1. Answer:B
SDHs are crescent in shape [see Figure 18.26] and are more common in patients with brain atrophy, including older adult and alcoholic patients, because the bridging vessels that cause these bleeds traverse greater distances in these patients. The bleed occurs between the dura and brain and is usually caused by acceleration-deceleration injuries. SDH is more common than epidural hematoma, occurring in up to 30% of patients with severe head trauma.
Figure 18.26
Head computed tomography.
A biconvex-shaped density refers to an epidural hematoma. Most epidural hematomas result from a direct impact injury that causes a forceful deformity of the skull. An epidural hematoma is less likely in this patient because it is primarily a disease of the young and is rare in older adults and children younger than 2 years.
White densities in the cisterns and sulci suggest a traumatic subarachnoid hemorrhage. Subarachnoid hemorrhage is common in patients with severe head injury and is associated with early mortality. Severe head trauma is described as a GCS score of 8 or lower. This patient has a GCS score of 12, which makes this diagnosis less likely.
A normal head CT can be seen in patients with mild head injury, GCS score of 13 to 15, or severe head injury who have diffuse axonal injury that is often not apparent on initial injury. Given that this patient has moderate head injury based on his GCS score, these diagnoses are less likely.
Test-taking tip: When faced with a question that asks the most likely diagnosis, consider demographics [e.g., age, gender] and mechanism/situation to settle on the best answer.
2. Answer:C
Indications for emergent evacuation of an acute SDH include:
•
An acute SDH with a thickness greater than 10 mm or a midline shift greater than 5 mm on CT scan regardless of the patient’s GCS score
•
A comatose patient [GCS score 40 mph], distracting painful injury, chest wall tenderness, sternal tenderness, thoracic spine tenderness, and scapular tenderness. If all of these are negative, then the rate of major thoracic injury is 30 mm Hg is indication of injury, while a pressure >40 mm Hg is indication for fasciotomy.
Test-taking tip: Brush up on the clinical findings of common syndromes that present to the ED.
75. Answer:D
This is a Jones fracture, which is a transverse fracture of the fifth metatarsal at the level of the intermetatarsal joint. It is common in athletes playing running/jumping sports, when there is a transverse force applied to a plantar-flexed foot.
These fractures have a high incidence of nonunion and thus are managed either operatively or, if nondisplaced, conservatively in a non–weight-bearing cast for a minimum of 6 weeks.
In contrast, a pseudo-Jones or “dancer’s” fracture is an avulsion of the base of the fifth metatarsal by the peroneus brevis tendon. This usually results from a plantar flexion/inversion injury, as is common in an ankle sprain. Thus, tenderness at the base of the fifth metatarsal is part of the Ottawa ankle rules. This fracture heals well and needs only a rigid soled shoe [cast shoe].
Test-taking tip: Eponyms are commonly tested on standardized medical exams, especially in orthopedics, so make sure to review them as part of a study plan.
76. Answer:D
This radiograph shows displacement of the lateral mortise due to rupture of the deltoid ligament. Any time a medial malleolus fracture or injury to the deltoid ligament is suspected, a Maisonneuve fracture [fracture of the proximal third of the fibula associated with rupture of the deltoid ligament or fracture of the medial malleolus and disruption of the syndesmosis] must be ruled out. The associated proximal fibula fracture is shown in Figure 18.30. Any time a patient has medial ankle tenderness and swelling, an associated proximal fibula fracture must be ruled out.
Figure 18.30
Knee radiograph.
The mechanism is usually eversion, not inversion, of the dorsiflexed foot in a high-intensity sport. This mechanism can result in a “high ankle sprain,” which may be associated with rupture of the anterior tibiofibular ligament and injury of the syndesmosis. If there is a positive “squeeze test” or “dorsiflexion external rotation” test, this patient may need stress radiographs by orthopedics/podiatry to rule out ligamentous instability. If weight-bearing films are possible, this will increase the sensitivity for ligamentous instability by showing displacement of the medial aspect of the mortise [increase in the width of the medial clear space].
The lateral ligament complex is usually injured by an inversion stress to the ankle.
