A cough is a protective reflex caused by irritation of the lining mucosa in the voice box (larynx) or windpipe (trachea). Sudden expulsion of air from the lungs at high speeds of up to 80 mph clears mucus or foreign material from the airway. A cough usually starts with a viral upper respiratory tract infection (URTI) which may spread to involve the sinuses (sinusitis) or lower down to the involve the trachea (tracheitis), bronchi (bronchitis) or lungs (pneumonia). Subsequent bacterial infection is common and prolongs the local inflammation irritation.
A chronic cough may occur if there is persistent local inflammation or a tumour. The violent jet of air propelled through the airway at the level of the vocal cords may also result in a frequent recurrent irritant effect, hence the importance of suppressant medicines in management.
Throat Swab for Microscopy and Culture
Infections caused by bacteria or fungi require antimicrobial treatment, which varies depending on the specific infective organism. Acute infections result in the production of pus, which is commonly thick yellow-green in colour and may have an unpleasant smell. When an infection is seen or suspected, a sample is therefore sent for laboratory analysis.
After inserting a sterile tongue depressor, a fine sterile cotton bud probe is inserted into the throat and rubbed over the tissue to be sampled. It is then immediately removed for storage in preservative for transfer to the laboratory. Examination under the microscope (microscopy) by the Microbiologist enables the presence and type of infective organism to be diagnosed. Subsequently, growing the organism on a special gel (culture) and applying various drugs allows the specific antimicrobial agent required to kill the infective organisms to be determined.
Rigid and Flexible Endoscopy
The mouth can be examined directly using a bright halogen headlight. The introduction of a sterile rigid endoscope with an angled lens into the mouth, or a sterile flexible endoscope whose tip can be manually rotated in various directions, allows a very detailed inspection of the whole of the tongue base, lower pharynx and vocal cords.
Flexible laryngoscopy is carried out with the patient seated in an upright position and requires initial preparation of the nasal lining with a topical spray. Cophenylcaine, a surface local anaesthetic and decongestant, is sprayed into each nostril held open by a dilator speculum. This drug is absorbed very quickly and numbs and shrinks the nasal lining. Although the introduction of a flexible endoscope into the nasal cavity is an unusual feeling it is not unpleasant. The subsequent examination will take less than 5 minutes.
Rigid laryngoscopy requires a seated patient with their head extended forwards. It involves gently placing a metal tube with an angled lens and attached camera into the back of the throat to examine the vocal cords in detail. Active movements on phonation can be recorded to provide an accurate clinical record and to document changes after treatment.
Flow Volume Loop Spirometry
The flow volume loop is a graph showing the airflow at different lung volumes, and plots inspiratory and expiratory function separately. It enables a clear diagnosis to be made between fixed and variable upper and lower airway obstruction, and gives quantitative data for assessment and monitoring purposes. It is particularly helpful in measuring the degree of airway obstruction in patients with vocal cord paralysis.
The subject is asked to breathe out completely to empty air from the lungs as much as possible. The airflow at the mouth is then recorded during a maximum forced inspiration, followed by a maximum forced expiration. The results undergo computer analysis and are recorded.
Computed tomography (CT) is a medical imaging method using X-ray tomography created by computer processing. It provides important diagnostic information in various anatomical planes. Conventional X-rays are not really helpful, as various anatomical structures superimposed on one another prevents proper assessment.
The main advantage of CT over MRI scanning is that it demonstrates bone as well as soft tissue features.
The scanning techniques involves lying still with the head in a medical “hair-dryer” open capsule for approximately 20 minutes. It is a completely painless procedure.
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to study internal soft tissue structures in detail. It provides good contrast between the different types of tissue, which is a major advantage over CT. MRI does not use ionising radiation unlike CT or traditional X-rays. Instead it uses a powerful magnetic field to align tissue atoms, and then uses radiofrequency fields to change and record their alignment. This scanned information is then used to construct images of specific parts of the body.
The patient lies still on a couch with their head in a metal tube for about 30 minutes. Some patients find this enclosed experience unpleasant, which has resulted in the development of so-called “open scanners”.Book Appointment