Weekly Roundup 9-6-2013

Put your white pants away! Due to Labor Day this was a shorter wrap-up than normal. Thanks to contributors.

Answer to last week's live survey: Alex Zider is in fact not a graduate of Devry University, but rather of Princeton University, whose eating clubs are the main setting of F. Scott Fitzgerald's debut novel, This Side of Paradise. For more from last week:

From Julia Goodnough (resident report):  This was a case of a man in his late 70's who presented for workup for mitral valve replacement who coincidentally had hemoptysis for several days. Radiologic and pathologic workup revealed diagnosis of granulomatosis with polyangiitis without urinary involvement, an unusual presentation and diagnosis in this population.

• Mean age at onset of GPA is 50 years old. Untreated GPA has a 1-year mortality of 80%.
• Classical GPA is characterized by granulomatous inflammation of upper and lower respiratory tracts, which can present with dyspnea, cough, chest pain, hemoptysis, epistaxis, sinusitis, rhinorrhea, hearing impairment. 
• Approximately 25% of cases of GPA are 'limited' to findings isolated to the upper respiratory tract or lungs. Interestingly, renal involvement is present in only 20% of patients at first presentation, but up to 80% will develop renal involvement at some point in their disease.
• The disease pathogenesis is multifactorial with contributions from genetics and environmental adjuvant exposures. The predilection for respiratory tract involvement is thought to reflect the role of infection in triggering autoimmunity through molecular mimicry or by triggering nonspecific activation of adaptive immunity through superantigens. The ANCA antibodies which are markers for the ANCA-associated vasculitides may also be pathogenic, which is an area of ongoing investigation.
• Patient was treated with rituximab and steroids - see NEJM 2010 paper of trial of rituximab versus cyclophosphamide for induction therapy. Results suggested non-inferiority of rituximab. In discussion with our expert guest Dr. Maureen McMahon, her general practice is to use cyclosphosphamide in younger patients who have longer life expectancy and better general performance status as this drug has longer follow-up data compared with rituximab. In elderly patients who are likely to experience significant side effects and whose life expectancy is shorter (such as this patient), rituximab is preferred.

Final Jeopardy: Ashman's phenomenon is an aberrantly conducted beat originating from the atrium that appears anomalous on EKG (usually RBBB morphology) due to ventricular refractoriness. This usually occurs when a short R-R interval occurs right after a long R-R interval, as the ventricular refractory period is also prolonged during a long R-R interval, resulting in a wide beat. This is to be distinguished from a PVC, which originates in the ventricle, and may even be confused with ventricular tachycardia if several beats exhibit this phenomenon. See example here and accompanying wikipedia entry (believe it or now it was the clearest explanation I could find).