Children with new-onset proptosis should be referred promptly to a pediatric ophthalmologist. The differential diagnosis includes several life- and vision-threatening disorders.

What Shouldn’t Be Missed

Proptosis is a serious condition that requires prompt evaluation and treatment. In particular, patients with decreased vision or signs of orbital cellulitis should be referred immediately.

• 1. Orbital tumors. The most common primary orbital tumor in children is rhabdomyosarcoma, which classically presents with rapid onset of painless proptosis (Figure 15–1). Optic pathway gliomas affecting the optic nerve sometimes present with rapid onset of proptosis due to mucinous degeneration. Metastatic lesions, including neuroblastoma, leukemia, and lymphoma, are less common.
  
• 2. Orbital cellulitis. Orbital cellulitis is a serious infection that most commonly results from contiguous spread of sinus disease (Figure 15–2). Prompt treatment with intravenous antibiotics is indicated. Orbital cellulitis is frequently associated with subperiosteal orbital abscesses, which may improve with antibiotics and not require surgical drainage.
  
• 3. Lymphangioma. Lymphangiomas are congenital lesions that may not be noticed initially. These lesions are prone to internal hemorrhage, which presents with the rapid onset of proptosis (Figure 15–3). This may be difficult to distinguish from an orbital tumor without a biopsy.
  
• 4. Orbital pseudotumor. Orbital pseudotumor is an idiopathic condition characterized by inflammation of the orbital tissue. It is often preceded by a systemic febrile illness, and presents with marked periocular pain. It may be localized to the extraocular muscles (myositis). It characteristically responds very promptly to systemic corticosteroid treatment.
  
• 5. Infantile glaucoma. Although not an orbital disorder, glaucoma that presents in infancy or early childhood may cause enlargement of the eyeball, with a clinical appearance similar to proptosis (Figure 15–4). Affected children often have cloudy corneas and excess tearing due to corneal irritation.
  
• 6. Other causes. Apparent proptosis may result from underlying abnormalities of the orbit or eyeball itself. Patients with craniofacial abnormalities or craniosynostosis may have shallow orbits, and patients who are markedly nearsighted (myopic) may have elongated eyes. Orbital hemorrhage due to trauma or bleeding disorders may also cause proptosis (Figure 15–5A and B).