How can we distinguish a colic from other kinds of diseases in a one month old infant? I heard sounds like "eeh" are indicators; is that always true?
If your one month old is regularly crying for 3 hour stretches or more and you've tried everything, then you are probably wondering if your child is a normal baby, is simply colicky, or if your child has another digestive issue.
The thinking about colic changes regularly. The standard definition is that colic is crying for 3 hours or more for 3 or more days a week for 3 or more weeks. Colic peaks around 6 weeks and disappears between 12 and 16 weeks. The cause is unknown. This site covers some possible causes with citations. This FAQ cites some popular authors on the issue of colic.
Possible Digestive Issues
The Reflux Rebels website is great for information, although be warned that it may leave parents of nearly any newborn convinced that their child has reflux. Signs of reflux include:
Occasionally a child may have reflux but not sipit up frequently. This is known as silent reflux. You can read more about silent reflux here. This is a list of possible silent reflux symptoms:
Milk Soy Protein Intolerance (MSPI)
A milk soy protein intolerance is the inability to tolerating eating anything that has milk or soy proteins. Formula that is not specially created usually has one, the other, or both. Milk proteins also pass through breastmilk so if a nursing mother eats or drinks dairy the child will be exposed to the milk protein in the milk. There is no test for MSPI - it is diagnosed based on symptoms [source] and symtpoms may appear as early as 4 weeks [Source]. If you suspect MSPI you need to discuss it with your child's medical caregiver, but the Reflux Rebels site has a great guide to how to feed your MSPI baby here.
The following are other, not usually mentioned by pediatrician causes of fussiness to consider and possibly addres:
Just Normal Baby Behavior?
As you may have already noticed and as WebMD eloquently points out, newborn behavior, colic symptoms, reflux symptoms, and MSPI symptoms can seem remarkably similar.
In fact there is a movement to term the first months of a baby's life the period of PURPLE crying [more] to make people aware that newborns cry - a lot. Purple stands for Peak, Unexpected, Resists Soothing, Pain-like face, Long Lasting, and in the Evening (though it may not always be evening with every baby). You can find more about the acronymn here.
A baby who is not truly colicky, a reflux baby, an MSPI baby, dealing with overactive letdown or foremilk-hindmilk imbalance, and so on may be calmed by the techniques in Harvey Karp's Happiest Baby on the Block book and DVD, referred to as the five 'S'-es. Karp believes that for the first 3 months of life babies are adjusting to the world and need the conditions of the womb recreated somewhat to help the adjustment period. His calming techniques work well for many babies. Some babies are more sensitive to the world than others; these people are known as spirited.
A year ago I was the author of the question Chrys linked. After all of my searching and wondering, my child's crying wake-ups proved to be a normal part of infant development. Normal newborn behavior is a challenge even without colic, reflux, MSPI, or any of those other concerns.
Colic is used with two different meanings:
You probably mean the first - how can I know there are abdominal pains? - since the second is a diagnosis of ruling everything else out. The two main signals are pulling their legs up (which may help them feel better) and the crying stopping after passing gas or filling their diaper. For more, see this related question: Is my pediatrician missing something about my 3 month old's gas pain?
First of, your pediatrician or visiting nurse should track babies weight gain as it is best method to rule out medical conditions with same symptoms. Also, all other conditions like acid-reflux or MSPI have some severe symptoms like excessive vomiting or blood in stool.
If you like to be informed you can go through all material @justkt presented in his answer but don't search for similarities only differences because my baby had 9 out of 10 given symptoms and none of listed conditions.