Sputum

Abnormal sputum
Cocci-shaped Enterococcus sp. bacteria taken from a pneumonia patient.
ICD-10 R09.3
ICD-9 786.4

Sputum ['spju.təm] is mucus that is coughed up from the lower airways.[1] In medicine, sputum samples are usually used for microbiological investigations of respiratory infections and cytological investigation of respiratory systems.

The best sputum samples contain very little saliva,[2] as this contaminates the sample with oral bacteria. This event is assessed by the clinical microbiologist by examining a Gram stain of the sputum. More than 25 squamous epithelial cells at low enlargement indicates salivary contamination.

When a sputum specimen is plated out, it is best to get the portion of the sample that most looks like pus onto the swab. If there is any blood in the sputum, this should also be on the swab.

Microbiological sputum samples are usually used to look for infections by Moraxella catarrhalis, Mycobacterium tuberculosis, Streptococcus pneumoniae and Haemophilus influenzae. Other pathogens can also be found.

Purulent sputum[3] contains pus, composed of white blood cells, cellular debris, dead tissue, serous fluid and viscous liquid (mucus). Mostly, it is yellow in color, as well as green. It is seen in cases of bronchiectasis, lung abscess, advanced stage of bronchitis, or acute upper respiratory tract infection (common cold, laryngitis).

Sputum can be:

  1. Bloody[4] (Hemoptysis)
    1. blood-streaked sputum - inflammation of throat, bronchi; lung cancer;
    2. Pink sputum - sputum evenly mixed with blood, from alveoli, small bronchi;
    3. massive blood - cavitary tuberculosis of lung, lung abscess, bronchiectasis, infarction, embolism.
  2. Rusty colored - usually caused by pneumococcal bacteria (in pneumonia)
  3. Purulent - containing pus. The sputum colour of patients with acute cough and no underlying chronic lung disease does not imply therapeutic consequences such as prescription of antibiotics.[5] The colour can provide hints as to effective treatment in Chronic Bronchitis Patients:[6]
    1. a yellow-greenish (mucopurulent) color suggests that treatment with antibiotics can reduce symptoms. Green color is caused by Neutrophil Myeloperoxidase.
    2. a white, milky, or opaque (mucoid) appearance often means that antibiotics will be ineffective in treating symptoms. (This information may correlate with the presence of bacterial or viral infections, though current research does not support that generalization.)
  4. Foamy white - may come from obstruction or even edema.
  5. Frothy pink - pulmonary edema

See also

References

  1. ↑ Sputum definition - Medical Dictionary definitions of popular medical terms easily defined on MedTerms
  2. ↑ Clinical Microbiology procedures handbook, American Society for Microbiology 2nd Ed. 2007 update
  3. ↑ Richard F.LeBlond. Diagnostics_expectoration. US: McGraw-Hill Companies, Inc. ISBN 0-07-140923-8.
  4. ↑ Richard F.LeBlond. Diagnostics_expectoration. US: McGraw-Hill Companies, Inc. ISBN 0-07-140923-8.
  5. ↑ Sputum colour for diagnosis of a bacterial infection in patients with acute cough
  6. ↑ Sputum Color is the Key to Treating Acute COPD Exacerbations

External links