Differentials
Osteoarthritis (OA)
SIGNS / SYMPTOMS
OA of the first carpometacarpal joint (or radiocarpal/wrist joint) may be associated with CTS, and CTS must be excluded as the two commonly coexist.
Painful, stiff thumb joint (and/or wrist), often worse in the evening. Tenderness and crepitus on exam.
INVESTIGATIONS
Diagnosis is clinical.
Electromyogram will be normal (unless CTS coexists).
Stroke, acute
SIGNS / SYMPTOMS
Often there is sensory and motor loss in a cortical-type pattern (i.e., whole hand or limb, worse distally) or spinal segmental pattern. Ipsilateral face and/or leg may also be affected.
INVESTIGATIONS
Electromyogram studies show a completely normal peripheral nervous system.
MRI or CT scan may show abnormalities in central nervous system (brain or spinal cord).
C6 radiculopathy
SIGNS / SYMPTOMS
Sudden onset of severe unilateral neck pain radiating to shoulder/arm/scapula. Associated with weakness (mainly shoulder movements and elbow flexion) and numbness predominantly of the dorsal aspect of first and second fingers and lateral aspect of forearm. Decreased or absent biceps and brachioradialis reflexes.
INVESTIGATIONS
Electromyogram (EMG) will show normal median nerve studies (including sensory responses to first and second fingers) and lateral antebrachial cut nerve studies.
On EMG needle exam there will be denervation in C6 paraspinal muscles and C6 innervated arm/shoulder muscles.
MRI of cervical spine will show abnormality such as a herniated disk or osteophyte impinging on the C6 nerve root (CT will be similar except not as sensitive).
C7 radiculopathy
SIGNS / SYMPTOMS
Sudden onset of severe unilateral neck pain radiating to shoulder/arm/scapula. Associated with weakness (mainly elbow, wrist, and finger extensors) and numbness predominantly of dorsal aspect of third finger. Decreased or absent triceps reflex.
INVESTIGATIONS
Electromyogram (EMG) will show normal median nerve studies (including sensory responses to third finger).
On EMG needle exam there will be denervation in C7 paraspinal muscles and C7 innervated arm/shoulder muscles.
MRI of cervical spine will show abnormality such as a herniated disk or osteophyte impinging on the C7 nerve root (CT will be similar except not as sensitive).
Ulnar neuropathy
SIGNS / SYMPTOMS
Sensory symptoms are on the medial aspect of the hand, distal forearm, and fourth and fifth fingers. Abduction of the first dorsal interosseous and fifth abductor digiti minimi is weak. There is no weakness of the thumb. More commonly it is the nondominant hand that is affected.
INVESTIGATIONS
Electromyogram will show normal median nerve studies and abnormalities in the ulnar nerve, most likely across the elbow region.
Amyotrophic lateral sclerosis/motor neuron disease
SIGNS / SYMPTOMS
Muscle weakness and atrophy is widespread, progressive, and involves more than just median nerve-innervated muscles. Fasciculations are usually prominent. There may be bulbar symptoms. There should be no sensory and no bowel/bladder complaints.
INVESTIGATIONS
Electromyogram (EMG) shows normal sensory nerves. Motor nerve studies and needle EMG show widespread acute or chronic denervation even in clinically normal muscles and very proximal muscles (e.g., tongue, paraspinals).
De Quervain tenosynovitis
SIGNS / SYMPTOMS
Pain on movement of thumb and/or wrist; commonly occurs in both wrists and worsens on heavy lifting.
Hardening and thickening of the radial styloid may be indicative.
INVESTIGATIONS
Electromyogram will be normal (unless CTS coexists). Degenerative or inflammatory joint conditions may be seen on plain x-ray or CT scans.
Lateral epicondylitis
SIGNS / SYMPTOMS
Pain in the lateral elbow and lateral forearm, due to overuse (e.g., tennis). The patient is tender around the lateral epicondyle.
May be associated with CTS.
INVESTIGATIONS
Typically clinical diagnosis; MRI may be confirmatory of extensor carpi radialis brevis degeneration.
Electromyogram will be normal (unless CTS coexists).
Rotator cuff tendonitis
SIGNS / SYMPTOMS
Pain associated with arm movement, especially reaching; pain in shoulder at night.
Tenderness on palpation around the shoulder.
May be associated with CTS.
INVESTIGATIONS
MRI may demonstrate inflammation and exclude a tear in the rotator cuff.
Electromyogram will be normal (unless CTS coexists).
Polyneuropathy
SIGNS / SYMPTOMS
Classically patients complain of symmetrical stocking and glove loss of sensation (worse in the feet) with or without mild weakness distally. Distal reflexes are usually reduced or absent.
However, there are many forms of polyneuropathy that do not follow this pattern and can present asymmetrically, affecting hands more than feet or motor more than sensory.
Polyneuropathy seems to worsen pre-existing entrapment neuropathies (CTS in particular), and so polyneuropathy patients can present purely with CTS symptoms.
INVESTIGATIONS
Electromyogram shows widespread symmetrical, length-dependent neuropathic changes without focal abnormalities in the median nerve across the wrist segment.
Screens for polyneuropathy may show diabetes or excess alcohol use (2 of the common causes in the developed world).
Liver, renal, thyroid, hematologic, and metabolic functions are usually also checked, together with vitamin screen (B₁₂ in particular) and protein electrophoresis (myeloma). Depending also on clinical findings, screens for vasculitis, connective tissue disease, and other paraneoplastic conditions may also be obtained.
Brachial plexopathies
SIGNS / SYMPTOMS
Most but by no means all have a history of trauma and are unilateral. Usually easily distinguished from CTS by more widespread motor and sensory symptoms and signs beyond median nerve territory.
True neurogenic thoracic outlet syndrome causes weakness in a median nerve territory. The sensory loss, however, is in the medial forearm, hand, and fingers.
INVESTIGATIONS
Electromyogram shows widespread neuropathy in a truncal, cordal, or mixed pattern.
MRI may show increased signal intensity in parts of the plexus and in denervated muscles. The cervical spine and cord is usually normal.
Proximal median neuropathies
SIGNS / SYMPTOMS
Numbness extends across the thenar eminence (palmar branch), and weakness includes forearm pronation (pronator teres) and wrist flexion (flexor carpi radialis). Usually unilateral.
INVESTIGATIONS
Electromyogram shows neuropathic changes in the palmar branch of the median nerve and in the pronator teres and flexor carpi radialis. There is no focal slowing in the median nerve across the carpal tunnel.
Multiple sclerosis (MS)
SIGNS / SYMPTOMS
In MS the sensory/motor loss may vary over time and place. Distinguishing features, if present, may include optic neuritis, constitutional symptoms, and neurogenic symptoms (bowel/bladder).
INVESTIGATIONS
Electromyogram studies show a normal peripheral nervous system. MRI or CT scan may show abnormalities in central nervous system (brain or spinal cord).
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