Stridor

Stridor is not a diagnosis but a physical sign of turbulent airflow. This type of noisy breathing occurs when there is an obstruction to breathing in (inspiratory stridor) or out (expiratory stridor) and may be present during both day and night. It is most commonly due to inflammatory conditions of the upper respiratory tract. Because an infant’s larynx is only one-third the size of an adults, stridor and airway problems are more frequent in this age group. Worsening or severe stridor is a medical emergency often requiring urgent treatment in hospital.

Diagnostics

Throat Swab for Microscopy and Culture

Why?

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.

How?

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.

Nasal Rigid / Flexible Endoscopy

Why?

The nostrils are quite small, so even using a very bright halogen headlight and a dilator instrument (speculum) to expand the nostril, it is impossible to see any more than the front part inside the nasal cavity. The introduction of a small sterile rigid endoscope with an angled lens, or a sterile flexible endoscope whose tip can be manually rotated in various directions, allows a very detailed inspection of the whole of the nasal cavity and the site of the sinus openings. Further back the nasopharynx and Eustachian tube openings can also be examined.

How?

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 an endoscope is an unusual feeling it is not unpleasant. The subsequent examination will take less than 5 minutes.

Videostroboscopy

Why?

The vocal cords vibrate very quickly when they are activated during phonation to produce sounds. This technique allows the rapid speed of movement of the vocal cords to be slowed down so that a detailed assessment of the rhythmic oscillations of the surface of the vocal folds can be made.

How?

The test involves placing a small external surface plate about the size of a stethoscope over one side of the voice box. This enables the frequency of the oscillations of the vocal folds to be measured. An exact adjustment of the wavelength of the special strobe xenon illuminating light can be made, which results in an image of the vocal cords vibrating at a very much slower rate.

CT Scan

Why?

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.

How?

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.

MRI Scan

Why?

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.

How?

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”.