Lymphadenitis
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.
Diagnosis
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
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.
Treatment
Medications
The medications given for lymphadenitis vary according to the bacterium or virus that causes it. For bacterial infections, the child will be treated with antibiotics , usually a penicillin, clindamycin, a cephalosporin, or erythromycin.
Supportive care
Supportive care of lymphadenitis includes resting the affected area and applying hot moist compresses to reduce inflammation and pain.
Surgery
Cellulitis associated with lymphadenitis should not be treated surgically because of the risk of spreading the infection. Pus is drained only if there is an abscess and usually after the child has begun antibiotic treatment. In some cases, biopsy of an inflamed lymph node is necessary if no diagnosis has been made and no response to treatment has occurred.
Inflammation of lymph nodes due to other diseases requires treatment of the underlying causes.
Prognosis
The prognosis for recovery is good if the child is treated promptly with antibiotics. In most cases, the infection can be brought under control in three or four days. However, in some cases it may take weeks or months for swelling to disappear; the length of recovery depends on the underlying cause of the infection. Children with untreated lymphadenitis may develop abscesses, cellulitis, or blood poisoning (septicemia), which is sometimes fatal.
Prevention
Prevention of lymphadenitis depends on prompt treatment of bacterial and viral infections.
Parental concerns
Parents may be concerned that enlarged lymph nodes in their child are malignant. They should seek immediate medical attention for the child so concerns can be addressed in a timely manner.
KEY TERMS
Hernia —A rupture in the wall of a body cavity, through which an organ may protrude.
Lymph nodes —Small, bean-shaped collections of tissue located throughout the lymphatic system. They produce cells and proteins that fight infection and filter lymph. Nodes are sometimes called lymph glands.
Lymphangitis —Inflammation of the lymphatic vessels. It often occurs together with lymphadenitis (inflammation of the lymph nodes).
Septicemia —A systemic infection due to the presence of bacteria and their toxins in the bloodstream. Septicemia is sometimes called blood poisoning.
Streptococcus —Plural, streptococci . Any of several species of spherical bacteria that form pairs or chains. They cause a wide variety of infections including scarlet fever, tonsillitis, and pneumonia.
Resources
BOOKS
Mandal, B., et al. Lecture Notes on Infectious Disease. Oxford, UK: Blackwell Publishing, 2004.
WEB SITES
Lymphadenitis. Available online at: http://www.emedicine.com/ped/topic32/htm.
Judith Sims Rebecca J. Frey, Ph.D.