A 3-year-old boy is brought to the emergency department by his stepfather due to right knee swelling. The knee swelled immediately after the patient fell while playing outside. He is generally healthy and very active. His stepfather reports that last week while climbing on the living room couch, he fell onto the floor and developed a large bruise to his left hip. Temperature is 36.7 C (98.1 F). Examination shows an uncomfortable-appearing boy with significant swelling of the right knee. The patient has pain with knee movement and limited range of motion. An area of ecchymosis is seen on the left hip. There are also scattered ecchymoses to the anterior shins. The remainder of the physical examination is normal. Laboratory results are as follows: Radiograph of the right knee shows a large effusion but no fracture. Which of the following is the best next step in management of this patient?

Question

A 3-year-old boy is brought to the emergency department by his stepfather due to right knee swelling.  The knee swelled immediately after the patient fell while playing outside.  He is generally healthy and very active.  His stepfather reports that last week while climbing on the living room couch, he fell onto the floor and developed a large bruise to his left hip.  Temperature is 36.7 C (98.1 F).  Examination shows an uncomfortable-appearing boy with significant swelling of the right knee.  The patient has pain with knee movement and limited range of motion.  An area of ecchymosis is seen on the left hip.  There are also scattered ecchymoses to the anterior shins.  The remainder of the physical examination is normal.  Laboratory results are as follows:  Radiograph of the right knee shows a large effusion but no fracture.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d69f_1795_bc81_03c2a43d7640_MD0003_00 This child's history of easy bruising and acute onset of joint effusion following minor trauma (suggestive of hemarthrosis) raise concern for hemophilia, a coagulation disorder. Hemophilia A and B, or deficiency of factor VIII and IX, respectively, are X-linked recessive disorders that typically affect boys. The severity of symptoms depends on the degree of factor deficiency, ranging from spontaneous bleeding (eg, intracranial hemorrhage) to delayed postprocedure bleeding (eg, oozing from dental extraction site). Hemarthrosis, or joint hemorrhage, is common and typically presents following mild injury with pain and swelling in weight-bearing joints (eg, knees, ankles). Recurrent hemarthroses in the same joint can lead to chronic hemophilic arthropathy. Initial screening tests for hemophilia include coagulation studies and a complete blood count. Hemophilia causes prolonged PTT due to absent factor VIII or IX but normal PT; platelet count is normal. (Choice A) Bone marrow evaluation is indicated for spontaneous bruising in patients with anemia, thrombocytopenia, and leukocytosis/leukopenia, which are findings suggestive of leukemia. This patient has normal cell counts, and bone marrow evaluation is contraindicated in severe hemophilia due to bleeding risk. (Choice C) A skeletal survey (full body x-ray) is indicated when nonaccidental trauma is suspected. Red flags include an inconsistent history of bruises that are patterned (eg, belt buckle) or in unusual locations (eg, abdomen, buttocks). This patient has a knee injury from a witnessed fall and bruising on the shins, which are typical of normal toddler injuries. nonaccidental trauma (Choice D) Reassurance and observation are appropriate for minor contusions or sprains. Hemarthrosis requires further evaluation and treatment to prevent recurrent bleeds. (Choice E) Coagulopathy may result from advanced liver disease, which impairs production of vitamin K-dependent clotting factors (II, VII, IX, X) and often causes thrombocytopenia. Coagulation studies should be obtained first, and if abnormal, further evaluation of the liver (eg, transaminases) should be conducted. (Choice F) Synovial fluid Gram stain and culture are indicated for septic arthritis, which typically presents with refusal to bear weight and signs of systemic inflammation (eg, fever, leukocytosis), which are not present in this patient. Educational objective: Hemarthrosis after minor trauma is suspicious for a bleeding disorder (eg, hemophilia), and coagulation studies should be obtained. Hemophilia presents with a prolonged PTT, normal PT, and normal platelet count. References: Pediatric hemophilia: a review. (http://www.ncbi.nlm.nih.gov/pubmed/22187396) Evaluating for suspected child abuse: conditions that predispose to bleeding. (http://www.ncbi.nlm.nih.gov/pubmed/23530171)

A 3-Year-Old Boy Is Brought to the Emergency Department by His