Which symptom may indicate a severe case of Bronchiolitis/RSV?

Cyanosis is a significant symptom indicating a severe case of Bronchiolitis or respiratory syncytial virus (RSV) infection. This condition occurs when there is inadequate oxygenation in the blood, leading to a bluish discoloration of the skin, particularly noticeable around the lips, face, and extremities. The presence of cyanosis suggests that the patient may be experiencing severe respiratory distress or failure, necessitating immediate medical attention.

In contrast, a low fever may be common in respiratory infections but does not typically signify the severity of the condition. A normal breathing rate is also not consistent with severe illness, as bronchiolitis often leads to increased respiratory effort and rate. Decreased appetite can occur with many illnesses but is not a specific indicator of the severity of bronchiolitis or RSV. Thus, cyanosis stands out as a critical sign of worsening respiratory compromise in these patients.