Case Study: Early Diagnosis and Treatment of Alzheimer’s Disease Using Beta-Amyloid PET Imaging

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder primarily affecting older adults. Early diagnosis is crucial for managing symptoms and slowing disease progression. This case study focuses on the use of beta-amyloid positron emission tomography (PET) imaging in the early diagnosis of AD. A 66-year-old male patient presented with mild cognitive impairment, and a beta-amyloid PET scan confirmed amyloid plaques in the brain, supporting a diagnosis of early-stage Alzheimer’s. Early intervention with cholinesterase inhibitors and lifestyle modifications was initiated. The case underscores the importance of advanced diagnostic tools in the early detection and treatment of AD, enabling more effective management of the disease.

Introduction

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that primarily affects older adults, leading to cognitive decline, memory loss, and eventually, loss of functional independence. Early diagnosis is crucial in managing the disease, as it allows for timely intervention that can slow the progression of symptoms and improve quality of life. Traditionally, Alzheimer’s diagnosis relied on clinical evaluation and exclusion of other causes of dementia, but recent advances in neuroimaging, particularly beta-amyloid positron emission tomography (PET) imaging, have transformed the diagnostic landscape.

Beta-amyloid PET imaging enables clinicians to visualize amyloid plaques in the brain, a hallmark of Alzheimer’s pathology, even in the early stages of the disease. This non-invasive technique offers a more accurate and early diagnosis, especially in patients with mild cognitive impairment (MCI), who are at higher risk of progressing to Alzheimer's. This case study presents a 66-year-old male with mild cognitive impairment, whose early diagnosis of Alzheimer's was confirmed through beta-amyloid PET imaging. The case emphasizes the importance of early detection and intervention in Alzheimer's management and the role of advanced imaging techniques in facilitating timely diagnosis and treatment.

Patient Information

• Age: 66

• Gender: Male

• Occupation: Retired engineer

• Family History: Father diagnosed with Alzheimer’s disease at age 75

• Medical History: Hypertension, hyperlipidemia, managed with medication

• Chief Complaint: Memory lapses and difficulty with problem-solving over the last six months

Clinical Findings

The patient presented with mild cognitive decline, reporting frequent memory lapses, difficulties in finding words, and trouble with problem-solving tasks. His family had noticed that he would often repeat questions and forget recent conversations or events. These symptoms had gradually worsened over six months, prompting a visit to his primary care physician.

1. Cognitive Testing: Mini-Mental State Examination (MMSE) score of 26/30, indicating mild cognitive impairment (MCI).

2. Neuropsychological Testing: Mild deficits in short-term memory, language, and executive function.

3. Physical Examination: No motor or sensory abnormalities; neurological exam normal.

4. Laboratory Tests: Normal thyroid function, vitamin B12, and folate levels; no signs of infection or metabolic disturbances.

Timeline

1. 6 months prior: The patient noticed memory lapses and problem-solving difficulties.

2. 4 months prior: The family noticed repetitive questioning and forgetfulness.

3. 3 months prior: Initial visit to primary care physician, cognitive testing showed mild impairment.

4. 2 months prior: Referred to a neurologist for further evaluation.

5. Present: Underwent beta-amyloid PET imaging to assess for Alzheimer’s disease.

Diagnostic Assessment

Given the patient's mild cognitive impairment and family history of Alzheimer's, the neurologist ordered a beta-amyloid PET scan to assess amyloid plaque buildup, a hallmark of Alzheimer’s disease.

• Beta-Amyloid PET Imaging: The scan revealed significant amyloid deposition in the cerebral cortex, consistent with early-stage Alzheimer’s disease. The presence of amyloid plaques provided strong evidence of the underlying pathology of Alzheimer’s, even though the patient’s symptoms were still relatively mild.

Other Diagnostic Evaluations

• MRI of the brain: Mild hippocampal atrophy, but no signs of cerebrovascular disease or other neurodegenerative conditions.

