After more than 80 years of scientific investigation and journalistic discussion, infantile colic continues to be a poorly understood syndrome. One of the few certainties is that infant, parent, and pediatrician are just as troubled by this entity today as when it was first described.
Colic is an affliction of infancy. The onset is typically in the first three weeks of life and may be seen as early as three days. 1 Patients are usually substantially better by 3 to 4 months of age.
SEEKING A DEFINITION
The symptoms most commonly accepted as being consistent with a definition of infantile colic are "unexplained paroxysms of irritability, fussing, or crying which may develop into agonizing screaming."2 Frequently associated with these symptoms is a change in posture. While fussing these infants draw their knees up against their chests and may exhibit clenched fists, flexed elbows, and a tense abdomen. Episodes are recurrent and can come and go with great rapidity.
Most physicians believe that crying and fussing must be excessive for the symptoms to warrant the diagnosis of colic. A major problem, then, in setting a precise definition of colic is distinguishing objectively just how much crying is abnormal. In 1962 Brazelton published a study of crying in normal infants. In 80 infants studied, the median daily crying time was VA hours in the second week of life, 2¾ hours at 6 weeks, and then decreased to less than one hour by 12 weeks of life.3 Furthermore, it was noted that infant fussing was greatest from 6 PM to 11 PM at 3 weeks of age and from 3 PM to midnight at 6 weeks. Similar crying patterns have been noted by other authors. 4 Therefore, it seems reasonable that for crying to be considered excessive, an infant's crying time should exceed the values described above.
Dietary proteins have been extensively studied with regard to colic. Early reports observed that certain proteins, when digested, would produce excessive intestinal gas and peristalsis. This was hypothesized to be a manifestation of allergy. Because colic is a disorder of infants, breast milk proteins became the most likely villain. Later cow's milk proteins and then soy proteins were implicated. Many authors have tried to prove or disprove this hypothesis.
In 1982 Lothe et al published a study concerning the relationship of infant feedings to colic.5 Twenty-nine percent of the colicky infants improved spontaneously while on cow's milk formula. Eighteen percent did not improve after one week of cow's milk formula, but seemed to respond to a one week trial of soy based formula. Fifty- three percent of the infants did not improve with either cow's milk formula or soy based formula. Of these infants, all improved when switched to Nutramigen. However, this last part of the study was not blinded. Although the authors failed to provide any statistical analysis, Leblanc's analysis of their data failed to demonstrate any significant benefit from switching colicky infants from cow's milk protein to soy protein based formula.6
In a later study, the relationship of maternal ingestion of cow's milk to the symptoms of colic in exclusively breast fed infants was evaluated. 7 Subjectively, and in a nonblinded study, 35 of 66 (53%) of colicky breast fed infants improved when cow's milk was removed from their mothers' diets. Of those infants who improved, 23 of 35 (66%) relapsed when their mothers began drinking cow's milk again. Effectively 35% of the infants seemed to have exacerbations of colic related to maternal cow's milk ingestion. Sixteen of the 23 infants who, as described above, seemed sensitive to cow's milk then entered into a doubleblind study in which their mothers were given capsules either containing whey powder or potato starch. Nine of the 16 infants reacted adversely to maternal ingestion of cow's milk whey, but not to the placebo. The most frequently offending protein in cow milk whey is beta lactoglobulin. Five of 16 did not react adversely to any challenge with capsules.
Related studies have shown that dietary bovine beta lactoglobulin is transferred to human breast milk.8,9 Samples of human breast milk analyzed by radioimmunoassay have contained levels of bovine beta lactoglobulin ranging from 0 to 800 µg/L. Daily cow's milk intake has not been shown to correlate with bovine beta lactoglobulin levels, and there has been no correlation demonstrated between varying bovine beta lactoglobulin levels in breast milk and the appearance, resolution, or reappearance of colic.
A recent study by Thomas et al disputes the alleged relationship between cow's milk protein and infantile colic.10 In infants fed cow's milk formula, 19% had colic. In the breast fed group, 21% of infants of mothers who drank cows milk had colic, whereas 28% of breast fed infants whose mothers did not drink cow's milk developed colic.
