title: Breakthrough pain in malignant and non-malignant diseases: a review of prevalence, characteristics and mechanisms.
abstract: Breakthrough pain or transient worsening of pain in patients with an ongoing steady pain is a well known feature in cancer pain patients, but it is also seen in non-malignant pain conditions with involvement of nerves, muscles, bones or viscera. Continuous and intermittent pain seems to be a general feature of these different pain conditions, and this raises the possibility of one or several common mechanisms underlying breakthrough pain in malignant and non-malignant disorders. Although the mechanisms of spontaneous ongoing pain and intermittent flares of pain (BTP) may be difficult to separate, we suggest that peripheral and/or central sensitization (hyperexcitability) may play a major role in many causes of BTP. Mechanical stimuli (e.g. micro-fractures) changes in chemical environments and release of tumour growth factors may initiate sensitization both peripherally and centrally. It is suggested that sensitization could be the common denominator of BTP in malignant and non-malignant pain.
authors.affiliation: Danish Pain Research Center, University Hospital of Aarhus, Noerrebrogade 44, Building 1A, 8000 Aarhus, Denmark. kristina@akhphd.au.dk
authors.forename: Kristina B
authors.initials: KB
authors.lastname: Svendsen
authors.forename: Steen
authors.initials: S
authors.lastname: Andersen
authors.forename: Sigurdur
authors.initials: S
authors.lastname: Arnason
authors.forename: Staffan
authors.initials: S
authors.lastname: Arnér
authors.forename: Harald
authors.initials: H
authors.lastname: Breivik
authors.forename: Tarja
authors.initials: T
authors.lastname: Heiskanen
authors.forename: Eija
authors.initials: E
authors.lastname: Kalso
authors.forename: Ulf E
authors.initials: UE
authors.lastname: Kongsgaard
authors.forename: Per
authors.initials: P
authors.lastname: Sjogren
authors.forename: Peter
authors.initials: P
authors.lastname: Strang
authors.forename: Flemming W
authors.initials: FW
authors.lastname: Bach
authors.forename: Troels S
authors.initials: TS
authors.lastname: Jensen
mesh_terms: D006801:Humans; D010146:Pain / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology*; D010147:Pain Measurement; D015995:Prevalence; D020886:Somatosensory Disorders / Q000503:physiopathology