Pulmonary Edema (Non-Cardiogenic): Given the presence of interstitial and ground glass edema without leukocytosis, a non-infectious cause such as pulmonary edema due to high altitude, fluid overload, or other non-cardiogenic causes is a strong consideration. The absence of leukocytosis leans away from an infectious process.

Atypical Pneumonia: Although leukocytosis is not present, atypical pneumonias (such as those caused by Mycoplasma pneumoniae, Chlamydophila pneumoniae, or viral infections) can sometimes present with minimal or no increase in white blood cell count. These infections can cause interstitial patterns on imaging.
Acute Interstitial Lung Disease (e.g., Acute Interstitial Pneumonia): This is a rare but possible cause of the described radiographic findings. It represents a spectrum of diseases that can present acutely and may not always have a clear infectious etiology.
Connective Tissue Disease: Certain autoimmune diseases can cause interstitial lung disease, which might present with ground glass opacities on CT. However, these conditions often have other systemic manifestations.

Influenza or Other Viral Pneumonias: Even without leukocytosis, severe viral infections can cause significant pulmonary involvement, including ground glass opacities. Missing these diagnoses could lead to severe consequences, especially in vulnerable populations.
COVID-19: Given its global impact, COVID-19 should be considered, especially if the patient has been exposed or is in a high-risk area. Early stages or mild cases might not present with significant leukocytosis.
Pneumocystis jirovecii Pneumonia (PCP): Typically seen in immunocompromised patients, PCP can present with ground glass opacities on CT and might not always be accompanied by significant leukocytosis.

Lymphangitic Carcinomatosis: A rare condition where metastatic cancer involves the lymphatic vessels of the lung, potentially causing interstitial patterns on imaging.
Eosinophilic Pneumonia: Characterized by an accumulation of eosinophils in the lungs, which can cause interstitial changes. It might not always present with leukocytosis, especially if the eosinophilia is confined to the lungs.
Idiopathic Pulmonary Hemosiderosis: A rare condition characterized by recurrent episodes of diffuse alveolar hemorrhage, which could potentially cause ground glass opacities on CT scans.