USMLE Rheumatology V

• It is common in patients with polytrauma, especially with multiple fractures of long bones.
• It is characterized by severe respiratory distress, petechial rash, subconjuctival hemorrhage, tachycardia, tachypnea, and fever.
• It may occur from 12 to 72 hours after the injury.
• Central nervous system dysfunction initially manifests as confusion and agitation but may progress to stupor, seizures, or coma and frequently is unresponsive to correction of hypoxia.

• Thrombocytopenia, anemia, and hypofibrinogenemia are nonspecific findings. Serial x-rays shows increasing diffuse bilateral pulmonary infiltrates within 24-48 hours of onset of clinical findings
• Diagnosis can be confirmed by presence of fat droplets in urine or presence of intra-arterial fat globules on fundoscopy
• Treatment should include prompt respiratory support. Use of heparin, steroids, and low molecular weight dextran is controversial.

• Hip fractures are classified by anatomic location and fracture type into either intracapsular ( eg, femoral neck and head) or extracapsular (eg, intertrochanteric, subtrochanteric).
• lntracapsular fractures have a higher chance of avascular necrosis; extracapsular fractures have a greater need for implant devices (eg, nails, rods).

• The specific surgical intervention required depends largely on the details of the individual case.
• In general, surgical repair should be done as soon as feasible to relieve pain, minimize complications, and reduce length of hospital stay.
• However, surgery may be delayed up to 72 hours if needed to address unstable medical comorbidity.

• They are the most common fractures in the pediatric population.
• Mechanism: The majority of cases result from a fall on an outstretched hand. The fracture is common in children as the supracondylar area is thin and weak due to physiologic remodeling in childhood.
• Most common complication is entrapment of the brachial artery or median nerve.
• Impingement of the brachial artery results in loss of the brachial and radial artery pulses.
• Distal perfusion should always be assessed on examination.
• Motor and sensory function should also be assessed due to the risk of median nerve injury.

• Treatment consists of analgesia and immobilization. Displaced fractures require orthopedic consultation.
• Neurovascular injury often resolves after orthopedic alignment and immobilization; patients who are treated promptly usually have a good prognosis

• • Brachial artery injury
• • Median nerve injury
• • Cubitus varus deformity
• • Compartment syndrome
• • Volkmann ischemic contracture

• It is a common knee injury caused by severe valgus stress (eg, blow to the lateral knee) or twisting injury. Examination findings may include ecchymosis and joint line tenderness at the medial knee. Appreciable laxity when the leg is forced into abduction (valgus stress test) is helpful for diagnosis but may be masked by swelling and muscle spasm.
• Acute effusion/hemarthrosis is uncommon unless there is concurrent injury to the anterior cruciate ligament.

• MRI is the most sensitive test for diagnosis but is generally reserved for patients being considered for surgical intervention.
• Patients with uncomplicated MCL tears can be managed nonoperatively with rest, ice, compression, and elevation (RICE measures) and analgesics with progressive return to activity as tolerated.

It is a chronic overuse injury characterized by anterior knee pain and tenderness.

• It often result from twisting force with the foot fixed. Patients generally report a popping sound followed by acute pain.
• Associated symptoms can include reduced extension, a sensation of instability, and a knee effusion.
• Because the meniscus is not directly perfused, the effusion typically is not apparent for many hours.
• The medial meniscus is more commonly injured than the lateral.

• Examination will show tenderness at the joint line on the affected side. Patients may also have palpable locking or catching when the joint is rotated or extended while under load (eg, Thessaly, McMurray tests).
• Older patients with tears due to chronic degeneration of the cartilage may show osteoarthritic changes on x-ray, but plain films are usually normal in young patients with traumatic tears.
• Diagnosis is confirmed with MRI or arthroscopy.

• Patients with short-term symptoms and minimal limitations in activity, or older patients with chronic tears due to degeneration of the cartilage, can be managed conservatively with rest and nonsteroidal anti-inflammatory drugs.
• But young patients who have significant symptoms lasting more than 3-4 weeks should be considered for surgical intervention to relieve the symptoms and reduce the risk of further joint injury.
• In such cases, MRI is recommended as it can clearly visualize the soft tissues of the knee and confirm the diagnosis.

