Leg or arm numbness can have various causes, ranging in severity from 'worrying' to 'generally fatal'. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose leg or arm numbness, we could:
Have you experienced a gradual loss of sensation (numbness) in the arms or legs within the past year?
Possible responses:→ No / don't know
→ Yes, but it was an episode more than a year ago
→ Yes, but it is improving now
→ Slight numbness, stable or getting worse
→ Significant numbness, stable or getting worse
Gradual loss of sensation in an arm or leg (numbness) can be due to a brain tumor.