What Is Mesenteric Adenitis?

Mesenteric adenitis, also known as mesenteric lymphadenitis, is a secondary syndrome caused by inflammation of the lymph nodes found in a membrane fold that joins the intestines to the abdominal wall, known as the mesentery. The main symptom of mesenteric adenitis is pain in the lower right side of the abdomen.

This article discusses the symptoms, causes, and treatment options for mesenteric adenitis.

Types of Mesenteric Adenitis

There are two types of mesenteric adenitis: primary and secondary. Primary mesenteric adenitis develops without inflammatory processes in the abdomen, whereas secondary is directly associated with inflammation of the mesentery.

What Are the Symptoms of Mesenteric Adenitis?

Mesenteric lymph nodes are located within the abdomen and are part of the lymphatic system. They produce white blood cells, lymphocytes, that help the immune system fight infection and disease. Lymph nodes also aid immunity by filtering out harmful pathogens, such as bacteria, from the body. 

When these lymph nodes become inflamed, mesenteric adenitis and its symptoms can develop, which include:

• Fever
• Severe pain and tenderness in the lower right side of the abdomen
• Pain that is constant and sharp
• Tenderness in the upper part of the abdomen below the rib cage
• Vomiting or nausea
• Diarrhea or constipation

Some of these symptoms can present similarly to appendicitis, but the two are different conditions.

What Causes Mesenteric Adenitis?

Primary mesenteric adenitis is idiopathic, meaning it develops for no known reason. When there are no abnormalities or heightened levels of inflammation in the abdomen causing the symptoms of mesenteric adenitis, it is considered primary.

Secondary, on the other hand, can be caused by a variety of factors, including:

• Inflammatory bowel diseases (IBD, including Crohn's disease and ulcerative colitis)
• Chronic inflammatory diseases such as sarcoidosis and systemic lupus erythematosus (lupus)
• Human immunodeficiency virus (HIV)
• Tuberculosis (serious illness mainly affecting the lungs)
• Infections such as mononucleosis (viral infection causing fever, sore throat, and swollen lymph glands), salmonella poisoning (bacterial infection caused by eating raw or undercooked meat and certain other foods), and yersiniosis (bacterial infection caused by eating raw or undercooked pork)
• Viral infections that cause inflammation of the ileum, which sits at the lowermost part of the small intestine
• Typhoid fever (or enteric fever, an illness caused by Salmonella bacteria)
• Stomach flu (viral gastroenteritis)

These infections cause the lymph nodes to swell when the body tries to filter them out of its system.

How Is Mesenteric Adenitis Diagnosed?

It often is difficult for healthcare providers to diagnose mesenteric adenitis because it presents similarly to appendicitis. Because of that, the diagnostic process starts by ruling out other, more dangerous health conditions.

When proper diagnostics rule out appendicitis, healthcare providers will conduct an ultrasound of the abdomen to determine if the mesenteric lymph nodes are inflamed. Typically, if the mesenteric lymph nodes are 8 millimeters in diameter or larger, you will be diagnosed with mesenteric adenitis.

Other tests used to confirm a diagnosis include:

• X-rays of the abdomen to check for excessive levels of fluids, masses, gasses, or obstructions
• Computed tomography (CT) scans (a series of X-ray images)
• A complete blood count (CBC) test to check for levels of immune cells

How Is Mesenteric Adenitis Treated?

Once healthcare providers have diagnosed mesenteric adenitis properly, they will create a treatment plan. Managing symptoms and treating the underlying cause is the mainstay therapy for the syndrome.

To treat the pain, healthcare providers will prescribe Tylenol (acetaminophen) pain medications. Nonsteroidal anti-inflammatories (NSAIDs), such as Advil or Motrin (ibuprofen), may also be used in combination with acetaminophen to reduce inflammation while managing pain.

Other methods of managing the condition include:

• Keeping hydrated
• Antibiotics for those with bacterial infections that led to mesenteric adenitis
• Using over-the-counter (OTC) fever and pain medications, such as Tylenol or Motrin and Advil

How to Cope With Mesenteric Adenitis

Coping with the pain associated with mesenteric adenitis can be challenging but not impossible. To cope with the symptoms while the syndrome heals, do the following:

• Get lots of rest.
• Drink lots of fluids, especially if vomiting and diarrhea have occurred.
• Use a warm water bottle or electric heating pad on painful areas.
• Take any pain medications, either prescribed or OTC, as directed.
• Take any antibiotics as prescribed to help rid the body of the infection that caused mesenteric adenitis.

Summary

Mesenteric adenitis is a non-life-threatening syndrome caused by inflammation of the lymph nodes found in the abdomen. It typically affects children, adolescents, and young adults following an infection. The symptoms—mainly pain and tenderness in the lower right part of the abdomen—mimic appendicitis.

Mesenteric adenitis will go away over time as the infection that causes it clears up. In the meantime, you can use prescribed or OTC pain and fever medications to manage symptoms. Hydration and rest are also important while recovering from mesenteric adenitis.