Introduction

Some patients with pulmonary infiltrates and a supposed infectious pneumonia may not respond in a seemingly appropriate fashion to antimicrobial therapy. Their progress may be unduly prolonged, the pneumonic process may recur or may not resolve on antibiotics. There are four possibilities viz: (a) a truly infectious pneumonia of common aetiology, e.g. caused by Streptococcus pneumoniae, Haemophilus or Legionella spp, which is resolving at a perceived slow but a normal expected rate; (b) an infectious pneumonia of either an uncommon aetiology, for example, Mycobacterium tuberculosis, or of a common aetiology but in which the organism is resistant, the mode of antimicrobial treatment is not appropriate (e.g. low dosages) or there are suppurative or indirect complications arising from the pneumonia, but which, once recognised and treated appropriately, will respond accordingly; (c) an infectious pneumonia which is resolving slowly or which recurs as a result of an underlying host mechanical defect, or immunocompromisation, including aged and pregnant patients; (d) an apparent infectious pneumonia which does not resolve or recurs and is in reality non-microbial in origin. This chapter will address each of these categories, highlighting some of the more major examples (Fig. 28.1). The special setting of nosocomial pneumonia is addressed in Chapter 19.

Definitions: slowly resolving, chronic and recurrent pneumonia

These terms are, to some extent, arbitrary and variable. Some reports focus on radiographical abnormalities, others on the accompanying acute/chronic pulmonary and systemic features such as cough, malaise and fatigue.