Carpal Tunnel Syndrome

Carpal Tunnel Syndrome
Description
• The median nerve, flexor digitorum profundus, flexor digitorum superficialis, and flexor pollicis longus are located in the carpal tunnel.
• Area bound by the carpal bones and the transverse carpal ligament
• Compression of the median nerve causes symptoms.
Etiology
• Occupational/overuse syndromes-high impact, repetitive motion
• Trauma
• Pregnancy, birth control pills
• Granulomatous disease: tuberculosis, sarcoidosis
• Mass lesions with median nerve compression
• Osteophytes
• Amyloid
• Multiple myeloma
• Rheumatoid arthritis
• Endocrine disorders: hypothyroidism, diabetes mellitus, acromegaly
• Chronic hemodialysis
• Idiopathic
Pediatric Considerations
• Idiopathic cause rare in children; most cases have correctable cause including:
o Trauma
o Mucolipidosis
o Hamartoma of the median nerve
o Anomalous flexor digitorum superficialis (FDS)
o Hemophilia with hematoma
Diagnosis
Signs and Symptoms
History
• Numbness/paresthesias in median nerve distribution:
o Thumb, index, middle, and radial aspect of ring finger
• Pain:
o Location: wrist or hand, sometimes radiating to elbow, forearm, or shoulder
o Often worse at night-relieved by shaking out the hand
o Exacerbated by repetitive wrist movement and by activities in which the wrist is flexed (e.g., driving)
Physical Exam
• Weakness of the abductor pollicis brevis and opponens muscles:
o Innervated by the recurrent branch of the median nerve
o Patient may complain of dropping things or having decreased fine motor control.
o Sensitivity of 29%; specificity of 80%, on average
• Loss of two-point discrimination:
o Late finding, highly specific
o Sensitivity of 24%; specificity of 94%
• Atrophy of thenar muscles:
o Late finding, highly specific
o Sensitivity of 18%; specificity of 94%
Essential Workup
• History of characteristic nocturnal pain and paresthesias in the median nerve distribution.
• Muscle weakness and thenar wasting are later findings.
• Provocative testing:
o Phalen test:
 Wrist flexion for 60 seconds produces numbness or tingling in the median nerve distribution.
 Sensitivity of 68%; specificity of 73%
o Tinel sign:
 Gentle tapping over the median nerve at wrist produces tingling in the fingers in the median nerve distribution.
 Sensitivity of 50%; specificity of 77%
o Carpal compression test:
 Thumb pressure applied over the proximal carpal ligament produces tingling in the fingers in the median nerve distribution.
 Sensitivity of 64%; specificity of 83%
o Tourniquet test:
 Blood pressure (BP) cuff inflated to just above the patient's systolic blood pressure for 2 minutes produces paresthesias in the median nerve distribution.
 Sensitivity of 59%; specificity of 61%
Tests
Lab
• Not indicated in most cases
• Thyroid function studies; rheumatoid factor and immune panel if indicated by history and physical exam
Imaging
• Wrist radiograph if trauma or degenerative arthritis suspected
• CT in select cases:
o May show encroachment of carpal tunnel
• MRI displays the soft tissues well but may not be justified in ED owing to time and cost:
o Findings: palmar bowing of transcarpal ligament, flattened median nerve, median nerve or synovial swelling, fluid in carpal tunnel, signal abnormality of median nerve
• Ultrasound can be diagnostic:
o Findings: median nerve swelling at proximal canal, median nerve flattening at distal canal, bowing of transcarpal ligament
Diagnostic Procedures/Surgery
Nerve conduction studies and electromyography are criterion standard tests.

Differential Diagnosis
• Cervical nerve root compression:
o Origin of median nerve is at the sixth and seventh cervical roots.
o Symptoms are aggravated by erect posture and neck movement.
• Hand-arm vibration syndrome:
o Characterized by Raynaud, numbness and tingling in ulnar and median nerve distributions when exposed to cold or vibration, weakened grip, and upper extremity myalgias
o Associated with prolonged exposure to vibration
• Thoracic outlet obstruction
• Osteoarthritis of the first carpometacarpal joint
• Brachial plexitis
• Generalized neuropathy
• Syringomyelia
Treatment
Initial Stabilization
None necessary
ED Treatment
• Splint wrist in neutral position (0 degrees).
• Aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs)
• Avoidance of repetitive wrist movement
• Wrist splint to be worn at night until follow-up
• Apply heat to involved wrists heating pad, hot water bottle, low-level heat wraps
• Referral to occupational medicine for ergometric testing if caused by repetitive motion, and tendon gliding or nerve gliding exercises
• May need referral to a hand surgeon for consideration of surgical release of transverse carpal ligament using either open or endoscopic technique
Medication (Drugs)
• NSAIDs (there are many choices; a few are listed below):
o Ibuprofen: 600 mg (peds: 5-10 mg/kg) PO q6h
o Ketorolac: 30 mg IV or IM q6h or 10 mg PO q4h-q6h
o Diclofenac: 50 mg PO b.i.d. or t.i.d.
o Piroxicam: 20 mg PO daily
• Local corticosteroid injection provides transient relief in two thirds of patients (many different regimens):
o Hydrocortisone: 25-100 mg
o Methylprednisolone: 40 mg
o Prednisolone suspension: 20-40 mg
o Triamcinolone: 20 mg
Follow-Up
Disposition

Discharge Criteria
Discharge to home with appropriate referral to either patient's primary care physician or directly to a specialist in occupational medicine or hand surgery.

