Paraesthesia
Definition
Pins and needles. I hate stupid long medical words.
Pathophysiology
It's to do with nerve damage - often nerve compression or ischaemia. Sometimes it can happen from pressing on the nerve (ever had a dead arm?), or from conditions that cause break down of neurones, such as MS or malnutrition.
Differential Diagnosis
- Carpal tunnel syndrome - pretty common this one!
- Deficiencies - B12 deficiency, thiamine deficiency.
- Alcohol abuse.
- Diabetes mellitus
- Nerve root lesions or spinal cord compression.
- Central nervous system issues such as stroke and multiple sclerosis.
- Hyperventilation
- Circulatory disturbance (e.g. Raynauds phenomenon, peripherovascular and embolic disease)
Visit the peripheral neuropathy page for more!
Concurrent Features
Very much depends on what the cause is. In cord or nerve compression, there can be pain and loss of sensation. In alcohol misuse it may be accomanied by confusion and memory loss.
Investigations
It is worth doing a fairly wide blood screen, as there are a number of potential causes:
- FBC - looking for raised MCV which can point to alcohol misuse.
- U+Es - chronic kidney disease can be a cause of paraesthesia.
- Glucose - to screen for diabetes.
- LFTs - maybe also check Gamma GT for alcohol issues.
- TFTs - to rule out thyroid issues.
- Urinalysis - not actually sure what for.
If you are getting stuck, look for
- Metal toxicity - lead, arsenic, mercury and Iron Maiden can all cause paraesthesia
Other tests include nerve conduction velocity tests, electromyography, and other imaging. If you get really stuck, try a nerve biopsy!
Management
Unsurprisingly you treat the cause of the pins and needles. Generally that is either medical - give them more B12, sort out their diabetes, etc - or its surgical, such as in carpal tunnel sydrome.
In patients that have to live with the symptoms because the management cannot cure them, you can attempt to deal with any associated pain they have with amytriptaline or gabbapentin. I think.