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hepatitis, splenomegaly, and neurologic involvement. Characteristic laboratory findings
include anemia, thrombocytopenia, and elevated liver enzymes, as well as extremely
elevated ferritin levels and hypertriglyceridemia. Immune and cytokine studies, as well as
genetic testing and bone marrow studies showing hemophagocytosis are used to establish
the diagnosis.
Finally, rare causes of systemic adenopathy include lipid storage diseases, such as
Gaucher disease and Niemann–Pick disease, which can cause diffuse adenopathy and are
almost always associated with hepatosplenomegaly. Bone marrow biopsy, showing lipidladen histiocytes, is diagnostic.

LIFE-THREATENING LYMPHADENOPATHY
In rare instances, lymphadenopathy can lead to a life-threatening condition. In children
and adolescents affected by Hodgkin or non-Hodgkin lymphoma or metastatic
neuroblastoma, bulky or rapidly enlarging mediastinal lymph nodes can cause
compression of the superior vena cava (SVC) or the tracheobronchial tree. In SVC
syndrome, lymph nodes that encircle the vena cava enlarge and cause obstruction to
central venous blood flow. This obstruction leads to clinical manifestations including
dilated chest and neck veins, facial swelling and plethora, and dyspnea. Progression may
lead to headaches, confusion, and altered mental status as well as progressive respiratory
distress. Children with bulky adenopathy of the mediastinal or paratracheal nodes may
present solely with respiratory symptoms, including stridor or wheezing, caused by
compression of the trachea or bronchi by enlarged lymph nodes. Emergency physicians
who take care of children with suspected lymphoma must be aware of the acute risk of
airway obstruction that may be exacerbated by changes in position (lying flat) or with
sedation or anesthesia. In addition, when treating children with SVC syndrome,
physicians must be careful to administer all intravenous therapy in the lower extremities,
as poor circulation in the upper extremities and torso because of venous obstruction
results in poor drug distribution and places the patient at increased risk of thrombus
formation.

EVALUATION AND DECISION
The pediatric emergency physician who evaluates a child with lymphadenopathy is faced

with an extensive differential diagnosis. However, a targeted history and thorough
physical examination can help focus evaluation of the patient and will often lead to the
correct diagnosis.
Historical data that need to be obtained include the time of onset, rate of growth, and
presence of other symptoms. Local symptoms suggestive of infection are particularly
relevant, including fever, conjunctivitis, otitis, pharyngitis, gingivostomatitis, or cellulitis,
as these may correlate with acute regional lymphadenopathy. In well-appearing children,
recent illnesses must be considered, particularly because reactive adenopathy may persist
for 2 to 3 weeks after the resolution of a viral illness. During evaluation, it is important to
note the presence of “red flag” constitutional symptoms, including prolonged fevers,