1.      Acute bronchitis

Acute bronchitis is usually a mild, self-limiting illness (an illness that resolves by itself without the need for medical treatment). Symptoms of acute bronchitis include:

• a persistent chesty cough
• coughing up yellow or green phlegm (thick mucus)
• breathlessness upon exertion (above the usual level)
• wheeziness
• dry mouth
• high temperature (fever) of 38C (100.4F) or above (in the majority of cases, although in some people, such as the elderly, their temperature may fall)
• headache
• loss of appetite

The cough usually lasts between seven to ten days, although it can persist for up to three weeks.

Acute bronchitis often causes headaches, and a sense of feeling generally unwell. As well as being caused by the infection, these symptoms can also sometimes be caused by dehydration. It is therefore very important that you drink plenty of fluid.

2.      Pneumonia

Common symptoms of pneumonia include:

• difficulty breathing – breaths are rapid and shallow
• a cough that brings up phlegm (thick mucus)
• rapid heart beat (tachycardia)
• high temperature (fever) of 38C (100.4F) or above
• chest pain

Less common symptoms of pneumonia include:

• coughing up blood
• headaches
• loss of appetite
• fatigue
• nausea
• vomiting
• joint and muscle pain
• a blue tinge to the skin (cyanosis)

Sometimes, elderly people with pneumonia may become confused and disorientated.

When to seek medical advice

You should contact your doctor if:

• you have a high temperature (this is usually a sign of a more serious type of infection)
• you feel so unwell that you are unable to manage and cope with your normal daily activities
• you feel confused and disorientated
• you experience symptoms of breathlessness when you are at rest, or you become more breathless than you would expect during physical activity
• you have a sharp pain in your chest
• you cough up blood stained phlegm (thick mucus)
• your symptoms last longer than three weeks
• you have a weakened immune system due to another condition, such as HIV, or as the result of treatment, such as chemotherapy

You should also contact your doctor if you have a chronic (long-term) health condition that could make you more vulnerable to the effects of a chest infection such as:

• heart disease - a condition where the blood supply to the heart is reduced
• diabetes – a condition where the body does not produce enough insulin, or is unable to make use of insulin in the right way
• kidney disease - a condition where the kidneys lose some of their ability to filter toxins out of the blood
• asthma – a condition where a number of substances, such as dust mites, or pollen, can cause the lungs to become inflamed leading to breathing difficulties
• chronic obstructive pulmonary disease (COPD) – a general term for a group of lung conditions that cause serious breathing problems

Causes of adult chest infection 

In order to understand what causes a chest infection, it is useful to learn about how the lungs work.

The lungs

Your lungs are like two large sponges that are filled with tubes. As you breathe in, you take in oxygen through your nose and mouth through a tube in your neck that is called the windpipe or trachea.

The trachea splits into two tubes, one for each lung, which are called the primary bronchi. The bronchi divide into smaller and smaller bronchi which have tiny air sacs (alveoli) at the end. The oxygen is passed into your blood from the alveoli, before being pumped around your body by your heart.

As well as oxygen, bacteria and viruses in the air can also be passed down into your lungs. This usually does not cause problems because your immune system (the body’s natural defence against infection) is able to kill the bacteria or viruses.

However, infection can occasionally take hold, particularly if your immune system has been weakened by other conditions, or your lungs have been irritated by cigarette smoke.

Acute bronchitis

Most cases of acute bronchitis are caused by viruses, although sometimes they are caused by bacteria.

Acute bronchitis is a temporary inflammation of the trachea and the major bronchi, caused by infection. The inflammation causes swelling of the airways and a build up of phlegm (thick mucus), which is cleared from the airways by coughing (which can sometimes last for up to three weeks).

Pneumonia

Pneumonia is an infection of the tissues of the lung. Germs that cause infections, such as pneumonia, are often passed around in the community. In some people, the germs cause pneumonia to develop.

In adults, the most common cause of pneumonia is a type of bacterium called streptococcus pneumoniae. This form of pneumonia is sometimes called pneumococcal pneumonia.

Less commonly, other types of bacteria can cause pneumonia including:

• haemophilus influenzae
• staphylococcus aureus

Viruses can also cause pneumonia, most commonly the respiratory syncytial virus (RSV). Other viral causes can include:

• varicella-zoster – the virus that causes chickenpox
• the flu (influenza) type A or B virus

Viral pneumonia tends to be more common in young children than in adults.Some groups of people have a higher risk of developing pneumonia. For example:

• babies and very young children
• elderly people
• people who smoke
• people with other health conditions
• people with a weakened immune system (the body’s natural defence against infection)

Other health conditions that increase the risk of pneumonia developing can include:

• another lung condition, such as asthma, or cystic fibrosis
• a heart condition
• a kidney or liver condition
• a lowered immune system

Your immune system can be lowered as a result of:

• a recent illness, such as flu
• treatment for cancer, such as chemotherapy
• taking medicines that suppress the immune system after an organ transplant
• a health condition, such as HIV or AIDS

Related posts:

1. Chest infection in adults
2. Diagnosing and treating bronchitis
3. Symptoms, causes and diagnosing aspergillosis
4. Respiratory tract infection — Bronchiolitis
5. Symptoms and causes of an aneurysm circulation disorder
6. Bronchiectasis