The first 5 manifestations are the most common. While there is no requirement for the number of clinical manifestations a patient must exhibit to meet diagnosis for PRIS, a prospective study showed that most patients exhibit at least 3 defining manifestations within 3 days of propofol use. In the same study, the incidence of PRIS was found to be a low 1% --similar to other estimates. However, PRIS is associated with high mortality, up to 30% in some studies . Moreover, because many of these manifestations are common, the presence of any of them could be attributed to another etiology, thus delaying diagnosis of PRIS. For instance, in the case vignette, the initial rise of CK was attributed to seizure rather than PRIS.
Pathophysiology of PRIS Inhibition of electron flow along the mitochondrial electron transport chain/ impairs oxygen utilization. Propofol or its metabolites inhibits fatty-acid oxidation leading to buildup of toxic fatty acid intermediates. As described in this nice review .
Risks of PRIS? Critical illness (especially, CNS illness); Use of propofol dosage more than 4 mg/kg/hr —the usual adult maintenance dose is 0.3 to 3mg/kg/hr; duration of Propofol use greater than 24hr; exogenous cathecholamines and corticosteroids; poor intake of carbohydrate, see this reference.
Management of PRIS Early recognition/diagnosis; Cessation of propofol infusion; Cardiopulmonary support; Hemodialysis (strongly advocated by expert opinion and outcome of case series). However, there are no known RCT of use of renal replacement therapy in the treatment of PRIS. Nonetheless, in case series, survivors of PRIS are more likely to have received HD/CVVH. Therefore, prolonged use of HD/CVVH is worth considering by renal consult service. Because propofol is lipophilic and has volume of distribution of 20-40L, it is poorly cleared by HD/CVVH, prolonged RRT is likely needed for PRIS management.
The patient in the case was treated with CVVH overnight, and then transitioned to intermittent HD. At the time of her discharge, she was off HD with her Cr back to baseline.
See this previous post by Nate on PRIS.
Posted by Opeyemi Olabisi