New Trick for the Old Dog

My subscription to the NEJM remains in force and I schedule two articles a week, even into retirement.  Often the Case of the Week attracts me the most since it challenges my skills.  I can usually get the differential reasonably close but some of the lab testing has passed me by, even in my own specialty where I recently fumbled with a presentation of Monogenic Diabetes.  I knew the forms and the genetic identification but did not know how to correlate phenotype genetic results.  More importantly, I did not know that the tests come as a commercial panel and that it is cost effective to order it, something that I avoided doing in my Medicaid and uninsured population, asking those patients to have their affected child tested for financial reasons.

Recently, they had a case of SIADH which I recognized easily and could get a reasonable differential diagnosis.  The case included treatment with saline and desmopressin together.  I thought a rare lapse in editing, expecting tolvaptan, but later it appeared again.  So I looked it up.  Apparently the vaptans have gotten too expensive.  Since saline of the right concentration and right amount will correct hyponatremia, the barrier has been the safety of overcorrecting.  Apparently desmopressin, while counterintuitive when ADH is already excessive, provides the protection against too rapid a rise in sodium with adverse neurological demyelination.  Good to know my curiosity and inclination to challenge what seems suspicious has not been seriously impaired by retirement.