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usually accompanied by enlargement of those organs, although hepatic dysfunction
may also be present. Bone marrow involvement is rare, but usually presents with
cytopenias, which should prompt a bone marrow aspirate and biopsy. Diabetes
insipidus (DI) due to involvement of the posterior pituitary is the most frequent
endocrine abnormality in LCH; some patients may present with an apparent
“idiopathic” presentation of DI before other lesions are identified. A few patients
may present with diarrhea or malabsorption as colitis related to LCH has been
described.
HLH is a very rare but severe and life-threatening systemic disease with rapid
progression from presentation to death without appropriate intervention. Thus,
consideration of this diagnosis in the ED can be critical to outcome. For these
reasons, it is essential for the emergency clinician to have some familiarity with this
disorder. Congenital HLH usually presents in infants and very young children. Other
forms of HLH develop secondary to Epstein–Barr virus (EBV) infection,
malignancy, or severe rheumatologic disorders or without a specific trigger.
Regardless of etiology, HLH presents with fever, hepatosplenomegaly, adenopathy,
and rash.
Clinical Assessment
All patients with suspected histiocytic disorders need a thorough history and
physical examination as well as a rapid assessment of severity of illness. Patients
with HLH may have significant systemic illness with organ dysfunction and vital
sign instability and will often require management in a critical care setting. At the
other extreme, patients with suspected localized LCH may require little to no
intervention in the ED but need only close oncologic follow-up.
Pulse oximetry should be checked to screen for hypoxia and a chest x-ray
obtained if hypoxia is detected. Laboratory evaluation should include CBC, liver
function testing, electrolytes to screen for DI, and inflammatory markers such as
erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). In HLH,
laboratory analysis may reveal a markedly high serum ferritin as well as
transaminitis, hypertriglyceridemia, hypofibrinogenemia, and cytopenias. Bone
marrow evaluation may show characteristic hemophagocytosis. Oncologic

consultation can guide the evaluation and management of systemically ill patients,
as in the case of HLH, or allow for careful follow-up of more stable patients with
suspected LCH.

TUMORS OF THE CENTRAL NERVOUS SYSTEM
Goals of Treatment