Carpal Tunnel Syndrome Flashcards
What is carpal tunnel syndrome?
Carpal tunnel syndrome (CTS) is a condition involving a compression of the median nerve within the carpal tunnel of the wrist, due to a raised pressure within this compartment.
Compression of the median nerve leads to symptoms of pain, numbness, and paresthesia in the lateral 3½ digits.
Who is commonly affected by carpal tunnel syndrome?
CTS accounts for 90% of all nerve compression syndromes. It is more common in women and has peak incidence between ages 45-60 (only 10% of CTS cases are in patients under 30 years of age).
What are the risk factors for carpal tunnel syndrome?
The main risk factors for developing carpal tunnel syndrome include female gender, increasing age, pregnancy, obesity and previous injury to the wrist.
Carpal tunnel syndrome is as associated with other conditions, such as diabetes mellitus, rheumatoid arthritis and hypothyroidism.
Individuals who have occupations involving repetitive hand or wrist movements (e.g. vibrating tools or assembly line work) are also at increased risk of CTS.
What are the clinical features of carpal tunnel syndrome?
Patients with carpal tunnel syndrome typically complain of pain, numbness, and/or paraesthesia throughout the median nerve sensory distribution.
Symptoms are typically worse during night and symptoms can often be temporarily relieved by hanging the affected arm over the side of the bed or by shaking it back and forth.
On examination there are often no visible findings during early stages of CTS. However, sensory symptoms can be reproduced by either percussing over the median nerve (Tinel’s Test) or holding the wrist in full flexion for one minute (Phalen’s Test).
In the later stages of carpal tunnel syndrome, there may be weakness of thumb abduction (due to denervation atrophy of the thenar muscles) and/ or wasting of the thenar eminence.
Why is the palm often spared in carpal tunnel syndrome?
The palm is often spared, due to the palmar cutaneous branch of the median nerve branching proximal to the flexor retinaculum and passing over the carpal tunnel.
Briefly describe Tinel’s and Phalen’s Test
Sensory symptoms can be reproduced by either percussing over the median nerve (Tinel’s Test) or holding the wrist in full flexion for one minute (Phalen’s Test).
What is shown in the image?
Wasting of the thenar eminence in a case of untreated CES.
What investigations should be ordered for carpal tunnel syndrome?
Carpal tunnel syndrome is a clinical diagnosis and is an evident pathology in most cases on history and examination.
However, in the more uncertain cases, nerve conduction studies may be useful to confirm median nerve damage (however a normal median nerve conduction does not rule out CTS).
Briefly describe the conservative management of carpal tunnel syndrome
Carpal tunnel syndrome can be treated conservatively initially with a wrist splint (commonly worn at night), preventing wrist flexion and holds the wrist as to not exacerbate the tingling and pain, alongside physiotherapy and various training exercises.
Corticosteroids injections can be trialled. They are administered directly into carpal tunnel to reduce swelling and in turn symptoms.
Some clinicians may also trials NSAIDs in an attempt to further reduce swelling, however there is limited evidence to support their routine use.
Briefly describe the surgical management of carpal tunnel syndrome
Surgical treatment is undertaken only in severely limiting cases where previous treatments have failed.
Carpal tunnel release surgery decompresses the carpal tunnel, involving cutting through the flexor retinaculum, in turn reducing the pressure on the median nerve. This can be done under local anaesthetic and is performed as a day case.
What are the complications of carpal tunnel surgery?
Complications of carpal tunnel surgery include persistent CTS symptoms (from incomplete release of ligament), infection, scar formation, nerve damage or trigger thumb.
However overall post-operative outcomes are good, with 90% of patients reporting improved symptoms afterwards.
What are the complications of carpal tunnel syndrome?
Long-term untreated CTS can lead to permanent neurological impairment that will not improve with surgery.
Briefly describe the innervation of the median nerve
Schematic of the cutaneous innervation of the branches of the median nerve.
What differentials should be considered for carpal tunnel syndrome?
- Cervical Radiculopathy
- Pronator teres syndrome (median nerve compression by pronator teres)
- Flexor carpi radialis tenosynovitis
How does cervical radiculopathy and carpal tunnel syndrome differ?
C6 nerve root involvement may produce pain or paraesthesia in a similar distribution however will likely have an element of neck pain or symptoms involving the entire arm length.