Test-taking tip: Answers B and D are contradictory to each other, increasing the likelihood that one of them is the correct answer.
77. Answer:A
A nondisplaced spiral fracture of the distal tibial shaft is also called a “toddler’s fracture” and is very common in ambulatory children with low-mechanism trauma. This injury is not suspicious for nonaccidental trauma. The fracture line may be difficult to see and may be mistaken for a nutrient vessel. Bony callus formation at follow-up confirms the diagnosis.
A “bucket handle” fracture, shown in Figure 18.31, is also called a metaphyseal “corner” fracture and results from intentional pulling and twisting. The shearing forces result in separation of the subperiosteal bone collar of the metaphysis, resulting in the disk-shaped fragment described as a “bucket handle.” This is very concerning for nonaccidental trauma, especially in a nonambulatory child.
Figure 18.31
Knee radiograph.
The most common fractures in nonaccidental trauma are transverse or spiral diaphyseal fractures of the long bones in a nonambulatory child. The physician should maintain a high suspicion of nonaccidental trauma in any fracture in a nonambulatory child, in a new presentation of an old fracture, in a child with multiple fractures at different stages, and when the clinical history does not seem to fit the expected mechanism of injury.
Test-taking tip: This is a “you know it or don’t” kind of question. If you don’t know it, choose an answer and move on. You can perhaps mark it for review when you are done at the end of the test. Don’t, however, let these kinds of questions get you stuck and waste your time.
78. Answer:D
Thoracic outlet syndrome is characterized by compression of the neurovascular bundle [brachial plexus, subclavian artery, and/or subclavian vein] as it courses through the thoracic outlet. Symptoms include pain, paresthesias/numbness [neurologic], swelling [venous], and arm ischemia [arterial]. The syndrome may be associated with a cervical rib, muscular anomalies, or injury.
The most reliable test is the EAST. This is performed by having the patient raise the hands above the head and open and close the fist for 3 minutes. Inability to complete the test due to pain or paresthesias is a positive test. Adson’s test evaluates specifically for arterial thoracic outlet syndrome [not neurologic or venous]. In this test, both radial pulses are palpated while the patient turns the head from side to side. Loss of the radial pulse is a positive test. If conservative therapy [physical therapy, weight loss] fails, thoracic outlet decompression may be needed.
Adhesive capsulitis or “frozen shoulder” is characterized by limited range of motion of the affected shoulder and trouble with activities of daily living. On passive testing of external rotation, a sense of mechanical restriction of joint motion can often be appreciated.
Acute rotator cuff tears present with point tenderness over the site of the tear [the greater tuberosity]. The drop-arm test, performed by passively abducting the arm to 90 degrees and asking the patient to hold the arm in this position, is positive with significant tears. Slight pressure on the distal forearm or wrist causes the patient to drop the arm suddenly.
Impingement syndrome of the shoulder is a spectrum of illness and is marked by progression of symptoms. The Hawkins-Kennedy impingement sign involves placing the arm into 90 degrees of flexion followed by internal rotation; the test is consider positive if the patient has pain with internal rotation.
Test-taking tip: This is a “you know it or don’t” kind of question. If you don’t know it, choose an answer and move on. You can perhaps mark it for review when you are done at the end of the test. Don’t, however, let these kinds of questions get you stuck and waste your time.
79. Answer:B
This radiograph shows a Salter-Harris II fracture, which extends through the metaphysis. The Salter-Harris classification refers to physial, or growth plate, fractures. Salter-Harris II is the most common, representing more than 75% of growth plate fractures. The system classifies fractures from I to V, generally with I being the least complex and V being the most complex. Complications can include premature physial fusion and growth disturbance. A mnemonic to remember the classification is as follows:
S – slipped—across physis, or nothing seen radiographically = Salter-Harris I
A – above the growth plate—through growth plate and metaphysis = Salter-Harris II
L – lower than the growth plate—through growth plate and epiphysis = Salter-Harris III
T – through the growth plate—through epiphysis, growth plate, and metaphysis = Salter-Harris IV
R – rammed—growth plate is crushed = Salter-Harris V
Test-taking tip: Brush up on your Salter-Harris classifications because they are frequently tested on emergency medicine standardized tests.
