MR Potpourri Through May 14

No MR blog updates in recent weeks due to ACP and vacation.  Had a few rare diseases recently - here are some recent pearls:

Neurofibromatosis:  Autosomal dominant disease, but half of cases arise from spontaneous mutations.  NF 1 has prominent cutaneous manifestations (fibromas, axillary freckling, cafe-au-lait spots).  You can observe lisch nodules in the iris of affected individuals.  NF2 has predominant central manifestations and less cutaneous disease.  Think this dx in a patient with bilateral acoustic neuromas.  Differentiate from tuberous sclerosis, another AD disease.  Predominant facial lesions known as adenoma sebaceum, central nervous system tumors, renal tumors (angiomyolipomas), developmental delay, and seizures are prominent findings.  Some cutaneous lesions likely to show up in challenge bowl include periungual fibromas and ash leaf macules.

Marfan Syndrome:  multisystem disorder with prominent aortic pathology (aortic regurgitation).  Primary defect is mutation in the fibrillin gene.  Patients are usually tall with unusually long limbs and fingers for height.  This disorder is a cause of sudden death in young athletes.  Differentiate from Ehlers-Danlos syndrome - multiple genetic defects with Type V and III collagen being the most prominent.  Skin and tendon laxity are prominent in this condition.  Mitral valve prolapse and regurgitation is the most common cardiac manifestation.  Osteogenesis imperfecta is caused by Type I collagen deficiency, with hallmark findings of fragile bones and blue sclerae.  (Aside - the villain played by Samuel L Jackson in Unbreakable was an OI sufferer) 

HIV Infection:  Covered recently in a couple morning reports, but one relatively new development in the field:  The new treatment initiation threshold is recommend at CD4 counts less than 500, and the guidelines indicate that treatment can be considered at any CD4 count on a case by case basis with highly motivated patients.  The guidelines panel was split 50/50 regarding making this latter threshold a formal recommendation.

Narrative Medicine:  Dr Lands' Grand Rounds on narrative medicine was one to remember.  The stories we tell tie us together as a profession and give practice deeper meaning than simple facts, stats, and p values.  A poem in the sudden death article linked above brings that home, and I close this entry with it:

The time you won your town the race / We chaired you through the market-place;

Man and boy stood cheering by, / And home we brought you shoulder-high.
To-day, the road all runners come, / Shoulder-high we bring you home,
And set you at your threshold down, / Townsman of a stiller town.
— A.E. Housman, "To an Athlete Dying Young" (1895)