Today we discussed an interesting case of a primary eating disorder that had been presented to the OHSU ED as a case of gastroparesis with the request to initiate TPN. A few interesting learning points from this case from the group:
- Always be vigilant against diagnostic momentum/inertia
- An objective evaluation for gastroparesis can include a scintogriphic gastric emptying study. Measurements of gastric clearance are made after 4 hours of ingestion of a standardized bolus of food. Normal is considered to be <10%, data-preserve-html-node="true" mild is 10-15%, moderate 15-35%, and severe >35%
- Treatments for gastroparesis tend to be either lacking in significant efficacy (dietery changes) or have narrow therapeutic index
- Erythromycin - effective in short doses; tachyphalaxis develops after ~2 weeks. Adverse effects include QTc prolongation and the standard complications associated with oral antibiotics
- Metoclopramide is considered first line pharmacotherapy for gastroparesis and appears to be effective though has not been studied over a long period of time. There is a black box warning against its use for greater than 12 weeks due to the risk of dystonia and tardive dyskinesia. It appears the incidence of tardive dyskinesia is somewhere in the vicinity of 1%, though compelling epidemiologic data is lacking
- TPN is usually resevered for patients short term with reversible conditions contributing to their malnutrition. TPN should not be used as a "bridge to nowhere," or in patients with a working alimentary tract, especially in patients with clinical signs and symptoms of malnutrition/hypovitaminosis.