain on urination may be related to a urinary tract infection (UTI), which is common in older adults with dementia 4, 5. UTIs can cause sudden changes in mental status, including confusion and agitation, which may be mistaken for worsening dementia symptoms. The relationship between UTIs and neurotransmitter changes is not well understood, but it is possible that the infection may exacerbate existing neurotransmitter imbalances.

Key Points

• The patient's symptoms suggest a diagnosis of dementia, likely Alzheimer's disease.
• Acetylcholine depletion is a hallmark of Alzheimer's disease, and acetylcholinesterase inhibitors can help increase acetylcholine levels.
• Other neurotransmitters, such as dopamine, serotonin, and norepinephrine, may also be affected in Alzheimer's disease.
• UTIs are common in older adults with dementia and can cause sudden changes in mental status, which may be mistaken for worsening dementia symptoms.