Weakness & Fatigue

Focal or diffuse? UMN or LMN? Hours or months?

Open full pathway

Educational first-pass aid. Reassess the patient, confirm doses and use local protocols.

1 · First minutes

Decide true motor weakness vs fatigue vs functional limit.
Map the pattern: brain, cord, root, nerve, NMJ, muscle — reflexes are the discriminator.
Watch NIF/VC in GBS and myasthenia.

2 · Escalate now if

Progressive ascending weakness or falling NIF/VC
Back pain with weakness or urinary retention (cauda equina / MSCC)
Sudden focal deficit (stroke pathway)
Respiratory symptoms in neuromuscular disease
Dark urine with muscle pain (rhabdo)
Bilateral leg weakness with a sensory level

3 · Immediate workup

Glucose; NIHSS if focal
NIF / vital capacity in suspected GBS or MG
Urine color for myoglobin; tick search
Post-void residual if CES is possible

4 · Don’t miss

Acute stroke / TIA
Sudden focal weakness — last-known-well, glucose, non-contrast CT. IV TNK/alteplase ≤4.5 h if eligible; EVT ≤24 h in selected patients using current vessel/imaging criteria, including some large-core infarcts (2026 AHA/ASA). Do not exclude EVT solely because 6 hours have passed.
Guillain-Barré syndrome
Ascending (or variant) weakness, areflexia; monitor NIF/VC — intubate before the crash. CSF may be normal in the first week.
Cauda equina / cord compression
Back pain + leg weakness ± saddle anesthesia, urinary retention — emergency MRI + spine surgery. Dexamethasone is for metastatic cord compression (NICE NG234), not routine for discogenic CES.
Myasthenic crisis
Fatigable weakness (ptosis, diplopia worse late in the day); NIF monitoring; avoid macrolides, fluoroquinolones, aminoglycosides.
Transverse myelitis
Sensory level, bladder dysfunction — MRI + steroids after infection is addressed.

5 · Disposition lane

Admit

GBS/MG under monitoring (even if ambulating), electrolyte derangements, moderate rhabdo on IV fluids, progressive unclear cases.

ICU / emergency intervention

Impending respiratory failure (NIF weaker than −30 cmH₂O, e.g. −20; VC <15–20 mL/kg; or 20/30/40 rule), cord compression, severe hyperkalemia, stroke needing intervention.