grunting

Why do babies and young children grunt? This is one of those apparently simple questions that bears a little thought. Grunting actually serves useful and healthy purposes in babies; it can also be a sign of serious disease. I get enough questions about it in daily practice to warrant some discussion.

Healthy babies

Healthy babies grunt quite a bit. They grunt

when having a bowel movement. They do this because their abdominal muscles are weak, and to push out the stool, they must bear down with the diaphragm against a closed larynx (voice box - technically, the glottis).
Some grunt with pleasure, perhaps with an occasional happy squeal thrown in for contrast.
Something you never considered: they grunt to open the air sacs in the lungs periodically. This is the baby equivalent of a sigh. During quiet, shallow respiration, many of the tiny air sacs in the lung (the alveoli) collapse due to the normal surface tension in the lungs. A sign or grunt in this case pops them open again so that air can again enter.

Sick children

The grunting of sick persons is different from the occasional grunt of the happy, healthy child. Grunting caused by illness is more regular, often with every breath. The child usually appears to be in some distress or to be ill. Grunting respirations in a baby with a fever or who appears to be sick is a very bad sign and demands immediate emergency medical attention. The grunting respirations could represent

pneumonia
asthma or in a baby, bronchiolitis with significant oxygen lack - look out for a blue coloration around the lips - cyanosis
sepsis
meningitis
heart failure with flooding of the lungs with fluid, in a child either known to have heart disease or previously undiagnosed

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