A 4-year-old boy is brought to the emergency department for evaluation of persistent fevers. About 6 weeks ago, the patient developed rhinorrhea, cough, and body aches. Although the other symptoms resolved, he still has intermittent fevers and aches. The fevers spike in the evenings and are accompanied by a pink, nonpruritic rash. Both features completely resolve by morning and he feels well during the day. However, he has had a fever and rash every evening for the last 5 days. Temperature is 39.1 C (102.4 F). There are several pink macules at the waist and bilateral axillae. The spleen is enlarged. There is swelling of both knees and tenderness with deep palpation. Complete blood count shows: Hemoglobin 10.6 g/dL Platelets 600,000/mm3 Leukocytes 17,000/mm3<br />Neutrophils 80% Eosinophils 1% Lymphocytes 19% Which of the following is the most likely diagnosis in this patient?

A 5-hour-old girl is evaluated for decreased movement of the left arm. She was born at 40 weeks gestation by vacuum-assisted vaginal delivery to a mother with gestational diabetes mellitus. The delivery was complicated by shoulder dystocia. Birth weight was 4.6 kg (10 lb). Palpation of the left clavicular bone reveals crepitus. Passive movement of the left upper extremity elicits crying. Moro reflex is decreased on the left. Bilateral extremities are neurovascularly intact. Which of the following is the best next step in management of this patient?

A 7-year-old boy is brought to the emergency department due to fever and right leg pain for 3 days. He has no history of trauma and is otherwise healthy. Immunizations are up to date. Temperature is 39.4 C (102.9 F). The patient walks with a limp. Examination of the right leg shows bony point tenderness, erythema, and warmth over the proximal tibia. Blood is drawn for culture. Which of the following organisms will most likely be isolated from this patient's blood?

A 13-year-old girl presents to the office for a preparticipation sports physical. Her coach is concerned that the girl's posture seemed abnormal. She has no medical conditions and has not undergone menarche. BMI is at the 50th percentile. Physical examination shows a right-sided lumbar prominence during forward bend test, and there is no tenderness of the spine. The remainder of the examination is normal. Which of the following is the best next step in the management of this patient?

A 3-year-old girl is brought to the clinic for evaluation of right knee swelling. Her mother first noticed the swelling and a limp 2 months ago but attributed them to roughhousing with her brother. Typically, the limping was present in the mornings and resolved by midday. However, while bathing the patient last night, her mother noticed that the right knee was more swollen than usual. The knee is not painful, and the patient has had no fever or rashes. She can bear weight on both legs but has a noticeable limp. The right knee is swollen and slightly warm. There is no tenderness to palpation. This patient is at greatest risk for which of the following complications?

A 13-month-old boy is brought to the clinic for a well-child visit. The patient has been walking since age 10 months. Solid food intake consists of homegrown baby food, including small portions of fruits, vegetables, and grains once a day. He breastfeeds 8-10 times a day. The patient was born full-term and has no chronic medical conditions. He takes no medications, vitamins, or supplements. On examination, the anterior fontanel is wide open. The skull bones are pliable to palpation. Bony prominences are palpated at the costochondral junctions bilaterally. Bilateral legs appear bowed and left leg is more bowed than the right. The remainder of his examination is normal. Which of the following is the most likely cause of this patient's findings?

A 6-month-old boy is brought to the office for a well-child visit. The patient drinks 24-28 oz daily of donated, pasteurized breast milk. He was adopted from Uganda at age 2 months. Immunizations are up to date. He has no chronic medical conditions and takes no medications or supplements. Height and weight are at the 20th and 40th percentiles, respectively. Head circumference is at the 30th percentile. The anterior fontanel is open and flat, and the skull bones are soft and flexible to pressure. Bilateral swelling of the wrist is present. Cardiopulmonary and abdominal examinations are normal. There are no skin rashes. An x-ray of the wrist shows metaphyseal widening with cupping, as shown in the exhibit. Which of the following is the most likely cause of this patient's x-ray abnormality?

A 2-week-old girl is brought to the office for a routine health visit. The patient was born to a 29-year-old primigrávida at 40 weeks gestation by cesarean delivery for breech presentation. Birth weight was large for gestational age at 4 kg (8 lb 13 oz); current weight is 4.2 kg (9 lb 4 oz). A complete physical examination reveals a palpable "clunk" of the right hip during attempted dislocation. An ultrasound of both hips is ordered and reveals a dislocated right hip with a flat acetabulum. Which of the following is the best next step in management of this patient?

A 14-year-old boy is brought to the office for evaluation of intermittent, anterior left knee pain for the past 2 months. The pain improves with rest but is exacerbated by running or climbing stairs. The patient is a running back on the high school football team and has had no injuries. On physical examination, he is afebrile with a swollen, tender area below his left knee at the insertion site of the patellar tendon. The pain is reproducible by left knee extension against forced resistance. The knee joint appears normal with no effusion or condylar tenderness. Which of the following is the best next step in management of this patient?

