Diagnosis

A careful history, physical examination, appropriate laboratory evaluation, and targeted imaging will usually help in deciding the need for tissue sampling.

 

Laboratory Studies

o Complete blood count (CBC)

o ESR

o C-reactive protein

 

However, these are not always helpful in determining the specific etiology of the disease process. Pan-cytopenia can be seen in leukemia; lymphocytosis is seen with mononucleosis, cytomegalovirus (CMV), and toxoplasmosis.

Based on the history and physical examination, more specific tests for Epstein-Barr virus (EBV), CMV, toxoplasmosis, brucellosis, histoplasmosis, syphilis, bartonellosis, and coc-cidioidomycosis should be considered. Tests for human immunodeficiency virus (HIV) should also be considered, based on the history as well as the tuberculin skin test.

Serum lactate dehydrogenase should be assayed when suspecting leukemia or lymphoma as a byproduct of high cell turnover.

Imaging Workup

§ Ultrasound (to evaluate for or follow progress of an abscess)

§ CT/MRI (to evaluate for abscess)

§ EKG/ECHO (if suspect Kawasaki Disease)

§ Chest X-ray (in case of cervical lymphadenopathy - to look for mediastinal lymphadenopathy)

 

Diagnostic Procedures

§ „Biopsy (FNA or Excisional)

 

Fluctuance and abscess formation will help guide therapies such as needle aspiration or incision and drainage.

Small, soft, mobile nodes should not undergo biopsy, because these are most likely benign unless they are in the supraclavicular region. Tissue diagnosis is helpful when lymph nodes persist or enlarge after adequate antibiotic therapy, when they are associated with signs or symptoms of malignancy, and, finally, if the diagnosis is questioned.

Most authors recommend waiting at least 4 to 6 weeks before obtaining tissue samples. Earlier biopsy should be considered for nodes in the supraclavicular or epitrochlear region, nodes greater than 3 cm in diameter, and for children with a history of malignancy, weight loss, night sweats, fever, or hepatosplenomegaly.

 

Fine-Needle Aspiration Fine-needle aspiration (FNA) - a diagnostic procedure used to investigate superficial (just under the skin) lumps or masses. In this technique, a thin, hollow needle is inserted into the mass for sampling of cells that, after being stained, will be examined under a microscope.

 

Aspirates should be sent for Gram stain, acid-fast stain, and cultures for aerobic/anaerobic bacteria, mycobacteria, and fungi.

However, the use of FNA in children has not become universal, because the aspirate usually provides a small sample, which limits the ability to perform flow cytometry, chromosomal analysis, and electron microscopy. Most pediatric hematologists and pathologists prefer excisional biopsy, because it allows the assessment of nodal architecture and permits the use of special stains. In addition, some children will not permit FNA without some sedation, which negates a primary benefit of FNA.

 

Excisional biopsy provides enough tissue to perform flow cytometry, chromosomal analysis, electron microscopy, and the use of special stains. Indications for an excisional biopsy include:

§ Lymph nodes that are hard/matted

§ Lymph nodes fixed to surrounding tissue

§ Progressively enlarging nodes without response to antibiotic therapy

§ Presence of abnormally enlarged nodes after 4 to 6 weeks

§ Supraclavicular, epitrochlear lymph nodes

§ Hepatosplenomegaly

§ Mediastinal or hilar masses

§ Laboratory anomalies, especially anemia, leukocytosis, leucopenia, and thrombocytopenia

§ Symptoms such as fever, weight loss, and night sweats

§ Suspicion of atypical mycobacterial adenitis

§ Diagnostic dilemma

 

 

ACUTE LYMPHADENITIS

The most common cause of self-limiting, acute, inflammatory lymph node is a viral infection. Acute bilateral cervical adenopathy is most often caused by a viral respiratory tract infection (rhinovirus, parainfluenza virus, influenza virus, respiratory syncytial virus, coronavirus, adenovirus, reovirus) and is usually hyperplastic in nature. Viral-associated adenopathy does not suppurate and usually resolves spontaneously.

Unilateral lymphadenitis is usually caused by streptococcal or staphylococcal infection in 40% to 80% of the cases. These are usually large (>2 cm), solitary, and tender in the preschool child. The submandibular, upper cervical, submental, occipital, and lower cervical nodes are affected in decreasing order of frequency. Suppurative adenitis is associated with group A streptococcal or penicillin-resistant staphylococci. Staphylococcus infection leading to lymphadenitis seems to occur more commonly in infants. Other less frequent causal organisms include Hemophilus influenzae type B, group B streptococci, and anaerobic bacteria. Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is now more commonly being isolated from superficial abscesses and suppurative lymphadenitis in children. Clindamycin is an appropriate agent to use under these circumstances.

Suppurative lymphadenitis presents with local inflammatory signs, including unilateral tender adenopathy involving the submandibular or deep cervical nodes draining the oropharynx. Erythema, fever, malaise, and signs of systemic illness may occur. The primary infection in the head and neck regions should be looked for with careful attention to the oropharynx and middle ear. Appropriate treatment should be started, usually an empirical 5- to 10-day course of an oral β-lactamase-resistant antibiotic. Intravenous antibiotics should be started if systemic signs are present or in very young infants. A response should be observable within 72 hours, and failure of therapy usually necessitates additional diagnostic testing. This is usually fine-needle aspiration or ultrasonography.

Aspirate culture by FNA can guide further organism-specific antibiotic treatment, including clindamycin if MRSA is encountered. If no fluid is aspirated, sterile saline can be injected and then aspirated to obtain material for culture. In addition, repeated aspiration together with antibiotics is an effective treatment for fluctuant lymphadenitis.

Ultrasonography may help to differentiate between solid and cystic masses and can identify fluid that may require operative drainage. Incision and drainage is a more definitive surgical approach to suppurative fluctuant lymphadenitis. Gauze packing has been used to prevent early skin closure and achieve hemostasis; however, the use of minimal incisions, with vessel loops functioning as drains, has been gaining wider acceptance recently.