Makindo Medical Notes

🧠 Alzheimer’s Disease (AD) = the commonest cause of dementia, affecting ~10% of people >65. Characterised by progressive cognitive decline, memory loss, and behavioural changes. Diagnosis is clinical, supported by cognitive testing, imaging, and history.

ℹ️ About

• Diagnosis = patient/family history + cognitive testing + exam + imaging.
• ⚠️ Progressive decline in cognition & daily function.
• Common in older age; prevalence increases markedly >80 yrs.

🧬 Aetiology

• Increased prevalence in Down syndrome (chromosome 21 link).
• Genetic link to apolipoprotein E4.
• Pathophysiology: reduced cholinergic, noradrenergic, dopaminergic activity.

🔬 Pathology

• ⬇️ Acetylcholine in brain/CSF.
• Neurofibrillary tangles: Tau protein inside neurons.
• Senile plaques: β-amyloid deposits in hippocampus, basal forebrain, cortex.

🧬 Genetics

• Rare autosomal dominant: Presenilin 1, Presenilin 2, APP genes.
• ApoE e4 homozygotes at much higher risk.

⚠️ Increased Risks

• Age, family history, traumatic brain injury.
• Diabetes, hypertension, cardiovascular disease.
• Down syndrome.

👩‍⚕️ Clinical Features

• 📉 Progressive memory loss (esp. episodic memory).
• 🧭 Disorientation, visuospatial difficulty.
• 🖐️ Dyspraxia, agnosia, impaired executive planning.
• 😟 Behavioural: anxiety, irritability, depression, aggression, loss of insight.

🔎 Investigations

• 🧪 Bloods: FBC, U&E, LFTs, TFTs, B12, folate (exclude reversible causes).
• 🖥️ Imaging: CT/MRI → hippocampal atrophy (MRI best for progression).
• EEG: mild nonspecific slowing.
• Histology (post-mortem): tau tangles & β-amyloid plaques.

🧾 Differential Diagnoses

• Dementia with Lewy bodies.
• Vascular dementia.
• Depression (pseudo-dementia).

🎯 Management Goals

• Maximise independence & quality of life.
• Support cognition, mood, behaviour.
• Provide safe environment & social support.

💊 Management

• Specialist assessment in memory clinic.
• Cognitive enhancers:
  • Donepezil 5–10 mg daily
  • Galantamine 8–24 mg daily
  • Rivastigmine 1.5–6 mg BD or transdermal patch
  • Memantine (NMDA antagonist)
• Depression: SSRIs.
• Agitation: low-dose antipsychotics (quetiapine, risperidone, olanzapine) — only if severe, non-pharmacological methods first.
• Social services, MDT support (OT, PT, social work, carers, support groups).

🌅 End-of-Life Care

• Focus shifts to palliation, advanced care planning.
• Mortality ~10% per year in advanced disease.

💡 Exam Pearl: Think Alzheimer’s when you see: older patient + progressive memory loss + hippocampal atrophy + no stepwise decline (unlike vascular dementia).