Carpal Tunnel Syndrome

Musculoskeletal System


Clinicals - History

Fact Explanation
{"ops":[{"insert":"Pain and paresthesia"},{"insert":"\n"}]}
{"ops":[{"insert":"This is most commonly felt in the palmar surface of the thumb, index, and middle fingers, plus the radial aspect of the ring finger; however, the whole hand can be affected.\n\nRarely, the pain can radiate to the elbow or even the shoulder. Note that paresthesias occurring proximal to the wrist are suggestive of an alternate diagnosis.\n\nThe underlying cause is compression of the median nerve as it passes through the narrowed carpal tunnel."}]}
{"ops":[{"insert":"Flick sign"},{"insert":"\n"}]}
{"ops":[{"insert":"Pain and paresthesias improve after shaking out hands. This is highly sensitive and specific (93% and 96%, respectively) for carpal tunnel syndrome (CTS)."}]}
{"ops":[{"insert":"Loss of motor function"},{"insert":"\n"}]}
{"ops":[{"insert":"Adduction and opposition of the thumb can be affected, leading to difficulty in grasping objects firmly, or in performing tasks requiring fine motor control (e.g., picking up a needle or buttoning a shirt).\n\nThis is because injury to the median nerve to leads to weakness and clumsiness of the hand."}]}
{"ops":[{"insert":"Workplace exposure"},{"insert":"\n"}]}
{"ops":[{"insert":"Workplace exposure to activities requiring prolonged wrist flexion or extension, overuse of flexor muscles, or exposure to vibration is a risk factor for CTS.\n\nThis type of exposure can be seen in manual workers employed in construction, logging, manufacturing, or certain service industries; and in artisans."}]}
{"ops":[{"insert":"Extrinsic and intrinsic risk factors"},{"insert":"\n"}]}
{"ops":[{"insert":"Extrinsic risk factors include obesity, hypothyroidism, pregnancy, menopause, renal failure, oral contraceptive use, and congestive heart failure. These conditions affect the body\u0027s fluid regulation, and can increase the fluid volume within the carpal tunnel.\n\nIntrinsic risk factors refer to tumors and similar pathologies that increase the pressure on the median nerve, by taking up space within the carpal tunnel."}]}
{"ops":[{"insert":"Pain and paresthesia"},{"insert":"\n"}]}
{"ops":[{"insert":"This is most commonly felt in the palmar surface of the thumb, index, and middle fingers, plus the radial aspect of the ring finger; however, the whole hand can be affected.\n\nRarely, the pain can radiate to the elbow or even the shoulder. Note that paresthesias occurring proximal to the wrist are suggestive of an alternate diagnosis.\n\nThe underlying cause is compression of the median nerve as it passes through the narrowed carpal tunnel."}]}
{"ops":[{"insert":"Flick sign"},{"insert":"\n"}]}
{"ops":[{"insert":"Pain and paresthesias improve after shaking out hands. This is highly sensitive and specific (93% and 96%, respectively) for carpal tunnel syndrome (CTS)."}]}
{"ops":[{"insert":"Loss of motor function"},{"insert":"\n"}]}
{"ops":[{"insert":"Adduction and opposition of the thumb can be affected, leading to difficulty in grasping objects firmly, or in performing tasks requiring fine motor control (e.g., picking up a needle or buttoning a shirt).\n\nThis is because injury to the median nerve to leads to weakness and clumsiness of the hand."}]}
{"ops":[{"insert":"Workplace exposure"},{"insert":"\n"}]}
{"ops":[{"insert":"Workplace exposure to activities requiring prolonged wrist flexion or extension, overuse of flexor muscles, or exposure to vibration is a risk factor for CTS.\n\nThis type of exposure can be seen in manual workers employed in construction, logging, manufacturing, or certain service industries; and in artisans."}]}
{"ops":[{"insert":"Extrinsic and intrinsic risk factors"},{"insert":"\n"}]}
{"ops":[{"insert":"Extrinsic risk factors include obesity, hypothyroidism, pregnancy, menopause, renal failure, oral contraceptive use, and congestive heart failure. These conditions affect the body\u0027s fluid regulation, and can increase the fluid volume within the carpal tunnel.\n\nIntrinsic risk factors refer to tumors and similar pathologies that increase the pressure on the median nerve, by taking up space within the carpal tunnel."}]}

