1. Chief Complaint:

A 37-year-old male presented with a gradual decline in cognitive function over the past 3 years.

2. History of Present Illness:

The patient initially noticed difficulties with complex calculations while working as an industrial researcher, leading him to change careers. However, frequent forgetfulness and worsening memory issues continued to impact his work performance, resulting in frequent job changes. Two years before his current presentation, he developed apraxia (difficulty performing familiar tasks) and apathy (loss of motivation). His cognitive decline progressed to disorientation in time and place, making independent daily activities, including commuting to work, challenging. At the time of admission, he required frequent reminders from his family for basic hygiene and experienced sleep disturbances with nighttime self-talk. He had visited two other hospitals before coming to our clinic, but no diagnosis or treatment was established.

3. Past Medical History:

Noncontributory.

4. Social History:

No significant social history details provided.

5. Family History:

Family history unknown.

6. Medications:

None on admission.

7. Allergies:

No known allergies.

8. Physical Examination:

No abnormal physical exam findings reported.

9. Laboratory Findings:

Routine laboratory tests, including HIV and syphilis serology, were within normal limits.

10. Neuropsychological Testing:

• Mini-Mental State Examination (MMSE): 22 (out of 30)
• Clinical Dementia Rating (CDR): 1
• Clinical Dementia Rating-Sum of Box Score (CDR-SB): 4.5
• Cognitive testing revealed significant impairments in memory (free recall, delayed recall, recognition) with relatively preserved language function.

11. Imaging:

• Brain MRI: Demonstrated mild global cerebral atrophy and moderate medial temporal lobe atrophy.
• Amyloid PET Scan: Revealed diffuse amyloid deposition with predominant involvement of the striatum.

12. Diagnosis:

Probable Alzheimer's Disease (based on NINCDS-ADRDA criteria) with high level of evidence.

13. Treatment:

• Donepezil 5mg was initiated during hospitalization.
• Donepezil was titrated to 23mg after discharge and combined with memantine (titrated to 20mg) for ongoing cognitive management.

14. Follow-up:

• The patient's cognitive decline has shown relative stabilization with ongoing medication management.
• Regular clinic visits are recommended for symptom monitoring.

15. Discussion:

This case highlights the unusual presentation of Alzheimer's disease in a young individual. Early-onset Alzheimer's disease is typically defined by symptom onset before the age of 65. The patient's progressive cognitive decline, affecting daily functioning, coupled with characteristic neuroimaging findings (amyloid PET) supported the diagnosis. Although treatment options for Alzheimer's disease are limited, medications like donepezil and memantine can help manage symptoms and potentially slow cognitive decline.

16. Limitations:

The case report lacks information about the patient's family history and specific details of the neuropsychological battery used.

17. Conclusion:

This case demonstrates the importance of considering Alzheimer's disease even in younger individuals with progressive cognitive decline. Early diagnosis can facilitate timely intervention and support for patients and families.