The symptom matrix: Using a formalism-based approach to address complex syndromes systematically

Complex rheumatological syndromes such as Systemic lupus erythematosus, Sjogren's Syndrome and many connective tissue disorders can be a challenge to classify and diagnose, due to their wide-ranging signs and symptoms, not all of which will necessarily be present in all patients. This can result in difficulties for the clinician, patient and researcher if signs and symptoms are either overlooked or are incorrectly included in the nosology or classification of diseases. This article presents a formalism-based approach to describing syndromes. This approach offers a more systematic way of representing signs and symptoms, to aid in diagnosis and classification of complex, heterogeneous and little understood syndromes. To illustrate this approach, Ehlers-Danlos Syndrome - Hypermobility Type is used as a worked example. This approach can also be applied to other syndromes in both clinical and educational settings, to assist with research, diagnosis, choice of treatment or intervention and nosology revision.