Lymphadenitis Health Article

Definition

Lymphadenitis is the inflammation of lymph nodes. It is often a complication of bacterial infections, although it can also be caused by viruses or other disease agents. Lymphadenitis may be either generalized, involving a number of lymph nodes, or limited to a few nodes in the area of a localized infection. Lymphadenitis is sometimes accompanied by lymphangitis, which is the inflammation of the lymphatic vessels that connect the lymph nodes.

Description

The lymphatic system is a network of vessels (channels), nodes (glands), and organs. It is part of the immune system, which protects against and fights infections, inflammation, and cancers. The lymphatic system also participates in the transport of fluids, fats, proteins, and other substances throughout the body. The lymph nodes are small structures that filter the lymph fluid and contain many white blood cells to fight infections. Lymphadenitis is marked by swollen lymph nodes that develop when the glands are overwhelmed by bacteria, virus, fungi, or other organisms. The nodes may be tender and hard or soft and "rubbery" if an abscess has formed. The skin over an inflamed node may be red and hot. The location of the affected nodes is usually associated with the site of an underlying infection, inflammation, or tumor. In most cases, the infectious organisms are Streptococci or Staphylococci. If the lymphatic vessels are also infected, in a condition referred to as lymphangitis, there will be red streaks extending from the wound in the direction of the lymph nodes, throbbing pain, and high fever and/or chills. The child will generally feel ill, with loss of appetite, headache, and muscle aches.

The extensive network of lymphatic vessels throughout the body and their relation to the lymph nodes helps to explain why bacterial infection of the nodes can spread rapidly to or from other parts of the body. Lymphadenitis in children often occurs in the neck area because these lymph nodes are close to the ears and throat, which are frequent locations of bacterial infections in children.

Lymphadenitis is also referred to as lymph node infection, lymph gland infection, or localized lymphadenopathy.

Demographics

Lymphadenitis and lymphangitis are common complications of bacterial infections.

Causes and symptoms

Streptococcal and staphylococcal bacteria are the most common causes of lymphadenitis, although viruses, protozoa, rickettsiae, fungi, and the tuberculosis bacillus can also infect the lymph nodes. Diseases or disorders that involve lymph nodes in specific areas of the body include rabbit fever (tularemia), cat-scratch disease, lymphogranuloma venereum, chancroid, genital herpes, infected acne, dental abscesses, and bubonic plague. Lymphadenitis can also occur in conjunction with cellulitis, which is a deep, widespread tissue infection that develops from a cut or sore. In children, tonsillitis or bacterial sore throats are the most common causes of lymphadenitis in the neck area. Diseases that involve lymph nodes throughout the body include mononucleosis, cytomegalovirus infection, toxoplasmosis, and brucellosis.

The early symptoms of lymphadenitis are swelling of the nodes caused by a build-up of tissue fluid and an increased number of white blood cells resulting from the body's response to the infection. Further developments include fever with chills, loss of appetite, heavy perspiration, a rapid pulse, and general weakness.

Physical examination

The diagnosis of lymphadenitis is usually based on a combination of the child's medical history, external symptoms, and laboratory cultures. The doctor will press (palpate) the affected lymph nodes to see if they are sore or tender, and search for an entry point for the infection, like a scratch or bite. Swollen nodes without soreness are sometimes caused by cat-scratch disease, which is an uncommon illness. In children, if the lymphadenitis is severe or persistent, the doctor may need to rule out mumps, HIV, tumors in the neck region, and congenital cysts that resemble swollen lymph nodes.

Although lymphadenitis is usually diagnosed in lymph nodes in the neck, arms, or legs, it can also occur in lymph nodes in the chest or abdomen. If the child has acutely swollen lymph nodes in the groin, the doctor will need to rule out a hernia in the groin that has failed to reduce (incarcerated inguinal hernia). Hernias occur in 1 percent of the general population; 85 percent of children with hernias are male.

Laboratory tests

The most significant tests are a white blood cell count (WBC) and a blood culture to identify the organism. A high proportion of immature white blood cells indicates a bacterial infection. Blood cultures may be positive, most often for a species of staphylococcus or streptococcus. In some cases, the doctor may order a biopsy of the lymph node to look for unusual infection or lymphoma.

When to call the doctor

If a child develops symptoms of lymphadenitis, he or she should be taken to the doctor or emergency room.