Cyclic vomiting syndrome (CVS), first described in children by Samuel Gee in 1882, is a chronic functional disorder of unknown etiology that is characterised by paroxysmal, recurrent episodes of vomiting.
The pathophysiology is unknown, but data suggest a strong genetic component in children with CVS, with evidence of mitochondrial heteroplasmies that predispose to CVS and other related disorders (eg, migraine and chronic fatigue syndrome). Other theories include autonomic dysfunction and, possibly, corticotropin-releasing factor (CRF) because stress is known to be a trigger for these episodes. The possible role of cannabis in causing CVS has been examined, though it remains controversial.
CVS is characterised by recurrent, discrete, stereotypical episodes of rapid-fire vomiting between varying periods of normal health. This on-and-off stereotypical pattern of vomiting is nearly pathognomonic.
Although periods of complete normality typically occur between episodes, many adult patients lose the cyclic pattern of symptoms over time, and 63% of them develop inter episodic symptoms (often nausea and pain) between episodes; this pattern is termed coalescence.
Although periods of complete normality typically occur between episodes, many adult patients lose the cyclic pattern of symptoms over time, and 63% of them develop inter episodic symptoms (often nausea and pain) between episodes; this pattern is termed coalescence.
Because no biochemical markers for CVS have been identified, physicians must initially look for alarming symptoms and then tailor the subsequent workup accordingly. Depending on the presenting symptoms and signs other than vomiting, different diagnostic approaches are recommended. In the absence of known pathophysiology, treatment of CVS remains empiric.
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