Overview
The patient's breath may reveal information about their oral hygiene, or suggest the presence of metabolic disease.
Halitosis
Halitosis is also known as foetor ex ore, oral malodour and 'bad breath'. The term refers to an offensive odour that may resemble rotten eggs / meat / fish or faeces.
This finding is suggestive of bacterial colonisation in the mouth, pharynx, respiratory or gastrointestinal tracts.
Causes of Halitosis
Oropharyngeal
- Xerostomia (dry mouth)
- Poor oral hygiene
- Mouth ulcer
- Dental caries
- Gingivitis
- Tongue colonisation
- Tonsilitis
- Sinusitis
Gastrointestinal
- Reflux
- H pylori infection
- Crohn's disease
Respiratory
- Bronchiectasis
- Bronchial tumour
Systemic
- Cirrhosis
- Ketosis
- Alcohol
- Uraemia
Foetor Hepaticus
Foetor hepaticus is a musty smell, sometimes described as a mix between rotten eggs and garlic.
This is associated with severe liver cirrhosis, likely due to sulphur compounds such as methyl mercaptan and dimethylsulphide.
Acetone Breath
Acetone breath manifests as a fruity smell, similar to nail polish remover; this is a reliable indicator of plasma ketosis.
Causes of Ketosis
- Diabetic ketoacidosis
- Alcoholic ketoacidosis
- Starvation-induced ketosis
- Ketogenic diet - high fat, high protein, low carbohydrate
- Toxicity - isopronanol, acetone, propylene glycol, aspirin, isoniazid
Alcoholic Foetor
The smell of alcohol on the breath suggests alcohol ingestion, which may indicate acute intoxication and may be present in patients with alcoholism.
Uraemic Foetor
Uraemic foetor manifests as the smell of ammonia, or a urine-like odour. This occurs in patients with end-stage renal failure.
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