Clinicals - Examination

Fact Explanation
{"ops":[{"insert":"Tinel\u0027s percussion test"},{"insert":"\n"}]}
{"ops":[{"insert":"Tapping the median nerve over the flexor retinaculum will worsen symptoms. This is because percussion of an irritated nerve can elicit paresthesia along its distribution.\n\nNote that the literature reports a wide range of values for the sensitivity and specificity (i.e., 48% to 73% and 30% to 94% respectively) for this test."}]}
{"ops":[{"insert":"Phalen\u0027s test"},{"insert":"\n"}]}
{"ops":[{"insert":"This is performed by having patient flex their wrists by joining the dorsal aspects of their hands together for one minute, thus stretching the median nerve. Increased pain or paresthesia of the hand constitutes a positive result."}]}
{"ops":[{"insert":"Signs of predisposing risk factors"},{"insert":"\n"}]}
{"ops":[{"insert":"There may be stigmata of medical conditions that predispose to CTS, e.g., obesity, acanthosis nigricans, myxedema, acromegaly, signs of pregnancy, etc."}]}
{"ops":[{"insert":"Neurological deficits"},{"insert":"\n"}]}
{"ops":[{"insert":"Patients with severe CTS may demonstrate neurological deficits such as hypalgesia (decreased pain sensation), lack of two-point discrimination, thenar atrophy, and weakness of thumb adduction and opposition.\n\nHypalgesia can be appreciated by comparing pain sensation of palmar surface of the index finger with that of the little finger of the same hand. Lack of two-point discrimination manifests as inability to distinguish between two objects touching the skin \u003C6 mm apart."}]}
{"ops":[{"insert":"Carpal compression test"},{"insert":"\n"}]}
{"ops":[{"insert":"This is performed by applying firm pressure over the carpal tunnel for 30 seconds. The appearance of sensorial symptoms indicates a positive compression test and has a sensitivity and specificity of 64 and 83% respectively."}]}
{"ops":[{"insert":"Square-shaped wrist"},{"insert":"\n"}]}
{"ops":[{"insert":"A wrist with an increased depth-to-width ratio has an odds ratio (OR) of 4.56 for CTS.\n\nThe reason for this association is unclear; it is postulated that a square-shaped carpal tunnel configuration predisposes to median nerve compression."}]}
{"ops":[{"insert":"Tinel\u0027s percussion test"},{"insert":"\n"}]}
{"ops":[{"insert":"Tapping the median nerve over the flexor retinaculum will worsen symptoms. This is because percussion of an irritated nerve can elicit paresthesia along its distribution.\n\nNote that the literature reports a wide range of values for the sensitivity and specificity (i.e., 48% to 73% and 30% to 94% respectively) for this test."}]}
{"ops":[{"insert":"Phalen\u0027s test"},{"insert":"\n"}]}
{"ops":[{"insert":"This is performed by having patient flex their wrists by joining the dorsal aspects of their hands together for one minute, thus stretching the median nerve. Increased pain or paresthesia of the hand constitutes a positive result."}]}
{"ops":[{"insert":"Signs of predisposing risk factors"},{"insert":"\n"}]}
{"ops":[{"insert":"There may be stigmata of medical conditions that predispose to CTS, e.g., obesity, acanthosis nigricans, myxedema, acromegaly, signs of pregnancy, etc."}]}
{"ops":[{"insert":"Neurological deficits"},{"insert":"\n"}]}
{"ops":[{"insert":"Patients with severe CTS may demonstrate neurological deficits such as hypalgesia (decreased pain sensation), lack of two-point discrimination, thenar atrophy, and weakness of thumb adduction and opposition.\n\nHypalgesia can be appreciated by comparing pain sensation of palmar surface of the index finger with that of the little finger of the same hand. Lack of two-point discrimination manifests as inability to distinguish between two objects touching the skin \u003C6 mm apart."}]}
{"ops":[{"insert":"Carpal compression test"},{"insert":"\n"}]}
{"ops":[{"insert":"This is performed by applying firm pressure over the carpal tunnel for 30 seconds. The appearance of sensorial symptoms indicates a positive compression test and has a sensitivity and specificity of 64 and 83% respectively."}]}
{"ops":[{"insert":"Square-shaped wrist"},{"insert":"\n"}]}
{"ops":[{"insert":"A wrist with an increased depth-to-width ratio has an odds ratio (OR) of 4.56 for CTS.\n\nThe reason for this association is unclear; it is postulated that a square-shaped carpal tunnel configuration predisposes to median nerve compression."}]}

