Bone and joint infections — MCQs

A 42-year-old man with a history of gout and hypertension presents to his family physician with a complaint of increased left knee pain over the past 2 days. He also reports swelling and redness of the left knee and is unable to bear weight on that side. He denies any prior surgery or inciting trauma to the knee. His temperature is 97.0°F (36.1°C), blood pressure is 137/98 mm Hg, pulse is 80/min, respirations are 13/min, and oxygen saturation is 98% on room air. Physical examination reveals a left knee that is erythematous, swollen, warm-to-touch, and extremely tender to palpation and with attempted flexion/extension movement. His left knee range of motion is markedly reduced compared to the contralateral side. Joint aspiration of the left knee is performed with synovial fluid analysis showing turbid fluid with a leukocyte count of 95,000/mm^3, 88% neutrophils, and a low glucose. Gram stain of the synovial fluid is negative. Results from synovial fluid culture are pending. Which of the following is the best treatment regimen for this patient?

A 3-year-old patient is brought to the emergency department by her mother due to inability to walk. The child has been limping recently and as of this morning, has refused to walk. Any attempts to make the child walk or bear weight result in crying. She was recently treated for impetigo and currently takes a vitamin D supplement. Physical exam is remarkable for an anxious appearing toddler with knee swelling, erythema, and limited range of motion due to pain. Her mother denies any recent trauma to the child's affected knee. Temperature is 103°F (39.4°C), pulse is 132/min, blood pressure is 90/50 mmHg, respirations are 18/min, and oxygen saturation is 99% on room air. Which of the following is the best initial step in management?

A 33-year-old man with a history of IV drug and alcohol abuse presents to the emergency department with back pain. He states that his symptoms started 3 days ago and have been gradually worsening. His temperature is 102°F (38.9°C), blood pressure is 127/68 mmHg, pulse is 120/min, respirations are 17/min, and oxygen saturation is 98% on room air. Physical exam is notable for tenderness over the mid thoracic spine. Laboratory values are only notable for a leukocytosis and an elevated ESR and CRP. Which of the following is the most likely diagnosis?

A 62-year-old man comes to the physician because of increasing pain in his right leg for 2 months. The pain persists throughout the day and is not relieved by rest. He tried taking acetaminophen, but it provided no relief from his symptoms. There is no family history of serious illness. He does not smoke. He occasionally drinks a beer. Vital signs are within normal limits. On examination, the right tibia is bowing anteriorly; range of motion is limited by pain. An x-ray of the right leg shows a deformed tibia with multiple lesions of increased and decreased density and a thickened cortical bone. Laboratory studies show markedly elevated serum alkaline phosphatase and normal calcium and phosphate levels. This patient is most likely to develop which of the following complications?

A 6-year-old girl is brought to the physician for intermittent fevers and painful swelling of the left ankle for 2 weeks. She has no history of trauma to the ankle. She has a history of sickle cell disease. Current medications include hydroxyurea and acetaminophen for pain. Her temperature is 38.4°C (101.2°F) and pulse is 112/min. Examination shows a tender, swollen, and erythematous left ankle with point tenderness over the medial malleolus. A bone biopsy culture confirms the diagnosis. Which of the following is the most likely causal organism?

A 56-year-old woman comes to the emergency department because of worsening pain and swelling in her right knee for 3 days. She underwent a total knee arthroplasty of her right knee joint 5 months ago. The procedure and immediate aftermath were uneventful. She has hypertension and osteoarthritis. Current medications include glucosamine, amlodipine, and meloxicam. Her temperature is 37.9°C (100.2°F), pulse is 95/min, and blood pressure is 115/70 mm Hg. Examination shows a tender, swollen right knee joint; range of motion is limited by pain. The remainder of the examination shows no abnormalities. Arthrocentesis of the right knee is performed. Analysis of the synovial fluid shows: Appearance Cloudy Viscosity Absent WBC count 78,000/mm3 Segmented neutrophils 94% Lymphocytes 6% Synovial fluid is sent for culture and antibiotic sensitivity. Which of the following is the most likely causal pathogen?

A 60-year-old woman presents to the physician with a 2-day history of fever and painful swelling of the left knee. She was diagnosed with rheumatoid arthritis about 15 years ago and has a 7-year history of diabetes mellitus. Over the past year, she has been admitted to the hospital twice for acute, painful swelling of the knees and hands. She is on insulin therapy and takes methotrexate, metformin, aspirin, and prednisolone 5 mg/day. Her temperature is 38.5°C (101.3°F), pulse is 86/min, respirations are 14/min, and blood pressure is 125/70 mm Hg. A finger-stick glucose test shows 230 mg/dL. Her left knee is diffusely swollen, warm, and painful on both active and passive motion. There is evidence of deformity in several small joints of the hands and feet without any acute swelling or pain. Physical examination of the lungs, abdomen, and perineum shows no abnormalities. The synovial fluid analysis shows the following: Color turbid, purulent, gray Viscosity reduced WBC 25,000/µL–250,000/µL Neutrophils > 90% Crystals may be present (presence indicates coexistence, but does not rule out infection) Which of the following is the most appropriate initial pharmacotherapy in this patient?

A 37-year-old man presents to the emergency department after he cut his hand while working on his car. The patient has a past medical history of antisocial personality disorder and has been incarcerated multiple times. His vitals are within normal limits. Physical exam is notable for a man covered in tattoos with many bruises over his face and torso. Inspection of the patient's right hand reveals 2 deep lacerations on the dorsal aspects of the second and third metacarpophalangeal (MCP) joints. The patient is given a tetanus vaccination, and the wound is irrigated. Which of the following is appropriate management for this patient?

Five days after undergoing right knee arthroplasty for osteoarthritis, a 68-year-old man has severe pain in his right knee preventing him from participating in physical therapy. On the third postoperative day when the dressing was changed, the surgical wound appeared to be intact, slightly swollen, and had a clear secretion. He has a history of diabetes, hyperlipidemia, and hypertension. Current medications include metformin, enalapril, and simvastatin. His temperature is 37.3°C (99.1°F), pulse is 94/min, and blood pressure is 130/88 mm Hg. His right knee is swollen, erythematous, and tender to palpation. There is pain on movement of the joint. The medial parapatellar skin incision appears superficially opened in its proximal and distal part with yellow-green discharge. There is blackening of the skin on both sides of the incision. Which of the following is the next best step in the management of this patient?

A 35-year-old man arrives at the emergency department within minutes after a head-on motor vehicle accident. He suffered from blunt abdominal trauma, several lacerations to his face as well as lacerations to his upper and lower extremities. The patient is afebrile, blood pressure is 45/25 mmHg and pulse is 160/minute. A CBC is obtained and is most likely to demonstrate which of the following?