The call came in at 4:00 a.m. Trent, a healthy four-year-old, was just fine when he went to bed at the usual time of 8:30 p.m. He was getting over a mild cold that was nothing of significance, and he had enjoyed an active day of playing hard.
Trent’s anxious dad made the call and spoke rapidly. Trent had awakened at midnight saying that he did not feel well and his stomach hurt. After taking his temperature which read at 99 degrees, they asked where it hurt. He pointed to his upper abdomen. It was a vague pain and difficult to describe. Mom thought he might be constipated. He sat on the toilet for a few minutes and actually did have a bowel movement. But it afforded little, if any, relief. When she gave him Tylenol he said he felt nauseated, but did not vomit.
Trent’s parents had him lay in their bed with them but he was restless, tossing and turning. Just when they thought he was going to fall asleep he would jerk and complain of the pain. By 3:00 a.m. they grew concerned as the pain was now localized to the right lower quadrant. He would moan, grab his right side, and say, “Make it stop hurting!”
After receiving this brief history I instructed the parents to have Trent lay flat on his back as comfortably as possible. They should think of the abdomen as four distinct quadrants; then begin gently pressing on each of the sections, starting on the left side of the abdomen. The left upper quadrant felt fine and did not hurt. The same was noted in the left lower quadrant. But pressing on the right upper quadrant he began to wince and said it sort of hurt. The pain was in the right lower abdomen, even though they were pressing on the upper abdomen. Before starting to press on the right lower abdomen Trent grabbed their hands and pushed them away, and started to cry.
Next, I instructed them to have Trent stand up straight and get into a squat like a catcher’s stance in baseball. Halfway down he stopped, stood right up and said it hurt. Lastly, I asked them to have him jump up and down. After doing it once and landing on his feet, he froze with a pained look on his face and refused to try again. This was a classic presentation for acute appendicitis and he should go directly to the emergency room. I would speak with the ER physician about my concerns. Dad said they were on their way.
The emergency room doctor agreed that it sounded like an appendicitis. When they arrived the examination proved classic appendicitis, whereupon routine labs were ordered. Of note, Trent’s white blood count was LOW, not high, as one would expect with appendicitis. His urinalysis was normal and did not suggest a urinary tract infection. An ultrasound was ordered, and it did not visualize the appendix. Usually an inflamed appendix will be seen as a large tubular structure that can be confirmatory when present. It is of no value if it is not seen. In other words, a non-visualized appendix does not completely rule out appendicitis.
The emergency room doctor called me to say that he agreed this was most suspicious for appendicitis. However, the labs did not support this, nor did the ultrasound. It was agreed to get a CT of the abdomen before we involved the surgeons. Sure enough, the CT showed a normal appendix, with two-to-three large lymph nodes in the right lower quadrant. This confirmed the diagnosis of mesenteric adenitis. Trent was sent home with conservative measures, and later in the day he was much improved.
The mesentery is a thin, apron-like membrane that attaches the intestines to the back wall of the abdominal cavity. Given that an adult has around 26 feet of intestines in the abdomen that are essentially free floating, the mesentery keeps the intestines from twisting on themselves. Coursing through the mesentery are blood vessels and lymph nodes. The lymph nodes help filter out bacteria and will localize any infection within the abdominal cavity to protect the intestinal tract. In mesenteric adenitis, some lymph nodes will become infected. Thus, they become enlarged and inflamed. The most likely cause of the inflammation is a virus. The symptoms include abdominal pain making it look just like an appendicitis. The virus that causes the inflamed node may cause fever, some loose stools, nausea and even vomiting.
Since most cases of mesenteric adenitis are caused by viruses, the treatment is supportive with no benefit from antibiotics. It is important to be sure that the patient is able to tolerate liquids to maintain good hydration. Acetaminophen or lbuprofen may give relief if given in the correct dosage. A heating pad to the abdomen or soaking in a nice warm bath may help.
Mesenteric adenitis typically occurs in children and adolescents. It is not very common after the age of 16 years. Some articles report a very slight increase in boys over girls. It usually lasts a few days and there may be an associated upper respiratory tract infection. When making a diagnosis of mesenteric adenitis it is CRITICAL that the physician rules out other possible causes.
I saw Trent the next afternoon for a follow-up. He was noticeably better. He had no fever and actually had an appetite, although his parents were giving him only clear liquids. There was a mild, almost negligible tenderness in the lower abdomen. Mom thought he had turned the corner. It was confirmed when I asked him what he would like to eat. His reply was, “A big pepperoni pizza!”