Weakness: documentation that holds up
"Weakness" spans a stroke, a compressed cord, a failing diaphragm, and a low potassium. The defensible chart separates true neurologic weakness from generalized fatigue, documents the glucose and neuro exam, and — for neuromuscular weakness — the respiratory assessment that catches impending failure.
▸Critical pathway
Original, evidence-based synthesis — the critical diagnoses you cannot miss, the tests that catch them, and the interventions that can’t wait. Apply local protocol and judgment.
- Immediate fingerstick glucose and a focused neurologic exam to separate focal from diffuse weakness; note last-known-well time.
- If acute focal deficit: activate the stroke pathway and obtain emergent imaging; if ascending or bulbar/respiratory weakness, monitor respiratory function closely.
- Fingerstick glucose and electrolytes (Na, K, Ca)
- Non-contrast head CT ± CT angiography/perfusion for acute focal deficit
- MRI of the spine when cord compression is suspected
- Negative inspiratory force / vital capacity for neuromuscular weakness
Acute ischemic stroke / TIA
- Trigger
- Sudden focal deficit within the treatment window
- Test
- Non-contrast CT, CT angiography/perfusion
- Intervention
- Thrombolysis and/or thrombectomy per pathway; permissive blood pressure
Spinal cord compression
- Trigger
- Bilateral weakness, a sensory level, or bowel/bladder dysfunction
- Test
- Emergent spinal MRI
- Intervention
- High-dose steroids where indicated; emergent neurosurgery/oncology
Metabolic cause
- Trigger
- Hypoglycemia or sodium/potassium derangement
- Test
- Glucose and electrolytes
- Intervention
- Correct the derangement promptly
Guillain-Barré syndrome
- Trigger
- Ascending symmetric weakness with areflexia
- Test
- Vital capacity / negative inspiratory force; LP/MRI to support
- Intervention
- Respiratory monitoring; IVIG or plasma exchange
Acute focal deficits and progressive neuromuscular weakness are admitted (stroke unit or monitored bed); a resolved TIA still warrants expedited risk stratification.
01What's at stake
The pattern points to the danger: focal weakness is a stroke or cord lesion until proven otherwise; ascending or bulbar weakness can be Guillain-Barré, myasthenia, or botulism heading toward respiratory failure; and generalized weakness is often metabolic (glucose, potassium). The misses are treating a cord compression as "back pain," and discharging a neuromuscular patient before their breathing fails.
02Can't-miss differential
- Acute stroke — focal deficit; last-known-well and the reperfusion clock (see the stroke and TIA guides).
- Spinal cord compression — bilateral weakness, a sensory level, bowel/bladder dysfunction; emergent MRI.
- Neuromuscular respiratory failure — Guillain-Barré (ascending, areflexic), myasthenic crisis, botulism (descending/bulbar), tick paralysis, organophosphate.
- Metabolic — hypoglycemia, hyper-/hypokalemia (incl. periodic paralysis), hypermagnesemia, hypophosphatemia.
03History & exam — the pattern
- Sudden, one-sided, with face/speech involvement? → stroke
- Bilateral, with a sensory level and bowel/bladder change? → cord compression
- Ascending and symmetric, or bulbar (diplopia, dysphagia, dysarthria)? → GBS / myasthenia / botulism
- Generalized, with palpitations or on diuretics/at risk for electrolyte shifts? → metabolic
- Confirm true weakness (objective motor deficit) vs fatigue; check a glucose; assess breathing (single-breath count, NIF/FVC) in neuromuscular patterns.
Skip the typing
Work the case in the Weakness / Focal Symptoms Workup — it records glucose, the neuro exam, last-known-well, and the respiratory assessment, and assembles an MDM that documents the can't-miss patterns were addressed.
04Workup & management
- Glucose first; electrolytes (K, Mg, PO₄, Ca), renal function; targeted tests by pattern.
- Focal: stroke pathway/imaging; cord signs: emergent MRI and steroids/neurosurgery for compression.
- Neuromuscular: serial respiratory measures (FVC/NIF) — declining values mean ICU and airway planning before a crash; treat the cause (IVIG/plasma exchange for GBS; the myasthenic vs cholinergic distinction; antitoxin for botulism; remove the tick).
- Metabolic: correct the derangement (and monitor, e.g., periodic paralysis can overshoot).
- Disposition — admit/monitor neuromuscular weakness with any respiratory involvement; don't discharge an evolving deficit.
05What to document
06Where charts fail
- Treating bilateral leg weakness/sensory level as "back pain" and missing cord compression.
- Not checking a glucose or electrolytes in generalized weakness.
- Discharging neuromuscular weakness without a respiratory assessment (the patient crashes at home).
- Calling subjective fatigue "weakness" without an objective motor exam — or vice versa, dismissing real weakness.
- Missing the bulbar/descending pattern of botulism or a myasthenic crisis.
07Sources
- Saguil A. Evaluation of the patient with muscle weakness. Am Fam Physician. 2005;71(7):1327-1336.
- Hughes RA, Cornblath DR. Guillain-Barré syndrome. Lancet. 2005;366(9497):1653-1666.
- Wijdicks EFM. The neurology of acutely failing respiratory mechanics. Ann Neurol. 2017;81(4):485-494.
- Asimos AW. Evaluation of the adult with acute weakness in the emergency department. Emerg Med Clin North Am. 2002;20(1):209-228.
© 2026 Kim Trinh, MD. All rights reserved. Educational only — synthesized from primary literature. Synthetic examples. Not medical advice — apply local protocol and judgment.