Brian P. Jacob, David C. Chen, Bruce Ramshaw, Shirin Towfigh (eds.) - The SAGES Manual of Groin Pain-Springer International Publishing (2016)

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P. Vahedifar and E. Kamrava
possibility of complex regional pain syndrome (CRPS). In these
circumstances, patients may have pain that is clearly more severe than
expected based on their injury. The pain in this subgroup does not usually
respond to typical treatments. The pain is often accompanied with
allodynia, with hyperesthesia, and with autonomic changes. This subgroup
of patients may have complex regional pain syndrome (CRPS).
Complex regional pain syndrome (CRPS) defines a range of painful
conditions following an insult, together with abnormal changes in autonomic
function. Pain in CRPS is disproportionate to any instigating
physical cause or injury. The goal of this chapter is to define CRPS and
to help identify the clinical presentations, treatments, and plausible
therapy as related to chronic groin pain.
Complex Regional Pain Syndrome
Type I and Type II
The terms “CRPS type I and II” have recently been used as a diagnostic
and descriptive tool for the previously known syndromes of reflex
sympathetic dystrophy and causalgia , respectively. This change in typology
occurred to help with diagnosis and to establish specific criteria for
the pain syndromes. The hallmarks of CRPS as defined by the International
Association for the Study of Pain ( IASP ) include the following: (a) specific
injury or noxious stimuli, which may include surgery; (b) continued
pain that is disproportionate to the noxious stimuli or injury, including
allodynia and hyperalgesia; (c) changes in localized skin, including edema
and changes in blood flow and coloration of the skin; and (d) no specific
dermatomal or nerve pattern. This diagnosis is excluded by the existence
of other conditions that would otherwise account for the degree of pain
and dysfunction [ 1 ]. Furthermore, type I designation is used to describe
conditions that are not associated with nerve injury, whereas type II is
used to describe those that are associated with nerve injury.
CRPS classification can also be clustered into four distinct groups.
Group 1 has pain-processing abnormalities such as allodynia and hyperesthesia.
Group 2 has skin color changes and vasomotor dysfunction.
Group 3 shows edema and pseudo-motor changes such as sweating and
piloerection. Group 4 has motor trophic signs such as localized atrophy,
spasticity, dystonia, and tremors [ 2 ].
Recently proposed clinical criteria for the diagnosis of CRPS
include painful conditions that are characterized by continuous pain