Korean J Med.
2005 Nov;69(5):466-473.
Difficult asthma
Abstract
- Five ten per cent of asthmatics remain symptomatic despite high-dose treatment. Difficult asthma must be distinguished from severe asthma. Difficult asthma was defined as persistence of symptoms despite treatment at step wise recommended. It is then important in patients with suspected difficult asthma to ensure that the diagnosis is correct, and that if the patient has asthma that the attributed symptoms are indeed all genuinely due to the asthma and not to coexisting physical or psychogenic respiratory conditions. It is also important to be alert to recognize both poor perceivers and over-reactors. Asthma may be difficult for the patient, for the clinician or both because of disease factors, doctor or nurse therapist factors, and/or patient factors. Investigation requires access to the full range of respiratory, imaging and allergy tests. There remains a small number of patients with genuine steroid-resistant asthma, brittle asthma and asthma with airway remodeling. The anti-inflammatory effects of GCs are mediated through receptors that modulate inflammatory gene expression. GC resistance results from an interaction between susceptibility genes, the host's environment, and immunologic factors. The management of these patients requires a systematic approach to rule out underlying conditions that lead to GC resistance or treatment failure, as well as the use of alternative strategies to inhibit tissue inflammation.
