Chest infections (bronchitis)There are different types of chest infections, ranging from the simple acute bronchitis that comes on with a cold, to more serious infections such as pneumonia and tuberculosis. Bronchitis is an inflammation of the lining of your bronchial tubes, which carry air to and from your lungs. Bronchitis may be either acute or chronic. Acute bronchitis is very common. It often develops from a cold or other respiratory infection. Chronic bronchitis is a more serious condition, involving a constant irritation or inflammation of the lining of the bronchial tubes, often due to smoking.When to see your doctorSee your doctor if you:have a cough on most days, or you have a cough that often returnsare coughing up bloodhave a high fever or shaking chillshave a low-grade fever for 3 or more daysare coughing up thick, greenish mucus, especially if it has a bad smellfeel short of breath or have chest painalso have a chronic illness, like heart or lung disease.Signs a chest infection is more seriousIf you or a family member is short of breath, coughing up blood, has a high fever or feels very unwell you need to see your doctor or call Healthline on 0800 611 116 straight away. These can be symptoms of pneumonia, where the infection has gone deep into your lungs, or other serious conditions like tuberculosis or lung cancer.