Peripheral neuropathies

Patient resources

Carpal Tunnel Syndrome – Information for Patients (Produced by NHS Lothian Neurology Department)

Definition

Carpal tunnel syndrome (CTS) is a collection of symptoms and signs caused by compression of the median nerve in the carpal tunnel at the wrist.

Typical signs and symptoms

• Symptoms are commonly reported in the distribution of the median nerve (the thumb, index finger, middle finger and radial half of the ring finger). In many cases, there may be discomfort of the whole hand and sometimes further up the arm
• Symptoms can be very mild or disabling, including;
  • Tingling, altered sensation, pain, weakness and impaired fine manipulation
  • Often worse at night and can disrupt sleep
  • Atrophy of the muscles of the thenar eminence, reduced strength of thumb abduction and dry skin on the thumb, index and middle fingers

Prevalence and risk factors

• It is the most common compression neuropathy of the upper limb
• It is more common in women than men
• Most common in females aged 45–54 years and in males aged 75–84 years
• Risk factors include:
  • Activities with high hand/wrist movement repetition rate, use of vibrating hand tools
  • Obesity, hypothyroidism, diabetes mellitus, inflammatory joint disease, OA of the thumb MCP joint

Prognosis

Good prognostic indicators included short duration of symptoms, young age, and CTS due to pregnancy.

Risk factors for poor outcome

Other considerations

Positive findings on clinical tests such as Phalen’s, Tinel’s and the carpal tunnel compression test support a diagnosis of CTS but should not be interpreted in isolation from the rest of the history and examination

Differential diagnosis

• C6/C7 radiculopathies
• Neurological disorder – including MS or MND
• Other peripheral neuropathy – including diabetic, hypothyroid, B12 deficiency etc
• Osteoarthritis or inflammatory arthritis
• De quervains tenosynovitis

Referral Guidance

• Carpal Tunnel Syndrome RefHelp Page (Neurology)
• Carpal Tunnel Syndrom RefHelp Page (Plastic & Hand Surgery)

Patient resources

Ulnar Neuropathy – Patient Fact Sheet (Neurodiagnosis.org)

Definition

Ulnar neuropathy is a collection of symptoms and signs caused by compression of the ulnar nerve.

Typical signs and symptoms

• Numbness and/or paraesthesia affecting the medial hand and fourth and fifth digits
• Symptoms can disturb sleep
• Muscle weakness and wasting in ulnar nerve distribution (little & ring fingers, intrinsic muscle weakness, wasting dorsal 1st web space)

Prevalence and risk factors

• Ulnar neuropathy at the elbow (cubital tunnel syndrome) is the second most common entrapment neuropathy
• Incidence is higher in men than women
• Risk Factors include:
  • Activities and occupations requiring repetitive elbow flexion and extension
  • Sustained elbow flexion e.g. driving or using phone
  • Habitual leaning on elbow
  • Previous fractures or dislocations at the elbow / elbow trauma
  • Sustained pressure on hypothenar eminence g. cyclists

Prognosis

Other considerations

• Ulnar nerve compression at the elbow typically occurs within the ulnar groove or the cubital tunnel. The nerve lies superficially in the ulnar groove, so it is prone to external compression (e.g. resting the elbow on an armchair) 
• Although less common than ulnar neuropathy at the elbow, compression of the ulnar nerve can also occur at Guyon’s canal (e.g. prolonged cycling; propelling a manual wheelchair)

Differential diagnosis

• C8/T1 radiculopathy
• Neurological disorder – including MS or MND
• Other peripheral neuropathy – including diabetic, hypothyroid, B12 deficiency etc

Referral Guidance

• Cubital tunnel syndrome RefHelp page (Plastic and Hand Surgery)
• Ulnar Neuropathy RefHelp page (Neurology)

Definition

Radial Neuropathy is a collection of symptoms and signs caused by compression of the radial nerve, commonly at the spiral groove in the humerus, or at the Arcade of Frohse (compression of the posterior interosseus nerve)

Typical signs and symptoms

• Difficulty straightening the wrist and fingers (‘wrist and finger drop’), with weakness of wrist extension, finger extension, and thumb extension
• If the compression is close to the origin of the nerve, the patient may also present with a weak elbow
• Numbness or tingling is often present over the back of the thumb, and sometimes the forearm

Prevalence and risk factors

• The exact prevalence of radial nerve injuries and neuropathies is unknown
• It is commonly caused by trauma, usually related to shoulder or elbow dislocations, or fractures of the humerus, elbow or forearm. It can also be caused by other injury or repetitive use
• The most common cause of a radial neuropathy, is sitting or sleeping with the arm over the back of a chair. This compresses the radial nerve at the spiral groove of the humerus. It is often referred to as ‘Saturday night palsy’ as it if often seen after heavy alcohol use, where the patient may remain in this uncomfortable position for a long time
• Similarly, improper use of axillary crutches can cause a radial neuropathy at the axilla, but this is much less common

