Emergency presentations of Parkinson's disease: early recognition and treatment are crucial for optimum outcome.

Parkinson's disease (PD) is a debilitating condition associated with significant morbidity and mortality. Pathophysiologically the illness is due to a disruption of dopamine production in the basal ganglia and leads to a wide array of symptoms. These symptoms are not restricted to the nervous system; thus, the illness often presents acutely to a wide range of specialties, many of which may have limited experience in the condition. Patients often become unwell with illnesses unrelated to their PD. However, these conditions frequently lead to a deterioration in PD control. In addition, there exist certain acute complications of PD which are often difficult to recognise and carry significant mortality. Discussing the acute presentations of the illness under the umbrella of PD is important as it enables clinicians to focus upon the specific concerns involved in managing patients with the illness. A number of conditions are extremely common in PD and include falls, orthostatic hypotension, swallowing difficulties, psychosis, and hyperkinetic movement disorders. Optimal treatment of these conditions requires the consideration of issues specific to PD. Lesser recognised acute presentations of PD include the serotonin syndrome and neuroleptic malignant-like syndrome. While encountered less commonly, these conditions have been well described in the literature and untreated may prove fatal. They require urgent management, with their importance being further highlighted by the fact they may often mimic other illnesses, making diagnosis difficult. Therapeutic interventions aimed at treating PD and preventing its complications are evolving rapidly.