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Emergency and Acute Medicine – Lymphadenopathy and Fever
Overview and Definitions
Lymphadenitis refers to inflammation of one or more lymph nodes, while lymphangitis involves inflammation of lymphatic channels; both may occur in acute or chronic disease. Mesenteric lymphadenitis results from inflammation of mesenteric nodes and may clinically mimic acute appendicitis. In most regions, lymph nodes larger than 1 cm are abnormal; epitrochlear nodes greater than 0.5 cm and inguinal nodes greater than 1.5–2 cm are considered enlarged, although palpable inguinal nodes are common in healthy adults. Generalized lymphadenopathy is defined as involvement of two or more noncontiguous nodal regions.
Clinical Approach
Fever commonly accompanies lymphadenopathy, with infection being the leading cause. Lymph node enlargement may be incidental or the primary presenting feature, and clinicians must determine whether observation or further investigation is required. A detailed history and comprehensive physical examination are essential. Duration is informative, as suppurative infections usually present within one week, whereas chronic lymphadenopathy suggests infections such as HIV or tuberculosis, malignancy, inflammatory, or autoimmune disease. Epidemiologic factors including travel, sick contacts, and animal exposure should be assessed. Associated symptoms include weight loss, fever, night sweats, sore throat, cough, pruritus, fatigue, lymph node pain, and myalgia or arthralgia. Examination should include all nodal regions to determine whether disease is localized or generalized, along with abdominal assessment for hepatosplenomegaly. Findings such as anemia, petechiae, or bleeding suggest bone marrow infiltration. While many infections cause fever with lymphadenopathy, pathogens such as Francisella tularensis, Bartonella henselae, and mycobacteria often present with a single prominent lymph node and fever.
Epidemiology
More than two-thirds of patients presenting to primary care with lymphadenopathy have nonspecific or upper respiratory causes. The likelihood of malignancy increases with age, particularly over 50 years. In primary care, approximately 1% of patients with lymphadenopathy have an underlying malignancy. Acute mesenteric lymphadenitis is more common in children. In developed countries, mycobacterial lymphadenopathy is more often due to nontuberculous species.
Etiology
Infectious causes include viral infections such as Epstein–Barr virus, cytomegalovirus, herpes simplex virus, dengue, rubella, measles, HIV, and West Nile virus; bacterial infections including streptococci, Staphylococcus aureus, Bartonella henselae, brucellosis, tularemia, plague, melioidosis, tuberculosis, nontuberculous mycobacteria, listeriosis, leptospirosis, secondary syphilis, diphtheria, typhoid fever, and lymphogranuloma venereum; fungal infections such as histoplasmosis, coccidioidomycosis, paracoccidioidomycosis, and cryptococcosis; parasitic infections including toxoplasmosis, leishmaniasis, trypanosomiasis, and filariasis; and rickettsial diseases. Immunologic causes include systemic lupus erythematosus, rheumatoid arthritis, vasculitides, Still’s disease, dermatomyositis, graft-versus-host disease, juvenile idiopathic arthritis, mixed connective tissue disease, serum sickness, and Sjögren’s syndrome. Malignant causes include Hodgkin and non-Hodgkin lymphomas, acute and chronic leukemias, hairy cell leukemia, amyloidosis, sarcomas, and metastatic disease. Other causes include lipid storage disorders, endocrine diseases such as hyperthyroidism and Addison disease, Castleman disease, Kikuchi disease, drug reactions, familial Mediterranean fever, and Kawasaki disease. In HIV infection, lymphadenopathy ranges from early follicular hyperplasia to opportunistic infections and malignancies, with common causes including lymphoma, mycobacterial infection, toxoplasmosis, systemic fungal infection, and bacillary angiomatosis.
Diagnostic Evaluation
Assessment of lymph nodes should document size, shape, consistency, mobility, and tenderness. Hard nodes suggest carcinoma, rubbery firm non-tender nodes are typical of lymphoma, and tender mobile nodes usually indicate reactive infection. Some malignancies, such as acute leukemia, may cause rapid enlargement with pain. Initial laboratory evaluation should be guided by risk factors and may include blood cultures, HIV testing, syphilis serology, heterophile antibody testing, toxoplasma, CMV, EBV serologies, Bartonella serology, urine histoplasma antigen, autoimmune markers, and other targeted tests. Fine-needle aspiration can be useful, but excisional biopsy provides superior diagnostic yield, particularly for lymphoma. Lymph node specimens should be evaluated with cultures, mycobacterial and fungal stains, cytology, and molecular diagnostics. Chest radiography may reveal pulmonary or mediastinal involvement. Ultrasonography is useful for superficial nodes, while CT or MRI better evaluate deep nodal disease and guide biopsy. PET imaging identifies metabolically active nodes. In the absence of high-risk features, observation for 2–4 weeks is appropriate, with biopsy indicated if lymphadenopathy persists.
Management
Treatment depends on the underlying etiology and should be directed at the identified cause. Empiric therapy may be required in severe infection, while malignancy or autoimmune disease requires disease-specific management.
Follow-Up and Prognosis
In patients without features concerning for malignancy or severe infection, clinical observation for 2–4 weeks after initial evaluation is appropriate before proceeding to biopsy.
Complications
Delayed diagnosis or treatment of infectious lymphadenopathy may lead to disseminated or severe infection.
