What is the diagnosis and management for an adult patient with memory loss and forgetting things?

Memory Issues and Forgetting Things: Diagnosis and Management

Initial Diagnostic Approach

Begin with validated cognitive screening using the Montreal Cognitive Assessment (MoCA) or Mini-Cog, followed by comprehensive laboratory testing and brain MRI to exclude reversible causes, then proceed to formal neuropsychological testing if screening suggests impairment. 1, 2

History Taking Strategy

• Obtain history from both the patient and a knowledgeable informant separately, as patients with cognitive impairment often have diminished insight into their condition 1, 3
• Ask open-ended questions about the patient's main concerns and what they hope to accomplish from the visit, noting any differences in perception between patient and informant 1
• Request specific examples of memory difficulties rather than accepting vague complaints, as "memory loss" may mean different things to patients than to clinicians 1
• Inquire about difficulties with learning and recalling newly acquired information and recent life events (episodic memory), including repetitive questions or conversations, misplacing personal belongings, forgetting events or appointments, and getting lost on familiar routes 4, 1

Functional Impact Assessment

• Assess changes in instrumental activities of daily living, including managing finances, medications, transportation, household tasks, missed appointments, showing up at incorrect times, and difficulty following instructions 4, 1
• Determine if there has been any decrease in self-care, unexplained decline in daily activities, or victimization by financial scams 4, 1
• The differentiation between mild cognitive impairment and dementia rests on whether there is significant interference in the ability to function at work or in usual daily activities 4

Temporal Pattern and Associated Symptoms

• Establish when memory problems first began and how symptoms have evolved over time in frequency, duration, and intensity 1
• Inquire about triggering events (surgery, trauma, illness) that coincided with symptom onset 1
• Screen for mood changes including new onset of depression or anxiety, as depression and cognitive impairment frequently coexist, with depression often presenting as an early symptom of dementia 1
• Ask about changes in personality, behavior, gait problems, tremor, balance issues, swallowing difficulties, or incontinence 4, 1

Objective Cognitive Testing

• Administer a validated cognitive screening tool immediately such as the MoCA (preferred), Mini-Cog, or MMSE to establish objective cognitive impairment 4, 1, 2
• Cognitive testing is mandatory because subjective reports alone are insufficient for diagnosis 2
• If screening tests suggest impairment, proceed to comprehensive neuropsychological assessment focusing on attention and memory domains 2
• Neuropsychological testing should be performed when routine history and bedside mental status examination cannot provide a confident diagnosis 4

Key Cognitive Domains to Assess

• Memory: Impaired ability to acquire and remember new information, including repetitive questions, misplacing belongings, forgetting events 4
• Executive function: Impaired reasoning, handling of complex tasks, poor judgment, inability to manage finances or plan sequential activities 4
• Language: Difficulty thinking of common words while speaking, hesitations, speech and writing errors 4
• Visuospatial abilities: Inability to recognize faces or common objects, difficulty operating simple implements 4
• Attention: Attention lapses are strongly correlated with memory failures and should be systematically evaluated 2

Laboratory Evaluation

Mandatory Tier 1 Testing (All Patients)

• Complete blood count (CBC) to screen for anemia and infection 2
• Comprehensive metabolic panel to evaluate electrolyte disturbances, renal function, glucose abnormalities, and hepatic function 4, 2
• Thyroid-stimulating hormone (TSH) with free T4 if abnormal, to diagnose hypothyroidism, a common reversible cause 4, 2
• Vitamin B12 and folate levels to identify deficiency, which can cause dementia that substantially improves with treatment 4, 2
• Liver function tests (ALT, AST) as hepatic encephalopathy can present with attention deficits and forgetfulness 2
• Hemoglobin A1c (HbA1c) to evaluate diabetes control 2
• Lipid panel for vascular risk stratification 2

Common Reversible Contributors to Screen For

• Metabolic disturbances: Electrolyte abnormalities, hypoglycemia/hyperglycemia, B12 or folate deficiencies, undetected thyroid dysfunction, anemia 4
• Medication effects: Toxic levels of antiepileptic or psychoactive medications, polypharmacy, drug-drug interactions 4
• Sensory deficits: Hearing loss, vision loss 4
• Sleep disorders: Sleep apnea and other undetected sleep disorders 4
• Pain: Undiagnosed or undertreated pain 4
• Mood disorders: Depression can cause symptoms similar to dementia and can co-occur with early dementia 4

Neuroimaging

• Brain MRI (non-contrast) is the preferred initial imaging modality to evaluate for structural causes including stroke, white matter disease, atrophy patterns, hydrocephalus, and space-occupying lesions 2
• MRI is superior to CT for detecting vascular lesions, hippocampal atrophy, and subtle structural abnormalities 2
• CT scan is acceptable if MRI is contraindicated or unavailable, with coronal reformations recommended to assess hippocampal atrophy 2
• 3T MRI should be favored over 1.5T if available and no contraindications exist 2