• CSF Biomarkers: Decreased amyloid-beta 42 levels and increased tau protein levels, further supporting the diagnosis of early-stage Alzheimer's disease.

Follow-Up and Outcomes

After confirming the diagnosis of early Alzheimer’s disease, a treatment plan was initiated. The patient was started on a cholinesterase inhibitor (donepezil) to slow cognitive decline. Additionally, the patient and his family were educated about the importance of lifestyle interventions such as regular physical exercise, a Mediterranean diet, and cognitive stimulation activities to potentially delay disease progression.

• 3-month follow-up: The patient reported some memory improvement, with fewer memory lapses and an improved ability to complete daily tasks. No significant side effects from the medication were reported.

• 6-month follow-up: MMSE score remained stable at 26/30, and the patient continued to manage daily activities independently. His family reported less frequent repetition in conversations.

• 12-month follow-up: The patient’s cognitive function had stabilized, with no significant decline. Continued use of donepezil and adherence to lifestyle changes were noted as contributing factors to the stable condition.

Discussion

Alzheimer’s disease is the most common cause of dementia and is characterized by progressive cognitive decline. The accumulation of amyloid-beta plaques in the brain is a key pathological feature of AD, and beta-amyloid PET imaging has become an important tool in diagnosing the disease early. This case demonstrates the utility of beta-amyloid PET imaging in confirming the diagnosis of AD in a patient with mild cognitive impairment.

Early diagnosis is critical in Alzheimer's, as it allows for timely intervention with medications like cholinesterase inhibitors, which can help manage symptoms and slow cognitive decline. In this case, the use of donepezil led to the stabilization of the patient's symptoms over 12 months, allowing for a better quality of life.

Additionally, lifestyle modifications such as exercise and cognitive training have been shown to have neuroprotective effects, potentially delaying the progression of Alzheimer’s. The patient in this case benefited from these interventions, highlighting the importance of a comprehensive, multidisciplinary approach to managing AD.

This case also underscores the role of family history in Alzheimer's risk. The patient's father had been diagnosed with Alzheimer’s, which likely contributed to the patient's elevated risk of developing the disease. A thorough family history is essential in evaluating patients with cognitive impairment, as it can guide clinicians in making timely diagnostic and therapeutic decisions.

Takeaway

Beta-amyloid PET Imaging is a valuable tool for the early diagnosis of Alzheimer's disease, especially in patients with mild cognitive impairment.

Early intervention with cholinesterase inhibitors and lifestyle changes can stabilize cognitive function and improve quality of life.

Family history plays an important role in assessing the risk of Alzheimer’s disease, and genetic factors should be considered during diagnosis.

Multidisciplinary care, including pharmacological treatment, lifestyle modifications, and cognitive training, offers the best outcomes for managing early-stage Alzheimer’s.

Patient's Perspective

The patient was relieved to receive a definitive diagnosis after months of uncertainty and memory lapses. Although the diagnosis of Alzheimer’s disease was difficult to accept, the patient felt empowered by having a clear treatment plan in place. He appreciated the non-invasive nature of the beta-amyloid PET scan and was motivated to adhere to the prescribed medication and lifestyle changes. The patient’s family also felt reassured by the stable course of the disease after 12 months of treatment.

Conclusion

This case study highlights the crucial role of beta-amyloid PET imaging in the early diagnosis of Alzheimer’s disease. By confirming the presence of amyloid plaques, clinicians can make more accurate diagnoses and initiate early treatment strategies. The combination of pharmacotherapy and lifestyle interventions provides a comprehensive approach to managing early-stage Alzheimer’s, allowing patients to maintain cognitive function and quality of life for as long as possible.

References

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3. Dubois B, Hampel H, Feldman HH, et al. Preclinical Alzheimer's disease: Definition, natural history, and diagnostic criteria. Alzheimers Dement. 2016;12(3):292-323.

4. Cummings JL, Isaacson RS, Schmitt FA, et al. A practical algorithm for managing Alzheimer's disease: What, when, and why? Ann Clin Transl Neurol. 2019;6(12):2436-2444.