When differentiating transient synovitis of the hip from septic arthritis in a child who presents with a history of inability to weight-bear, which ONE of the following features is MOST likely to be helpful towards diagnosing transient synovitis?
Answer: A: Diagnosing transient synovitis of the hip in a limping or non-weight-bearing but otherwise well young child can be a challenge. This is a diagnosis that should be arrived at by exclusion of significant causes affecting the hip in this age group (3–6 years). History, examination, radiological and laboratory findings generally overlap between transient synovitis and other conditions.
Differential diagnosis of conditions affecting the hip include:
Predictors of septic arthritis of the hip have been described. The presence of all four of fever, inability to weight bear, WCC of >12 × 106 /L and ESR > 40 mm gives a 93–99% likelihood of having septic arthritis. If none of these predictors are present the likelihood of septic arthritis seems to be very low.
Two-thirds of the cases of transient synovitis is associated with a joint effusion. In transient synovitis, medial joint space widening, lateral displacement of the femoral epiphysis with flattening of the surface (Waldenstrom’s sign) secondary to joint effusion can be seen. However, these findings are not specific to transient synovitis and the finding of an effusion on ultrasound cannot be used to confirm the diagnosis of transient synovitis. In some patients, joint aspiration under ultrasound guidance, MRI and nuclear scanning may need to be used to exclude other potential conditions.
A child with transient synovitis is more likely to appear well and have a hip that is pain free on passive movements carried out by the examiner. Internal rotation and abduction can be slightly restricted.
Reference:
Regarding interpretation of children’s cervical spine radiographs, all of the following are correct EXCEPT:
Answer: D: In children younger than 8 years of age, upper cervical spine injuries (above C 3–4) level are more common than lower cervical spine injuries. These injuries are often fatal but survivors may only have subtle radiological abnormalities. Children over 8 years of age typically sustain lower cervical spine injuries. Compounding the difficulties in assessing a young child’s cervical spine and neurology, interpretation of radiology is challenging because many features may mimic fractures in the growing cervical spine. Some of these features include:
References:
Regarding injuries to the sternoclavicular joint and medial part of the clavicle, which ONE of the following statements is TRUE?
Answer: B: The sternoclavicular joint is the most frequently mobile non-axial joint of the body. It is one of the most stable joints because it is strengthened by the surrounding strong ligaments. Consequently, dislocations are rare unless a high degree of forces are involved. Similarly, fractures involving the medial (proximal) clavicle account only for 5% of all clavicular fractures. Routine clavicular X-ray may not precisely show the fracture and dislocations in this area. Comparison with the normal side and special views of the medial clavicle may be helpful. Contrast CT scan is indicated where uncertainty of the fracture or dislocation exist or when there is high suspicion for injuries to the superior mediastinal vessels and other structures secondary to posterior dislocation or displacement of the fracture.
In these injuries pneumothorax should be excluded by both clinical examination and CXR. Evidence for impingement on superior mediastinal structures should be sought during physical examination. Injuries and compresssion to the great vessles, trachea and oesophagus can occur. Posterior streno-clavicular dislocations will require closed or open reduction under anaesthetic to prevent significant functional impairment.
Which ONE of the following is INCORRECT regarding an acute rotator cuff tear?
Answer: D: Acute rotator cuff tears occur as a result of significant traumatic mechanisms such as hyperabduction and hyperextension, as occurs when falling on an outstretched arm or lifting a very heavy object. Individuals with chronic impingement syndrome due to repetitive overhead use of an arm (as in heavy labour and in sports) may progress to an advanced stage of injury (stage 3 inmpingement syndrome) to a rotator cuff injury that involves acute tears. They are more prone to tears during acute injury as well. Rotator cuff tears can be partial or complete. The most commonly affected component is the supraspinatus tendon and muscle.
In the acute stage the diagnosis is based on clinical features. Tears cause pain and weakness typically on abduction of the shoulder at 60–120 degrees and also on external rotation. A positive drop arm test is due to the inability to hold and lower an abducted arm at 90 degrees without dropping it. Other tests of shoulder impingement may become positive. Most rotator cuff tears can be adequately assessed using ultrasound, although this test is operator-dependent. USS has a relatively high sensitivity in identifying and assessing both partial and full thickness tears.
Regarding the radiographic appearance of posterior dislocation of the shoulder joint, which ONE of the following statements is INCORRECT?
Answer: B: Only 2% of the shoulder dislocations are posterior and can be classified according to the final resting postion of the humeral head – subacromial (most common), subglenoid, subspinous (both are rare). The mechanism of injury in posterior shoulder dislocations is often forced internal rotation and adduction. This may occur in falls and sudden muscular contractions as in convulsions and due to accidental electric shock. A direct anterior force to the shoulder can dislocate it posteriorly as well.
Posterior dislocations are notoriously difficult to diagnose on standard X-rays of the shoulder. The AP view may appear normal unless careful attention is directed to identify subtle indications of posterior dislocation. These include:
The transcapular (‘Y’) view confirms the posterior location of the humeral head. Other specific views such as axillary and posterior oblique can be obtained. These views can identify any associated humeral head and posterior glenoid rim fractures.
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