A 16-year-old boy is brought to the office for pain and limited motion of the right knee. The patient has had previous episodes of sudden swelling in his right knee and does not recall them being associated with injury. This current episode of knee pain began 6 months ago. Initially the pain was controlled with heating pads and acetaminophen, but it has gradually worsened over the last 2-3 months. The patient now has difficulty walking. He is worried that he will be unable to go on his annual camping trip with his family. The patient had an episode of prolonged bleeding after a tooth extraction several years ago. He is sexually active, has 2 lifetime partners, and uses condoms intermittently. Temperature is 36.7 C (98 F). On examination, the patient is alert and in no distress. The right knee is swollen and boggy with a small effusion present. The knee is not fully extendable with either active or passive motion. Which of the following is the most likely cause of this patient's knee joint findings?

Question

A 16-year-old boy is brought to the office for pain and limited motion of the right knee.  The patient has had previous episodes of sudden swelling in his right knee and does not recall them being associated with injury.  This current episode of knee pain began 6 months ago.  Initially the pain was controlled with heating pads and acetaminophen, but it has gradually worsened over the last 2-3 months.  The patient now has difficulty walking.  He is worried that he will be unable to go on his annual camping trip with his family.  The patient had an episode of prolonged bleeding after a tooth extraction several years ago.  He is sexually active, has 2 lifetime partners, and uses condoms intermittently.  Temperature is 36.7 C (98 F).  On examination, the patient is alert and in no distress.  The right knee is swollen and boggy with a small effusion present.  The knee is not fully extendable with either active or passive motion.  Which of the following is the most likely cause of this patient's knee joint findings?

Quizplus · Accepted Answer

11ec25c8_d69f_b3d6_bc81_7d99cbbbcea9_MD0003_00 This patient's history of excessive bleeding after a dental procedure is concerning for hemophilia, an X-linked recessive bleeding disorder caused by deficiency of Factor VIII (hemophilia A) or Factor IX (hemophilia B). Disease severity varies based on degree of factor activity. Often, patients present with joint pain and swelling following little or no trauma due to spontaneous bleeding into a joint (hemarthrosis). Recurrent hemarthroses, as seen in this patient, can result in long-term complications such as hemophilic arthropathy. Hemophilic arthropathy refers to joint damage caused by intra-articular bleeding. Hemosiderin deposition within the joint triggers synovial inflammation, which leads to fibrosis and destruction of cartilage and bone. Chronic, worsening joint pain and swelling are accompanied by limited mobility on examination. Although severe hemophilic arthropathy may be visible on x-ray, MRI allows for earlier detection and characterization of the degree of joint damage. Early prophylaxis with factor concentrates can significantly reduce the risk of developing arthropathy. x-ray MRI (Choice A) Autoimmmune cartilage destruction occurs in conditions such as rheumatoid arthritis. Although inflammatory arthritis may cause joint pain and swelling, it would not explain the patient's bleeding symptoms. (Choice B) Avascular necrosis of the femoral head is seen in sickle cell disease (SCD) and Legg-Calvé-Perthes disease (LCP). LCP typically presents with hip pain and limp in children age 4-12. SCD can cause recurrent vaso-occlusive episodes affecting the joints but is not associated with excessive bleeding. (Choice C) Lyme arthritis is caused by Borrelia burgdorferi infection and can present with large joint (eg, knee) swelling and limited range of motion. However, Lyme arthritis does not account for this patient's bleeding. (Choice D) Disseminated gonococcal infection can lead to acute arthritis, which presents with abrupt onset of joint pain and swelling. Infection is unlikely in this patient with 6 months of symptoms. (Choice F) Urate and calcium pyrophosphate deposition cause gout and pseudogout, respectively. Both conditions are uncommon in children and not associated with abnormal bleeding. Educational objective: Hemophilic arthropathy is a consequence of recurrent hemarthroses and is associated with hemosiderin deposition leading to synovitis and fibrosis within the joint. The risk of hemophilic arthropathy is reduced by prophylactic treatment with factor concentrates. References: Pathophysiology of hemophilic arthropathy and potential targets for therapy. (http://www.ncbi.nlm.nih.gov/pubmed/27890816) Pathophysiology of hemophilic arthropathy. (http://www.ncbi.nlm.nih.gov/pubmed/28672826)

A 16-Year-Old Boy Is Brought to the Office for Pain