Hypertensive Urgencies and Emergencies

Methods

The present study was done at the Emergency Department of the Martini Hospital (Turin, Italy) from June 1, 1992, to May 31, 1993. The Italian National Health Service is available to all Italian citizens. Citizens have access to a public emergency department 24 hours a day, either directly or when sent there by their doctor. There are no private emergency departments either in Turin or the whole Piedmont region of Italy.

All patients over 18 years of age who presented to the emergency department with a hypertensive crisis were included in the study; all patients were white. The criteria used to define hypertensive crisis were those of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure¹ and included diastolic blood pressure ≥120 mm Hg, according to previous reports.^{5 6 7 8} Both patients previously recognized to be hypertensive (those with known hypertension) and those who were not previously known to have hypertension (those with unknown hypertension) were considered. We classified as hypertensive emergencies all cases in which the increase in blood pressure was associated with one or more of the following types of acute or ongoing end-organ damage¹ : hypertensive encephalopathy; stroke (cerebral infarction or intracerebral or subarachnoid hemorrhage); acute pulmonary edema, congestive heart failure, left ventricular failure, or aortic dissection; acute myocardial infarction or unstable angina pectoris; progressive renal insufficiency; and eclampsia. All these conditions were diagnosed clinically and by diagnostic tests (blood and urine chemistry, eye fundus examination, ECG, roentgenogram, computed tomography, and ultrasound imaging) as appropriate; computed tomographic scanning in particular was performed in all patients with neurological symptoms. In the absence of end-organ damage all other hypertensive crises were considered by exclusion to be hypertensive urgencies.¹

Each patient underwent a complete history, physical examination, and routine blood and urine chemical analyses. Blood pressure was measured with the patient in the recumbent position by use of a mercury sphygmomanometer according to a standard technique. The average of two consecutive readings taken 30 seconds apart was used. Each patient was monitored at the emergency department for at least 24 hours and treated according to his or her condition with nifedipine, captopril, clonidine, sodium nitroprusside, or furosemide.^{5 7 9 10} All subjects gave informed consent to participate in the study.

The prevalence of hypertensive crises, urgencies, and emergencies is expressed both as a percentage of the total number of patients applying to the Internal Medicine Section of the Emergency Department and as a percentage of all medical urgencies-emergencies. We included in medical urgencies-emergencies any critically ill patient; that is, any patient with an illness or injury that by its nature and/or severity is a direct threat to life or places the patient at high risk of life-threatening complications.¹¹

All results were expressed as mean±SD. Statistical analysis was performed by Student’s t and χ² tests.

Results

The number of patients who applied to the Internal Medicine Section of the Emergency Department during the year of the study was 14 209, whereas the number of all medical urgencies-emergencies was 1634 (11.5%). The number of hypertensive crises according to Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure criteria and a presenting diastolic blood pressure ≥120 mm Hg was 449. No patient showing features of a hypertensive emergency had a diastolic pressure <120 mm Hg. The numbers of hypertensive crises, urgencies, and emergencies are reported in Table 1⇓; mean values of age and diastolic blood pressure were significantly higher in hypertensive emergencies than urgencies (P<.002 to P<.001), and there were more women than men in all groups. Hypertension was unknown in 23% of patients presenting with a hypertensive crisis, including 28% of those with a hypertensive urgency and 8% of those with a hypertensive emergency.

The Figure⇓ presents the distribution of hypertensive urgencies and emergencies by age class in men and women: the peaks of urgencies and emergencies were earlier in men than women (51 to 60 versus 61 to 70 years of age and 61 to 70 versus 81 to 90 years of age, respectively). The circadian and circannual distributions of hypertensive urgencies and emergencies showed two peaks during the day (at 9 am and 7 to 8 pm) and one peak during the year (January), respectively.

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Figure 1.

Bar graphs show distribution of cases of hypertensive urgencies and emergencies by decades of age in men and women.