Prognosis

• Non-traumatic radial nerve palsy has a good prognosis and usually recovers over weeks to months. A wrist splint can be considered in the management of a patient with a radial neuropathy

Risk factors for poor outcome

• Older age
• Requirement for surgical repair

Other considerations

The radial nerve gives off several branches, the largest of which is the posterior interosseus nerve

• The posterior interosseous nerve innervates muscles controlling forearm supination, ulnar wrist extension, finger extension and thumb extension
• The superficial sensory branch supplies sensory innervation to the dorsal lateral hand 

Differential diagnosis

It can be difficult to distinguish radial neuropathies from central nervous system lesions, as they can both cause wrist extension weakness. The brachioradialis muscle, is commonly weak in a peripheral radial nerve injury and less affected with a CNS disorder

Referral Guidance

Radial Neuropathy RefHelp page (Neurology)

Brachial Neuritis 

Also known as neuralgic amytrophy, Parsonage-Turner syndrome, brachial neuropathy, neuritis of the shoulder girdle or shoulder-girdle-syndrome.

• A rare condition, incidence rates 1.64 cases per 100000 reported
• Typically affecting young adults, although a second peak of incidence in 7th decade also reported with male predominance 2:1- 11.5:1 
• Unknown aetiology - has been associated with various factors proposed to cause the neuritis including trauma, infection, virus, heavy exercise, surgery, autoimmune conditions and vaccinations 
• Clinical presentation characteristically presents with 3 stages:

1. 1. Acute onset of severe pain in the shoulder which may refer both distally into the arm and proximally into the neck which may persist for days to weeks
   2. Resolution of pain and the onset of painless paresis, atrophy and sensory impairment of the shoulder girdle and/or upper limb due to involvement of the brachial plexus or its component nerves
   3. Gradual recovery

• Presentation can vary greatly dependent upon the predominant site of the lesion i.e. upper, lower or whole brachial plexus, or the uncommon involvement of a single peripheral nerve. Typically the upper trunk of the plexus is affected with supraspinatus, infraspinatus serratus anterior and deltoid particularly vulnerable
• Management is conservative, prognosis is good with 75% fully recovered at 2 years  

Suprascapular Nerve Entrapment

• Uncommon, ~0.4%-2% of sufferers with shoulder pain 
• Suprascapular nerve is a mixed motor and sensory, supplying supraspinatus and infraspinatus, sensory fibres to acromioclavicular and glenohumeral joint capsule, but no cutaneous sensory innervation
• Neuropathy as a result of compression or traction at the suprascapular notch or spinoglenoid region 
• Causes include: space occupying lesions, direct trauma, virus, idiopathic, repetitive/ forceful scapular movement
• Clinical presentation: pain, weakness and atrophy of supraspinatus / infraspinatus
• Compressive lesions are often managed with surgery 

 Long Thoracic Nerve Entrapment

• Long thoracic nerve, a purely motor nerve, arises from branches of C5,6 and 7, and innervates the serratus anterior
• Aetiology: non-traumatic including infection, virus, inflammatory, toxins, prolonged shoulder depression
• Possible manifestation of brachial neuritis. Traumatic cases are thought to account for 53% of cases with vulnerability for injury from multiple sources 
• Clinical presentation: severe burning, aching pain, followed by weakness of serratus anterior and medial scapula winging (accentuated during elevation with elbows extended), limitation of shoulder elevation 
• Most recover serratus anterior function with conservative treatment but may take 2 years or more 

Dorsal Scapular Nerve Entrapment

• Dorsal scapular nerve arises from C5, passes through the middle scalene innervating the rhomboids. It may also innervate levator scapulae. No cutaneous sensory innervation 
• Susceptible to entrapment through the middle scalene 
• Clinical Presentation: typically scapular pain, possibly referring to the lateral shoulder, lateral scapular winging (best shown during return to neutral from elevation) 

Spinal Accessory Nerve Entrapment

• Otherwise known as cranial nerve XI, and is the sole innervator of trapezius 
• Superficial course in the posterior cervical triangle makes it susceptible to injury 
• Iatrogenic injury to the nerve after a surgical procedure is one of the most common causes
• Other causes include penetrating injury and idiopathic 
• Clinical Presentation: dysfunction of trapezius, leading to a drooping shoulder, lateral winging scapula (best shown with shoulder abduction), weakness of elevation 
• For idiopathic causes: treatment is conservative with >80% patients recovering within 6-12 months 
• Traumatic cause, surgical exploration indicated 

Axillary Nerve Entrapment

• Arises from C5,6 supplying teres minor and deltoid, with a cutaneous branch supplying skin superficial to lateral aspect of deltoid 
• Associated with anterior shoulder dislocation, direct trauma to shoulder, space occupying lesions, quadrilateral space syndrome
• Clinical Presentation: symptoms are usually vague, pain poorly localised around the anterolateral shoulder, with possible paraesthesia in a non-segmental pattern, weakness and atrophy of deltoid