Differential Diagnoses

Fact Explanation
{"ops":[{"insert":"Cervical radiculopathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Pain and neurological deficits of the hand can occur in patients with cervical radiculopathy. Age-related degeneration of the cervical spine, a condition known as cervical spondylosis, is the most common cause. However, these patients often demonstrate symptoms proximal to the carpal tunnel, such as neck pain.\n\nDiagnostic maneuvers include the Spurling test, shoulder abduction test, neck distraction test, and the valsava maneuver. The Spurling test is considered positive if symptoms are reproduced by exerting the neck to extension, ipsilateral rotation, and downward pressure on top the head.\n\nRadiographs of the neck, MRI, and computerized tomograpy (CT) scan play an important role in the work up of suspected cervical radiculopathy."}]}
{"ops":[{"insert":"Proximal median neuropathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Examples are pronator teres syndrome (PTS) and anterior interosseous nerve (AIN) syndrome; these can present with signs and symptoms similar to carpal tunnel syndrome (CTS), such as pain and paresthesia of the hand, loss of grip, and positive Phalen\u0027s and Tinel\u0027s tests.\n\nHowever, involvement of musculature proximal to the carpal tunnel is more suggestive of PTS. EMG and NCS can pinpoint where the median nerve entrapment occurs, thus distinguishing between PTS and CTS."}]}
{"ops":[{"insert":"De Quervain tendinopathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Sometimes referred to as \u0022gamer\u0027s\u0022 or \u0022mother\u0027s\u0022 thumb, de Quervain tendinopathy is a common condition that leads to hand pain and poor grip.\n\nUnlike CTS, which is due to nerve entrapment, de Quervains tendinopathy is caused by irritation of the the abductor pollicis longus and the extensor pollicis muscles from thickening of the synovial sheath that encases them.\n\nPatients present pain with Finkelstein\u0027s test but not the paresthesia seen in CTS."}]}
{"ops":[{"insert":"Thoracic outlet syndrome"},{"insert":"\n"}]}
{"ops":[{"insert":"Thoracic outlet syndrome (TOS) can present with pain and paresthesia of the hand and arm resulting from the compression of one of more of the nerves of the brachial plexus and\/or subclavian blood vessels that traverse the opening between the first rib and the axila.\n\nThe vascular subset of this condition can produce painful swelling, chest pain, cyanosis, thromboembolic events, and potentially fatal ischemia.\n\nRadiography, MRI, and CT can be used to distinguish between the different causes, which can be categorized as either soft-tissue or osseous abnormalitis."}]}
{"ops":[{"insert":"Peripheral neuropathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Peripheral neuropathy can manifest as paresthesias and sensorial deficits of the hands; this can be secondary to a range of conditions such as diabetes mellitus, human immunodeficiency virus (HIV) infection, chemotherapy, vitamin deficiencies, and dysproteinemias.\n\nA detailed history and physical exam will reveal clues as to the underlying cause; depending on the suspected etiology, investigations that may be needed include complete blood counts, renal function tests, fasting blood glucose, hemoglobin A1c (HbA1c), thyroid stimulating hormone, vitamin b12 levels, and screening for HIV and Lyme disease."}]}
