Update July 3, 2018
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Primary myelofibrosis is a myeloproliferative neoplasm that results in marrow fibrosis and extramedullary hematopoiesis. A leukoerythroblastic peripheral smear with nucleated erythrocytes, dacryocytes (teardrop-shaped cells), immature myeloid precursors, and occasional circulating blasts is a common finding.
Confirming a diagnosis of primary myelofibrosis requires a bone-marrow biopsy, which typically reveals fibrosis that is evident from deposits of reticulin, collagen, or both. The JAK2 V617F mutation is identified in 50% to 60% of patients with primary myelofibrosis. Primary myelofibrosis is a diagnosis of exclusion, so secondary causes of marrow fibrosis or leukoerythroblastosis (e.g., tumors metastatic to the bone marrow, granulomas, and autoimmune conditions) must be ruled out. Chronic myelogenous leukemia (CML) may present with similar features but does not typically demonstrate thrombocytopenia, frequent dacryocytes, or nucleated erythrocytes. Bone-marrow examination can usually distinguish CML from myelofibrosis. However, if there is any doubt about the diagnosis, testing for the BCR-ABL rearrangement should be performed to exclude a diagnosis of CML.
Positron-emission tomography/CT would be helpful in diagnosing certain malignancies, such as lymphoma.
Serum protein electrophoresis would be useful in diagnosing multiple myeloma, but a patient with multiple myeloma does not typically present with splenomegaly or leukoerythroblastosis.
Peripheral-blood flow cytometry has no diagnostic role in primary myelofibrosis.
Splenomegaly, anemia, and elevated lactate dehydrogenase could suggest an autoimmune hemolytic anemia, but leukoerythroblastosis would not be present. Therefore, a direct antiglobulin (Coombs) test is not initially appropriate.
Spivak JL. Myeloproliferative neoplasms. N Engl J Med 2017 Jun 1; 376:2168. > View Abstract
In a retrospective study of over 1 million patients, ulnar neuropathy (persisting for more than 3 months) occurred in approximately 1 in 2700 patients.1 Of interest, initial symptoms were most frequently noted more than 24 hr after a surgical procedure. Risk factors included male gender, hospital stay greater than 14 days, and very thin or obese body habitus. More than 50% of these patients regained full sensory and motor function within 1 yr.
Anesthetic technique was not implicated as a risk factor; 25% of patients with ulnar neuropathy underwent monitored care or lower extremity regional technique.
The ASA Closed Claims Project findings support most of these results, including the delayed onset of symptoms and the lack of relationship between anesthesia technique and injury. This study also noted that many neuropathies occurred despite notation of extra padding over the elbow area, further negating compression as a possible mechanism of injury. Finally, the ASA Closed Claims Project investigators found no deviation from the standard of care in the majority of patients who manifested nerve damage perioperatively.
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