Functional neurological symptoms

Abstract

Around one-third of neurology outpatients have symptoms that neurologists rate as only 'somewhat' or 'not at all' explained by disease. Around 20% of patients brought into hospital in apparent status epilepticus and about one in seven patients attending a 'first fit' clinic have a diagnosis of dissociative (non-epileptic) attacks. Patients with functional weakness are at least as common as patients with multiple sclerosis and represent the leading misdiagnosis in patients wrongly given thrombolysis for presumed stroke. A recent study of 3,781 new neurology patients in Scotland found that around 5% had a primary diagnosis of a functional motor or sensory symptom such as non-epileptic attacks, functional weakness or functional movement disorder. 1,2 aBstRact Functional neurological symptoms refer to neurological symptoms that are not explained by disease. They may also be called psychogenic, non- organic, somatoform, dissociative or conversion symptoms. The most common functional neurological symptoms are non-epileptic attacks and functional weakness. These are common in neurology and general medical practice, especially in emergency situations, where they can be mistaken for epilepsy or stroke. Many studies have shown that these symptoms often persist, are associated with distress and disability and, in the right hands, have a low rate of misdiagnosis. Physicians are often uncertain how to approach patients with these problems. Are patients making up the symptoms? How can the diagnosis be made confidently? What is the best way to explain the diagnosis to the patient? Does treatment ever help? This review takes readers through these questions with practical tips for avoiding common pitfalls, both in diagnosis and management. There is no good evidence that these symptoms are any more 'made up' than irritable bowel symptoms or chronic pain. The diagnosis should usually be made by a neurologist on the basis of positive signs of inconsistency such as Hoover's sign or the typical features of a non-epileptic attack. A 'functional' model of the symptoms is useful both in thinking about the problem and when explaining the symptoms to the patient. There are many useful steps in management that do not require a detailed understanding of aetiology in an individual patient.