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.
Causes of sinusitis. Sinusitis is caused by too much mucus, or a swelling of the lining of the sinuses and nose, which can block the narrow channels. This can occur during a cold, or may be due to allergy (for example, hayfever) or irritation of the linings of the sinuses (for example, from chlorine in a swimming pool).