A 78-year-old woman is brought to the physician by her daughter for evaluation of pain and swelling of the left shoulder for the past 6 weeks. The swelling has progressively worsened in the past 2 weeks, with severe pain and impairment of her activities of daily living. She has a remote history of falls onto the shoulder but no recent trauma. The patient has no fever or pains in her other joints.
Her past medical history is significant for pacemaker implantation for complete heart block.
Vital signs are stable and the patient is afebrile. The left shoulder is tender with anterior swelling and a palpable fluid collection. Attempted movement at the shoulder is limited and elicits severe pain. An x-ray of the left shoulder is ordered. Laboratory results are as follows:

Which of the following is the most likely diagnosis in this patient?

Question

A 78-year-old woman is brought to the physician by her daughter for evaluation of pain and swelling of the left shoulder for the past 6 weeks.  The swelling has progressively worsened in the past 2 weeks, with severe pain and impairment of her activities of daily living.  She has a remote history of falls onto the shoulder but no recent trauma.  The patient has no fever or pains in her other joints.
Her past medical history is significant for pacemaker implantation for complete heart block.
Vital signs are stable and the patient is afebrile.  The left shoulder is tender with anterior swelling and a palpable fluid collection.  Attempted movement at the shoulder is limited and elicits severe pain.  An x-ray of the left shoulder is ordered.  Laboratory results are as follows:

Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec193a_993b_e6df_853d_3157579e6a0a_MD0002_00 This patient - an elderly woman with painful subacute shoulder arthropathy and a large hemorrhagic effusion - has features of basic calcium phosphate (BCP) deposition disease, also known as Milwaukee shoulder. This condition is characterized by aggressive joint destruction involving the glenohumeral joint and rotator cuff. Initial x-rays in Milwaukee shoulder often show periarticular calcification and destructive arthritis, and MRI is helpful for a more detailed assessment. Synovial fluid is typically hemorrhagic and contains BCP (predominantly hydroxyapatite) crystals. However, the crystals are not seen under routine polarized microscopy and require special staining that is generally done only in research laboratories. The diagnosis is therefore primarily clinical. (Choice A) Synovial fluid in osteoarthritis is noninflammatory and typically has a white blood cell count <2000/µL. (Choice C) Osteosarcoma is a rare malignancy that affects primarily children and adolescents; it is most often characterized by a palpable soft-tissue mass. (Choice D) Needle-shaped monosodium urate crystals (gout) or rhomboid-shaped calcium pyrophosphate crystals (pseudogout) can sometimes be missed during examination of synovial fluid. However, aggressive joint destruction is not often seen at the time of initial diagnosis, and hemorrhagic effusions are uncommon. (Choice E) Rheumatoid arthritis (RA) may occasionally present as an acute monoarthritis, but symmetric polyarthritis involving the small joints of the hands is more common. Although RA may cause aggressive, destructive joint disease, this is usually a late finding and is less common in seronegative RA. Educational objective: Basic calcium phosphate (BCP) deposition disease of the shoulder - Milwaukee shoulder - is characterized by aggressive destruction of the glenohumeral joint and rotator cuff. It often presents with a large hemorrhagic effusion, but BCP crystals may not be visible on conventional joint fluid microscopy. __________ References: Milwaukee shoulder syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/23019991) Milwaukee shoulder: correlating possible etiologic variables. (http://www.ncbi.nlm.nih.gov/pubmed/12567134)

A 78-Year-Old Woman Is Brought to the Physician by Her