Investigation of Disordered Respiratory Defences

Man’s respiratory tract is a major and intimate interface with his environment. Any deficiency in its defences will be quickly capitalized upon by microorganisms, and any generalized host defence defect will therefore often have its major manifestation or presentation as respiratory symptoms.

A high index of suspicion of a deficiency in respiratory defences must therefore be exercised when considering severe or frequent upper and/or lower respiratory tract infections.

The clinical and laboratory investigations of a suspected deficiency should proceed from the simple clinic screening to more complex tests, a few requiring admission to hospital. Non-immunological deficiencies should be considered as well as immunity deficiencies because a considerable part of the lung’s defences are non-specific. Logical investigation will lead to accurate diagnosis and logical treatment.

A final decision should always be made as to whether any defect demonstrated is truly primary or merely secondary to underlying disease.