The most common pediatric neck mass is an enlarged lymph node caused by infection. Be careful to consider masquerading lesions such as salivary gland infections, acutely infected congenital lesions, and, most importantly, malignancies.
Cervical lymph nodes drain the skin of the head and neck as well as the entire nasal, oral, and pharyngeal mucosa (Figure 122-2). Submandibular and cervical nodes are most common because they drain much of the oropharynx, including the adenoids and tonsils.3,4 Supraclavicular lymphadenopathy is suspicious for metastasis because it drains the abdomen and thorax.4
Cervical lymph node drainage.
Palpable cervical lymph nodes are found in about 28% to 44% of healthy infants and children, with the incidence peaking in early childhood.3,5,6 Lymph nodes ≤1 cm in children <12 years old are considered normal.7,8 Most lymphadenopathy represents nonspecific reactive hyperplasia, often due to a viral upper respiratory tract infection.9 Lymphadenitis is lymph node inflammation (swelling, tenderness, warmth, erythema) and is most commonly due to viral or bacterial causes. Infection with a pyogenic organism may lead to liquefactive necrosis (suppuration) and abscess formation (Figure 122-3). If the immune system is unable to eradicate a particular organism, macrophages will attempt to contain it, forming a chronic granulomatous lymphadenitis.
Suppurative lymphadenitis. [Reproduced with permission from Shah BR, Lucchesi M, Amodio J (eds): Atlas of Pediatric Emergency Medicine, 2nd ed. © 2013, McGraw-Hill Education, New York, NY, Figure 3-2.]
ACUTE BILATERAL LYMPHADENOPATHY
Acute bilateral lymphadenopathy is usually due to viral infection and is self-limited. Common viruses include rhinovirus, parainfluenza, influenza, respiratory syncytial virus, coronavirus, reovirus, and adenovirus.10 Treatment is symptomatic and expectant.
Alternative viral causes include infectious mononucleosis, characterized by fever, exudative pharyngitis, and significant lymphadenopathy (Figure 122-4). Heterophile antibodies or Epstein-Barr virus–specific immunoglobulin M confirms the diagnosis, and in immunocompetent patients, treatment is symptomatic. The classic viral exanthems associated with lymphadenopathy are measles (Koplik spots, conjunctivitis, and a descending rash) and rubella (associated with Forchheimer spots, rash, and polyarthritis). Acute bilateral lymphadenopathy and oral lesions may also be due to herpes simplex virus (gingivostomatitis) or coxsackie virus (herpangina). Pharyngitis caused by group A Streptococcus is accompanied by cervical lymphadenopathy.11 Bilateral swelling that extends over the jaw suggests parotid gland involvement due to mumps and may be associated with orchitis and a rash.
Infectious mononucleosis typically presents with bilateral lymphadenopathy. A 6-year-old girl demonstrating bilateral lymphadenopathy. [Reproduced with permission from Shah BR, Lucchesi M: Atlas of Pediatric Emergency Medicine. © 2006, McGraw-Hill Education, New York, NY, Figure 11-14.]
ACUTE UNILATERAL LYMPHADENOPATHY
Acute unilateral lymphadenopathy is most often due to bacterial lymphadenitis (Figure 122-5) caused by Staphylococcus aureus and group A Streptococcus.12 Lymph nodes will likely have signs of inflammation, and if an abscess has developed, fluctuance may be appreciated. Often the source of group A Streptococcus is the pharynx, whereas S. aureus originates from a break in the skin. Careful examination of the head, neck, throat, skin, and ears may identify a source that can be cultured.
An infant with unilateral lymphadenitis due to Staphylococcus aureus infection. [Photo Contributed by Dr. J. P. Ludemann, BC Children's Hospital, Vancouver, British Columbia, Canada.]
Generally, lymph nodes <1 cm are normal and do not need treatment. If lymphadenitis measures between 1 and 3 cm, appropriate antibiotics treating group A Streptococcus and Staphylococcus for up to 2 weeks should lead to complete resolution.13 Nodes >3 cm raise suspicion for malignancy, but if the nodes are acute and inflammatory, a course of antibiotics and observation is reasonable.
Due to increasing β-lactamase–resistant Staphylococcus, first-line oral antibiotic choices are first-generation cephalosporins, cloxacillin/dicloxacillin/oxacillin, or clindamycin.12,14,15 If the child is unwell or immunocompromised, treat with IV cefazolin, nafcillin, or clindamycin. Reassess in 48 hours, and if no improvement is appreciated, consider changing antibiotics to treat methicillin-resistant S. aureus.16,17
Fluctuance of the node suggests abscess formation due to pyogenic bacteria, with the source often from the tonsils.15 Fluctuant nodes typically respond to antibiotics alone, but needle aspiration after local anesthesia may be helpful to avoid incision in cosmetically important areas.15 If a superficial abscess is pointing or not resolving within 2 weeks of antibiotics, then evaluation by US and incision and drainage may be necessary.18 When associated with torticollis or trismus, suspect a retropharyngeal abscess, and obtain imaging and/or surgical consultation (see chapter 123, "Stridor and Drooling in Infants and Children").