80. Answer:D
This radiograph shows a large elbow effusion that presents with a posterior fat pad, which is always pathologic for an occult fracture, as well as an anterior sail sign. A normal elbow radiograph may have a small anterior fat pad, but a large anterior sail sign, as shown in this radiograph, indicates an elbow effusion. This can be the only radiographic abnormality seen with a radial head fracture, usually in adults, or a supracondylar fracture in children.
Test-taking tip: This is a “you know it or don’t” kind of question. If you don’t know it, choose an answer and move on. You can perhaps mark it for review when you are done at the end of the test. Don’t, however, let these kinds of questions get you stuck and waste your time.
81. Answer:C
Finkelstein’s test refers to ulnar deviation of the fisted hand and will reproduce the pain in de Quervain’s tenosynovitis. De Quervain’s tenosynovitis is an overuse inflammatory condition that causes pain on the radial side of wrist. This is due to inflammation of the abductor pollicis longus and the extensor pollicis brevis as they pass through the first dorsal compartment of the wrist. Treatment is with thumb spica splint, NSAIDs, or in severe cases, surgery.
Tinel’s test, percussion of the median nerve at the wrist, and Phalen’s test, maximal palmar flexion at the wrist, both refer to tests for carpal tunnel syndrome that have recently come under some scrutiny for not having adequate sensitivity or specificity.
Thompson’s test is used to detect Achilles tendon rupture. If the foot does not plantar-flex when the calf is squeezed, this is a positive Thompson’s test and is consistent with an Achilles tendon rupture.
Test-taking tip: Brush up on your musculoskeletal tests and signs because they are frequently tested on emergency medicine standardized tests.
82. Answer:D
When a child presents with pain and/or a limp, it is important to consider all of the diagnoses listed. Toxic [transient] synovitis is the most common cause of a painful hip in children, while septic arthritis is the most common cause of a painful hip in infants.
The patient with toxic synovitis is usually 3 to 8 years of age and presents with an acutely painful hip or knee and a limp. These patients are generally well-appearing but may have a slightly elevated temperature and erythrocyte sedimentation rate [ESR]. They respond well to NSAIDs. This is, however, a diagnosis of exclusion, after a septic joint has been ruled out.
The patient with septic arthritis will typically present acutely ill-appearing, have a fever, and have an elevated ESR and white blood cell count. The most common organism overall is S. aureus. Salmonella is characteristic in patients with sickle cell disease. Neisseria gonorrhoeae should be suspected in adolescents.
The characteristic patient with SCFE is an obese adolescent male who presents with insidious onset of hip, groin, thigh, or knee pain.
The patient with Legg-Calvé-Perthes disease is typically 4 to 8 years old and presents with insidious onset of pain and limp due to idiopathic avascular necrosis of the femoral head. Temperature and ESR will be normal. If radiographs are normal and the patient cannot bear weight, consider obtaining an MRI because plain films may be normal early in the course of the disease.
Test-taking tip: This is a “you know it or don’t” kind of question. If you don’t know it, choose an answer and move on. You can perhaps mark it for review when you are done at the end of the test. Don’t, however, let these kinds of questions get you stuck and waste your time.
83. Answer:D
This radiograph shows a Lisfranc injury, which is characterized by disruption of the TMT joint. The Lisfranc ligament connects the medial cuneiform to the second metatarsal and provides midfoot stability. This may or may not be associated with a fracture. In this case, it is not, and the radiographic abnormality is the increased space between the first and second metatarsals. Any time there is a fracture of the base of the second metatarsal [where the Lisfranc ligament attaches], a Lisfranc injury should be suspected. If the patient can tolerate a weight-bearing radiograph, this will help in making the diagnosis by making any space between the first and second metatarsals more evident. This injury needs urgent podiatry or orthopedic consultation to determine whether it will be managed conservatively [6 weeks in a non–weight-bearing cast] or operatively.
Test-taking tip: When one answer [urgent consultation] stands out for three similar answers [all weight-bearing immobilization methods], the different answer is probably correct.