The relationship, if any, between milk proteins and infant colic is not yet clear. It may be that a small group of infants experience symptoms apparently consistent with infantile colic in the presence of certain milk proteins. This very limited number of infants may have milk protein allergy, but not infantile colic. Physicians need to be aware of and look for other signs and symptoms of allergy to help distinguish this entity from colic.
Between about 1901 and the mid 1950s, hypertonicity was in vogue as the etiology of colic.11 It was believed that hypertonicity of both smooth and "striped" muscle existed in these infants. Because of this hypertonicity the affected infants were thought to experience an exaggerated response to both internal and external stimuli. In particular, the hypertonic gut would undergo a spasm that would produce the symptoms we recognize as colic. It was Haas's belief that this hypertonicity resulted from an autonomic imbalance.12 Bruce suggested that hypertonicity was an inherited disorder.13 Shawsky believed hypertonicity to be related to an increased pace of civilization.14 Despite all the interest, it has not been possible to demonstrate convincingly that generalized hypertonicity of the infant causes colic.
In 1954 Wessel suggested infantile colic was related to "family tension."1 This was defined as "the presence of emotional turmoil and tension . . . evident to various observers . . . noted both before and after the weeks during which the infant was fussy." He found that 72% of infants in 43 families with family tension had colic as opposed to 26% in 42 families without prominent family tension.
Paradise in 1966 found that mothers who gave a history of "heightened emotional tension or depression or both during pregnancy" had a statistically significant higher incidence of infants with colic than did a group of mothers without this history.15 In the same study, using a more objective assessment of maternal personality, Minnesota Multiphasic Personality Inventory (MMPI) data revealed no significant differences between groups of mothers whose infants were without colic, or mildly, moderately, or severely colicky. Furthermore, there was no significant difference in anxiety scores between mothers of colicky and noncolicky infants.
Carey takes a middle-of-the-road approach in proposing an "interaction model" of colic. ,6 In this theory, the infant's intrinsic factors such as temperament and sensory threshold interplay with extrinsic factors such as parental anxiety and inexperience, and environmental influences. He implies that developmental changes allow these infants to outgrow colic.
Crying for Specific Reasons
The question of whether colic is a problem of infant or parent is taken one step further by Taubman.17 He studied the effect of altering parental interaction on crying time in 30 colickly infants. In a subgroup of 20 of these infants, parents were instructed in detail how to search out and respond to possible infant needs. In this group, mean crying time decreased from 2.6 ± 1.1 to 0.8 ±0.3 hours per day (P <0.001). In a second treatment group of six infants, parents were instructed to decrease their interactions with their crying infants by laying them down and letting them cry when efforts failed to console them. Although five of these infants subjectively improved, review of diaries did not demonstrate any significant change in crying time. This study suggests that infants cry and fuss for specific reasons and by counseling parents pediatricians can make them more capable of meeting their infants' needs.
Theories about the etiology of colic all fail to explain why colic is self-limited. In Wessel's study group, the majority of infants were no longer fussy by the end of the second month, although some remained so until the end of the third month and beyond.2 Illingsworth names infantile colic "three-months colic" because based on his experience babies "get better" by age 3 months.3
A Functional Disorder
Although colic has never been demonstrated to be the result of any organic disease it does appear to relate to the irritable bowel syndrome. Infants who are genetically predisposed to produce unrelenting obstructive spasm of the distal colon when under sufficient stress suffer abdominal pain from excessive distension of more proximal large bowel. The distending material is usually gas, which is regularly ingested by the young infant as a result of the combined and coordinated breathing-suckling activity. The stomach is normally filled with air during feedings and if this is not eliminated with burping it must pass through the colon to be eliminated as flatus. Infants with a tendency to constipation and increased rectal spasm may have difficulty eliminating the gas, thus causing the more proximal colon to become overdistended and inducing the pain of colic.
It has been noted in an earlier study that 23% of children diagnosed as having irritable bowel syndrome had a history of infantile colic. 18 The problem of colic is thus not isolated, but rather tends to appear early in the individual's age spectrum as the first troublesome manifestation of the functional disorder called the irritable bowel syndrome.
