--- module: 031-01 language: en chapter: 31 title: "Neurological History, Examination, Localisation, and Investigations" module_title: "Foundations" source_sha256: e7b0f0365ca2cdb2ed426aa52806d8d373dcae07fb22b818b0e5f598c6a17440 --- # Neurological history, examination, and localisation ## Orientation and time course ### Where is the lesion, then what process ### Coherent localisation guides testing #### Incidental imaging never replaces anatomy ### Last-known-normal time for sudden symptoms ### Maximal at onset: embolism, bleed, seizure, migraine ### Hours to days: inflammation, infection, compression ### Weeks to months: tumour, immune, degeneration ### Recurrent stereotyped: seizure, migraine, channel ## Symptom definition and background ### Ask what failed, not the label #### Dizziness: vertigo, presyncope, imbalance #### Weakness: power, pain, fatigue, incoordination ### Witness account of episodic events ### Vascular risks, cancer, immune, toxins, family ### Review anticoagulants, sedatives, dopamine blockers ### Baseline mobility, cognition, handedness, wishes ### Red flags: thunderclap, meningism, sphincter loss #### Stabilisation precedes complete examination ## Mental status ### Arousal and attention first #### Impairment invalidates downstream testing ### Memory, language, visuospatial, executive as needed ### Scores biased by education, language, culture ### Acute fluctuation and inattention suggest delirium ### Aphasia versus dysarthria, deafness, low arousal ### Capacity judged for the specific decision ## Cranial nerves ### Acuity, fields, pupils, fundi, eye movements ### Relative afferent defect: asymmetric optic dysfunction ### Papilloedema neither immediate nor universal ### Upper motor neuron face spares forehead #### Lower motor neuron: whole ipsilateral face ### Palate, voice, cough, swallowing safety #### Lower cranial failure threatens airway, nutrition ## Motor examination ### Bulk, fasciculation, involuntary movement ### Tone at different speeds #### Spasticity velocity-dependent, rigidity uniform #### Paratonia varies with cooperation, frontal ### True weakness versus pain, fatigue, give-way ### Pyramidal: arm extensors, leg flexors weaker ### Neuropathy distal, myopathy proximal ### Junction weakness fluctuates and fatigues ### Hyperreflexia, clonus, extensor plantar: UMN ### Reduced reflexes may be a normal variant ## Sensory examination ### Map symptoms, eyes closed, avoid rhythm and leading ### Cortical tests need primary sensation, attention ### Sensory level: spinal cord ### Saddle loss: cauda equina or conus ### Dermatomal root, named nerve, stocking ### Crossed face-body pattern: brainstem ### Functional: prefer positive signs to exclusion ## Coordination, stance, and gait ### Finger-nose, heel-shin, rapid alternation ### Dysmetria may reflect weakness or sensory loss ### Romberg: stance without vision #### Eyes-closed falls: proprioceptive or vestibular ### Describe gait pattern, not just abnormal ### Never test an unsafe patient unassisted ## Localisation framework ### Hemisphere: contralateral deficit plus cortical signs ### Brainstem: cranial nerve plus contralateral body ### Cerebellum: ipsilateral incoordination, no weakness ### Cord: bilateral signs below a level #### Segmental LMN at level, UMN below #### Hemicord: crossed pain-temperature loss ### Cauda equina: asymmetric LMN, saddle, sphincter ### Root: radiating pain, myotome, dermatome, reflex ### Junction and myopathy spare sensation ## Investigations ### CT: blood, mass effect, hydrocephalus, fracture ### MRI: infarct, demyelination, posterior fossa, cord ### Urgency follows clinical risk ### Incidental findings common, correlate with exam ### Lumbar puncture: pressure, cells, protein, glucose #### Image first if herniation risk suspected #### Do not delay antimicrobials ### Short normal EEG does not exclude epilepsy ### Nerve conduction: axonal versus demyelinating ## Integration and communication ### One sentence: syndrome, site, mechanism, tempo ### State uncertainty, repeat examination ### Driving, water safety, falls, swallowing ### Functional disorder by positive signs ### Rehabilitation begins alongside diagnosis