Cannabinoid hyperemesis syndrome
Cannabinoid hyperemesis syndrome is a disorder that is characterized by recurrent nausea, vomiting and colicky abdominal pain. These symptoms have been reported to be alleviated temporarily by taking a hot shower or bath or more permanently by abstaining from the use of cannabis. The syndrome was described by Allen and colleagues (2004), and Sontineni and colleagues (2009) who offer simplified clinical diagnostic criteria. A subsequent, larger study reported a case series of 98 subjects with cannabinoid hyperemesis syndrome, confirming the earlier reported findings.
Signs and symptoms
The long-term and short-term effects of cannabis use is associated with behavioural effects leading to a wide variety of effects on the body systems and physiologic states. The phenomenon of cannabinoid hyperemesis and clinical diagnosis remained obscure until recently. In spite of these early reports, uncertainty remained among the doctors and scientists regarding the existence of the cannabinoid hyperemesis syndrome. Sontineni and colleagues (2009) discuss the cannabinoid hyperemesis syndrome to offer guidelines for the clinical diagnosis. The "suggested criteria for the diagnosis" are: Essential feature: 1) history of regular cannabis use for years; Major clinical features of syndrome: 2) severe nausea and vomiting, 3) vomiting that recurs in a cyclic pattern over months and 4) resolution of symptoms after stopping cannabis use. In addition diagnosis has supportive features of - 1) compulsive hot baths with symptom relief; 2) colicky abdominal pain; and 3) no evidence of gall bladder or pancreatic inflammation. Since the publication of these clinical guidelines, the syndrome is more easily recognized and treated.
Pathogenesis
Various pathogenic mechanistic theories attempting to explain symptoms have been put forward. These theories fall into two themes: 1) dose dependent buildup of cannabinoids and related effects of cannabinoid toxicity. 2) the functionality of cannabinoid receptors in the brain and particularly in the hypothalamus (which regulates body temperature and the digestive system). But the mechanisms by which cannabis causes or controls nausea and the adverse consequences of long-term cannabis toxicity remain unknown and organic disease should not be ruled out as a possible cause.
The neurobiology of the compound has led to the discovery of an endogenous cannabinoid system. The therapeutic potential of cannabinoids has been recognized and these compounds are utilized as antiemetics. Several studies have demonstrated the therapeutic effects of cannabinoids for nausea and vomiting in the advanced stages of illnesses such as cancer and AIDS.
Epidemiology
Cannabinoid hyperemesis was first reported in the Adelaide Hills of South Australia. Since then, several cases have been recognized worldwide. Cannabis is by far the most widely cultivated, trafficked and used illicit substance. In the present decade, cannabis use has grown more rapidly than cocaine and opiate use. The most rapid growth in cannabis use since the 1960s has been in developed countries in North America, Western Europe and Australia. Cannabis has become more closely linked to youth culture and the age of initiation is usually lower than for other illicit drugs.
