It is estimated that up to 20 percent of children who are diagnosed with acute appendicitis actually do not have appendicitis, but acute mesenteric lymphadenitis - also called non-specific mesenteric adenitis.
Mesenteric lymphadenitis is the inflammation of the lymph nodes on the wall of the mesentery (the covering of the intestines) in the absence of appendicitis, leading to abdominal pain.
In some children, there will be associated nausea, vomiting and fever.
Typically, the child with mesenteric adenitis will look well, or just mildly unwell, yet with complaints of abdominal pain.
Our intestines are clasped and hung in place by a sheet of thick membrane like a free-flowing towel called the mesentery. This allows the intestines to be free to move as well as fixed to the floor of back of our abdomen.
The mesentery contains arteries, veins and lymph nodes.
Like lymph nodes elsewhere in the body, they swell to produce and recruit white blood cells to fight off invading bacteria, fungi or virus if we catch an infection. You almost certainly must have had one of such swollen lymph nodes or glands in your neck sometime in the past when you had a very bad cold.
When lymph nodes along the edge of the mesentery of your child swells in response to an infection, it can cause abdominal pain. This is what is referred to as mesenteric lymphadenitis (inflammation of the lymph nodes along the mesentery).
The following are the usual causes of mesenteric lymphadenitis:
Several studies have shown that up to 60 percent of mesenteric lymphadenitis are caused by viruses. The common cold viruses are the most implicated, including:
Bacteria contamination of food can mesenteric lymphadenitis. The following are the often implicated bacteria causing mesenteric adenitis. They include:
While Streptococcus viridans, Campylobacter and Pseudo tuberculosis infection are common world wide, infection by Yersinia enterocolitica is mostly found in the cold regions of the world, especially in Europe and America.
Parasitic protozoa has also been shown to cause mesenteric adenitis. These include:
Any of these infections - virus, bacteria or parasite can get into our intestine and get trapped inside the lymph nodes on the mesentery and trigger and inflammation, leading to the enlargement of the lymph nodes and the symptoms of mesenteric lymphadenitis.
Mesenteric adenitis is more common in the first 10 years of life, especially before the 6th birthday. It affects boys and girls equally, although Yersinia-linked infections are seen more in boys.
The signs and symptoms of mesenteric lymphadenitis are very similar to those of appendicitis, except for some subtle differences.
They include :
Is mesenteric lymphadenitis painful? Yes. Abdominal pain is the most frequent symptom of mesenteric lymphadenitis. The following are the characteristics of the pain in lymphadenitis of the mesentery.
One symptom that gives away the diagnosis of mesenteric lymphadenitis is that of the presence of cold or sore throat in the days or week before the onset of abdominal pain.
There may even still be an on going cough and cold in the child. The neck glands, if examined may be swollen.
About half of children with mesenteric lymphadenitis would have associated fever.
The degree of fever may vary from very mild - 37.5 to 39, but averages 38 degrees Celsius.
A few patients with mesenteric lymphadenitis will vomit. Those who vomit tend to do so very early in the course of their illness and around when they start complaining of pain in the abdomen.
Appendicitis is most unlikely if a child vomits before onset of abdominal pain. This is usually a late symptom in acute appendicitis.
Diarrhoea is one of the not very frequent but possible symptoms your child could have if suffering with mesenteric lymphadenitis. This is even more so in the case of Yersinia induced infection. Recent pork ingestion is also a pointer to possible Yersinia infection as the culprit.
Children with acute appendicitis can also suffer with diarrhoea, but this is often a later symptom and the diarrhoea in acute appendicitis is usually mild.
More often than not, with mesenteric lymphadenitis, your child would still be able to eat and drink. Appetite is more likely to be preserved. If a your child complains of abdominal pain and his or her appetite remains good, it is mesenteric lymphadenitis. In acute appendicitis, appetite is lost pretty quickly and in most cases.
Nothing is more distressing than to see your child suffering with pain in the abdomen and doctors trying to make up their mind if this is a case of acute appendicitis that requires an immediate operation or if this is a case of acute mesenteric lymphadenitis that does not require a surgical operation.
The main aim of the doctor is to establish that this is indeed an adenitis of the mesenteric lymph glands and not a more serious condition like:
Or indeed any other condition that mimics acute non-specific mesenteric lymphadenitis that may require surgery or other form of specific intervention. You can see a list of conditions that mimics mesenteric lymphadenitis here.
To make a firm diagnosis of acute mesenteric lymphadenitis, at least all the following 3 conditions must be met:
In other to arrive at this findings, the following tests need to be done:
This is a simple quick blood test routinely done for many conditions. Also called complete blood count, it is a test that shows the amount and quality of the components of blood itself - the amount of red blood cells, white blood cells, platelets, and percentage of plasma.
