Hereditary Coproporphyria Mimicking Guillain-Barré Syndrome After COVID-19 Infection.

Hereditary coproporphyria (HCP) is a rare disorder caused by a deficiency of an enzyme, coproporphyrinogen oxidase, in the heme synthetic pathway. This disease has a highly variable clinical presentation with acute attacks of neurologic symptoms that can last from days to months. Rarely, it and other acute porphyrias may cause ascending paralysis, which is difficult to distinguish from Guillain-Barré syndrome (GBS). Acute attacks can be triggered by factors that increase the synthesis of heme, such as hormonal changes, certain medications, dietary changes, and infections. We report a 26-year-old female with HCP who presented with acute ascending flaccid paralysis and respiratory failure after coronavirus disease 2019 (COVID-19) infection and was initially misdiagnosed and treated for GBS. She was transferred to our neurosciences intensive care unit, where the diagnosis of acute porphyria was established. Initial improvement occurred during treatment for several weeks with hemin (Panhematin®) and continued with givosiran (Givlaari®), which was recently introduced for the prevention of acute attacks. We suggest that acute porphyria should be part of the differential diagnosis when GBS is suspected. To our knowledge, this is the first report of an attack of acute hepatic porphyria (AHP) that developed after a COVID-19 infection and the first with advanced paresis to be treated with givosiran. Her response suggests that givosiran may contribute to recovery from advanced neurological manifestations of acute porphyrias.

Stimulant-induced changes in smoking and caloric intake: influence of rate of onset.

Rate-of-onset modulates the subject-rated effects of stimulants. Results of two studies from our laboratory demonstrate that immediate-release methylphenidate increases smoking and decreases caloric intake. Whether rate-of-onset influences the effects of methylphenidate on smoking and eating is unknown. The present experiment examined the influence of a range of doses of immediate- (7.5-30 mg) and sustained-release (18-72 mg) methylphenidate as well as placebo on smoking and eating. Eight cigarette smokers participated. A double-dummy drug administration procedure was used to maintain the double blind because immediate-release methylphenidate produces peak plasma concentrations 1.5-2 h and the sustained-release formulation produces peak plasma concentrations 6-8 h after oral administration. Smoking and eating were assessed for 4 h across the predicted peak effects of both methylphenidate formulations. Measures of smoking included total cigarettes, puffs, and carbon monoxide levels. Snacks and decaffeinated beverages were available ad libitum and caloric intake was monitored during the four-hour smoking session. Immediate- and sustained-release methylphenidate increased smoking and decreased caloric intake. The effects of methylphenidate generally did not vary as a function of formulation. The results of this study may have important implications for the treatment of disorders that require stimulant medications. Smoking should be monitored in patients that are prescribed stimulant medications, regardless of the formulation type.