الفهرس 
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Abstract
hypertensive crisis is characterized by a rapid, elevated (usually with diastolic blood pressure [DBP] ≥ 120 mmHg) and often symptomatic rise in blood pressure (BP) in patients both with known or unknown arterial hypertension.1
The pathophysiology of this clinical condition is mainly due to sudden elevation of systemic vascular resistance 248, and the magnitude of the BP elevation is probably less important than the rapidity of the increase.2
Hypertensive emergencies [HE] encompass a spectrum of clinical presentations where elevation of blood pressure complicated by evidence of impending or progressive target organ dysfunction 3. The most important complications include ischemic stroke, encephalopathy, hemorrhagic stroke and myocardial ischemia 249. Morbidity and mortality depend on the extent of organ damage at presentation and on the degree of BP reduction250.
On the other hand, Hypertensive urgency [HU] is a severe elevation in blood pressure without progressive target organ dysfunction 3.
B-type natriuretic peptide (BNP), with the inactive fragment N-Terminal pro hormone brain natriuretic peptide (NT-pro BNP), is a peptide synthesized by atrial and ventricular cardiomyocytes, with a potent vasodilator, diuretic and natriuretic action; it decreases sympathetic outflow and inhibits vasopressin release.6
The contribution of the measurement of BNP and NT-pro BNP to the diagnosis and the prognosis of both acute heart failure and coronary syndromes has been well documented.251,252
There was no enough data on the potential diagnostic and prognostic role of BNP detection in distinguishing between HE and HU except for only one study done by Di Somma et al.256
The aim of our study was; to assess the role of BNP in the course of hypertensive crisis, to evaluate the possible role of BNP in the differential diagnosis between HE and HU; and to investigate the relationship between BNP concentration and BP acute burden with consequent myocardial ischemia or brain damage.
Our study was conducted on 30 patients admitted to inpatient wards and Critical Care Department in Kasr Al-Ainy hospital for rapid severe elevation of blood pressure. They were recruited between August 2010 and February 2011.
All patients with hypertensive crises, including hypertensive emergency patients with cardiac or neurological involvement and hypertensive urgency patients, were included in the study with exclusion for patients with age ˂18 or >90, heart failure, chronic renal failure (serum creatinine >2.5 mg/dl), liver cirrhosis, thyrotoxicosis and atrial fibrillation.
Peripheral venous blood samples were collected in all patients on admission and plasma BNP level was estimated by established methods.
Our study included patients with age ranged from 29-74 years with mean age (58.5± 12). We compared BNP in different ages and found that there is no significant correlation between BNP and age. (P = 0.3 and r = -0.17).
Our study included 17 males (56.67%) and 13 females (43.33%). On comparison of BNP level with both sexes we found there was no significant difference in BNP level between males (223.35±179.2) and females (131.77±255.2) (p= 0.257).
In our study, patients were grouped on the basis of clinical findings into hypertensive emergency (H.E) (15 patients) and hypertensive urgency (H.U) (15 patients).
Hypertensive emergency patients (15 pts.) were subdivided into 6 patients with acute coronary syndrome (ACS) whom accounted for 40% of H.E cases; all of them presented with unstable angina and 9 patients with neurological involvement whom accounted for 60% of H.E cases and included 4 patients with ischemic stroke (IS) whom accounted for 26.7%, 4 patients with hemorrhagic stroke (HS) whom accounted for 26.7%, and only 1 patient with hypertensive encephalopathy (HEn) whom accounted for 6.6%.
We compared BNP level in both main groups and found that BNP was significantly higher in H.E patients (324.33 ±233.16) than H.U patients (43±13.5) (p= 0.00) and it was higher in both groups than in the control group (8.13±5.8) (p=0.00). But There was no significant difference in BNP level between hypertensive emergency patients with cardiac and neurological involvement (p= 0.8) nor between patients presented with ischemic stroke, hemorrhagic stroke and hypertensive encephalopathy (p= 0.3).
In our study, in both studied groups with their subdivisions as well as in the control group there was no significant correlation between BNP level and systolic B.P (SBP), diastolic B.P (DBP), mean arterial pressure (MAP), pulse pressure (PP) and creatinine clearance (Cr.cl).
By statistical analysis; an optimal cutoff value of BNP level of 90 pg/ml was determined for the diagnosis and differentiation between HE and HU with very high sensitivity and specificity of 98% & 95% respectively.