Lung diseases in the tropics. Part 1: Tropical granulomatous disorders of the lung: diagnosis and management.

International travel, student and cultural exchanges and changing immigration patterns are insidiously transforming the face of medicine in the United States, Europe and other developed countries. It is essential that the practising clinician be aware of the increasing prevalence of various new and exotic tropical lung diseases. The definitive diagnosis of the pulmonary granulomas that constitute the bulk of lung disorders in the tropics is important since the treatment varies significantly. At the same time, recent developments in molecular biology, immunology and biochemistry have increased the diagnostic accuracy and therapeutic effectiveness related to tropical granulomatous disorders. Clinicians in the developing countries can now supplement their clinical acumen with rapid advances in immunology and histopathology enabling them to grasp the fundamental mechanisms of granuloma formation. Mycobacterial, fungal, parasitic, spirochetal and other infections must be differentiated from a variety of non-infectious granulomas including sarcoidosis, hypersensitivity pneumonitis, drug reaction and generalized vasculitis since therapy is vastly different. The treatment, if inappropriate, may not only be worthless but, in many cases, extremely harmful and even fatal.