The common cold is generally mild and self-limiting with most symptoms generally improving in a week. Half of cases go away in 10 days and 90% in 15 days. Severe complications, if they occur, are usually in the very old, the very young, or those who are immunosuppressed.
Types of sick sinus syndrome and their causes include: 1  Sinoatrial block. Electrical signals move too slowly through the sinus node, causing an abnormally slow heart rate. 2  Sinus arrest. The sinus node activity pauses.  Bradycardia-tachycardia syndrome.
Acute sinusitis usually follows a viral infection in the upper respiratory tract, but allergy-causing substances (allergens) or pollutants may also trigger acute sinusitis. Viral infection damages the cells of the sinus lining, leading to inflammation. The lining thickens, obstructing the nasal passage. This passage connects to the sinuses.