Approach

The key to diagnosis of hypertensive emergency is a rapid but thorough evaluation. The main areas of focus should be the neurological, cardiovascular, and renal systems. Emergency treatment should be initiated while conducting a full diagnostic appraisal.

History

Any prior history of hypertension and previous treatment (including treatment adherence) should be identified.[7]​[18]​ Prior or existing history of neurological, cardiac, and renal impairment should also be determined.

Clinical features that may identify specific organ compromise include:[18][24][40]​​[54]

  • Neurological compromise: for example, blurry vision, dizziness, headache, seizures, change in mental status from baseline, dysphagia, loss of sensation, paraesthesia, or loss of movement

  • Cardiac compromise: for example, chest pain, shortness of breath, diaphoresis, orthopnoea, paroxysmal nocturnal dyspnoea, palpitations, or oedema

  • Renal compromise: for example, decrease in urine output.

When appropriate, use of street drugs, particularly sympathomimetics (cocaine, amphetamines, phenylpropanolamine, phencyclidine, ecstasy, LSD) should be investigated.[7]​[18]

A diagnosis of pre-eclampsia or eclampsia should be considered in pregnant patients.[48][55]​ Commonly described features of pre-eclampsia headache include severe bilateral frontal headache and blurry vision, which may progress to bilateral cortical blindness.[55][56]​ The headache typically develops in temporal relation to the onset of pre-eclampsia, or substantially worsens or improves in parallel with worsening or improvement of pre-eclampsia.[55]​ In the setting of pre-eclampsia and headache, it is important to consider alternative secondary aetiologies (e.g., reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome, or infection) if accompanied by an altered level of consciousness, vomiting, or fever.[55]

Physical examination

An appropriately sized cuff should be used for blood pressure (BP) readings, so that the bladder encircles 80% of the arm.[1][57] The arm should be supported at heart level during recordings. Using too large a cuff could result in an underestimation of BP; conversely, too small a cuff could lead to over-estimation. It should be noted if a larger- or smaller-than-normal cuff size is used.[1]

BP readings should be taken from both arms.[7]​[54]​ Readings should be repeated after 5 minutes to confirm. If there is a more than 20 mmHg pressure difference between arms, aortic dissection should be considered.[58][59]​ If blood pressure is elevated, a second measurement should be taken.[60]

A fundoscopic examination should be performed, with the aid of slit lamp examination and pupillary mydriasis if necessary, looking for the presence of arteriolar spasm, retinal oedema, retinal haemorrhages, retinal exudates, papilloedema, or engorged retinal veins.[7]​[18][Figure caption and citation for the preceding image starts]: Fundus photograph of the right eye with multiple dot-blot haemorrhages typical of hypertensive retinopathyCourtesy Angie Wen MD, Attending Faculty, New York Eye and Ear Infirmary, New York; used with permission [Citation ends].com.bmj.content.model.Caption@305d029a[Figure caption and citation for the preceding image starts]: Fundus photograph of the left eye with multiple cotton-wool spots typical of hypertensive retinopathyCourtesy Angie Wen MD, Attending Faculty, New York Eye and Ear Infirmary, New York; used with permission [Citation ends].com.bmj.content.model.Caption@7c938dd3[Figure caption and citation for the preceding image starts]: Fundus photograph of the right eye centred on the optic nerve, showing multiple cotton-wool spots and macular exudates in a radiating star configuration around the foveaCourtesy Angie Wen MD, Attending Faculty, New York Eye and Ear Infirmary, New York; used with permission [Citation ends].com.bmj.content.model.Caption@30cc4424

A rapid bedside neurological examination is also required, including testing cognition, cranial nerve function, dysarthria, motor strength, gross sensory function, upper extremity pronator drift, and gait.

Cardiopulmonary status should be assessed, examining in particular for the presence of new murmurs, friction rubs, additional heart sounds, lateral displacement of the apex beat, jugular venous distension, carotid or renal artery bruits, rales, and lower extremity oedema.

Abdominal examination should be performed. Tenderness to palpation in the right upper quadrant is seen in severe pre-eclampsia and HELLP (haemolysis, elevated liver enzymes, low platelets) syndrome.[61][62]​​ Phaeochromocytoma may be associated with an abdominal mass.

Renovascular hypertension should be suspected in patients with severe hypertension who have abdominal bruits and/or unexplained renal deterioration with angiotensin-converting enzyme inhibitor treatment, although the clinical presentation is variable.

