Red flag symptoms: Numbness

Causes of numbness vary from benign to life-threatening, says Dr Mehul Mathukia - Loss of control of limb movement

Urgent referral is needed if a stroke is suspected
Urgent referral is needed if a stroke is suspected

Numbness is defined as abnormal sensations that can occur anywhere in the body, but most commonly felt in the fingers, hands, feet, arms or legs.

Red Flag symtoms
  • Confusion or loss of consciousness
  • Slurred speech
  • Change in vision
  • Loss of bladder or bowel control
  • Difficulty walking
  • Numbness after a head, neck or back injury

It is often described by pat-ients in conjunction with tingling or paraesthesia and is a very common symptom encountered in primary care.

There are many causes, ranging from the relatively benign to severely life-threatening. These include neurological causes, such as nerve compression, nerve damage due to trauma or nerve toxicity, and vascular causes, such as stroke, TIA or Raynaud's.

History
The key points to establish are where exactly the numbness is, which side of the body, and which aspect of the body part is involved (i.e. dorsal or ventral part of the wrist).

It is paramount to note the onset and duration of the numbness and whether it has been continuous or intermittent. It is also important to note if there is any change in colour or temperature of the affected body part as well as if the patient has had any other symptoms, particularly red flag symptoms.

Any history of cancer or risk factors for cancer should be elicited. Risk factors for stroke, diabetes and thyroid disease are all relevant as, are occupational and drug histories.

Neurological examination
Numbness in the presence of any red flag symptom warrants further investigations and possibly urgent admission, especially if a stroke is suspected.

A comprehensive neurological exam should look at both the cranial and peripheral nerves.

Establishing if there is any weakness, asymmetry, drooping of the face, upper or lower motor neurone signs and saddle anaesthesia will guide as to the urgency.

Patients may need to be referred to hospital. Further investigations may include blood tests such as FBC, U&Es, TFT, glucose, vitamin levels and possibly a toxicology screen.

Imaging may include CT or MRI head and spine, and possibly ultrasound and also X-rays of the affected areas. Also electromyography and lumbar puncture may be performed depending on the clinical indication.

  • Dr Mathukia is a GP principal in Ilford, Essex

Possible causes

  • Stroke/TIA
  • Spinal nerve compression - metastatic malignancy, herniated disc
  • Peripheral nerve compression - tumour, enlarged blood vessels, infection
  • Seizures
  • MS
  • Nerve damage due to trauma
  • Vascular - atherosclerosis and Raynaud's
  • Endocrine - diabetes, hypothyroid
  • Vitamin deficiency - B12
  • Nerve toxicity - alcohol, lead
  • Electrolyte disturbances - sodium, potassium and calcium

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