TREATMENT OF COLIC
Therapeutic approaches to colic have been based on presumptions about the etiology. Those who believe that colic is a disorder of parent rather than infant have tried to alter the parent- infant interaction. Diets have been altered in numerous ways to treat maldigestion, allergy, excessive intestinal gas, overfeeding and underfeeding. Various methods have been tried to alter the sensory input of infants on the belief that colic is caused by an increased sensitivity to stimuli. We all have heard of or seen infants who are apparently soothed by monotonous sounds or motion. One recent invention (SleepTight, St. Charles, Missouri) that attaches to the baby's crib is supposed to "reduce the symptoms of infant colic and derived parental stress" by simulating the sound and motion of a car riding at 55 MPH.
With all these remedies available, what should pediatricians recommend.7 Dietary alterations generally have little beneficial effect in the treatment of infantile colic. Colicky infants should not be switched to soy or casein hydrolysate formulas unless other signs and symptoms of milk intolerance or allergy exist such as diarrhea, wheezing, exanthema, hematochezia, or weight loss. Too many fruitless dietary changes are discouraging to parents and further aggravate the problem.
The physician confronted with a colicky infant should initially take a careful history and perform a proper physical examination to rule out organic disorders. The next approach should be to reassure the parents and develop a strategy for managing the distal spasm, since the greatest infant relief from discomfort is achieved with this approach. Because the administration of medication or laxative might increase peristaltic activity, probably augment the amount of colonic gas, and increase discomfort, the relief of distal spasm must be direct from below. Introduction of suppositories or a well greased thermometer with gentle stimulation of the rectal area will usually break up the rectal spasm with an explosive passage of retained material, including accumulated colonic gas, and should afford some relief of the colic.
A less direct approach which relieves rectal spasm follows application of heat to the abdomen. Placing babies in a warm bath for 15 to 20 minutes is frequently rewarding. Massage and kneading of the abdomen may serve equally well in some cases. Massage with one hand and rectal stimulation with the other is often a successful combination.
Drugs have limited value in the treatment of colic, and the pharmacologic treatment of the spasm is difficult. Anticholinergics, antiflatulents, barbiturates and other sedatives, as well as motility-enhancing drugs, have been prescribed with limited success. Although it is possible to relieve upper intestinal spasm with phenothiazine analogs, even after induction with morphine derivatives, it is not possible to do so in colonic spasm. From rectal motility studies we have ample evidence that the use of various antiperistaltic and parasympatholytic agents does not effectively relieve colonic spasm, but that alcohol appears may be the one pharmacologic agent that does.
We occasionally administer relatively small amounts of alcohol to infants with severe and unremitting colic. One teaspoonful of 20 proof wine, or 1.5 mL of 80 proof liquor of any variety added to 2 ounces of warm water and small bit of sugar for flavor are given. Breastfeeding mothers sometimes find that if they take an occasional cocktail, especially before the evening feeding when children are most likely to be fussy, they may achieve the same salutary effect from the small amount of alcohol transmitted in the breast milk.
Lest anyone believe that this amount of alcohol is intended in inebriate the baby we should remember that it was customary in former years to calculate infant doses from the adult pharmacopoeia. Infants and children of various ages were usually given between one tenth to one seventh of adult doses. Going in the opposite direction we would multiply the infant dose of 1. 5 mL of alcohol by ten and calculate 15 mL or one half ounce. This is hardly an inebriating dose, even for a teetotaler, but it does promote relaxation of rectal spasm and permit relief from distension by passage of the accumulated material.
In the infant with colic, it is advisable to practice prophylaxis against permitting swallowed gas to pass through the pylorus. This would limit the passage to the intestine of air which is ingested at the time of feeding. We, therefore, recommend that infants be fed in an upright position so that air will remain above the milk at the top of the stomach and be more easily burped. We also try to limit each period of sucking at the bottle or breast to about ten minutes. Beyond this time, excessive amounts of air are swallowed relative to the amounts of milk that are taken. This tends to promote the amount of gas that traverses the pylorus and leads to greater intestinal discomfort.
The overall approach to this troublesome self-limited condition requires some individualization. For many families reassurance, confidence, and a clear explanation of these practical feeding and handling techniques will suffice. In other cases, continuing support and advice with reiteration of the appropriate management need to be given regularly until the condition finally clears at 3 or 4 months of age.
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2. Wessel MA, Cobb SC, Jackson EB, et al: Paroxysmal fussing in infancy sometimes called "colic." ftdtarics 1954: 14:421-434.
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