Pain
-
The aim of the study was to evaluate the effects of pre- and postinjury infiltration with lidocaine on alterations in mechanical and thermal sensitivity after heat injury to the skin. In the first part of the study, burn injuries (15 x 25 mm rectangular thermode, 50 degrees C, 7 min) were produced twice in each subject on the medial side of the left and right calves at least 24 h apart in 8 healthy, unmedicated male volunteers, in order to investigate the effects of the injury on sensitivity in untreated skin. In the second part of the study, burn injuries (15 x 25 mm rectangular thermode, 50 degrees C, 6 min) were produced twice in each subject on the medial side of the left and right calves at least 24 h apart (n = 10). ⋯ In the second part of the study, it was observed that pre-injury infiltration with lidocaine reduced hyperalgesia to pinprick and brush outside the injury more effectively than postinjury block, but only for the first 70 min after injury, while no significant difference was observed 100-190 min after injury. Likewise, there was no difference in thermal thresholds inside the injury between pre- and postinjury treatment at the end of the study period. It is concluded, that a shortlasting 'preemptive' infiltration with lidocaine may postpone but not prevent the occurrence of hyperalgesia outside a thermal injury.
-
In a cross-sectional epidemiological study of headache disorders information on precipitating factors, age at onset, influence of menstruation and pregnancy and use of oral contraceptives was collected. The presence of migraine and tension-type headache was ascertained by a clinical interview and examination using the operational diagnostic criteria of the International Headache Society. The prevalence of migraine and tension-type headache was also analysed in relation to variables of lifestyle: physical activity, smoking, consumption of coffee, alcohol intake and sleep pattern. ⋯ Smoking, coffee and alcohol consumption showed no significant associations with the headache disorders. Sleep pattern was significantly associated with migraine and tension-type headache in both univariate and multivariate analyses. In conclusion, migraine and tension-type headache seem to be different with regard to a number of endogenous and exogenous factors.
-
Painful diabetic neuropathy is one of the most common complications of insulin-dependent diabetes in man. Conflicting results have been obtained in experimentally diabetic animals subjected to pain stimuli. This work aimed to systematically study the response of rats made diabetic (hyperglycemia > or = 14 mM) by injection of streptozocin (STZ) (75 mg/kg, i.p.), to various pain stimuli: mechanical, thermal (warm and cold) and chemical. ⋯ Spontaneous motor activity of the rats was lowered. This model is thus of interest as the observed reactions to noxious and non-noxious stimuli correspond to hyperalgesia and allodynia, symptoms encountered in painful diabetic neuropathy in man. Operating conditions for this model are discussed.
-
Peripheral tissue damage or nerve injury often leads to pathological pain processes, such as spontaneous pain, hyperalgesia and allodynia, that persist for years or decades after all possible tissue healing has occurred. Although peripheral neural mechanisms, such as nociceptor sensitization and neuroma formation, contribute to these pathological pain processes, recent evidence indicates that changes in central neural function may also play a significant role. ⋯ We also assess the physiological, biochemical, cellular and molecular mechanisms that underlie plasticity induced in the central nervous system (CNS) in response to noxious peripheral stimulation. Finally, we examine theories which have been proposed to explain how injury or noxious stimulation lead to alterations in CNS function which influence subsequent pain experience.
-
The impact of invasive procedures on preterm neonates has received little systematic attention. We examined facial activity, body movements, and physiological measures in 56 preterm and full-term newborns in response to heel lancing, along with comparison preparatory and recovery intervals. The measures were recorded in special care and full-term nurseries during routine blood sampling. ⋯ Facial activity increased with the gestational age of the infant. Specificity of the response to the heel lance was greatest on the facial activity measure. Identification of pain requires attention to gestational age in the preterm neonate.