During pregnancy, hypertension in a previously normotensive woman with proteinuria or evidence of systemic involvement (e.g., renal insufficiency, impaired liver function, neurological complications, haematological complications) is diagnostic of pre-eclampsia.[48][61]​

Pre-eclampsia should be considered in patients with headache who are at least 20 0/7 weeks of gestation, or within 6 weeks postnatally, and who have blood pressure ≥140 mmHg systolic or ≥90 mmHg diastolic.[55]​

At least two measurements should be made, at least 4 hours apart.[48]​ The neurological examination is typically normal in pre-eclampsia.[55]​

See Pre-eclampsia (Diagnostic approach).

Laboratory evaluation

Baseline blood and urine samples must be collected prior to administration of treatment. Laboratory evaluation should include the following:[7]​[18][54]

  • Blood chemistry panel, including creatinine and electrolytes

  • Full blood count, including peripheral blood smear

  • Urinalysis with microscopy.

In some circumstances, the following may also be indicated:

  • Liver function tests, if pre-eclampsia or HELLP (haemolysis, elevated liver enzymes, low platelets) syndrome are suspected.[48][61]​​

  • Cardiac enzymes and/or brain natriuretic peptide, if acute coronary syndrome or acute heart failure is suspected.[18]

  • Coagulation profile, if disseminated intravascular coagulation is suspected.[18]

  • Urine or serum pregnancy test (in women of childbearing age not known to be pregnant).[18]

  • A urine drug screen, if illicit drug use is suspected.[63]

  • Plasma renin activity and aldosterone levels, if primary aldosteronism is suspected (e.g., in patients with diastolic hypertension with persistent hypokalaemia and metabolic alkalosis).

  • Spot urine or plasma-free metanephrine levels, if phaeochromocytoma is suspected (e.g., in patients with hypertension and palpitations, headaches, and/or diaphoresis, although clinical presentation is very variable).[18][63]​ These tests need to be interpreted carefully, with consideration for possible confounding factors such as drugs (e.g., tricyclic antidepressants, clozapine, phenoxybenzamine, beta-blockers, sympathomimetics, buspirone), or major physiological stress.

  • Thyroid function tests, if signs of hypo- or hyperthyroidism.

  • 24-hour urinary free cortisol, if Cushing syndrome is suspected.

  • Sleep study, in cases of resistant hypertension and for patients with signs or symptoms of obstructive sleep apnoea.[34]

Further investigation

ECG and chest x-ray should be strongly considered.[7]​[54]​ If aortic dissection is considered possible, urgent thoracic computed tomography angiography (CTA) scan with contrast is recommended.[64][65]​​​ For patients who cannot receive iodinated contrast, computed tomography (CT) without contrast is an acceptable alternative. Transthoracic echocardiography (TTE) may be used in the accident and emergency department, intensive care unit (ICU), or operating room for acute proximal dissections if the patient is clinically unstable and there is any question about the diagnosis, or if CTA is unavailable or contraindicated.[64][65]​ See Aortic dissection.

In clinical situations with high suspicion for renal artery disease, the use of doppler ultrasound, usually recommended as first-line imaging. This may be followed by magnetic resonance angiography and/or CTA.[66]​ Due to the potential risks with invasive procedures, angiography is generally limited to visualisation and quantification of the stenosis before vascular intervention.[66]

If ischaemic stroke or intracranial haemorrhage is suspected (e.g., in patients with decreased consciousness or those with focal neurological deficits), an urgent non-contrast CT scan of the head and/or a magnetic resonance imaging scan should be requested, depending on local availability.[18]​ Typically patients initially undergo a non-contrast head CT, in order to exclude a brain haemorrhage and guide treatment.[67]​ The mismatch between diffusion-weighted imaging and fluid-attenuated inversion recovery findings on magnetic resonance imaging (MRI) can be useful for selecting those who may benefit from intravenous thrombolysis.[67]​ However, MRI may take more than 30 minutes to complete, and is not universally available. See Ischaemic stroke and Stroke due to spontaneous intracerebral haemorrhage.

The American College of Obstetricians and Gynecologists recommends evaluating headaches in pregnancy that warrant brain or vascular imaging with magnetic resonance techniques that limit the use of gadolinium.[55]

Venepuncture and phlebotomy animated demonstration
Venepuncture and phlebotomy animated demonstration

How to take a venous blood sample from the antecubital fossa using a vacuum needle.

How to perform an ECG animated demonstration
How to perform an ECG animated demonstration

How to record an ECG. Demonstrates placement of chest and limb electrodes.

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