CARPAL TUNNEL SYNDROME
GENERAL FEATURES
• The carpal tunnel is formed anteriorly by the flexor retinaculum and posteriorly by the carpal bones. It contains the tendons of the finger flexors and the median nerve.
• Carpal tunnel syndrome (CTS) occurs when the median nerve is compressed due to swelling within this space.
• CTS is the most common nerve entrapment.
• Women are more likely than men to develop CTS. People who have jobs that require repetitive wrist flexion, grasping, or pinching are more at risk. Other risk factors include genetic predisposition, pregnancy, and certain diseases such as diabetes and rheumatologic disorders.
CLINICAL ASSESSMENT
• History
– The most common symptom of carpal tunnel syndrome is numbness in the thumb, index finger, and middle finger. Sensory changes may be accompanied by a loss in grip strength.
– Discomfort at the wrist may radiate into the forearm or hand.
– Many patients complain of symptoms worsening at night and awakening them.
• Physical examination
– The Tinel sign, Phalen maneuver, and carpal compression test are used to diagnose CTS.
– Tingling in the median nerve distribution with percussion of the volar aspect of the carpal tunnel
is a positive Tinel sign.
– If a patient places his or her wrists in maximal flexion for 60 seconds and develops numbness and tingling in the median nerve distribution, this is a positive Phalen maneuver.
– If sustained compression over the palm in the region of the median nerve causes numbness and tingling, this is a positive carpal compression test.
– Of the three tests, the carpal compression test is the most sensitive and specific for CTS.
– Thenar muscular atrophy may be present in long-standing cases of CTS.
– The loss of two-point discrimination is suggestive of severe CTS.
DIAGNOSIS
• Diagnosis of CTS is usually made on history and physical examination alone.
• If central nerve compression is suspected (eg, cervical radiculopathy), electromyography (EMG) and/or nerve conduction test should be considered, although a negative EMG result does not rule out carpal tunnel syndrome.
TREATMENT
• Primary conservative treatment of CTS includes modification of provocative activity accompanied by the use of neutral wrist splinting.
• NSAIDs may offer temporary relief but should not be used over the long term.
• Injection of corticosteroid into
the carpal tunnel is also an option for temporary relief, but if symptoms return, surgery should be considered.
• Surgical options include open or endoscopic carpal tunnel release and should be considered when other treatments have not resulted in permanent relief.
QUESTION & ANSWER
1. Which of the following signs/symptoms is indicative of severe carpal tunnel syndrome?
a. Numbness in the lateral three digits
b. A positive Tinel sign
c. Loss of two-point discrimination
d. Tingling in the median nerve distribution with compression over the carpal tunnel
Answer: c
Explanation: The remaining signs and symptoms are expected in all forms of CTS, including mild or moderate.
PULMONARY
EMBOLUS
GENERAL FEATURES
• More than 600,000 cases of pulmonary embolus (PE) occur each year, resulting in more than 60,000 deaths.
• Mortality from undiagnosed PE
is 30%.
• Pregnancy and childbirth are the most common conditions associated with PE.
• Risk factors include venous stasis and hypercoagulable states related to immobilization, surgery and trauma, oral contraceptives and estrogen replacement, malignancy, travel greater than 4 hours a month, smoking, central venous instrumentation, stroke, heart failure, chronic obstructive pulmonary disease, obesity, obstructive sleep apnea, varicose veins, inflammatory bowel disease, and inherited and acquired hypercoagulable states.
• Deep venous thrombosis (DVT)
is strongly associated with PE; 50% of patients with PE have DVT
and 70% of these cases will be asymptomatic.
• Most clinically significant and fatal emboli arise from thrombi in the proximal deep veins of the legs.
CLINICAL PRESENTATION
• History
– Common symptoms are dyspnea, pleuritic chest pain, cough, and hemoptysis.
– Acute-onset chest pain, shortness of breath, or both often occur postoperatively in patients with PE.
– Other symptoms include seizures, syncope, fever, productive cough, wheezing, decreased level of consciousness, new onset of atrial fibrillation, delirium, and shock.
• Physical examination
– PE is most commonly associated with tachypnea. Other findings may include rales, tachycardia, fourth heart sound, and accentuated pulmonic component of the second heart sound.
DIAGNOSIS
• Equivocal studies
– An arterial blood gas analysis is not specific for PE but may show hypoxemia, hypocapnia, and/or respiratory alkalosis.
– ECG readings may be normal or show nonspecific changes. There may be evidence of right heart failure.
– A chest radiograph is nondiagnostic, revealing normal or nonspecific changes such as atelectasis, pulmonary infiltrate, pleural effusions, and/or prominent pulmonary vasculature.
– Troponins and brain natriuretic peptide (BNP) have little predictive value.
• More definitive studies
– D-dimer assays are most reliable in younger patients. A negative result with low clinical probability of PE reliably excludes PE. This assay has a low negative predictive value when clinical probability is high.
– Lower extremity ultrasounds positive for DVT may be definitive evidence of PE. However, as many as 40% of patients with negative study findings are shown to have a PE on angiogram.
– CT angiography (CTA) is the current standard of care except in centers where CTA is not available or in patients with IV dye allergy. In those cases, a V/Q (ventilation/perfusion) scan should be done.
– V/Q lung scans are most sensitive for large defects with mismatched defects of abnormal perfusion and normal ventilation.
– Echocardiography has low sensitivity and specificity for central and peripheral PE, but transesophageal echocardiography is more sensitive.
– MRI is inadequate for diagnosis of subsegmental emboli, requires gadolinium-enhanced angiography and venography, is dependent on a technically adequate study, and is poorly interpreted if pulmonary hypertension is present.
– Pulmonary angiography is the gold standard but requires contrast and significant technical and mechanical capabilities with the risk associated with all arterial studies.
TREATMENT
• Full anticoagulation for suspected PE
– Begin heparin and warfarin.
– Heparin dose should be titrated to 1.5 times baseline control or the upper limit of aPTT (activated partial thromboplastin time).
– Discontinue heparin in 5 to 7 days or when international normalized ratio (INR) is 2.
– Low molecular weight heparin (LMWH) may be used without compromise.
– Fondaparinux (Arixtra) is possible instead of LMWH, but no controlled clinical proof of benefit has been shown.
– Anticoagulants should be used for 3 months for first event of PE. In the case of recurrence or ongoing risk factors, anticoagulation should be used for 6 months. Lifetime anticoagulation is indicated for patients with irreversible risk factors.
• Thrombolytics are given to hemodynamically unstable patients with massive PE.
• Pulmonary artery thrombectomy is
– Used for hemodynamically unstable patients with massive PE and with risk factors causing exclusion from hemolytics
– Utilized in patients with phlegmasia cerulea dolens
– A benefit for patients with high rate of recurrent PE
– An elective procedure for patients with chronic large vessel thromboembolic pulmonary hypertension
• Inferior vena cava filter is used in patients with
– Absolute contraindication to anticoagulant therapy or in survivors of massive PE in whom another PE would be fatal
– Documented recurrent thrombolic event despite adequate anticoagulation
• Early ambulation is now preferred over prolonged bed rest. JAAPA
QUESTION & ANSWER
1. Which of the following would not increase a patient's risk for an acute pulmonary embolism?
a. Oral contraception
b. Postoperative state
c. Travel in a car for 30 minutes to 1 hour once a month
d. Obesity
Answer: c
Explanation: Travel for greater than 4 hours increases the risk of pulmonary embolism. The risk is greatest in the first week after travel.