{"ops":[{"insert":"Cervical radiculopathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Pain and neurological deficits of the hand can occur in patients with cervical radiculopathy. Age-related degeneration of the cervical spine, a condition known as cervical spondylosis, is the most common cause. However, these patients often demonstrate symptoms proximal to the carpal tunnel, such as neck pain.\n\nDiagnostic maneuvers include the Spurling test, shoulder abduction test, neck distraction test, and the valsava maneuver. The Spurling test is considered positive if symptoms are reproduced by exerting the neck to extension, ipsilateral rotation, and downward pressure on top the head.\n\nRadiographs of the neck, MRI, and computerized tomograpy (CT) scan play an important role in the work up of suspected cervical radiculopathy."}]}
{"ops":[{"insert":"Proximal median neuropathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Examples are pronator teres syndrome (PTS) and anterior interosseous nerve (AIN) syndrome; these can present with signs and symptoms similar to carpal tunnel syndrome (CTS), such as pain and paresthesia of the hand, loss of grip, and positive Phalen\u0027s and Tinel\u0027s tests.\n\nHowever, involvement of musculature proximal to the carpal tunnel is more suggestive of PTS. EMG and NCS can pinpoint where the median nerve entrapment occurs, thus distinguishing between PTS and CTS."}]}
{"ops":[{"insert":"De Quervain tendinopathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Sometimes referred to as \u0022gamer\u0027s\u0022 or \u0022mother\u0027s\u0022 thumb, de Quervain tendinopathy is a common condition that leads to hand pain and poor grip.\n\nUnlike CTS, which is due to nerve entrapment, de Quervains tendinopathy is caused by irritation of the the abductor pollicis longus and the extensor pollicis muscles from thickening of the synovial sheath that encases them.\n\nPatients present pain with Finkelstein\u0027s test but not the paresthesia seen in CTS."}]}
{"ops":[{"insert":"Thoracic outlet syndrome"},{"insert":"\n"}]}
{"ops":[{"insert":"Thoracic outlet syndrome (TOS) can present with pain and paresthesia of the hand and arm resulting from the compression of one of more of the nerves of the brachial plexus and\/or subclavian blood vessels that traverse the opening between the first rib and the axila.\n\nThe vascular subset of this condition can produce painful swelling, chest pain, cyanosis, thromboembolic events, and potentially fatal ischemia.\n\nRadiography, MRI, and CT can be used to distinguish between the different causes, which can be categorized as either soft-tissue or osseous abnormalitis."}]}
{"ops":[{"insert":"Peripheral neuropathy"},{"insert":"\n"}]}
{"ops":[{"insert":"Peripheral neuropathy can manifest as paresthesias and sensorial deficits of the hands; this can be secondary to a range of conditions such as diabetes mellitus, human immunodeficiency virus (HIV) infection, chemotherapy, vitamin deficiencies, and dysproteinemias.\n\nA detailed history and physical exam will reveal clues as to the underlying cause; depending on the suspected etiology, investigations that may be needed include complete blood counts, renal function tests, fasting blood glucose, hemoglobin A1c (HbA1c), thyroid stimulating hormone, vitamin b12 levels, and screening for HIV and Lyme disease."}]}

