Rare pleural diseases
Encyclopedia of Respiratory Medicine
School of Medical and Health Sciences / Graduate Research
Pleural effusions have over 60 recognized underlying causes and pose a diagnostic challenge in clinical practice. Although cardiac failure, cancer and infection account for a large proportion of pleural effusions, many less common conditions can drive pleural abnormalities. These conditions are often overlooked and may explain the portion of pleural conditions without a diagnosis (up to 20% in many series). In addition, it is increasingly recognized that pleural effusions may arise from multiple etiologies and rarer causes may be “buried” under more common concurrent diagnoses. These less common pleural diseases are usually considered only after initial investigations for more common causes are ruled out, and only by clinicians who maintain a high index of suspicion. New pleural conditions continue to be uncovered, therefore clinicians must remain up-to-date with diagnostic progress to avoid missing these etiologies. In this article, we highlight several less common pleural conditions that may easily be missed, with adverse consequences for the patient. Most of these conditions have identifying features either based on history (family history in Birt-Hogg-Dube syndrome [BHDS]) or physical examination (nail changes in yellow nail syndrome), imaging (lung cysts in BHDS), serology (raised IgG4 levels) or pleural fluid appearance (pseudochylothorax/chylothorax).