Infants have a higher incidence of infection with group B Streptococcus rather than S. aureus or group A Streptococcus. Group B streptococcal infection can be associated with bacteremia, pneumonia, and meningitis.19,20 Infections originating from the oral mucosa, seen most commonly in children age 5 to 15 years with periodontal disease, are more likely to contain anaerobic bacteria requiring coverage with penicillin V, amoxicillin-clavulanic acid, or clindamycin.14 Sialoadenitis is characterized by unilateral swelling crossing the jaw and tenderness after meals, and can be associated with purulent discharge from Wharton's and Stensen's ducts (Figure 122-6). Sialolithiasis can cause recurrent infections due to outflow obstruction of the gland.
Sialoadenitis. A. Unilateral swelling crossing the angle of the mandible. B and C. Purulent drainage from Stensen's and Wharton's salivary ducts, respectively. [Reproduced with permission from Knoop KJ, Stack LB, Storrow AB: Atlas of Emergency Medicine, 2nd ed. © 2002, McGraw-Hill, New York, Figures 5-32 and 5-33.]
Chronic lymphadenopathy is defined as persistence for 6 weeks without resolution. Persistent lymphadenopathy, generalized lymphadenopathy, or failure to respond to 2 to 4 weeks of antibiotics requires evaluation for uncommon infectious, congenital, and neoplastic causes. Persistent infectious agents evade eradication by granuloma formation. Generally, the course of evolution is slower than a typical inflammatory lymphadenitis and may be characterized by a violaceous overlying skin change. Refer to otolaryngology for definitive diagnosis and management.21,22,23 Refer immunocompromised patients to an infectious disease specialist. Some of the more common causes of granulomatous lymphadenitis are covered below.
Chronic cervical lymphadenitis may be due to tuberculous (Mycobacterium tuberculosis) or nontuberculous mycobacterial strains. Clinically, both varieties of lymphadenitis are characterized by a chronic, minimally tender, "cold abscess," with overlying violaceous skin. Spontaneous drainage can transform into a chronic draining sinus.22 It is important to differentiate between tuberculous and nontuberculous strains because treatment is different. Differential Mantoux testing with a combination of antigens can identify strains in about 93% of patients.24 Consider M. tuberculosis lymphadenitis in children with risk of tuberculosis exposure, in those exhibiting constitutional signs, and in those with an abnormal chest x-ray and with a strongly reactive purified protein derivative skin test,25 and treat for 8 to 12 months. Treatment for nontuberculous lymphadenitis is surgical excision.26
Cat-scratch disease is caused by Bartonella henselae, with inoculation by a scratch or a bite from a kitten. The inoculation site develops into a painless, erythematous vesicle or pustule after 3 to 10 days, which may disappear before other symptoms develop. After 1 to 3 weeks, regional lymphadenopathy typically develops. Suppuration is uncommon. Diagnosis involves serologic testing, but because antibody development may be delayed and the primary lesion may have resolved, rely on a strong history of cat exposure and an inoculating lesion. No treatment is needed. Serious complications (encephalitis) can develop in immunodeficient patients, with treatment options based primarily on case reports.
Toxoplasma gondii is a protozoan parasite with a complex life cycle that can infect humans through ingestion of undercooked meat, exposure to oocysts in cat feces, or through maternal-fetal transmission (congenital toxoplasmosis). Infection is widespread; an estimated 22.5% of children in the United States are infected by the age of 12 years old; in some countries, up to 95% of the population has been infected. The lymphatic system is the most common organ system involved. Diagnosis is usually made serologically with antibody titers. Treatment is not typically needed in healthy children.
Tularemia is caused by the bacteria Francisella tularensis, which is transmitted by arthropod bites, handling infected animals (classically rabbits), and contaminated food and water. The most common forms are ulceroglandular and glandular tularemia. In the ulceroglandular form, the inoculation site develops from an erythematous tender papule into an exudative ulcer within days. Regionally draining lymphadenopathy subsequently develops that may spontaneously suppurate and drain if not treated. Tularemia is diagnosed serologically with microagglutination testing. Gentamicin is the treatment of choice.
Other causes of cervical lymphadenopathy include recent immunizations (diphtheria, pertussis, and tetanus; polio; typhoid), blood transfusions (causing Epstein-Barr virus, cytomegalovirus, or human immunodeficiency virus exposure), various medications (including phenytoin, carbamazepine, isoniazid, and hydralazine) and systemic disease (Kawasaki's disease; sarcoid; periodic fever, aphthous stomatitis, pharyngitis, and adenitis; and autoimmune) (Tables 122-1 and 122-2).