Numbness and Paraesthesiae
Paraesthesiae and numbness are taken here to mean sensations of tingling, pins-and-needles, subjective numbness, and feelings of cold and heat. They may appear spontaneously or be a result of touching the area of skin concerned. Patients are often alarmed and may make an immediate association with serious disease. The differential is huge but most cases in primary care involve anxiety, nerve entrapment or cerebrovascular disease.
Differential diagnosis
Common Diagnoses
- Anxiety with Hyperventilation
- Carpal Tunnel (CT) Syndrome
- Sciatica
- Diabetic Neuropathy
- Cervical Spondylosis
Occasional Diagnoses
- Multiple Sclerosis and Dorsal Myelitis
- Peripheral Polyneuropathy (Especially Alcohol; Also Vitamin B12 and Folate Deficiency, Iatrogenic, Metabolic, Connective Tissue Disorder, Malignancy and Rare Causes Such as Guillain–Barré, Leprosy)
- Stroke and TIA
- Trauma/Compression Involving a Peripheral Nerve or Spinal Cord
- Migraine with Focal Neurological Signs
Rare Diagnoses
- Intramedullary Spinal Cord Tumour
- Syringomyelia
- Trauma, Brain Tumour and Epilepsy Affecting Sensory Cortex
- Functional Neurological Disorder
- Vascular: Ischaemic Heart Disease, Peripheral Vascular Disease
Ready reckoner
Key distinguishing features of the most common diagnoses
| Anxiety | CT Syndrome | Sciatica | Diabetes | Cervical Spondylosis | |
|---|---|---|---|---|---|
| Associated Dizziness | Yes | No | No | No | No |
| Episodic | Yes | Possible | Possible | Possible | Possible |
| Associated Pain | No | Yes | Yes | Possible | Yes |
| Worse at Night | No | Yes | No | Possible | Possible |
| Associated Weakness | No | Possible | Possible | No | Possible |
Possible investigations
Likely: Urinalysis, blood sugar or HbA1c.
Possible: FBC, LFT, γGT, U&E, serum calcium, B12 and folate, TFT, serum electrophoresis, nerve conduction studies.
Small Print: Autoimmune screen, cervical spine X-ray, secondary care investigations (MRI/ CT scan, lumbar puncture, carotid imaging, angiography, myelography).
- Urinalysis: To pick up glycosuria in undiagnosed diabetes.
- Blood sugar or HbA1c: To confirm diabetes.
- FBC: To look for macrocytosis (sign of alcohol excess or B12/folate deficiency). May be anaemia of chronic illness or malignancy.
- LFT and γGT if alcoholic neuropathy suspected.
- Metabolic screen (including U&E, calcium, LFT, B12 and folate).
- TFT: Hypothyroidism can cause a polyneuropathy or precipitate carpal tunnel syndrome.
- Serum electrophoresis: To exclude myeloma.
- Autoimmune screen: To help diagnose a connective tissue disorder.
- Nerve conduction studies: To confirm a diagnosis of nerve compression prior to surgical treatment.
- X-ray cervical spine: Confirms clinical diagnosis of cervical spondylosis, but not really helpful as positive findings common and don’t correlate well with symptoms, and the investigation is unlikely to alter the management.
- Secondary care investigations might include: Lumbar puncture (MS, Guillain–Barré syndrome), carotid imaging (TIA), CT or MRI scan (spinal pathology or compression, MS, cerebral tumour, syringomyelia), angiography (vascular causes), myelography (cord compression).
Top Tips
- Intermittent perioral paraesthesiae are pathognomic of hyperventilation.
- Use a logical approach: a careful history will often reveal the likely underlying problem. For example, a well-demarcated area in anatomically explicable distribution may indicate peripheral nerve entrapment; a larger area or one limb may suggest a root compression; involving the whole side of body, possible cerebral lesion; affecting hands and feet suggests peripheral neuropathy; involving legs alone, possible cord lesion.
- Wasting of the thenar eminence suggests significant CT syndrome which will require decompression.
- Remember to tell women taking the combined oral contraceptive who develop migraine with focal symptoms to use an alternative method of contraception.
Red Flags
- Sudden and progressive bilateral leg symptoms with sphincter disturbance suggest cord compression – admit immediately.
- Intermittent paraesthesiae in varying distributions – especially with other features, such as vertigo or optic neuritis – suggest MS.
- A patient with a TIA within the preceding week should be given aspirin 300 mg immediately and referred for a specialist assessment to take place within 24 hours.
- The borders of sensory loss in functional neurological disorder are often sharply demarcated and do not correspond to an anatomical pattern.
- Constant, progressive paraesthesiae, especially with other neurological symptoms or signs, suggest significant pathology. Refer urgently.