Aspiration Pneumonia

Authored by Dr Laurence Knott, Reviewed by Prof Cathy Jackson on | Certified by The Information Standard

Aspiration pneumonia is infection from germs (present in body fluid or matter) that have leaked into the lungs from the stomach or mouth.

You're unlikely to get it if you're a young fit adult. It often hits kids and the elderly. It can involve people living at home and people in hospital.

  • Healthy adults can fight a few germs that enter the lungs from other areas of the body. It's not surprising therefore that aspiration occurs mainly in the elderly and frail. Men are affected more than women.
  • It's fairly common. Research suggests that of all the cases of pneumonia that occur outside hospital (community-acquired pneumonia) about 1 in 10 is caused by aspiration pneumonia.
  • It's also common in children.
  • It occurs frequently in hospitals, where lots of germs may be involved in causing it.

When it starts it'll probably feel like the worst case of flu you've ever had, with a high temperature, headache and aches and pains. Sooner or later you'll develop a cough with phlegm that can be a green or yellow colour. You might become breathless and develop chest pain on deep breathing. A doctor examining you may find various unusual features such as a rapid heartbeat and breathing rate.

What are the early symptoms of aspiration pneumonia?'

  • You may feel generally unwell, with a high temperature (fever), headache, sickness (vomiting) and muscle aches. You might go off your food and lose a little bit of weight.
  • A cough is the key feature, sometimes with yellow or green phlegm.
  • Your breathing rate and pulse may become rapid.
  • Other symptoms you may notice include breathlessness and chest pain which is worse when you breathe in deeply.
  • A doctor listening to your chest with a stethoscope might hear that your breathing sounds muffled and that the covering of your lungs makes a sound when you breathe in and out (a pleural rub).
  • If your chest wall is tapped, the doctor may find an area of dullness.
  • Untreated, pneumonia can make you feel very ill. The oxygen you breathe in may have difficulty getting to parts of your body distant from your lungs (for example, your lips and tongue) and may develop a blue tinge.

The basic cause is spit, bits of food or stomach contents entering the lungs. Any of these will also bring germs (bacteria) with them into the lungs, which sets up an infection.

There are many situations in which the risk of aspiration is increased. This includes any condition which makes you drowsy or completely unconscious, such as fits, strokes, or being under the influence of booze or drugs.

Any condition which increases the likelihood that muck will enter the lungs, like an opening between the food tube and the main airway (tracheo-bronchial fistula), gum disease or acid reflux, can lead to aspiration pneumonia.

Aspiration pneumonia is caused by saliva, food or stomach acid leaking into the lungs. Germs (bacteria) introduced by this route set up an infection of the lung tissue, resulting in pneumonia. This is unlikely to happen if you're a young, fit adult. However, certain factors increase the risk of getting aspiration pneumonia. These include:

  • Being drowsy or unconscious - when you are awake you are continually clearing your throat to protect the lungs from inhaled saliva, drinks or bits of food. If your consciousness is reduced, the throat muscles tend to relax, increasing the risk of aspiration. This can happen if you:
    • Are under the influence of alcohol or drugs.
    • Have an anaesthetic.
    • Have a fit.
    • Have a stroke.
    • Have a disease of the nervous system.
    • Have problems swallowing - for example, due to a stroke, a tumour of the lower part of the throat (pharynx), or a disease affecting the nerves and muscles involved in swallowing (for example, multiple sclerosis).
  • Having a condition that increases the amount of fluid near the lungs - for example:
    • Tracheo-oesophageal fistula - a channel between the airway and the food tube.
    • Artificial ventilation.
    • Gum disease.
    • Acid reflux.
    • Nasogastric feeding - feeding via a tube through the nose into the stomach. With modern nursing, this is less of a risk than it used to be,

A variety of bacteria may be involved - for example:

  • Those that are always around the mouth and throat, such as Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae.
  • Those acquired in hospitals, such as Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and meticillin-resistant S. aureus (MRSA).

 If you develop typical symptoms (see the section called 'Symptoms') and come into the category of someone who is at risk of aspiration pneumonia, the doctor will consider this diagnosis. Other conditions that can cause similar symptoms include:

Will I need any tests?

You will probably need some tests to help the doctor sort out the diagnosis. This may include blood tests, a test of your phlegm (sputum culture), a chest X-ray and sometimes a lung scan.

  • If there is something obstructing the airway, like a foreign object or piece of food, an attempt can be made to remove it. Depending on how far down the airway system the obstruction is, you may need suctioning of the upper airway (the trachea) or a bronchoscopy.
  • You may need to have a tube put into your trachea and connected to a ventilator to help you breathe.
  • Antibiotics will probably be required.
  • You may also need fluid through a drip, medication (called bronchodilators) to relax your airways, and physiotherapy to help get the phlegm off your chest.
  • You may also need therapy to help with any swallowing difficulties that might have caused the aspiration in the first place.
  • If the aspiration pneumonia develops at home and your symptoms are mild, you may not need hospital admission to start with. However, if your symptoms are severe or you don't respond to treatment, you may need to be admitted to hospital.

If aspiration pneumonia isn't treated, you can end up with a lung abscess (a collection of pus in the lung tissue) or bronchiectasis. You can also develop acute respiratory distress (a condition in which the lungs suddenly fill up with fluid and breathing becomes very difficult).

The chance of recovering from aspiration pneumonia depends on the original cause, how well you were before you developed it and whether you had any complications. It also depends on how quickly the condition was recognised and how soon effective treatment was started.

If you are bed-bound and at risk of aspiration, keeping the head end of the bed raised at an angle of 30° may help.

If you have swallowing difficulties, reduced sensitivity to irritants at the back of your throat, or have some other condition that makes you prone to aspiration, feeding through a nasogastric tube may reduce the risk.

Further reading and references

  • Armstrong JR, Mosher BD; Aspiration pneumonia after stroke: intervention and prevention. Neurohospitalist. 2011 Apr1(2):85-93. doi: 10.1177/1941875210395775.

  • Ebihara S, Sekiya H, Miyagi M, et al; Dysphagia, dystussia, and aspiration pneumonia in elderly people. J Thorac Dis. 2016 Mar8(3):632-9. doi: 10.21037/jtd.2016.02.60.

  • Kovesi T; Aspiration Risk and Respiratory Complications in Patients with Esophageal Atresia. Front Pediatr. 2017 Apr 35:62. doi: 10.3389/fped.2017.00062. eCollection 2017.

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