Associations between infants' crying, sleep and cortisol secretion and mother's sleep and well-being.

BACKGROUND: Infants' continuous crying is a challenge both for the child and the principal caregiver. However, the links between infants' sleep, crying and cortisol secretion and mothers' well-being and sleep have been scarcely investigated. The aim of the present study was therefore to examine the link between cortisol secretion, crying and sleep of infants characterized by infantile colic (IC) and mothers' psychological well-being and own sleep. METHODS: Mothers of 24 infants characterized by IC (mean age = 8 weeks, SD = 1.5 weeks) completed a series of questionnaires regarding the infant's crying and sleeping patterns. Infants' sleep was objectively assessed with actigraphs. Cortisol secretion was measured by means of saliva samples in the mornings after waking. After 4 weeks, infants were assessed once again. Mothers completed questionnaires assessing their psychological well-being (depressive symptoms, family strain) and sleep. RESULTS: Mothers' psychological well-being and sleep was greatly predicted by infants' morning saliva cortisol levels, sleep disruptions and crying intensity, whereas infants' crying duration and volume had low predictive value. CONCLUSIONS: Mothers with infants characterized by IC are at increased risk for reporting impaired sleep, developing depressive symptoms and reporting higher family strain. Most importantly, this risk seems to be greater if their infants' sleep is fragmented.

The role of melatonin and cortisol circadian rhythms in the pathogenesis of infantile colic.

BACKGROUND: Despite the high prevalence of infantile colic, the pathogenesis remains incompletely understood. Cortisol and melatonin hormones affect gastrointestinal system development in several ways, and interestingly, both cortisol and melatonin's circadian rhythms begin around the 3rd month in which infantile colic symptoms start to decrease. We hypothesized that infantile colic might associate with desynchronization of normal circadian rhythms of these hormones. In this study, we aimed to investigate the role of melatonin and cortisol in the pathogenesis of infantile colic. METHODS: Patients who were diagnosed as infantile colic according to Wessel's "rule of three" were enrolled in the colic group. We measured the saliva melatonin and cortisol levels of colic group and control group infants. In both groups, the saliva samples were taken in mornings and at evenings, at the time of diagnosis and 6th month. RESULTS: Fifty-five infants finished the study. Melatonin circadian rhythm developed earlier in the control group than the infantile colic group in our study. We found no significant difference between the daily mean cortisol levels. However, infants with colic had flatter daily cortisol slope than controls which pointed out the probability that they had a less clearly defined cortisol rhythm than infants without colic. CONCLUSIONS: We found an association between melatonin levels and infantile colic. However, more research is needed to fully understand the role of hypothalamic-pituitary-adrenal axis and hormone's role on infantile colic physiopathology.

Effects of tramadol on behavioural indicators of colic pain in a rat model of ureteral calculosis.

This study investigated the effect of prolonged administration of tramadol vs. placebo on behavioural indicators of ureteral pain and referred lumbar muscle hyperalgesia in a rat model of artificial ureteral calculosis. Four groups of 10 rats each (female, Sprague-Dawley) were treated twice a day, for 4 days, with i.p. injections of tramadol 1.25 mg/kg, 2.5 mg/kg, 5 mg/kg or saline, respectively. The first injection was delivered 45 min before laparotomy (under pentobarbital anaesthesia) for formation of the stone in the upper left ureter via injection of dental cement. All rats were video-taped 24 h non-stop from the immediate postoperative period until the 4th day for recording of behavioural ureteral crises indicative of colic pain. Lumbar muscle sensitivity was tested daily over the same period by verifying presence or absence of vocalization upon pinching of the parietal layers at L1 level, bilaterally, at a constant predefined pressure value with calibrated forceps. Tramadol significantly reduced number and global duration (ANOVA, P < 0.008 and P < 0.004) of ureteral crises with respect to saline and the effect was dose-dependent (linear regression analysis between doses and parameters of crises, P < 0.003 and P < 0.002). The drug also significantly reduced the incidence of referred muscle hyperalgesia (ANOVA, P < 0.0001). It is concluded that tramadol is highly effective in controlling pain phenomena from urinary stones and can represent a valid therapeutic approach in patients with urinary colics.

Behavioral and physiological responsivity, sleep, and patterns of daily cortisol production in infants with and without colic.

To describe the behavioral and physiological responses associated with colic, the responses of 20 two-month-old infants with and 20 without colic were studied during a physical examination. Parents kept a diary of infant behaviors (including crying and fussing) for 3 days following the visit. Using Wessel, Cobb, Jackson, Harris, & Detwiler criteria, colic was defined as fussing/crying for 3 hr or more on each of the 3 days. Behavioral data coded by "blind" observers showed that during the physical exam, colic infants cried twice as much, cried more intensely, and were more inconsolable than were control infants. Despite these behavioral differences, heart rate, vagal tone, and cortisol measures indicated no appreciable difference in physiological responsivity for the two groups. At home, parents collected saliva cortisol samples at wakeup, midmorning, midafternoon, and evening for 2 days. In a finding similar to that shown by the laboratory data, the colic and control infants did not have different levels of daily average cortisol. These laboratory and home data provide no evidence of greater responsivity in the physiological substrate of difficult temperament for colic infants and are consistent with evidence of similarity in temperament once colic is resolved. At home, compared with control infants, colic infants did display a blunted rhythm in cortisol production. By diary, they also slept about 2 hr less per day than did control infants. Nighttime sleep was still significantly different when fussing/crying was statistically controlled. These data suggest that colic might be associated with a disruption or delay in the establishment of the circadian rhythm in activity of the hypothalamic-pituitary-adrenocortical axis and associated sleep-wake activity.