A 6-year-old boy is brought to the office for follow-up of a limp. His symptoms began 2 months ago as a dull ache in the left knee with an intermittent limp. The patient went to an urgent care clinic at that time; laboratory evaluation and x-rays of the knees and hips were normal. The pain has not worsened, but he now has a persistent limp with no other joint or muscle pain. Temperature is 37.1 C (98.8 F), blood pressure is 95/65 mm Hg, and pulse is 80/min. BMI is at the 60th percentile. Examination shows a well-appearing child. Range of motion, particularly internal rotation and abduction, of the left hip is markedly limited. The remainder of the examination is normal. Which of the following is the most likely diagnosis in this patient?

A 12-year-old girl is brought to the clinic by her mother for evaluation of leg pain. The patient first noticed a dull ache in her left thigh a month ago. The pain is intermittent, worse after skipping rope with friends, and typically resolves after rest or ibuprofen. She does not recall any inciting injury to the leg. Temperature is 37.5 C (99.5 F). BMI is at the 97th percentile for age. The left hip demonstrates decreased range of motion with internal rotation. There is no increased warmth over the joint. The left foot points laterally during ambulation. Which of the following is the most likely underlying cause of this patient's symptoms?

A 5-year-old girl is brought to the clinic with joint pain and rash. Last week, the patient developed pain in her knees. The pain resolved after a few days, but now her ankles and wrists are tender. She has alsoLeukocytes 6,500/mm3<br />Neutrophils 56%<br />Lymphocytes 33%<br />C-reactive protein 32 mg/L (normal: <3 mg/L)<br />Erythrocyte sedimentation rate 62 mm/h<br />Which of the following is the most likely diagnosis in this patient? developed a nonpruritic, pink rash on her back. The patient had previously been healthy except for a sore throat a few weeks ago that resolved on its own. Temperature is 38.3 C (101 F). The wrists and ankles are stiff and tender to manipulation. Multiple large, well-demarcated, erythematous, nonpruritic patches with a slightly raised outline are present on the trunk and proximal limbs. Laboratory results include:

A 7-year-old boy is brought to the emergency department after falling during recess. He jumped off a swing and fell onto his outstretched left arm. The patient developed immediate pain in the arm and now refuses to move it at the elbow. On examination, the left arm is grossly deformed, swollen, and slightly pale. The radial pulse is intact. The patient's x-ray is shown above. Two hours later, while the patient is awaiting surgery, pain and swelling continue to increase despite administration of nonsteroidal anti-inflammatory drugs and opioid analgesics. Which of the following complications is most likely present in this patient?

A 5-year-old girl is brought to the emergency department after falling off her bike. The patient has been holding her right arm, with the elbow flexed, at her side and refuses to move it and the shoulder. She cries in pain on passive movement of the shoulder. The right wrist and elbow have full range of motion and strength. Brachial and radial pulses are 2+ and sensation is intact. X-ray is shown in the image above. Which of the following is the most appropriate management of this patient's condition?

A previously healthy 11-month-old child is brought to the emergency department with a right arm injury. Her mother tried to lift her up out of the stroller by holding onto her right hand while she was still buckled in. The infant started crying immediately and has been refusing to use the right arm. When shown an object, the infant will grasp with the left, but not the right, hand. She holds the right arm in extension with the forearm pronated. There is no tenderness to palpation of the humerus or forearm. No swelling or deformity is noted. Which of the following is the best next step in management of this child?

A 13-year-old boy is brought to the emergency department due to fever and refusal to bear weight on the right leg. He has had vague right knee pain for the last 4 days that is now localized to the proximal thigh. He has had no recent trauma. Temperature is 38.9 C (102 F), and BMI is >95,h percentile. Palpation over the anterior femur elicits point tenderness. Bilateral hips have full range of motion. The skin overlying the right proximal femur is slightly swollen and erythematous. The remainder of the examination is normal. Which of the following best describes the pathogenesis of this patient's current condition?

A 5-year-old boy is brought to the office for a routine well-child visit. He has been growing and developing well and recently reached the weight limit of his forward-facing car seat. Physical examination is normal. Which of the following is the most appropriate recommendation regarding injury prevention for this patient?

A 3-year-old girl is brought to the emergency department due to acute onset of right elbow pain. She was playing in the snow and started crying when her father pulled her by the arm to take her inside. On examination, the patient keeps her hand in a pronated position, refuses to use it, and cries when her elbow is moved. There is no swelling or deformity. Palpation of the radial head elicits mild tenderness. A click is felt when the forearm is hyperpronated, and she stops crying and starts to use her arm. What is the most likely etiology of this patient's symptoms?

