Page 375 Guide to Pain Management in Low-Resource Settings

Appendix: Glossary 363

Bradykinin schools. While “alternative medicine” often is in con-
Bradykinin is generated in the blood by the action of fl ict with mainstream medicine and includes sometimes
the plasma kallikrein-kinin system (involving prekalli- rather bizarre methods, complementary medicine is
krein activator, prekallikrein, kininogen, and kininases). “extending” the conventional medical approaches to en-
It produces infl ammation and activates nociceptors via hance its eff ects. Well-known complementary medicine
bradykinin B1 and B2 receptors. modalities include acupuncture, low-level laser therapy,
meditation, aromatherapy, dance therapy, music thera-
Calcitonin gene-related peptide
py, herbalism, osteopathy, and naturopathy.
Calcitonin gene-related peptide (CGRP) is a neuro-
Delirium
peptide expressed in sensory neurons. It works as a
stimulatory (pronociceptive) neurotransmitter when A disturbance of the brain function that causes confu-
it is released centrally, and as a proinfl ammatory me- sion and changes in alertness, attention, thinking and
diator when it is released peripherally. Th e central reasoning, memory, emotions, sleeping patterns, and
role of CGRP in primary vascular headaches (e.g., mi- coordination. Th ese symptoms may start suddenly,
graine) has led to the search for suitable antagonists are due to some type of medical problem, and may get
of CGRP receptors. worse or better multiple times. Typical causes for de-
lirium include acute infection or cancer progress (with
Causalgia (complex regional pain syndrome liberation of TNF-alpha), sudden renal failure, certain
type II)
drugs including opioids (the incidence for opioids is
Pain, usually burning pain, that is associated with auto- around 1–2%), and electrolyte imbalances. If opioids are
nomic changes (changes in the color of the skin, chang-
suspected to be the cause of delirium, a switch (rota-
es in temperature, changes in sweating, and swelling). tion) to another opioid usually terminates the delirium
Causalgia is rare and diffi cult to treat and occurs after a
with hours.
nerve injury. Th e pathophysiology of causalgia includes
local infl ammation and reorganization processes in the Dependence
central nervous system. If causalgia is suspected, diag- Physical dependence is a state in which the continuous
nosis and treatment should be left to a pain specialist. presence of a drug is required to maintain normal func-
Central pain tions of an organism. Discontinuation of the drug re-
sults in a withdrawal syndrome. Dependence is a “nor-
Pain initiated or caused by a primary lesion or dys-
mal” phenomenon occurring with a number of diff erent
function in the central nervous system. It occurs in
drugs. As a consequence, when opioids have been ad-
some patients after stroke and may limit the quality of
ministered for a prolonged period of time (> 3 weeks)
life considerably. Only tricyclic antidepressants have
in a dose of 50–100 mg oral morphine equivalents per
been able to show any analgesic eff ectivity in these pa-
day or more, they should never be acutely discontinued
tients. All other treatment options are supported only
but tapered with a daily dose reduction (e.g., a 10% daily
by anecdotal evidence.
dose reduction).
Chronic pain
Depression
Chronic pain is diagnosed if pain persists longer than 6
Depression is a risk factor for pain chronifi cation. Cer-
months. For clinical practice it is probably more help-
tain screening questions aid in diagnosis. Common
ful to defi ne chronic pain as pain that is complicated
fi ndings are sleeping problems, unrest, a lack of ener-
by certain risk factors according to the biopsychosocial
gy that is pronounced in the fi rst half of the day, and
concept of pain chronifi cation: central sensitization to
loss of interest. Some common screening instruments
painful stimuli, depression or anxiety, or somatoform
for depression are the Center for Epidemiologic Studies
disorders, as well as confl icts at the workplace or in the
Depression Scale (CES-D), the Beck Depression Inven-
family.
tory for primary care, and the Profi le of Mood States
Complementary medicine (POMS). A psychopathological result should howev-
Approaches to medical treatment that are outside er always form the basis and include an evaluation of
of mainstream medical training received in medical suicidal tendency. In accordance with the fi ndings of