A child may present with a complaint of swelling or masses in the neck. In such a case apart from a complete history from the parent and a detailed physical examination some of the laboratory workup is important to reach a proper diagnosis and then appropriate management.
CBC with Differentials: May show an elevated WBC count in infectious processes, including cervical adenitis, retropharyngeal abscess and peritonsillar abscess. The test should also be performed if malignancy is suspected.
Blood Chemistries: including renal and hepatic function tests and urinalysis.
Blood culture: can help guide to proper antibiotics if positive.
Gram stain, areobic and anareobic cultures: can be obtained through needle aspiration or incision and drainage; may reveal causative agent in the diagnosis of acute cervical lymphadenitis or abscess.
Purified protein derivative ( PPD ) skin testing: it is recommended for children with subacute or chronic cervical lymphadenitis to rule out Mycobacterium tuberculosis especially if risk factors are present or there is poor response to initial treatment.
Other laboratory tests: depending on the history and physical examination specific tests may be considered for example Bartonella henselae for cat scratch disease and Monospot test for EBV.
Histopathologic evaluation of tissue: is performed following excisional biopsies to rule out malignancy.
Radiographic and other studies
Lateral X-ray neck: Obtain during inspiration with patient’s neck hyperextended. widening of prevertebral soft tissues suggests retrophayrngeal infection. an air fluid level may be seen in some patients with retropharyngeal abscess. False results are common.
Ultrasonography: Can be used for soft fluctuant masses e.g lymphangiomas, hemangiomas and lipomas. Also suspected thyroglossal duct cyst can be sometimes identified. Color-flow doppler imaging is helpful to assess blood flow through certain lesions.
CT scan of neck with contrast or MRI scan: May show inflammation in retropharyngeal cellulitis or a ring enhancing abscess in patients with a cervical node or retropharyngeal abscess and is helpful in distinguishing cellulitis from abscess. CT or MRI typically are used when malignancy is suspected