Investigations - Diagnosis

Fact Explanation
{"ops":[{"insert":"Nerve conduction studies"},{"insert":"\n"}]}
{"ops":[{"insert":"Nerve conduction studies (NCS) are the gold standard for the diagnosis of carpal tunnel syndrome (CTS). An action potential is induced along the nerve to be studied. Then, electrodes located distally or proximally detect depolarizations and thus the rate and amplitude of nervous impulse conduction can be quantified.\n\nFindings suggestive of CTS include decreased velocity of sensory and motor conduction and increased latency. Usually reserved for atypical cases when other diagnoses are considered."}]}
{"ops":[{"insert":"Ultrasonography"},{"insert":"\n"}]}
{"ops":[{"insert":"Used to measure the cross-sectional area of the median nerve. A value greater than 9 mm^2 is highly suggestive of CTS. Other ultrasonographic findings include flattening of the median nerve as it passes the carpal tunnel and palmar bowing of the flexor retinaculum (PBFR).\n\nBenefits include low-cost, patient comfort, and the ability to detect mass lesions, tenosynovitis, and other causes of wrist pain. Highly user dependent."}]}
{"ops":[{"insert":"Magnetic resonance imaging (MRI)"},{"insert":"\n"}]}
{"ops":[{"insert":"Usually not indicated but is the best imaging modality for diagnosing rarer causes of CTS such as bone deformities, ganglions, or vascular tumors that may have significant impact on treatment strategy.\n\nFindings suggestive of CTS include nerve swelling, increased signal intensity, and palmar bowing of the flexor retinaculum (PBFR). Usually preferred by patients over NCS, but very expensive."}]}
{"ops":[{"insert":"Nerve conduction studies"},{"insert":"\n"}]}
{"ops":[{"insert":"Nerve conduction studies (NCS) are the gold standard for the diagnosis of carpal tunnel syndrome (CTS). An action potential is induced along the nerve to be studied. Then, electrodes located distally or proximally detect depolarizations and thus the rate and amplitude of nervous impulse conduction can be quantified.\n\nFindings suggestive of CTS include decreased velocity of sensory and motor conduction and increased latency. Usually reserved for atypical cases when other diagnoses are considered."}]}
{"ops":[{"insert":"Ultrasonography"},{"insert":"\n"}]}
{"ops":[{"insert":"Used to measure the cross-sectional area of the median nerve. A value greater than 9 mm^2 is highly suggestive of CTS. Other ultrasonographic findings include flattening of the median nerve as it passes the carpal tunnel and palmar bowing of the flexor retinaculum (PBFR).\n\nBenefits include low-cost, patient comfort, and the ability to detect mass lesions, tenosynovitis, and other causes of wrist pain. Highly user dependent."}]}
{"ops":[{"insert":"Magnetic resonance imaging (MRI)"},{"insert":"\n"}]}
{"ops":[{"insert":"Usually not indicated but is the best imaging modality for diagnosing rarer causes of CTS such as bone deformities, ganglions, or vascular tumors that may have significant impact on treatment strategy.\n\nFindings suggestive of CTS include nerve swelling, increased signal intensity, and palmar bowing of the flexor retinaculum (PBFR). Usually preferred by patients over NCS, but very expensive."}]}

Investigations - Management

Fact Explanation
{"ops":[{"insert":"Nerve conduction studies"},{"insert":"\n"}]}
{"ops":[{"insert":"Should be performed before surgery not only to confirm the diagnosis but to predict the outcomes. Patients with severe carpal tunnel syndrome (CTS) may have less benefit with surgery, but serial NCS showing improvement following non-surgical measures may provide reassurance and encouragement."}]}
{"ops":[{"insert":"Magnetic resonance imaging (MRI)"},{"insert":"\n"}]}
{"ops":[{"insert":"Useful to predict surgical outcomes by measuring the length of the portion of the median nerve displaying an abnormal signal. Can be used following failed carpal tunnel surgery or to guide treatment when space-occupying lesions are suspected."}]}
{"ops":[{"insert":"Nerve conduction studies"},{"insert":"\n"}]}
{"ops":[{"insert":"Should be performed before surgery not only to confirm the diagnosis but to predict the outcomes. Patients with severe carpal tunnel syndrome (CTS) may have less benefit with surgery, but serial NCS showing improvement following non-surgical measures may provide reassurance and encouragement."}]}
{"ops":[{"insert":"Magnetic resonance imaging (MRI)"},{"insert":"\n"}]}
{"ops":[{"insert":"Useful to predict surgical outcomes by measuring the length of the portion of the median nerve displaying an abnormal signal. Can be used following failed carpal tunnel surgery or to guide treatment when space-occupying lesions are suspected."}]}

