Chapter 33: Lymphadenopathy

Patient Story

A 2-year-old girl presented to her pediatrician with a one month history of swollen glands in her neck and under her arms. Physical examination revealed non-tender firm lymphadenopathy in the anterior and posterior lymph node chains bilaterally (Figure 33-1). Work-up revealed anemia, neutropenia and thrombocytopenia. Biopsy of the lymph nodes and bone marrow biopsy showed acute lymphoblastic leukemia. She underwent induction chemotherapy and has responded well.

Introduction

Lymphadenopathy refers to nodes that are abnormal in either size, consistency, or number. In children, causes of lymphadenopathy can be divided into two large groups-inflammatory versus malignant. Cervical adenopathy due to inflammatory causes is by far the most common. Malignancy is less common but must be considered in the differential diagnosis based on certain concerning features in the history and physical exam.

Synonyms

Lymphadenitis, lymph node enlargement.

Epidemiology

• Almost all children develop lymphadenopathy at some point during childhood with nearly 2/3 of them developing enlarged nodes within infancy.²

Etiology and Pathophysiology

• Lymph nodes are organized centers of immune cells that filter antigenic material such as infectious agents from lymphatics draining from areas of inflammation.

• When activated due to infection or antigenic stimulation, the nodes enlarge in size largely due to proliferation of cells intrinsic to the node such as plasma cells, macrophages, and others.

• Enlargement of nodes can also occur due to infiltration of malignant cells.²

Risk Factors

• Risk factors for inflammatory causes of lymphadenopathy are most commonly associated with exposure to pathogens.

• Viral illnesses that lead to lymphadenopathy are common in childcare centers.

• Parasitic and atypical infections can occur from a variety of exposures, including Bartonella henselae infection from a cat scratch and toxoplasmosis from exposure to cat feces.

• Lymphadenopathy associated with human immunodeficiency virus (HIV) infection can result from perinatal exposure, exposure to intravenous drug use, or unprotected sexual behavior.

• Certain infectious etiologies of lymphadenopathy can be regional in nature, such as exposure to coccidiomycosis in the southwest US and histoplasmosis exposure in the southeastern or central US.

• Medications, such as phenytoin or penicillin, can be associated with the development of lymphadenopathy.

• Odontogenic infections may cause a lymphadenopathy adjacent to the site of the infection.

• Risk factors for malignant causes of lymphadenopathy include exposures to Epstein-Barr virus (EBV) in cases of lymphoma or nasopharyngeal carcinoma.

Diagnosis

Clinical Features

• Localized lymphadenopathy occurs in 75 percent of the cases and generalized lymphadenopathy ...