If the windpipe becomes inflamed or infected we call it tracheitis and croup sounds , if the branches it is bronchitis and a wheeze can be heard and if the alveoli its alveolitis and one can hear fine crepitations .When secretions fill these alveoli we say the patient has pneumonia . The lung sounds dull on tapping the skin and xrays show white patches of consolidation.

Viruses are tiny germs ,a bit bigger than large molecules ie a few millionths of a millimeter (nanometers). Mycoplamsa are slighly bigger .Bacteria are about a 1000 times larger , about a thousandth of a mm (microns) , and can be seen under the microscope . Viruses usually give mild fever , cough and slight chest pain . Mycoplasma a more persistent dry cough and patchy white infiltrations on the chest x ray, and bacteria usually give greenish or yellowish sputum , fever and general unwellness and solid white areas on the xray.

The most common viruses are common cold , and influenza .

The most common bacterium is the streptoccocus (strep= chain like )

Sputum examination can sometimes be useful . A dye called Gram stain , colors strep blue (positive) as above and H Inf red (negative) as below
. White count and serology are rarely done. Moraxella is another and in the elderly E Coli due to aspiration .

Amoxycillin or cephalosporins are used for the very common streptoccus .Erythromycin or tetracycline for mycoplasma , augmentin or erythrmycin or clarithromycin for H Inf .

Acute means of recent onset , chronic of long duration over 8 weeks . Acute viral bronchitis gives rise to cough , slight fever and slight chest pain and may need antibiotics if it persists longer than a week. Chronic bronchitis can worsen acutely due to H Inf and augmentin or erythromycin are used to treat . Patients not getting better may need sputum culture or chest x ray .

Streptoccocus (commonest) -Amoxyl ,Ampicillin , Erythromycin, Cephalosporins
H Inf (chronic bronchitis)- augmentin , septrin , clarithromycin ,ciproxin
Mycoplasma (bouts of dry cough) -erythromycin , tetracycline,ciproxin.
Moraxella-Augmentin

Staphylococcus (staph=grape like) stains blue

and during epidemics of influenza can cause very severe illness and may need flucloxacillin .

Amoxyl , Ampicillin and Erythromycin are considered safe during pregnancy. In general drugs are avoided if possible in the first 12 weeks.

Influenza vaccine in the autumn can be useful in the over 50s . Peumovax against strep pneumonia for over 65s is given once in a lifetime.

TB

can also cause cough , night sweats and will be discussed in another article.