Have you ever been so involved in a good book or movie only to discover that your foot or part of your bottom has gone numb, from sitting so long? This kind of numbness may be completely harmless, and will go away as soon as you shake your leg around. But what about other causes of numbness? When is numbness a symptom of a serious problem?
What is meant by “numbness” as a symptom?
- numbness refers to a loss of sensation, or a loss of feeling in an area or part of the body
- the fancy word used by doctor is “paresthesia”
- it can also accompany feelings of pins-and-needles, prickling, itching, burning, tingling, a feeling of warmth or coolness in an area, or severe stabbing pain (neuralgia)
numbness can affect: - the central nervous system/CNS (brain and spinal cord) or,
- the peripheral nervous system (the nerves that supply the rest of the body, running down to the arms, legs, fingers, toes etc.)
Numbness results from either:
- damage to a nerve/s
- compression of a nerve/s
- irritation of a nerve/s
- it can involve several nerves, or a single branch of a nerve
What are some of the causes of numbness?
- a common cause includes sitting or lying in one position for too long
- injury to a nerve (i.e. in association with a fracture, spinal cord injury)
- pressure on nerves of the spine (i.e. a herniated disc of the back or neck, a spinal abscess or tumour, spinal stenosis, cervical spondylosis)
- pressure/compression of a peripheral nerve (i.e. carpal tunnel syndrome or ulnar nerve palsy)
- peripheral neuropathy (due to diabetes, alcohol abuse, atherosclerosis, vitamin B1 or B12 deficiency)
- conditions affecting the brain (brain aneurysm/AVM, brain tumour, seizures, migraine with aura)
- stroke, mini-stroke/TIA
- lack of blood supply to an area or vasculitis (atherosclerosis, frostbite, rheumatoid arthritis, Raynaud’s phenomenon, Sjogren’s syndrome)
- multiple sclerosis
- Guillain-Barre syndrome
- animal or insect bites or, seafood toxins
- infections (shingles, rabies, leprosy, syphilis, Lyme’s disease)
- toxins (lead, tobacco, alcohol), side effects of medication (especially chemotherapy and anti-HIV drugs) and radiotherapy
- miscellaneous: panic disorder with hyperventilation, end-stage kidney disease, porphyria, underactive thyroid gland
When should you see a doctor urgently about numbness?
- if it is of sudden onset
- if your face is involved, and/or if there is weakness involving your face
- if your entire arm and/or leg is involved
- if your speech is slurred or you are having difficulty speaking
- if you experience weakness of your arm and/or leg
- if you experience a change in your vision
- if there is a loss of bladder and/or bowel control
- if you have a rash
- if you have a sudden onset, severe headache
- recent back, neck or head injury
- if you have difficulty walking
- if there is confusion or, if there has been a period of a loss of consciousness
- associated dizziness
- tingling or numbness in your legs which increase whilst walking
- if you have a fever