Extended diagnostic workup for lymphadenopathy is guided by the specific risk factors in the history and physical examination findings. Chest radiograph, throat culture, antistreptolysin O titer, and serologic tests for CMV, toxoplasmosis, syphilis, tularemia, Brucella, histoplasmosis, and coccidioidomycosis may be indicated. Genital tract evaluation and specimens should be obtained with regional inguinal lymphadenopathy (see Chapter 116). Screening for tuberculosis can be performed using the standard tuberculin skin test or an interferon gamma release assay; both may be positive with atypical mycobacterial infection.
Aspiration is indicated for acutely inflamed, fluctuant cervical lymph nodes, especially those larger than 3 cm in diameter or not responding to antibiotic treatment. Ultrasound orcomputed tomography may help in establishing the extent oflymphadenopathy and defining whether the mass is solid, cystic, or suppurative with abscess formation. Pus from fluctuantlesions should be examined by Gram and acid-fast stains andcultured for aerobic and anaerobic bacteria and mycobacteria. Biopsy should be performed if lymphoma is suspectedbecause of firm, matted, nontender nodes and other systemicfindings.
If the diagnosis remains uncertain and lymphadenopathy persists despite empirical antibiotic therapy for presumed S. aureus and group A streptococcus, excisional biopsy of the entire node should be performed, if possible. This is curative for nontuberculous mycobacterial lymphadenitis. Biopsy material should be submitted for histopathology as well as Gram, acid-fast, Giemsa, periodic acid-Schiff, Warthin-Starry silver (B. henselae), and methenamine silver stains. Cultures for aerobic and anaerobic bacteria, mycobacteria, and fungi should be performed.
1:320 1:160 1:80 1:40
Figure 99-1 The development of antibodies to vari-1:20 ous Epstein-Barr virus antigens in patients with infectious mononucleosis. The titers are geometric mean values expressed as reciprocals of the serum dilution. The IgM 1:10 response to viral capsid antigen (VCA) is divided because of the significant differences noted according to the age of the patient. (From Jenson HB, Ench Y: Epstein-Barr virus. In Rose NR, Hamilton RG, Detrick B: Manual of Clinical Laboratory Immunology, ed 7, Washington DC, 2006, American Society for Microbiology Press, p 640.)
Noninfectious causes of cervical swelling and/or lymphadenopathy include congenital and acquired cysts, Kawasakidisease, sarcoidosis, benign neoplasms, and malignancies.The differential diagnosis for generalized lymphadenopathy includes juvenile idiopathic arthritis; systemic lupuserythematosus; and serum sickness and other adverse drugreactions, especially with phenytoin and other antiepileptic medications, allopurinol, isoniazid, antithyroid medications, and pyrimethamine. Leukemia, lymphoma, and occasionally neuroblastoma may have lymph nodes that areusually painless, uninflamed, matted, and firm (see Chapters 155 and 156). A syndrome of periodic fever, aphthous stomatitis, pharyngitis, and adenitis is an occasional cause of recurrent fever and cervical lymphadenitis (seeChapter 103).