Differentiating Depression from Cognitive Impairment

• Depression and cognitive impairment frequently coexist, with more than half of patients who subsequently develop dementia having depression or irritability symptoms before cognitive impairment became apparent 1
• Assess core DSM-5 depression symptoms including depressed mood, anhedonia, sleep disturbance, appetite changes, fatigue, feelings of worthlessness, and suicidal ideation 1
• Depression pattern is characterized by decreased motivation to perform tasks but retained ability when prompted, and refusal to participate rather than inability 1

Diagnostic Algorithm for Depression vs. Dementia

• Treat the depression first with SSRIs and reassess cognition after 8-12 weeks of adequate antidepressant treatment 1
• If cognitive deficits persist despite mood improvement, this strongly suggests underlying neurodegenerative disease 1
• Do not delay dementia workup while treating depression, as both conditions frequently coexist 1
• Do not assume memory complaints in older adults are "just depression" without objective cognitive testing 1

Management Based on Diagnosis

Mild Cognitive Impairment (MCI)

• Cognitive testing scores for MCI are typically 1 to 1.5 standard deviations below the mean for age and education-matched peers on culturally appropriate normative data 4
• Schedule follow-up assessment every 6-12 months using the same cognitive instrument to track changes over time and determine if the patient is declining, stable, or improving 1, 3
• Patients with severe isolated memory loss have an increased risk of developing dementia (48% progressed to dementia over mean follow-up of 48 months) and should be closely followed 5

Dementia Due to Alzheimer's Disease

• For mild to moderate Alzheimer's disease, cholinesterase inhibitors (donepezil, galantamine, rivastigmine) are indicated 6
• Donepezil is initiated at 5 mg once daily for 28 days, then increased to 10 mg once daily 6
• For moderate to severe Alzheimer's disease, donepezil 23 mg/day may provide additional benefit over 10 mg/day, with statistically significant improvements in cognitive function (SIB scores) and overall clinical effect 6
• Memantine (NMDA receptor antagonist) may be considered for moderate to severe Alzheimer's disease 6

Vascular Cognitive Impairment

• Treat hypertension according to guidelines, with antihypertensive therapy strongly considered for average diastolic BP ≥90 mmHg and systolic BP ≥140 mmHg 4
• In middle-aged and older persons with vascular risk factors, a systolic BP treatment target of <120 mmHg may decrease risk of developing mild cognitive impairment 4
• All patients with cognitive symptoms should receive guideline-recommended treatments to prevent first-ever or recurrent stroke 4
• Cholinesterase inhibitors and memantine may be considered for vascular cognitive impairment in selected patients 4

Cognitive Rehabilitation

• Patients should be assessed for cognitive deficits and given cognitive retraining for attention deficits, visual neglect, memory deficits, and executive function/problem-solving difficulties 4
• Training to develop compensatory strategies for memory deficits is beneficial in patients with mild short-term memory deficits who are fairly independent in daily function, actively involved in identifying their memory problems, and motivated to incorporate use of the strategy 4
• Patients with multiple areas of cognitive impairment may benefit from a variety of cognitive retraining approaches involving multiple disciplines 4

Critical Pitfalls to Avoid

• Do not dismiss subjective forgetfulness as "normal aging" without objective assessment, as changes that may be common with advancing age are not always normal and warrant diagnostic evaluation 2
• Do not focus exclusively on memory; assess other cognitive domains including executive function, language, and visuospatial abilities 1
• Do not attribute cognitive symptoms solely to depression or anxiety without thorough evaluation, as both can coexist with early dementia 1
• Do not delay comprehensive workup in patients with early-onset cognitive impairment (<65 years), as this has different diagnostic implications including higher likelihood of atypical or non-Alzheimer's pathology 2

Specialty Referral Indications

• Refer to neurology, geriatric psychiatry, or a memory disorders specialist if cognitive testing confirms impairment, diagnosis remains unclear, or patient/family requests discussion of genetic testing 3
• Refer when diagnostic uncertainty persists after initial evaluation or when atypical presentations occur 1

ICD-10 Coding Considerations

• R41.81: Age-related cognitive decline (for subjective memory complaints without objective impairment)
• G31.84: Mild cognitive impairment (for objective cognitive impairment without functional decline meeting dementia criteria)
• F03.90: Unspecified dementia without behavioral disturbance (for dementia of unclear etiology)
• G30.9: Alzheimer's disease, unspecified (when Alzheimer's disease is confirmed)
• F01.50: Vascular dementia without behavioral disturbance (when vascular etiology is established)