[Approach to the patient in vegetative state. Part II: differential diagnosis]

A prerequisite to the diagnosis of vegetative state is the exclusion of apparently similar syndromes, in which the patient retains the consciousness partially or even completely. Some syndromes are not separate nosological entities and should be abandoned: the apallic state, the neocortical death, the decerebrate and decorticate state, the alpha-coma, the vigil or prolonged or irreversible coma are among them. Three conditions deserve special consideration. The term locked-in syndrome describes a patient completely paralysed and mute, but fully conscious, and is usually caused by ischemic lesions of the pons. Several variants do exist, either in the causes and site of lesion. Some patients may become paralysed and mute, but conscious because of polyneuropathies, that is in the absence of any lesions of the central nervous system. The akinetic mutism is a rare condition characterised by loss of speech and nearly absent bodily movements. Painful stimulation may cause appropriate withdrawing, and wakefulness and self-awareness may be preserved, but cognitive impairment is usually present. It must be emphasised that this condition can be due to potentially treatable lesions, such as hydrocephalus and craniopharyngioma. The term "minimally responsive" or "minimally conscious" describes severely disabled patients in whom meaningful responses can be demonstrated, although inconstantly. This condition, the true diagnostic challenge, often represents a transition phase of vegetative patients recovering consciousness. Physicians, physiotherapists and patient's relatives should work all together to reach a correct diagnosis, by using current available methods to monitorize the recovery of consciousness.