Memory Loss

Definition: Memory loss is a decline in the ability to store or retrieve information. It may be due to neurodegenerative, vascular, psychiatric, metabolic, infectious, pharmacological, or structural causes. The clinical challenge is to distinguish reversible from progressive pathology.

📋 Common Causes

• Neurodegenerative 🧬: Alzheimer’s disease, Dementia with Lewy bodies, Parkinson’s dementia, Frontotemporal dementia – typically insidious and progressive.
• Vascular 💔: Multi-infarct dementia, chronic small vessel disease – often stepwise decline.
• Psychiatric 😔: Depression (“pseudodementia”), anxiety – disproportionate subjective complaint with rapid onset.
• Medication-related 💊: Anticholinergics, benzodiazepines, opioids, polypharmacy in frail adults.
• Nutritional 🍊: B12, folate, thiamine deficiency (Wernicke–Korsakoff).
• Neurological Injury 🩸: TBI, subdural haematoma, post-encephalitic syndromes.
• Metabolic/Endocrine ⚖️: Hypothyroidism, hyponatraemia, hepatic/renal encephalopathy.
• Substance Misuse 🍷: Chronic alcohol, illicit drug use.
• Sleep Disorders 💤: Obstructive sleep apnoea, chronic insomnia.
• Infective/Inflammatory 🦠: HIV, neurosyphilis, prion disease, autoimmune encephalitis.

🧪 Key Investigations

• Bloods 🧾: FBC, U&E, LFTs, TFTs, calcium, CRP/ESR, glucose, HbA1c, B12/folate, syphilis serology, HIV (if at risk).
• Neuroimaging 🧲:
  • CT head: exclude structural lesions, subdural haematoma, hydrocephalus.
  • MRI brain: hippocampal atrophy (Alzheimer’s), white matter changes (vascular dementia).
• Cognitive Testing 📝: MMSE, MoCA, ACE-III – for baseline and monitoring progression.
• Other 🔎: EEG (seizures), polysomnography (OSA), CSF studies (if inflammatory/infective suspected).

💊 Management Principles

• Treat reversible causes: Correct B12, manage hypothyroidism, treat depression, rationalise medications.
• Pharmacological:
  • Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) – mild/moderate Alzheimer’s & Lewy body dementia.
  • Memantine – moderate/severe Alzheimer’s or intolerance to first-line therapy.
• Vascular risk factor control: Antihypertensives, statins, antiplatelets, diabetes control.
• Non-pharmacological: Cognitive stimulation therapy, structured routines, occupational therapy, carer education.
• Advance Care Planning 🤝: Discuss prognosis, capacity, and long-term support needs early.

🚨 Red Flags – Urgent Referral

• Acute or rapidly progressive memory loss (days–weeks).
• Associated focal neurology (e.g., hemiparesis, dysphasia, visual loss).
• New-onset seizures or delirium.
• Marked personality/behavioural change (aggression, disinhibition, psychosis).
• Gait disturbance + urinary incontinence + cognitive decline → think normal pressure hydrocephalus.

🔑 Clinical Pearls

• Not all memory loss = dementia. Always exclude reversible causes (depression, thyroid, B12, drugs).
• Stepwise decline → vascular; fluctuating cognition + hallucinations → Lewy body dementia.
• “Pseudodementia” (depression) may improve with treatment, unlike progressive dementias.
• Neuroimaging and screening bloods are essential in first presentations – do not diagnose dementia without them.

💡 Exam Tip: Dementia diagnosis is clinical + supported by investigations. Always screen for reversible causes first, then consider neurodegeneration. Structured approach: History → Examination → Bloods → Imaging → Specialist referral.

📊 Comparison of Major Dementia Subtypes