84. Answer:C
This patient likely has a significant crush injury, based on mechanism, which is a relative contraindication to replantation because the tissues and neurovasculature are likely too severely damaged to undergo successful repair. That said, all digit amputations should be treated with rapid consultation with a hand surgeon. All patients are candidates for surgical repair until the surgeon deems otherwise. Tetanus and antibiotic prophylaxis should be given. The amputated part should be wrapped in moist gauze and placed in a clean, sealed plastic bag or specimen cup; then the sealed bag or cup should be placed in ice.
Some of the indications for replantation include amputation of the thumb at any level, amputation of multiple digits, virtually all pediatric amputations, and hand amputations through the palm and distal wrist. Some relative contraindications include severely crushed parts, amputations at multiple levels, and prolonged time of ischemia.
Test-taking tip: When one answers stands out as different from the others [run over by a tractor vs. all other minor mechanisms], it is probably the correct answer.
85. Answer:B
This is a Monteggia fracture, which is a fracture of the proximal third of the ulnar shaft associated with radial head dislocation. A Monteggia fracture is more common in children than in adults. It can be associated with a radial nerve injury. In pediatrics, there may be a bowing/plastic deformity of the ulna rather than a fracture associated with a radial head dislocation, so it is important to pay attention to the radiocapitellar line. It is very uncommon to see an isolated radial head dislocation in children [though it is common to see a subluxation of the radial head, i.e., nursemaid’s elbow]. Treatment in adults is ORIF; however, in children, it is usually closed reduction and immobilization.
A Galeazzi fracture is a fracture of the shaft of the radius with dislocation of the distal radioulnar joint. The ligaments of the inferior radioulnar joint are ruptured, and the head of the ulna is displaced from the ulnar notch of the radius.
A nightstick fracture is a fracture of the ulna, radius, or both. It is usually a defensive injury when a person uses the forearm to self-protect from a blow or a solid object.
Test-taking tip: You can eliminate choice A because its description of the fracture is not consistent with the radiograph. Study up on your fracture eponyms because they are commonly tested.
86. Answer:A
The Ottawa ankle rules include all of the above except A. The rules include tenderness along the posterior edge of the distal 6 cm of the medial or lateral malleolus, not the anterior edge. These rules have been validated by numerous clinical studies and provide guidelines for which patients do not need a radiograph of the ankle if they have none of the criteria.
Test-taking tip: Brush up on common rules such as Ottawa and NEXUS because they are commonly tested on emergency medicine standardized tests.
87. Answer:B
This radiograph shows a lateral tibial plateau fracture. The degree of depression and whether there is any associated ligamentous injury will help determine whether surgical management is indicated.
A tibial plateau fracture and any tibia or fibula fracture may be associated with compartment syndrome
Lateral tibial plateau fractures may be associated with a deep peroneal nerve injury; thus, the physician should examine and document sensation in the first dorsal webspace of the foot [between the great toe and second toe] and evaluate the patient’s ability to dorsiflex the foot [rule out footdrop].
The most common complication is post-traumatic arthritis.
Test-taking tip: This is a “you know it or don’t” kind of question. If you don’t know it, choose an answer and move on. You can perhaps mark it for review when you are done at the end of the test. Don’t, however, let these kinds of questions get you stuck and waste your time.
88. Answer:A
A nightstick fracture is a nondisplaced fracture of the ulnar shaft [it can also involve the radial shaft]. A concomitant radial head dislocation [Monteggia fracture-dislocation] must be ruled out. A nightstick fracture may be associated with a radial nerve injury, and complications include nonunion.
A Colles fractures is of the distal radius with dorsal displacement and volar angulation, with or without an ulnar styloid fracture.
A Galeazzi fracture is a fracture of the shaft of the radius with dislocation of the distal radioulnar joint. The ligaments of the inferior radioulnar joint are ruptured, and the head of the ulna is displaced from the ulnar notch of the radius.
The Salter-Harris classification [I–V] refers to physial, or growth plate, fractures in children.
Test-taking tip: Brush up on your fracture eponyms because they are commonly tested on emergency medicine standardized tests.