Overview and Definitions
Lymphadenitis refers to inflammation of one or more lymph nodes, while lymphangitis involves inflammation of lymphatic channels; both may occur in acute or chronic disease. Mesenteric lymphadenitis results from inflammation of mesenteric nodes and may clinically mimic acute appendicitis. In most regions, lymph nodes larger than 1 cm are abnormal; epitrochlear nodes greater than 0.5 cm and inguinal nodes greater than 1.5–2 cm are considered enlarged, although palpable inguinal nodes are common in healthy adults. Generalized lymphadenopathy is defined as involvement of two or more noncontiguous nodal regions.
Clinical Approach
Fever commonly accompanies lymphadenopathy, with infection being the leading cause. Lymph node enlargement may be incidental or the primary presenting feature, and clinicians must determine whether observation or further investigation is required. A detailed history and comprehensive physical examination are essential. Duration is informative, as suppurative infections usually present within one week, whereas chronic lymphadenopathy suggests infections such as HIV or tuberculosis, malignancy, inflammatory, or autoimmune disease. Epidemiologic factors including travel, sick contacts, and animal exposure should be assessed. Associated symptoms include weight loss, fever, night sweats, sore throat, cough, pruritus, fatigue, lymph node pain, and myalgia or arthralgia. Examination should include all nodal regions to determine whether disease is localized or generalized, along with abdominal assessment for hepatosplenomegaly. Findings such as anemia, petechiae, or bleeding suggest bone marrow infiltration. While many infections cause fever with lymphadenopathy, pathogens such as Francisella tularensis, Bartonella henselae, and mycobacteria often present with a single prominent lymph node and fever.
Epidemiology
More than two-thirds of patients presenting to primary care with lymphadenopathy have nonspecific or upper respiratory causes. The likelihood of malignancy increases with age, particularly over 50 years. In primary care, approximately 1% of patients with lymphadenopathy have an underlying malignancy. Acute mesenteric lymphadenitis is more common in children. In developed countries, mycobacterial lymphadenopathy is more often due to nontuberculous species.
Etiology
Infectious causes include viral infections such as Epstein–Barr virus, cytomegalovirus, herpes simplex virus, dengue, rubella, measles, HIV, and West Nile virus; bacterial infections including streptococci, Staphylococcus aureus, Bartonella henselae, brucellosis, tularemia, plague, melioidosis, tuberculosis, nontuberculous mycobacteria, listeriosis, leptospirosis, secondary syphilis, diphtheria, typhoid fever, and lymphogranuloma venereum; fungal infections such as histoplasmosis, coccidioidomycosis, paracoccidioidomycosis, and cryptococcosis; parasitic infections including toxoplasmosis, leishmaniasis, trypanosomiasis, and filariasis; and rickettsial diseases. Immunologic causes include systemic lupus erythematosus, rheumatoid arthritis, vasculitides, Still’s disease, dermatomyositis, graft-versus-host disease, juvenile idiopathic arthritis, mixed connective tissue disease, serum sickness, and Sjögren’s syndrome. Malignant causes include Hodgkin and non-Hodgkin lymphomas, acute and chronic leukemias, hairy cell leukemia, amyloidosis, sarcomas, and metastatic disease. Other causes include lipid storage disorders, endocrine diseases such as hyperthyroidism and Addison disease, Castleman disease, Kikuchi disease, drug reactions, familial Mediterranean fever, and Kawasaki disease. In HIV infection, lymphadenopathy ranges from early follicular hyperplasia to opportunistic infections and malignancies, with common causes including lymphoma, mycobacterial infection, toxoplasmosis, systemic fungal infection, and bacillary angiomatosis.
Diagnostic Evaluation
Assessment of lymph nodes should document size, shape, consistency, mobility, and tenderness. Hard nodes suggest carcinoma, rubbery firm non-tender nodes are typical of lymphoma, and tender mobile nodes usually indicate reactive infection. Some malignancies, such as acute leukemia, may cause rapid enlargement with pain. Initial laboratory evaluation should be guided by risk factors and may include blood cultures, HIV testing, syphilis serology, heterophile antibody testing, toxoplasma, CMV, EBV serologies, Bartonella serology, urine histoplasma antigen, autoimmune markers, and other targeted tests. Fine-needle aspiration can be useful, but excisional biopsy provides superior diagnostic yield, particularly for lymphoma. Lymph node specimens should be evaluated with cultures, mycobacterial and fungal stains, cytology, and molecular diagnostics. Chest radiography may reveal pulmonary or mediastinal involvement. Ultrasonography is useful for superficial nodes, while CT or MRI better evaluate deep nodal disease and guide biopsy. PET imaging identifies metabolically active nodes. In the absence of high-risk features, observation for 2–4 weeks is appropriate, with biopsy indicated if lymphadenopathy persists.
Management
Treatment depends on the underlying etiology and should be directed at the identified cause. Empiric therapy may be required in severe infection, while malignancy or autoimmune disease requires disease-specific management.
Follow-Up and Prognosis
In patients without features concerning for malignancy or severe infection, clinical observation for 2–4 weeks after initial evaluation is appropriate before proceeding to biopsy.
Complications
Delayed diagnosis or treatment of infectious lymphadenopathy may lead to disseminated or severe infection.
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