Table 2⇓ reports the prevalences of hypertensive crises, urgencies, and emergencies, whereas Table 3⇓ reports the frequency of each type of end-organ damage in the group with hypertensive emergencies. The majority (83%) of the patients with hypertensive emergencies showed only one type of end-organ damage, whereas in small groups (14% and 3%, respectively) two or three types of end-organ damages were present simultaneously.

Table 4⇓ reports the frequency of signs and symptoms in all hypertensive crises, urgencies, and emergencies; headache, epistaxis, psychomotor agitation, and arrhythmia were more frequent in urgencies than emergencies (P<.04 to P<.001), whereas chest pain, dyspnea, and neurological deficit were more frequent in emergencies (P<.02 to P<.001).

Discussion

The present study provides an estimate of the prevalence of hypertensive crises in an emergency department during 1 year. This accounts for only 3% of the total patients but approximately one fourth (27%) of the urgencies-emergencies. To our knowledge, this last finding has never been reported before and indicates that hypertensive crises represent an important and common event in emergency medicine and require appropriate resources for their diagnosis and treatment. Data on the incidence of hypertensive crises in the general or hypertensive population would be most interesting from the epidemiological viewpoint, but to our knowledge they are not available in the literature and unfortunately cannot be estimated from the present study. Using the operational classification of hypertensive crises in urgencies and emergencies proposed by the Joint National Committee¹ we found that hypertensive urgencies are more frequent than hypertensive emergencies (76% and 24%, respectively). Although hypertensive emergencies represent only one fourth of hypertensive crises, they are by definition characterized by end-organ damage so that the medical staff devotes a lot of time and effort to these patients. Other reports on this topic could enable us to compare the data from various areas of the same country or different countries.

As far as the time of presentation of hypertensive crises is concerned, as previously noted, we found two peaks during the day (at 9 am and 7 to 8 pm) and one peak during the year (January). The peaks during the day do not represent the time at which the crises occurred, owing to the variability of the latency period between the appearance of symptoms and arrival at the Emergency Department either by their own choice or having been sent by their doctor (transport time). On the other hand, the circadian and circannual rhythms of hypertensive crises are unknown, even though the Framingham Study showed that sudden cardiac death had a circadian variation with a peak at 7 to 9 am.¹²

In our series of patients presenting with a hypertensive crisis, ≈60% were women (Table 1⇑). This high percentage of women is also present in hypertensive urgencies and probably reflects the larger number of women than men present in hypertensive populations.¹³ However, this excess disappears in hypertensive emergencies (Figure⇑), which suggests that hypertensive men are more susceptible than hypertensive women to end-organ damage. In addition, postmenopausal age seems to increase the susceptibility to end-organ damage.

Approximately one fourth of the patients presenting with hypertensive crises had unknown hypertension (Table 1⇑), indicating that a hypertensive crisis occurs most commonly in patients with known hypertension. These data confirm a previous report¹⁴ that suggested that often hypertensive patients did not take medication as prescribed or received inadequate therapy. Furthermore, the proportion of our patients with unknown hypertension is higher in hypertensive urgencies (28%) than emergencies (8%). Another interesting result of the present study deals with the frequency of signs and symptoms of hypertensive urgencies and emergencies and the pattern of end-organ damage in hypertensive emergencies. We found headache and epistaxis to be the most frequent signs at presentation in hypertensive urgencies (22% and 17%, respectively), whereas chest pain, dyspnea, and neurological deficit were the most frequent signs in hypertensive emergencies (27%, 22%, and 21%) (Table 4⇑). Furthermore, the most frequent end-organ damage associated with hypertensive emergencies were cerebral infarction, acute pulmonary edema, and hypertensive encephalopathy (24%, 23%, and 16%, respectively); cerebral hemorrhage accounted for only 4.5% (Table 3⇑). The clinical pattern of presentation of hypertensive crises had never been studied before and is of some interest in clarifying the natural history of the disease in this respect.

In conclusion, the present study indicates that hypertensive urgencies and emergencies represent one fourth of all events in emergency medicine, that a quite differentclinical pattern of presentation is present in hypertensive urgencies versus emergencies, and that cerebral infarction and acute pulmonary edema are the most frequent types of end-organ damage in hypertensive emergencies.