References
1. Al-Qattan MM, Thompson HG, Clarke HM. Carpal tunnel syndrome in children and adolescents with no history of trauma. J Hand Surg. 1996;21B(1):108-111.
2. Kanaan N, Sawaya RA. Carpal tunnel syndrome: modern diagnostic and management techniques. Br J Gen Pract. 2001;51:311-314.
3. MacDermid JC, Wessel J. Clinical diagnosis of carpal tunnel syndrome: a systematic review. J Hand Ther. 2004;17(2):309-319.
4. Michlovitz SL. Conservative interventions for carpal tunnel syndrome. J Orthop Sports Phys Ther. 2004;34(10):589-600.
5. O'Gradaigh D, Merry P. Corticosteroid injection for the treatment of carpal tunnel syndrome. Ann Rheum Dis. 2000;59:918-919.
6. Sternbach G. The carpal tunnel syndrome. J Emerg Med. 1999;17:519-523.
7. Whitley JM, McDonnell DE. Carpal tunnel syndrome. A guide to prompt intervention. Postgrad Med. 1995;97(1):89-96.
Codes
ICD9-CM
354.0
G56.0

Acute Coronary Syndrome: Drug Induced

Acute Coronary Syndrome: Drug Induced

Description
Imbalance in myocardial blood supply and oxygen requirement
Etiology
• Sympathomimetics are associated with myocardial oxygen mismatch due to induced vasoconstriction:
o Cocaine
o Cocaethylene is a toxic compound formed by hepatic transesterification of alcohol and cocaine further exacerbates the sympathomimetic effects of cocaine.
o Amphetamines (crank)
o Ephedrine (dietary supplement), pseudoephedrine (decongestant)
o Ma huang (herbal diet supplement)
o Dipivefrin (glaucoma eye drop)
o Phenylpropanolamine (nasal decongestant)
o Epinephrine
o Methylene 3,4 dioxymethamphetamine (ecstasy)
• Cocaine-induced chest pain also caused by:
o Increased myocardial workload
o Accelerated atherosclerosis
o Activation of platelets and promotion of thrombosis
• Antimigraine therapy—sumatriptan, methysergide, ergotamine, and isometheptene:
o Vasoconstrictors
o Particularly with cardiac risk factors or known coronary disease
• Calcium channel blockers—nifedipine:
o Reflex tachycardia and vasoconstriction
• Beta-blockers (metoprolol and propanolol):
o α-adrenergic mediated coronary vasospasm
• Carbon monoxide found with gas heaters, smoke inhalation, furniture stripping with methylene chloride:
o Decreasing oxygen-carrying capacity
o Shifting the oxyhemoglobin dissociation curve to the left
o Binding to myoglobin
• Bromocriptine:
o Vasoconstrictor
o Used for acromegaly, Parkinson disease, hyperprolactinemia, amenorrhea/galactorrhea, lactation cessation
o Risk increased by predisposing conditions:
 Pregnancy-induced hypertension
 Other vasospastic conditions (Raynaud disease or migraine headaches)
• Other dopaminergic agents (dopamine):
o Vasoconstriction and vasospasm
• Sildenafil:
o Vasodilatory properties
o Transient decreases in supine blood pressure
o Increase the risk of cardiac event during sexual activity
• Oral contraceptives:
o Prothrombotic
o Higher incidence of MI in young women with concomitant smoking
Diagnosis
Signs and Symptoms
• Chest pain
• Substernal pressure
• Heaviness
• Squeezing
• Burning sensation
• Tightness
• Sympathomimetic toxidrome symptoms:
o Agitation
o Tremulousness
o Tachypnea
o Tachycardia
o Hypertension
o Hyperthermia
o Moist skin
o No urine retention
History
• Recent ingestion of medication/drug that induces coronary vasospasm
• Cardiac risk factors or known cardiac disease
Physical Exam
• Physical exam is usually unrevealing
• Blood pressure (BP) is usually elevated during symptoms
Essential Workup
History is critical in diagnosing and differentiating drug-induced and unusual causes of acute coronary syndromes.
Tests
• ECG:
o Normal approximately 50% of the time
o Compare to prior tracings
o New ST segment changes or T-wave inversions
o 1-mm depression of the ST segment below the baseline
o 80 msec from the J point
o Helpful in diagnosing other etiologies
• ECG in carbon monoxide poisoning:
o Premature ventricular contractions:
o Dysrhythmias
o Tachycardia
o Nonspecific ST-T wave abnormalities
o Acute MI: ST elevation or depression
Lab
• Serial cardiac enzymes
• Troponin may be more helpful.
• Creatine kinase may be elevated in cocaine-induced rhabdomyolysis
• Carboxyhemoglobin level for suspected carbon monoxide (CO) toxicity
• Serum toxicology screening
Imaging
• Chest radiograph:
o Usually normal
o May show cardiomegaly
o Congestive heart failure
o May identify other etiologies of chest pain such as pneumonia
• Exercise stress testing: Identify underlying atherosclerosis.
• A technetium Tc-99m perfusion scan: myocardial damage/MI
• ECG: wall motion abnormalities
Diagnostic Procedures/Surgery
• Gold standard: cardiac catheterization
• Most patients will have angiographically normal coronary arteries.
Differential Diagnosis
• Anxiety
• Aortic dissection
• Biliary colic
• Costochondritis
• Esophageal reflux
• Esophageal spasm
• Herpes zoster
• Hiatal hernia
• Mitral valve prolapse
• Myocardial infarction
• Panic disorder
• Peptic ulcer disease
• Pneumonia
• Psychogenic
• Pulmonary embolus
• Unstable angina
Treatment
Pre Hospital
• Remove patient from contaminated environment if carbon monoxide toxicity is a consideration.
• IV access
• Oxygen
• Cardiac monitoring
• Sublingual nitroglycerin for symptom relief
Alert
• All chest pain should be treated and transported as a possible life-threatening emergency.
• Avoid β-adrenergic antagonists in cases of suspected cocaine use.
Initial Stabilization
• Place patient on a monitor
• IV access should be obtained
• O2: 100% oxygen
• Nitrates

