Dear Doctor Samson,
Question 1: My 12-month-old baby occasionally has bright green bowel movements. My mother-in-law tells me that in her experience this means an infection of the bowel. My child seems to be doing well but, nevertheless, the grandmother does have a lot of experience raising children and I am concerned that my daughter may have some bowel problem that I am not providing adequate care for. What is the significance of green bowel movements?
Question 2: My 3-year-old son has many episodes of nasal congestion and discharge which may be due to allergy or repeated colds. I have been told that when the nasal discharge turns green it is the sign of infection. Since this seems to happen frequently my child is on antibiotics repeatedly. I am beginning to wonder if every time the nasal discharge develops a greenish tinge that it really does mean infection. Does green-tinged, thick nasal discharge always mean infection and, therefore, does an antibiotic always have to be used?
It is interesting that not only fever but the color of body fluids causes grave concern on the part of parents. There is no question that blood-tinged body fluid is always a sign of a potentially significant problem, mandating consultation with the patient's physician. It should be noted that green, in the eyes of most laymen, warrants almost as much concern as the color red. In some cases green does herald a significant problem. For example, green-stained vomitus may indicate bowel obstruction. In reference to the two questions that were posed, that is green bowel movements and green nasal discharge, these are certainly not signs of life-threatening illnesses, but nevertheless are extremely bothersome to parents.
Let me address Question 1 first: A bowel movement has any color at all based on two factors. 1) the pigment in the food eaten. 2) the bile that is produced by the liver and infused into the bowel by the gall bladder. Bile is emerald-green in color and is changed chemically to a brown color through the various processes of the intestinal tract. It takes time for the chemical processes to change the bile from green to brown, so any condition which speeds up the transit of the waste material through the intestinal tract will provoke a green bowel movement. At times this is associated with disease processes, such as intestinal viral or bacterial infections. Certain food substances and chemicals augment bowel motility and in turn decrease the transit time. Thus, a green bowel movement is produced without the presence of infection. Intermittent green stools in a child without fever or any other symptoms are of no significant importance.
Question 2 brings up another situation where green body fluids alarm parents. Despite this, it must be remembered that green nasal discharge does not always mean a bacterial infection. If we keep in mind why nasal discharge changes from clear to a cloudy green color I think the question will be easily answered. When the nasal lining or mucus membrane is infected by virus or bacteria, or reacts to some allergen or irritant a profuse watery discharge is noted. As the process progresses three things can cause a nasal discharge to thicken: 1) White blood cells migrate from the blood vessels through the mucus membrane of the nose into the clear fluid discharge transforming it into a thick mucus. 2) Medication such as antihistamines or decongestants can cause the nasal secretions to become more viscous and thus cloudy. 3) Decrease in humidity physically dries the secretions and causes thickened nasal discharge. As the secretions become thicker a pastel green-tinge is noted which then provokes the concern of the parent.
When confronted with a child who has thick or "green nasal discharge" it becomes imperative to know what other signs and symptoms are present, and what medication the child has been on. If the cause is unclear a microscopic exam of the secretions will identify if white blood cells are present and which type. If no cells are seen then medication, decreased humidity or local irritant is probably the cause. If cells are seen they may be of an infectious or allergic type. So, in answer to your question, thick greenish-tinged nasal discharge does not always mean infection. It can indicate the child has 1) a heavy out-pouring of allergy type blood cells (eosinsphils), 2) been on a medication which causes the viscosity of the fluid to increase, 3) been in a low humidity environment, 4) exuded many infection fighting blood cells (neutrophils) into the nasal mucus as seen in a bacterial nasal infection.
In summary, green does not always indicate infection. In bowel movements it indicates primarily the time it takes for the bowel contents to go from the small to the end of the large bowel. In nasal secretions, it indicates an increased viscosity and usually the presence of white blood cells, not always of the infectious type. Thus, green discharge need not always mandate the use of an antibiotic. No matter what is said and done I fear green will always be looked upon as a sign of disease, provoking unwarranted parental worry.