Central Nervous System (Upper / Lower Limb)

CNS

History

  • Weakness, sensory change, paraesthesia (distribution, onset)
  • Bladder/bowel, sphincter, sexual function
  • Headache, fits, faints, falls, cognition
  • PMH: stroke, MS, DM, alcohol, B12

Examination sequence

  • WIPE — expose limbs fully, compare sides
  • Inspection: posture, wasting, fasciculations, scars, tremor, involuntary movements
  • Tone: rigidity, spasticity, clonus (3+ beats abnormal)
  • Power: MRC 0–5, all major movements proximal to distal
  • Reflexes: biceps/triceps/supinator (C5-T1); knee/ankle/plantars (L3-S1)
  • Coordination: finger-nose, dysdiadochokinesia, heel-shin
  • Sensation: pinprick, light touch, vibration, proprioception, temperature
  • Gait: normal, heel-toe, Romberg

Positive findings

  • UMN: spasticity, hyperreflexia, upgoing plantars, weakness in pyramidal pattern
  • LMN: wasting, fasciculations, hypotonia, hyporeflexia
  • Cerebellar: DANISH (dysdiadochokinesia, ataxia, nystagmus, intention tremor, slurred speech, hypotonia)

Differentials

  • Sudden hemiparesis → stroke (TACS/PACS/LACS)
  • Distal + sensory loss + absent reflexes → peripheral neuropathy
  • Mixed UMN/LMN signs → MND

Viva questions

Q. How to distinguish stroke from Bell's palsy?

A. Bell's involves forehead (LMN); stroke spares forehead (UMN).

Q. Top differentials for spastic paraparesis?

A. Cord compression, MS, transverse myelitis, hereditary spastic paraparesis, B12 deficiency.

Common mistakes

  • Forgetting to test gait
  • Not comparing sides
  • Skipping cranial nerves when asked for full CNS
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