A 36-year-old man presented with sudden difficulty standing after waking. Both legs were weak and, within hours, the arms also felt heavy.
There was no facial asymmetry, aphasia or sensory loss. Reflexes were reduced. Because the weakness felt “sudden,” a vascular event was initially feared.
The laboratory clue
Serum potassium was profoundly low.
The history then revealed a previous shorter episode that had resolved spontaneously. The final assessment favored hypokalemic paralysis rather than stroke.
The diagnostic twist
Not every acute motor deficit is cerebrovascular. Distribution, cranial nerve findings, reflexes and metabolic testing can redirect the diagnosis quickly.
Clinical pearls
- Check electrolytes in acute generalized or symmetrical weakness.
- Look for sensory signs, cortical signs and cranial nerve involvement.
- Consider medication use, gastrointestinal losses, renal losses and periodic paralysis.
- Severe potassium abnormalities can be cardiac emergencies as well as neurological mimics.
Take-home message
A stroke mimic is still an emergency—it simply needs a different treatment.
Educational note: This is a fictionalized/composite teaching case created for clinical reasoning. It is not a record of an identifiable patient and is not a substitute for local protocols, specialist advice or patient-specific clinical judgement.