Management - Supportive

Fact Explanation
{"ops":[{"insert":"Reduce exposure"},{"insert":"\n"}]}
{"ops":[{"insert":"Includes avoiding or minimizing the use of vibrating tools or objects requiring a prolonged, tight grip during at least one month. Strategies includes alternating task assignment, increased number of breaks, or taking sick leave."}]}
{"ops":[{"insert":"Conservative therapies"},{"insert":"\n"}]}
{"ops":[{"insert":"May be offered to patients with mild or moderate carpal tunnel syndrome (CTS). Options include splinting, corticosteroid therapy, non-steroidal anti-inflammatory drugs (NSAIDs) physical therapy, yoga, vitamins B6 and B12 administration and therapeutic ultrasonography.\n\nShort-term benefits are usually seen after two to six weeks. Lack of improvement after six weeks warrants consideration of an alternate approach. Other purported therapies involving the use of magnets or chiropratic treatment have failed to show a significant benefit."}]}
{"ops":[{"insert":"Splinting"},{"insert":"\n"}]}
{"ops":[{"insert":"Immobilizes the wrist joint to prevent extreme flexion and\/or extension and reduce carpal tunnel pressure. Initial treatment for mild to moderate CTS. Simple, low cost, well tolerated, and easily removable. Particularly useful in cases of CTS due to temporary or medically treatable causes such as pregnancy or hypothyroidism."}]}
{"ops":[{"insert":"Corticosteroid administration"},{"insert":"\n"}]}
{"ops":[{"insert":"Improves symptoms on a short-term basis by inhibiting inflammation and edema. However, reduced collagen and proteoglycan synthesis may lead to diminished tenocyte function resulting in decreased tendon strength and degeneration. Furthermore, studies have failed to show long-term improvement with this therapy."}]}
{"ops":[{"insert":"Reduce exposure"},{"insert":"\n"}]}
{"ops":[{"insert":"Includes avoiding or minimizing the use of vibrating tools or objects requiring a prolonged, tight grip during at least one month. Strategies includes alternating task assignment, increased number of breaks, or taking sick leave."}]}
{"ops":[{"insert":"Conservative therapies"},{"insert":"\n"}]}
{"ops":[{"insert":"May be offered to patients with mild or moderate carpal tunnel syndrome (CTS). Options include splinting, corticosteroid therapy, non-steroidal anti-inflammatory drugs (NSAIDs) physical therapy, yoga, vitamins B6 and B12 administration and therapeutic ultrasonography.\n\nShort-term benefits are usually seen after two to six weeks. Lack of improvement after six weeks warrants consideration of an alternate approach. Other purported therapies involving the use of magnets or chiropratic treatment have failed to show a significant benefit."}]}
{"ops":[{"insert":"Splinting"},{"insert":"\n"}]}
{"ops":[{"insert":"Immobilizes the wrist joint to prevent extreme flexion and\/or extension and reduce carpal tunnel pressure. Initial treatment for mild to moderate CTS. Simple, low cost, well tolerated, and easily removable. Particularly useful in cases of CTS due to temporary or medically treatable causes such as pregnancy or hypothyroidism."}]}
{"ops":[{"insert":"Corticosteroid administration"},{"insert":"\n"}]}
{"ops":[{"insert":"Improves symptoms on a short-term basis by inhibiting inflammation and edema. However, reduced collagen and proteoglycan synthesis may lead to diminished tenocyte function resulting in decreased tendon strength and degeneration. Furthermore, studies have failed to show long-term improvement with this therapy."}]}

Management - Specific

Fact Explanation
{"ops":[{"insert":"Carpal tunnel release (CTR)"},{"insert":"\n"}]}
{"ops":[{"insert":"Surgical referral should be made when symptoms are severe, progressive neurological deficit is present, or no improvement is seen after three months of conservative management.\n\nMore effective than splinting, CTR consists of dividing the transverse carpal ligament (TCL) to relieve pressure on the median nerve. More than 70% of patients have long-term improvement.\n\nApproach options include open CTR (OCTR) and endoscopic CTR (ECTR). OCTR is the most reliable approach and is indicated for the treatment of carpal tunnel syndrome (CTS) due to any pathology, including refractory cases. Advantages of ECTR over OCTR include ECTR provides less scarring,less postoperative pillar pain, and faster recovery. However, there is increased risk of iatrogenic nerve injury with ECTR."}]}
{"ops":[{"insert":"Carpal tunnel release (CTR)"},{"insert":"\n"}]}
{"ops":[{"insert":"Surgical referral should be made when symptoms are severe, progressive neurological deficit is present, or no improvement is seen after three months of conservative management.\n\nMore effective than splinting, CTR consists of dividing the transverse carpal ligament (TCL) to relieve pressure on the median nerve. More than 70% of patients have long-term improvement.\n\nApproach options include open CTR (OCTR) and endoscopic CTR (ECTR). OCTR is the most reliable approach and is indicated for the treatment of carpal tunnel syndrome (CTS) due to any pathology, including refractory cases. Advantages of ECTR over OCTR include ECTR provides less scarring,less postoperative pillar pain, and faster recovery. However, there is increased risk of iatrogenic nerve injury with ECTR."}]}

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