89. Answer:C
With tenderness in the anatomic snuff box, one must assume that this patient has a scaphoid fracture. The scaphoid is the most commonly fractured carpal bone. Initial radiographs can be negative, so any patient with tenderness in the anatomic snuff box should be placed in a thumb spica splint and have repeat radiographs in 2 weeks. If at 2 weeks a fracture is still clinically suspected but the radiograph remains negative, MRI should be ordered.
This is an important injury not to miss because there is a high incidence of avascular necrosis owing to the poor vascularity of the scaphoid. This is especially true of injuries to the proximal portion of the scaphoid, which is the least well vascularized, because blood supply flows from the distal to the proximal portion of the bone.
Test-taking tip: This is a “you know it or don’t” kind of question. If you don’t know it, choose an answer and move on. You can perhaps mark it for review when you are done at the end of the test. Don’t, however, let these kinds of questions get you stuck and waste your time.
90. Answer:B
A forearm fracture of both bones requires a significant amount of force; thus, these fractures are usually displaced. This usually requires ORIF. The most significant complication is compartment syndrome. Other complications include reduced ability to pronate and supinate, nonunion, and neurovascular injury.
Supracondylar fractures are most common in children between the ages of 5 and 10 years and area associated with nerve injuries, with the anterior interosseous nerve being the most commonly injured.
Monteggia fracture-dislocation is a fracture of the ulna diaphysis with anterior dislocation of the radial head. Complications include malunion, nonunion, synostosis, stiffness, and nerve palsy.
Galeazzi fracture-dislocation involves a fracture of the distal third of the radius with an associated dislocation of the distal radioulnar joint. Complications include malunion, nonunion, limited range of motion, and chronic pain.
Test-taking tip: Brush up on common causes of common presentations, such as compartment syndrome.
91. Answer:B
Thompson’s test is performed with the patient prone and the knee flexed to 90 degrees. The calf is then squeezed, and the foot should passively plantar-flex. If there is no passive plantar flexion, this is a positive Thompson’s test and indicates a complete tear of the Achilles tendon.
Thompson’s test should be negative [the foot does passively plantar-flex with calf squeeze] with a gastrocnemius rupture.
Both an Achilles tendon rupture and gastrocnemius rupture occur with sudden contraction of the calf.
With a patellar tendon rupture, the patient will be unable to extend the leg or maintain a passively extended leg in extension. A patellar tendon rupture occurs with sudden contraction of the quadriceps, as occurs in jumping sports.
Test-taking tip: Brush up on your musculoskeletal tests and signs because they are frequently tested on emergency medicine standardized tests.
92. Answer:B
This is a torus fracture, which is an incomplete fracture characterized by buckling of the cortex. Children’s bones are soft and pliable and tend to bend before they break.
A greenstick fracture is a fracture of a long bone in children where there is disruption of only one side of the cortex. Torus fractures are much more common than greenstick fractures.
A plastic deformity is when a bone bends but does not break. This usually occurs in the radius and ulna.
A Salter-Harris fracture is a fracture through the growth plate.
Test-taking tip: Torus fractures are subtle. Practice reading some pediatric radiographs before the test.
93. Answer:A
The most commonly injured nerve with a humeral shaft fracture is the radial nerve. The radial nerve supplies sensation for the first dorsal webspace of the hand and is responsible for thumb and wrist extension.
Choice B describes the median nerve function. Choice C describes the ulnar nerve function. Choice D is an incorrect answer and does not describe a particular peripheral nerve function.
Test-taking tip: Brush up on major nerve sensation and function.
94. Answer:B
This radiograph shows osteochondritis dissecans, an idiopathic process that occurs in adolescents and results in separation of a bone fragment from the articular cartilage. This bone fragment can result in a joint locking. Osteochondritis dissecans most commonly affects the medial condyle of the femur. It may also affect the elbow [at the capitellum] or the ankle [at the talus]. Initial treatment is generally nonoperative and consists of immobilization and limited weight bearing.
Test-taking tip: This is a “you know it or don’t” kind of question. If you don’t know it, choose an answer and move on. You can perhaps mark it for review when you are done at the end of the test. Don’t, however, let these kinds of questions get you stuck and waste your time.