Chest infection, adult - Complications 

Complications of adult chest infection 

Both acute bronchitis and pneumonia can cause a variety of complications.

Acute bronchitis

Acute bronchitis can cause a secondary infection in your lungs. The lungs can be weakened by the original infection and become more vulnerable to secondary infection by bacteria.

If you develop a secondary infection, it can be more serious than acute bronchitis. It can usually be treated with antibiotics. Occasionally, acute bronchitis can lead to pneumonia, particularly if you have other health conditions.

See your GP if:

  • you develop symptoms of a high temperature (fever) of 38C (100.4F) or above, or your existing high temperature suddenly worsens
  • you become drowsy, confused or disorientated
  • you develop chest pains
  • your breathing suddenly becomes more rapid
  • you become short of breath
  • your cough lasts more than three weeks
  • you have recurring bouts of acute bronchitis


Pleural effusion

Pleural effusion is a common complication of pneumonia that affects around 1 in 2 people who are admitted to hospital for moderate to severe pneumonia.

A pleural effusion is where an excess amount of fluid gathers inside the double-layered membrane (covering) that surrounds the lungs, known as the pleura.

The fluid can place pressure on the lungs, making breathing difficult. Pleural effusion will usually resolve itself when pneumonia is treated.

In cases of pleural effusion, it is usually recommended that a fluid sample is taken and checked to determine whether the fluid has become infected (see below). If no infection is present, a ‘watch and wait’ strategy is usually recommended because most cases of pleural effusion will be resolved once the underlying pneumonia infection has passed.


In around 10% of pneumonia cases that are treated in hospital, the fluids that make up a pleural effusion will become infected by bacteria. This is known as empyema. The bacteria can cause a build-up of pus, which can sometimes reach up to around a quarter of a pint (142.5mm)

Symptoms of empyema include:

  • chest pain, which is made worse when breathing in
  • dry cough
  • high temperature (fever) of 38C (100.4F) or above
  • chills
  • excessive sweating, particularly at night
  • shortness of breath
  • general sense of feeling unwell

Empyema is usually treated using a combination of antibiotics and a procedure that drains the pus out of the pleura. This is usually done by making a small incision (cut) in your chest (under a local anaesthetic), and then inserting a tube into the pleura to drain away the pus and fluid.

The most serious cases of empyema may require surgery to remove the pus and repair any underlying damage to your pleura and lungs.

Lung abscess

A lung abscess is a rare complication of pneumonia and is mostly seen in people who have a serious, pre-existing illness or those with a history of severe alcohol misuse.

A lung abscess is a pus-filled cavity that develops inside the tissue of the lungs. The symptoms of a lung abscess are the same as those of severe pneumonia. In addition, you may begin to cough up unpleasant-smelling phlegm (thick mucus) and experience swelling in your fingers and toes.

Most cases of lung abscesses can be treated using antibiotics. This usually involves an initial course of intravenous antibiotics (directly into a vein through a drip) followed by oral antibiotics (tablets) for four to six weeks.

Most people who have a lung abscess will experience an improvement in their symptoms within three to four days. It is important to finish your recommended course of antibiotics, even if you feel perfectly healthy, to prevent re-infection of your lungs.

Around 10% of people will require surgical treatment because they fail to respond to the antibiotics. Surgery usually involves draining the pus out of the abscess or removing the affected section of the lung.

Metastatic infection

Another rare and serious complication of pneumonia is metastatic infection. Metastatic infection means that the infection has spread from the lungs to another part of the body.

The first place that an infection usually spreads to is the blood, which is known as septicaemia.

Symptoms of septicaemia include:

  • high temperature (fever) of 38C (100.4F) or above
  • fast heartbeat (tachycardia)
  • fast breathing
  • low blood pressure (hypotension) which will cause you to feel dizzy when you stand up
  • a change in mental behaviour, such as confusion or disorientation
  • diarrhoea
  • reduced urine flow
  • cold, clammy skin
  • pale skin
  • loss of consciousness

Once your blood has become infected, it is possible for the infection to spread to other organs in your body, such as:

These types of metastatic infections are usually very serious and require aggressive treatment with high-dose intravenous antibiotics.

Page last reviewed: 14/05/2012

Next review due: 14/05/2014


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The 2 comments posted are personal views. Any information they give has not been checked and may not be accurate.

NGoldberger said on 18 December 2013

I came upon this page as I too, like DeanneB12 get frequent chest infections and it seems they get worse and worse. I don't smoke, and it's taken up to 2 months for it to clear up in the past. It usually starts off as a cold, and/or a sore throat. Then the coughing starts, and green gunk accumulates in my lungs and gets expelled over about 2 days.
I have been to the doctor's most times, and they have told me in the past that antibiotics will not work as it's a virus, not bacteria. Although it's gotten so bad, I wonder if it has developed into something listed above, as I develop a temperature, I feel faint & like blacking out a lot, I have no energy, I sweat in the night and feel 'not-quite-compus-mentus' where my head is really fuzzy.
I still don't know if antibiotics have helped or not. It still takes ages to clear up completely.
I have been advised by a family friend to make an appointment with a pulmonologist, but unsure how to go about this. I've had a cold since Sunday and a sore throat, and just this evening, I have started to cough, so I know what's coming, it feels like it's the start of something quite nasty :(
Any help would be greatly appreciated.x

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deanneb12 said on 17 September 2013


I have been having chest infection after chest infection i've been going to my gp and they keep giving me antibiotics and i went in to the doctors today and they gave me even more antibiotics but last time i went in about a month ago they said they will refer me to the hospital for a chest scan. I am trying to stop smoking and ive cut down a lot but they just keep coming back!

can you give me some advice please as im scared its something more serious then a chest infection

Many thanks x

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