• RCT results from repetitive activity above shoulder height (eg, painting ceilings) and is most common in middle-aged and older individuals.
• Chronic tensile loading and compression by surrounding structures can lead to microtears in the rotator cuff tendons (especially supraspinatus), fibrosis, and inflammatory calcification.
• In addition to the rotator cuff itself, pain may also emanate from the subacromial bursa and the tendon of the long head of the biceps.

• On flexion or abduction of the humerus, the space between the humeral head and acromion is reduced, causing pressure on the supraspinatus tendon and subacromial bursa.
• Impingement syndrome, a characteristic of RCT, refers to compression of these soft tissue structures.
• Impingement can be demonstrated with the Neer test: With the patient's shoulder internally rotated and forearm pronated, the examiner stabilizes the scapula and flexes the humerus. Reproduction of the pain is considered a positive test.

• Untreated, chronic RCT can increase the risk for rotator cuff tear.
• Patients with a tear typically present with weakness of abduction following a fall or other minor trauma

• It typically present with pain at the radial wrist proximal to the base of the thumb.
• Examination shows tenderness in the shallow depression at the dorsoradial wrist bounded medially by the tendon of the extensor pollicis longus and laterally by the tendons of the abductor pollicis longus and extensor pollicis brevis ("anatomic snuffbox").
• Scaphoid fractures carry a significant risk of osteonecrosis because the blood supply enters at the distal pole and flows proximally, and can be disrupted by the fracture.

• Initial x-rays can be normal in nondisplaced scaphoid fractures.
• If scaphoid fracture is suspected, CT scan or MRI can confirm the diagnosis, or repeat x-rays can be performed in 7-10 days.
• Displaced fractures should be considered for surgical intervention.
• Wrist immobilization with a cast can be considered for nondisplaced fractures, but patients should be monitored with serial x-ray to rule out osteonecrosis of the proximal segment and nonunion of the fracture.

It follows a fall on an outstretched hand can cause compressive neuropathy of the median nerve.

Scaphoid fractures are characterized by tenderness in the anatomic snuffbox, a shallow depression at the dorsoradial wrist bounded medially by the tendon of the extensor pollicis longus and laterally by the tendons of the abductor pollicis longus and extensor pollicis brevis.

• The arterial supply (from the radial artery) enters the scaphoid through foramina in the bone's distal pole before proceeding to the proximal pole.
• As a result of this tenuous blood supply to the proximal pole, scaphoid fractures are at risk for avascular necrosis and nonunion.

• Displaced scaphoid fractures may be visible on x-ray immediately following injury, but compressed or nondisplaced fractures may not be visible for 7-10 days.
• If immediate diagnosis is needed, CT or MRI of the wrist can confirm the fracture

• Displaced scaphoid fractures should be considered for surgical intervention.
• Nondisplaced distal fractures can be treated with immobilization in a cast thumb Spica for 4-6 weeks.

• It commonly occurs in athletes (eg, runners, dancers) or other individuals who suddenly increase their activity level.
• These types of fractures are caused by repeated tension or compression without adequate rest, and are especially common in women who have low bone density associated with low caloric intake and hypomenorrhea/amenorrhea (female athlete triad).
• Other factors contributing to stress fractures include improper footwear, biomechanical abnormalities (eg, weak calf muscles, high-arched feet), and inadequate calcium and vitamin D intake.
• In addition to the tibia, stress fractures can also be seen in the metatarsals, tarsal bones (eg, navicular, calcaneus), and, less commonly, the femur and pelvis.

• The diagnosis is based primarily on clinical factors, including localized activity-related pain, swelling, and point tenderness on palpation.
• X-rays are frequently normal (especially in the first few weeks) but may reveal periosteal reaction at the site of the fracture.
• MRI and bone scan are more sensitive but not usually necessary.

• It causes anterior leg pain resembling that of a stress fracture.
• It is usually seen in casual runners and is characterized by regional rather than focal tenderness.
• Shin splints are more common in overweight than underweight individuals

• Fractures of the second, third, and fourth metatarsals are managed conservatively as the surrounding metatarsals act as splints and nonunion is uncommon.
• Initial interventions include rest and simple analgesics (eg, acetaminophen).
• Some experts advise against nonsteroidal anti inflammatory drugs due to a possible delay in healing times.
• Patients who continue to have pain despite activity restrictions may additionally be managed with a wide, hard-sole podiatric shoe.

Stress fractures of the fifth metatarsal shaft are at increased risk for nonunion and are usually managed with casting or internal fixation.