Dyspepsia means that there is upper abdominal discomfort. In lots of folks with dyspepsia it gets worse after eating, or only happens after eating. In adults dyspepsia has been studied carefully. Endoscopy may show an inflammatory or acid-related disease that can be treated with drugs. However, most dyspepsia is functional, meaning that the symptoms are real but there is no easily discovered disease.
Functional dyspepsia occurs through one or more of three mechanisms:
- visceral hyperalgesia
- defective receptive relaxation with consequent increases in intragastric pressure
- abnormal motility.
Visceral hyperalgesia occurs when sensory nerves in the stomach become over sensitive. Then the pain nerves send messages to the brain that there is pain, even after events that should not cause pain, like normal stomach contractions. Newborn infants, especially ill preemies, may be more susceptible to visceral hyperalgesia for several reasons, including: 1) non-functioning descending pain-inhibitory nerve pathways, 2) no coping mechanisms, 3) repeated pain experiences.
Infants are unable to say when they have dyspepsia. However, infants do not eat if it hurts to eat. Therefore, if an infant refuses to eat, clinicians should always consider why it hurts to eat, or why the infant is afraid it will hurt to eat. Functional dyspepsia is not an accepted diagnosis for children unable to provide an accurate pain history. However, it seems like postprandial dyspepsia may be a common cause for infants and toddlers to refuse to eat. A fundoplication may further complicate dyspepsia by creating more dyspepsia by reducing stomach receptive relaxation and stimulating more pain nerves in the stomach area.
If a child refuses to eat and there is no anatomic reason to explain the symptom, dyspepsia is high on the list of diagnostic possibilities. If a child refused to eat and has a normal endoscopy, it is reasonable to treat for functional dyspepsia at any age. In everyone except those with seizures or cardiac conduction defects I recommend a tricyclic antidepressant. Tricyclics are used for chronic pain everywhere in the body, and work well to treat visceral hyperalgesia. If the child is irritable and/or has trouble sleeping through the night or diarrhea, amitriptyline is the drug of choice, beginning at 0.2 to 0.3 mg/kg an hour or two before bedtime, and increasing by the same amount once a week until there is a response or stop at 1 mg/kg, whichever comes first. Side effects of amitriptyline are relaxation, sedation and constipation. Sometimes the side effects are desirable. Imipramine is midway in side effects between amitriptyline and nortriptyline. Cyproheptidine may be used as well, for its serotonin 1 receptor antagonism probably resulting in improving stomach receptive relaxation. For children with seizures or cardiac conduction defects, I start with gabapentin.
I avoid all unnecessary procedures on children with visceral hyperalgesia, because procedures may cause further hyperalgesia secondary to discomfort and arousal. Therefore I advocate a trial of pain medicine before manometry in most cases. (Sometimes parents or referring docs request manometry before treating, because who wants to use drugs when you are not sure what you are treating? Manometry always shows what works and what does not work.) More than half the time treating pain results in a happy baby and an overjoyed family. If there is no response, and no overt central nervous system reason for food refusal, it is reasonable to find out what works and what does not work in upper GI tract motility. We can do esophageal and gastrointestinal manometry at an age, any size.
Dr. Paul Hyman
Professor of Pediatrics and Pediatric Gastrointestinal Motility Specialist,
Louisiana Children’s Hospital, New Orleans