Differential Diagnosis for Acute Onset Bilateral Proptosis in a 9-Year-Old Child
Single Most Likely Diagnosis
- Acute Lymphoblastic Leukemia (ALL): Given the history of low-grade fever, slowly evolving bilateral lower limb weakness, severe pallor, and acute onset bilateral proptosis, ALL is a strong consideration. The proptosis could be due to orbital infiltration by leukemic cells, and the limb weakness might be related to spinal cord or nerve root involvement. Severe pallor suggests anemia, which is common in ALL due to bone marrow infiltration.
Other Likely Diagnoses
- Lymphoma: Similar to ALL, lymphoma can cause systemic symptoms like fever and pallor. Orbital involvement can lead to proptosis, and neurological symptoms can arise from spinal cord compression or infiltration.
- Neuroblastoma: This pediatric cancer can cause proptosis due to orbital metastasis and limb weakness from spinal cord compression or metastasis to the spine. Fever and pallor can also be present.
- Infectious causes (e.g., Orbital Cellulitis): Though less likely given the combination of symptoms, severe infections can cause proptosis and systemic symptoms like fever. However, the slowly evolving limb weakness and severe pallor are less typical for a primary infectious process.
Do Not Miss Diagnoses
- Metastatic Disease: Although rare in children, any diagnosis of metastatic cancer (e.g., from a primary site like the kidney or adrenal glands in neuroblastoma) is critical and potentially life-threatening if not promptly addressed.
- Thyroid Ophthalmopathy: Though more common in adults, thyroid disorders can cause proptosis. In the context of a child, this would be unusual but could be considered, especially if there are other signs of thyroid disease.
- Vascular Malformations or Thrombosis: Conditions like cavernous sinus thrombosis can cause acute proptosis and are medical emergencies.
Rare Diagnoses
- Histocytosis: Disorders like Langerhans cell histiocytosis can cause a wide range of symptoms including proptosis, bone lesions, and systemic symptoms, but are less common.
- Sarcoidosis: Though rare in children, sarcoidosis can cause proptosis among other systemic symptoms, but would be an unusual diagnosis in this age group.
- Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A rare autoimmune disorder that can cause a variety of symptoms including proptosis, but is uncommon in children.