Troy Schmanke, Ph.D.

🧠 7 CAUSES OF ATAXIA Ataxia is a sign, not a diagnosis. The key is to localize the lesion first, then identify the cause. ⸻ 1️⃣ Cerebellar Ataxia 📍 Lesion in the cerebellum or its pathways 🔹 Dysmetria 🔹 Intention tremor 🔹 Nystagmus 🔹 Scanning speech 🔹 Broad-based gait 🧠 Causes: ➊ Stroke ➋ Tumor ➌ Cerebellitis ➍ Degenerative disease ⸻ 2️⃣ Sensory Ataxia 📍 Loss of proprioception from dorsal columns or peripheral nerves 🔹 Positive Romberg sign 🔹 Stamping gait 🔹 Worse in darkness 🔹 Loss of vibration sense 🧠 Causes: ➊ Vitamin B12 deficiency ➋ Tabes dorsalis ➌ Peripheral neuropathy ➍ Friedreich ataxia ⸻ 3️⃣ Vestibular Ataxia 📍 Vestibular apparatus or vestibular nerve lesion 🔹 Vertigo 🔹 Nausea & vomiting 🔹 Nystagmus 🔹 Imbalance 🔹 Falls toward affected side 🧠 Causes: ➊ Vestibular neuritis ➋ Labyrinthitis ➌ Ménière disease ➍ Vestibular schwannoma ⸻ 4️⃣ Alcohol-Related Ataxia 🍺 Chronic alcohol toxicity 🔹 Wide-based gait 🔹 Cerebellar degeneration 🔹 Poor coordination 🔹 Nutritional deficiency 🧠 Associated with: ➊ Thiamine deficiency ➋ Wernicke encephalopathy ——— 5️⃣ Vitamin B12 Deficiency Ataxia 🟠 Subacute Combined Degeneration 🔹 Sensory ataxia 🔹 Positive Romberg 🔹 Paresthesia 🔹 Loss of vibration sense 🔹 Cognitive symptoms 🧠 Examination: ➊ Reduced proprioception ➋ Dorsal column signs ➌ Spasticity (late) ⸻ 6️⃣ Multiple Sclerosis (MS) 🧠 Demyelination affecting cerebellar pathways 🔹 Ataxia 🔹 Diplopia 🔹 Optic neuritis 🔹 Limb weakness 🔹 Sensory symptoms ⸻ 7️⃣ Cerebrovascular Disease (Stroke) 🚨 Acute onset cerebellar or brainstem lesion 🔹 Sudden ataxia 🔹 Vertigo 🔹 Vomiting 🔹 Dysarthria 🔹 Cranial nerve deficits 🧠 Causes: ➊ Cerebellar infarction ➋ Cerebellar hemorrhage ➌ Brainstem stroke ⸻ 📚 Master Neurology the High-Yield Way with the MedicoNotes Neurology Book. 🌐 Visit our website: mediconotes.com #Neurology #Ataxia #MRCP #USMLE #plab

🧠 MCA vs ACA vs PCA — Localise the Stroke in 5 seconds! ⸻ 1️⃣ MCA — Middle Cerebral Artery 🔸 Contralateral Face & Arm weakness 🔸 Contralateral Face & Arm sensory loss 🔸 Aphasia → if dominant hemisphere 🔸 Gaze deviation TOWARD the lesion 🔸 Visual field: Contralateral Homonymous Hemianopia 🧩 Why? MCA supplies the lateral cortex — face, arm, and language areas ⸻ 2️⃣ ACA — Anterior Cerebral Artery 🔸 Contralateral LEG weakness (arm spared!) 🔸 Contralateral LEG sensory loss 🔸 Abulia / Apathy → behavioural changes 🔸 Urinary incontinence 🔸 Visual field: Contralateral Homonymous Hemianopia 🧩 Why? ACA supplies the medial frontal and parietal lobes — leg area and motivation circuits ⸻ 3️⃣ PCA — Posterior Cerebral Artery 🔸 Contralateral Visual Field Loss → often isolated 🔸 Visual Hallucinations → Charles Bonnet Syndrome 🔸 Visual Agnosia → impaired visual recognition 🔸 Visual field: Contralateral Homonymous Hemianopia with macular sparing 🧩 Why? PCA supplies the occipital lobe (vision) and inferior temporal lobe (visual memory) ⸻ 🧩 The 5-Second Localisation Rule ➊ Face + Arm weak + Aphasia → MCA ➋ Leg weak + Behavioural change → ACA ➌ Vision loss only + Hallucinations → PCA ⸻ ⚠️ The Exam Trap 🔹 All three can cause Contralateral Homonymous Hemianopia 🔹 ACA and MCA → full field defect 🔹 PCA → macular SPARING (occipital cortex has dual blood supply) ⸻ 📚 Master all neurology conditions in our high-yield neurology book: 🔗 mediconotes.com ⸻ #StrokeSyndromes #Neurology #medicine #internalmedicine #usmle