MEDSURG | PART 1 Primer Neurological System

🧠 High-Yield Neurology Study Guide (RN Prep)1️⃣ Neuron Basics & Injury PatternsNeurons: Excitable cells that transmit impulses via action potentials & neurotransmitters.Glial cells: Support neurons. 🧩 Astrocytes form scar tissue; Oligodendrocytes (CNS) + Schwann cells (PNS)make myelin.UMN Lesions: Weakness, spasticity, hyperreflexia, ↑ tone. (Think: stroke, SCI.)LMN Lesions: Flaccid paralysis, atrophy, fasciculations, ↓ reflexes. (Think: Guillain-Barré, spinal root injury.)2️⃣ Neuro Protection & FluidMeninges: Dura → Arachnoid → Pia.CSF: 150 mL circulates; cushions brain; made in choroid plexus.BBB: Blocks toxins; lipid-soluble drugs cross easiest.3️⃣ Neuro Assessment EssentialsVitals: HR 60–100 bpm, RR 15–20, SpO₂ > 95%, BP 100–140/60–90.LOC: GCS = Eyes + Verbal + Motor.Pupils: PERRLA = equal, round, reactive, accommodate.Language: • Broca = expressive (can’t speak) 🗣️ • Wernicke = receptive (word salad).Speech Motor: Dysarthria; often w/ dysphagia.4️⃣ Red-Flag Findings ⚠️Nystagmus: Cerebellar/brainstem lesion or toxicity.Areflexia: LMN issue.Hyperreflexia/Clonus: UMN lesion.Analgesia/Anesthesia: Sensory tract damage.Astereognosis: Parietal cortex lesion.5️⃣ Cranial Nerves 🧩 (key ones) I = Smell 👃 II = Vision 👁️ III, IV, VI = Eye movement/pupil V = Face sensation + chew VII = Expression/taste (ant 2/3) X = Gag, swallow, voice6️⃣ Diagnostics & Nursing PearlsLumbar Puncture: L3-L5; flat after, ↑ fluids 💧. ⚠️ Contra: ↑ICP, anticoag use.Post-LP HA: from ↓ CSF pressure.CSF: • Bacterial: ↑P, ↑WBC (poly), ↓glucose • Viral: ↑mono cells, nml glucose • SAH: RBCs + xanthochromia (yellow).CT: Fast for bleed/TBI; if contrast → hold Metformin 48 h.MRI: No metal! (pacers, implants, shrapnel).Angiography: NPO; monitor site/bleeding; leg flat 4-6 h.7️⃣ Labs & Metabolic LinksNa⁺↓ (SIADH/CHF) → confusion/seizure.Na⁺↑ (dehydration) → irritability.K⁺↓ (diuretics) → muscle weakness.K⁺↑ (renal fail, ACEi) → arrhythmias.Vit B₁₂↓ → neuropathy + megaloblastic anemia.Thiamine (B₁)↓ → Wernicke’s encephalopathy (alcohol use).Ammonia ↑ → hepatic encephalopathy (liver fail).