What Is Mesenteric Lymphadenitis?

Mesenteric lymphadenitis, which is also known as mesenteric adenitis, involves inflammation of the lymph nodes in the mesentery (part of the small intestine). Predominantly, it occurs in children, teens, and young adults and presents with abdominal pain and fever. It is a self-limiting condition that usually resolves on its own in 2 to 4 weeks with no complications.

Overview

Mesenteric lymphadenitis is a condition that causes the inflammation of the lymph nodes in the mesentery. It is also known as mesenteric adenitis. Lymph nodes are small round clusters of cells that are a part of the body's immune system. They filter out viruses and bacteria, preventing the spread of infection. The mesentery is a thin tissue membrane that connects the intestines to the wall of the abdomen. Mesenteric lymph nodes consist of 100 to 150 lymph nodes that lie between layers of the mesentery.¹ 

Mesenteric lymphadenitis is usually caused by a viral infection. It is rare and can be a painful condition. Since many cases resolve on their own and don't require treatment, it is difficult to determine the exact occurrence of this condition. As physical examination alone in children can be difficult and often gives limited results, imaging studies are required to make the diagnosis.² It can be diagnosed by visualisation of 3 or more lymph nodes on ultrasound or CT imaging.³ 

Mesenteric lymphadenitis is mainly seen in children, adolescents, and young adults. It can occur in both sexes although people assigned male at birth may be slightly more frequently affected than people assigned female at birth. The majority of the time, mesenteric lymphadenitis resolves on its own and is rarely associated with mortality or any complications.³ However, persistently swollen lymph nodes may be an indication of a more serious condition. If a severe bacterial infection has caused the lymph nodes to swell and is left untreated, it may move to the bloodstream and cause sepsis (infection of the blood). Sepsis is considered a life-threatening condition. Hence, it is important to contact a healthcare professional if the swollen lymph nodes persist.

Causes of mesenteric lymphadenitis

Mesenteric lymphadenitis can be divided into either primary or secondary types. Primary mesenteric lymphadenitis is an inflammation of lymph nodes without an identifiable cause. Whereas, secondary mesenteric lymphadenitis is associated with a detectable cause such as an infection.⁴ Yersinia enterocolitica (a bacteria found in raw or undercooked meat) is considered the main causative organism for secondary mesenteric lymphadenitis if caused by infection.³

Other secondary causes of Mesenteric Lymphadenitis include:^3,5

• Infection in the digestive tract, for example, a gastroenteritis infection caused by rotavirus or norovirus, can cause inflammation in the lymph nodes of the mesentery.
• E. coli
• Inflammatory bowel diseases- such as ulcerative colitis and Crohn's disease
• Salmonella
• Tuberculosis
• Appendicitis
• HIV infection

Signs and symptoms of mesenteric lymphadenitis

The presentation of mesenteric lymphadenitis may resemble that of acute appendicitis, intussusception (a condition in which part of the intestine slides into another part of the intestine), constipation, inflammatory bowel diseases, and urinary tract infection. Mesenteric lymphadenitis is a syndrome characterized by right lower abdomen pain due to inflammation of the mesenteric lymph nodes.⁵ Other possible signs and symptoms of mesenteric lymphadenitis include:^3,5

• Abdominal pain, commonly in the lower right side or general abdominal tenderness
• High fever 
• Mesenteric lymph node enlargement
• Nausea and vomiting

Diagnosis

Sometimes mesenteric lymphadenitis causes no symptoms and may be spotted while doing imaging tests for some other cause. The recommended diagnostic workup for anyone presenting with severe abdominal pain includes a complete blood count (CBC), C-reactive protein (CRP), and urine analysis to rule out urinary tract infections. The WBC (white blood cells) and CR-P are often mildly to moderately elevated; however, these laboratory studies will not help the doctor differentiate between a diagnosis of a range of diseases.³ Therefore, imaging techniques are required to confirm whether it is mesenteric lymphadenitis.

