From malignant hypertension to hypertension-MOD: a modern definition for an old but still dangerous emergency

The prevalence of malignant hypertension has clearly fallen with the advent of anti-hypertensive medication but has remained stable over the past 30-40 years in spite of progress in diagnosis and management of hypertension. A diagnosis of malignant hypertension is usually based on the association of severely elevated blood pressure with a Keith and Wagener stage III or IV retinopathy. We believe that this definition can be reconsidered for several reasons. Although simple and pragmatic, this definition corresponds to a time when there were few techniques for assessment of hypertensive target organ involvement, and does not take into account involvement of kidney, brain and heart; whereas the overall prognosis largely depends on how much they are affected. On the contrary, the acute blood pressure level and especially diastolic should not be a hard diagnostic criterion as it does not itself constitute the prognosis of the condition. We propose to consider that malignant hypertension with retinopathy is only one of a number of possible presentation(s) of acute hypertension with multi organ damage (hypertension multi organ damage (MOD)) and that the recognition of these hypertensive emergencies, when retinopathy is lacking, be based on acute elevation of BP associated with impairment of at least three different target organs. The objective of a new and expanded definition is to facilitate recognition of these true emergencies. The condition is more common than usually perceived and would have a much worse prognosis than the usual forms of hypertension. Early recognition and management of hypertension-MOD are fundamental to any improvement in prognosis