A 3-year-old girl is brought to the office because the patient's knees have "turned in" more than before. The patient has had no fever, joint pain, or swelling. She started walking at age 14 months and now can climb up and down stairs. Height and weight are at the 60th percentile. Physical examination reveals a steady gait, legs swinging outward as she walks. No medial thrust is observed with ambulation. Legs are equal in length. With the legs extended and knees touching, a small gap is present between the ankles. There is mild valgus angulation at the knee. Which of the following is the most appropriate advice regarding this patient's condition?

A 7-year-old boy is brought to the office for evaluation of worsening chronic left thigh pain for 8 months. Recently, the patient began to limp. He has had no fever, additional joint pain, or chronic medical conditions. While walking to the examination table, the patient avoids bearing full weight on the left leg. Examination shows significantly limited range of motion of the left hip and atrophy of the left proximal thigh muscle. The remainder of the examination is unremarkable. X-ray of the pelvis is shown above. Which of the following is most likely cause of this patient's condition?

A 5-year-old boy is brought to the emergency department due to fever and knee pain. The patient was diagnosed with streptococcal pharyngitis 2 weeks ago and completed a 10-day course of amoxicillin. Two days ago, he developed fever and fatigue. Today, he cries every time he bends the right knee and refuses to walk. Temperature is 39.4 C (102.9 F). On examination, the right knee is swollen and tender to palpation. The patient holds the knee in a flexed position and has pain with passive range of motion. Laboratory results are as follows:<br />Leukocytes 16,000/mm3<br />C-reactive protein 62 mg/L (normal: <8 mg/L)<br />Erythrocyte sedimentation rate 44 mm/hr<br />X-ray of the right knee shows joint effusion and soft tissue swelling. Which of the following is the best next step in management of this patient?

An 11-year-old girl is brought to the emergency department due to right shoulder pain. The patient first noticed the pain 4 days ago. The pain has gradually increased, awakens her at night, and today she is unable to lift her right arm to brush her teeth. Four months ago, the patient was diagnosed with polyarticular juvenile idiopathic arthritis for which she takes methotrexate. Temperature is 38.5 C (101.3 F). The patient holds her right arm at her side, and she resists attempts to move the shoulder due to pain. The shoulder joint is aspirated, and synovial fluid analysis reveals leukocyte count of 55,000 cells/mm3, with 80% polymorphonuclear cells. Which of the following is the best next step in management of this patient?

A 2-week-old girl is brought to the office for a routine health visit. The patient was born by cesarean delivery for breech presentation. Her parents have no concerns. Birth weight was large for gestational age at 4 kg (8 lb 13 oz). Vital signs are normal. Physical examination shows asymmetric gluteal skinfolds and an increased number of thigh creases on the right compared with the left. Which of the following additional findings would most likely be present on examination?

A 13-year-old boy has had progressive pain of the left knee for 3 months, triggered by playing basketball and relieved by rest. The patient has had no fever, weight loss, or night sweats. Vital signs are normal. Physical examination reveals tenderness over the left tibial tubercle, which appears more prominent than the right. The left knee has full range of motion and no palpable effusion. Extension of the left knee against resistance and squatting reproduces the pain. Which of the following is the most likely cause of this patient's knee pain?

A 13-year-old girl is brought to the clinic for evaluation of a limp. She first noticed mild pain in the right groin 2 weeks ago and took ibuprofen, which initially helped. The pain acutely worsened 2 days ago after the patient fell. Temperature is 37.2 C (99 F). When the right hip is flexed, there is external rotation of the hip. When the left hip is flexed, the hip remains in a neutral position. There is no redness or edema overlying the hips. The patient has a limp and bears little weight on her right side when walking. Bilateral hip radiograph with frog-leg lateral view is shown above. Which of the following is the best next step in management of this patient?

A 10-year-old boy is brought to the office due to worsening left thigh pain and difficulty walking for several months. The pain is continuous, nonradiating, and is worse at night. Ibuprofen has provided no relief. He has had occasional fever over the last month; temperature today is 37.2 C (99 F). The patient has an antalgic gait and favors the right side. The left thigh is swollen and erythematous, and has a palpable tender, immobile mass. X-ray shows a central lytic lesion in the diaphysis of the femur with cortical layering, a "moth-eaten" appearance, and extension into the soft tissue. Which of the following is the most likely diagnosis in this patient?

A 13-year-old girl is brought to the clinic due to difficulty walking. The patient noticed a mild ache in both hips 2 months ago that occurred most days after walking. The aches usually resolved after rest but this week, the aches have worsened to the point where she has difficulty walking, and ibuprofen only minimally relieves the symptoms. Height is at the 75th percentile, and weight is at the 97th percentile. Temperature is 37.4 C (99.3 F). The patient has a waddling gait with both feet turned laterally. Both hips externally rotate during hip flexion, and there are no palpable clicks when the hips are brought back to extension. There is limited internal rotation bilaterally. Which of the following is the most likely diagnosis in this patient?