The gold standard for diagnosing mesenteric lymphadenitis is an abdominal ultrasonography. Abdominal ultrasound (US), which spares children from radiation exposure, is frequently the first imaging method used in clinical settings. Mesenteric lymphadenitis can be diagnosed by the presence of swollen mesenteric lymph nodes and the absence of an inflamed appendix to rule out appendicitis. The presence of at least one abnormally enlarged lymph node measuring 8 mm or more in its short-axis diameter, or a cluster of three or more lymph nodes measuring more than 5 mm is diagnostic for mesenteric lymphadenitis.⁵ A CT scan can also be used to visualize the enlarged lymph nodes. The use of a CT scan helps in differentiation between normal and enlarged mesenteric lymph nodes and between different causes of mesenteric lymph node enlargement based on morphology, distribution, and enhancement pattern that may give an indication of the underlying condition causing the enlargement.¹ If mesenteric lymphadenitis precedes or occurs in conjunction with diarrhoea, like in the case of infection caused by Yersinia enterocolitica, stool testing is used to detect the bacteria.³

Management and treatment for mesenteric lymphadenitis

Acute mesenteric lymphadenitis is self-limiting and requires no treatment. The abdominal pain usually disappears within 2-3 weeks. 

The initial step of management is to rule out other diseases that may require surgical treatment and therefore, treat them appropriately.³ However, once a diagnosis of mesenteric lymphadenitis has been made, supportive care is recommended, including hydration and pain relief with NSAIDs (like ibuprofen).⁵Antibiotics can be used if the cause of mesenteric lymphadenitis is a moderate or severe bacterial infection.

FAQs

How can I prevent mesenteric lymphadenitis?

The risk of developing mesenteric lymphadenitis caused by infection can be reduced by steps taken to stop the spread of bacteria.

 Precautions that can be taken include:

• Frequent hand washing with the use of soap and water
• Avoid being in close proximity to those who are sick 
• Precautions are taken while preparing food:
  • Wash hands before touching food
  • Keeping food preparation areas clean.
  • Cooking raw food, especially meat, to an internal temperature of 165°F.
  • Using separate utensils and cutting boards for meat and vegetables.

How common is mesenteric lymphadenitis?

Mesenteric lymphadenitis is a rare condition. Since many cases resolve on their own and don't require treatment, it is impossible to determine the exact frequency of incidence.

Who is at risk of mesenteric lymphadenitis?

Mesenteric lymphadenitis is likely more common in children and young adults. It is distinctly uncommon after the age of 20 years.

What can I expect if I have mesenteric lymphadenitis?

Children who have mesenteric lymphadenitis may feel mild pain or a throbbing sensation in their lower right abdomen or elsewhere in their abdomen. A heating pad or warm compress can ease this. The doctor will prescribe painkillers if the patient's pain is severe. They may also experience flu-like symptoms and feel sick. Children will require plenty of rest and hydration when unwell.

Is mesenteric lymphadenitis contagious?

If the cause of mesenteric lymphadenitis is a viral infection, then the virus itself may be contagious.

When should I see a doctor?

As abdominal pain can be common in children and teens, it can be hard to know when to see the doctor. However, some conditions will require immediate medical attention. It is important to contact your doctor immediately if your child has unresolved abdominal pain associated with:

• Fever
• Diarrhoea or vomiting
• Change in bowel habits
• Loss of appetite

Contact the doctor immediately if abdominal pain is a sudden, or severe pain that interferes with sleep.

Summary

Mesenteric lymphadenitis is caused by inflammation of the mesenteric lymph nodes that can have an unknown cause or be due to other infectious, malignant, or inflammatory causes. The inflamed lymph nodes are mostly found in the right lower abdomen region. Symptoms of mesenteric lymphadenitis are similar to those of appendicitis or intussusception and the doctor may require imaging tests, such as an ultrasound or CT scan, to rule them out as they are considered as medical emergencies. Ultrasonography is the best tool to rapidly differentiate mesenteric lymphadenitis from acute appendicitis without exposure to radiation. The diagnosis can be made by visualization of lymph nodes on ultrasound. As the condition mostly resolves on its own, treatment is supported. Treatment mostly consists of rest, hydration, and medication for pain. Mesenteric lymphadenitis has a good prognosis with full recovery in three to four weeks and no associated complications.