In most cases of acute inflammation or infection, the white blood cell (WBC) count will be raised, particularly the subtypes called the neutrophils and sometimes the lymphocytes.
This test will not tell us much except that there is evidence of infection. In the first day or two, there will be increase in white blood cells (leucocytosis) which settles on the third day, while in acute appendicitis, the white blood cell count increases with every day of infection until the diseased appendix is removed or treated with antibiotics.
This is also a blood test.
Where there is a history of recent pork consumption or if you live in an area where there is an outbreak of Yersinia infection, a Yersinia serology may be necessary to make a diagnosis of Yersinia enterocolitica mesenteric adenitis.
This is even more so if your child has diarrhea as well as right lower abdominal pain, anorexia and fever.
This is a test to check the urine of your child to be sure that his or her symptoms are not due to a urinary tract infection - infection involving the bladder or kidneys.
Your child will be required to pass urine sample which is tested for the presence or absence of blood, leucocytes and nitrates as well as ketones and sugar.
Acute DKA or diabetic ketoacidosis can mimic mesenteric lymphadenitis in children as well as acute appendicitis and UTI.
This is often the first preferred investigation in children, since it is non –invasive, and there is no exposure to radiation (X-rays).
It may help demonstrate small pebble shaped and sized hypo-echoic 5 to 8 mm nodules, which will be quite different from the surrounding tissues. Thickening of the mesentery will also support a diagnosis of mesenteric adenitis.
As well as the presence of these swollen lymph nodes, the appendix will show normal signs with no evidence of inflammation to make a diagnosis of acute mesenteric lymphadenitis.
With the huge improvement in CT scan technology, providing better resolution with lesser amount of radiation exposure, as well as its increased available in many countries, a CT scan is almost routine now in the investigation of abdominal pain.
A new onset pain in the right lower abdomen is certainly an indication for the use of CT scan. This will help increase the chances of a definite diagnosis and avoid an unnecessary surgical operation.
In acute mesenteric lymphadenitis, a CT scan with both oral and intravenous contrast is necessary.
A contrast CT will demonstrate enlarged mesenteric lymph nodes. The contrast helps to differentiate the lymph nodes from blood vessels better than when a contrast or dye is not used. CT scan is better able to measure the lymph nodes to be greater than 5 mm in size to be classified as enlarged, in the mesentery.
This plus a normal appendix helps in the confirmation of this condition.
A barium enema is rarely necessary in the workup for the diagnosis of mesenteric lymphadenitis. It is nevertheless an option available in countries where access the CT scan is limited.
Barium enema done for lymphadenitis of the mesentery may show indentation of the bowel walls from pressure by the enlarged mesenteric lymph nodes.
If the diagnosis is still in doubt, a laparoscopy may lay it to rest.
At laparoscopy, the lymph nodes surrounding the terminal ileum and colon may be found to be more in number and enlarged, with swelling of the mesentery, and a normal looking appendix.
One or two enlarged lymph nodes could be harvested and cultured as well as examined under the microscope (histology) to determine the exact cause of the lymphadenitis is desired.
Mesenteric lymphadenitis is usually a benign illness, which will get better on its own without treatment.
Once the diagnosis is confirmed, the approach to treatment will depend on what is suspected to be the exact cause of the lymphadenitis.
The following are the treatment options for acute mesenteric lymphadenitis depending on what the presumed or confirmed cause is:
If your child had cold symptoms followed by complaints of pain in his or her right lower abdomen, then the most likely cause is virus. As stated above, cold viruses are the most frequent causes of acute non-specific mesenteric lymphadenitis.
In such a case, treatment will be mainly symptomatic or supportive. Treatment will include:
If you live in an area where Yersinia infection outbreak is declared or common or if there your child had eaten pork in the past few days, then Yersinia infection is likely.
The best treatment option for Yersinia infection involve the use of the following antibiotics:
Protozoa induced mesenteric adenitis can be treated with the appropriate anti-protozoan medication.
A few cases of mesenteric lymphadenitis could be serious and a broad spectrum antibiotics as well as intravenous fluid administration may be necessary or even outright surgical operation to remove a section of diseased bowel plus the appendix.
Is mesenteric lymphadenitis serious? This is a commonly asked question. The short answer is no. It is not serious usually.
Most children who develop this condition will get well without any intervention in a few days or up to 4 weeks. However, in a few cases, it could led to serious infection needing treatment as stated above.
The ICD10 diagnostic code for mesenteric lymphadenitis or adenitis is 188.0 and the ICD 9 CM code for this condition is 289.2.