ED Treatment
• Aspirin
• β-adrenergic blockers should be avoided in patients who are suspected to have used cocaine.
• Benzodiazepines: cocaine use
• Reduce BP and heart rate.
• Decreasing myocardial oxygen demand
• Heparin or enoxaparin
• Thrombolytics: Use with caution in suspected vasospasm induces acute coronary syndrome
• Cardiac catheterization: diagnostic and/or therapeutic
• Carbon monoxide toxicity:
o 100% O2
o Hyperbarics if
o Carboxyhemoglobin level is >25–40%.
o Any period of coma
o Neurologic deficits
o Persistent metabolic acidosis
o Pregnant and carboxyhemoglobin level is >15%.
o Cardiac instability
o Acute MI, unless hemodynamically unstable
• Half-life of carboxyhemoglobin:
o Room air: 300 minutes
o 100% O2: 90 minutes
o Hyperbaric chamber at 3 ATM: 20 minutes
Medication (Drugs)
• Aspirin: 160-325 mg PO
• Enoxaparin (Lovenox): 1 mg/kg SC q12h
• Heparin: 80 units/kg IV bolus, then 18 units/kg/hr
• Labetalol: 20 mg IV or 100 mg PO
• Lorazepam: 1-2 mg IV
• Metoprolol: 5 mg IV q5min-q15 min followed by 25-50 mg PO starting dose as tolerated (note: beta-blockers contraindicated in cocaine chest pain)
• Morphine: 2 mg IV, may titrate upward in 2-mg increments for relief of pain assuming no respiratory deterioration and SBP >90 mm Hg
• Nitroglycerin: 0.4 mg sublingual
• Nitroglycerin: IV drip at 5-10 µg/min
• Nitropaste: 1-2 inches transdermal
• Tenecteplase: for 60-kg person, 30 mg; >60-69 kg, 35 mg; 70-79 kg, 40 mg; 80-89 kg, 45 mg, >90 kg, 50 mg given IV; or Reteplase, 10 units IV over 2 minutes, repeat in 30 minutes
Follow-Up
Disposition

Admission Criteria
• Similar to patients with acute coronary syndromes of atherosclerotic origin
• New-onset chest pain
• Rest chest pain
• Accelerated chest pain symptoms
Discharge Criteria
Chronic stable chest pain

References
1. Lai TI, Hwang JJ, Fang CC, Chen WJ. Methylene 3,4 dioxymethamphetamine-induced acute myocardial infarction. Ann of Emerg Med. 2003;42(6):759-762.
2. Lange RA, Hillis LD. Cardiovascular complications of cocaine use. N Engl J Med. 2001;345:351-358.
3. Manini AF, Kabrhel C, Thomsen. Acute Myocardial Infarction after over-the-counter use of Pseudoephedrine. Ann of Emerg Med. 2005;45(2):213-218.
4. Marius-Nunez AL. Myocardial infarction with normal coronary arteries after acute exposure to carbon monoxide. Chest. 1990;97:491-494.
5. Ottervanger JP, Wilson JH, Stricker BH. Drug-induced chest pain and MI. Reports to a national center and review of the literature. Eur J Clin Pharmacol. 1997;53:105-110.
6. Qasim A, Townend J, Davies MK. Esctasy induced myocardial infarction. Heart. 2001;85(6):E10
7. Tanis BC, van den Bosch MA, Kemmeren JM, et al. Oral contraceptives and the risk of myocardial infarction. N Engl J Med. 2001;345:1787-1793.
8. Wasson S, Jayam VK. Coronary vasospasm and myocardial infarction induced by oral sumatriptan. Clin Neuropharmocol. 2004;27(4):198-200.
Codes
ICD9-CM
411.1
ICD10
I20.9
T88.7