Overview
Definition:
Hypertensive emergency in a pediatric patient is defined by a severely elevated blood pressure (typically systolic BP > 99th percentile for age, sex, and height, or > 180/120 mmHg, although specific targets may vary based on underlying condition and patient age) with evidence of acute, ongoing target organ damage
This is a medical emergency requiring immediate BP reduction to prevent irreversible organ injury.
Epidemiology:
Hypertensive emergencies are relatively uncommon in children compared to adults, with an incidence of approximately 0.1% to 0.5% in pediatric hospital admissions
However, they can occur in various pediatric populations, including neonates with congenital anomalies, infants with renal disease, and older children with conditions like hemolytic uremic syndrome (HUS), neuroblastoma, or coarctation of the aorta
Risk factors include prematurity, prematurity, renal disease, neurologic disorders, and certain genetic syndromes.
Clinical Significance:
Prompt and appropriate management of hypertensive emergencies in the PICU is crucial to prevent severe morbidities such as stroke (hemorrhagic or ischemic), myocardial infarction, acute kidney injury, pulmonary edema, retinal hemorrhage, and encephalopathy
Early recognition and effective blood pressure control can significantly improve patient outcomes and reduce long-term sequelae
Understanding the specific properties and indications of IV antihypertensive agents like labetalol and nicardipine is paramount for pediatric intensivists.
Clinical Presentation
Symptoms:
Symptoms can be non-specific and may include severe headache
Visual disturbances like blurred vision or scotomas
Nausea and vomiting
Lethargy or altered mental status
Seizures
Chest pain or shortness of breath
Decreased urine output
Irritability.
Signs:
Extremely elevated blood pressure readings (e.g., >99th percentile for age or >180/120 mmHg)
Tachycardia or bradycardia
Signs of neurologic compromise (e.g., focal deficits, papilledema)
Pulmonary rales or gallops
Peripheral edema
Signs of poor perfusion
Organ-specific findings related to target organ damage (e.g., ECG changes for cardiac involvement, elevated creatinine for renal involvement).
Diagnostic Criteria:
No single universal set of diagnostic criteria exists for pediatric hypertensive emergency, but it is generally defined by the presence of severely elevated blood pressure and evidence of acute target organ dysfunction
Key components include: 1
Severely elevated blood pressure
2
Evidence of acute target organ damage (neurologic, cardiovascular, renal, ocular, or aortic dissection)
3
Absence of other identifiable causes for the severe hypertension if it is newly diagnosed.
Diagnostic Approach
History Taking:
Detailed birth history in neonates and infants (e.g., prematurity, birth asphyxia)
History of known renal disease, cardiac anomalies, or neurologic disorders
Family history of hypertension or cardiovascular disease
Recent infections or illnesses (e.g., HUS)
Medication history (e.g., use of sympathomimetics, corticosteroids)
Symptoms suggestive of target organ damage (headache, visual changes, seizure).
Physical Examination:
Accurate and repeated blood pressure measurements using appropriately sized cuffs in all extremities
Thorough cardiovascular examination (auscultation for murmurs, gallops, rubs)
Neurological examination (assess mental status, cranial nerves, motor and sensory function, reflexes, signs of meningeal irritation)
Funduscopic examination for papilledema, hemorrhages, or exudates
Assessment for peripheral edema
Palpation of peripheral pulses for adequacy and symmetry (to rule out coarctation).
Investigations:
Complete blood count (CBC) with differential to assess for anemia, thrombocytopenia (relevant in HUS)
Renal function tests (serum creatinine, BUN) to assess kidney injury
Electrolytes (sodium, potassium, chloride, bicarbonate)
Urinalysis for proteinuria, hematuria, and casts
Electrocardiogram (ECG) to assess for cardiac strain or ischemia
Echocardiogram to evaluate cardiac function and structure
Chest X-ray to assess for pulmonary edema
Neuroimaging (CT or MRI brain) if neurologic deficits are present or suspected
Arterial blood gas (ABG) for acid-base status and oxygenation
Serum lactate dehydrogenase (LDH) and haptoglobin if hemolysis is suspected
Coagulation profile (PT, PTT, INR) if disseminated intravascular coagulation (DIC) is a concern.
Differential Diagnosis:
Essential hypertension (primary)
Secondary hypertension due to identifiable causes (renal parenchymal disease, renovascular hypertension, endocrine disorders like pheochromocytoma or hyperaldosteronism, coarctation of the aorta, neurologic disorders)
Hypertensive urgency (severely elevated BP without target organ damage)
Overdose of certain medications (e.g., stimulants)
Withdrawal from certain medications (e.g., clonidine, antihypertensives).
Management
Initial Management:
Immediate assessment of airway, breathing, and circulation (ABCs)
Secure intravenous (IV) access
Continuous cardiac and blood pressure monitoring
Prompt initiation of IV antihypertensive therapy
Goal is gradual reduction of mean arterial pressure (MAP) by approximately 20-25% in the first hour, followed by further gradual reduction as tolerated, to avoid cerebral hypoperfusion
Avoid rapid drops in BP below autoregulatory limits.
Medical Management:
Choice of IV antihypertensive agents depends on the clinical presentation and suspected etiology
Two commonly used agents in PICU are Labetalol and Nicardipine:\n\n**Labetalol**: A combined alpha and beta-adrenergic blocker
It is often a first-line agent due to its rapid onset and predictable effect
Dosage: Initial bolus of 0.1-1 mg/kg IV over 30 minutes (max 20 mg)
Can repeat bolus every 10-20 minutes as needed
Maintenance infusion: 0.5-2 mg/kg/hr
Contraindications: Asthma, certain types of heart block, significant bradycardia, decompensated heart failure.\n\n**Nicardipine**: A dihydropyridine calcium channel blocker
It causes potent peripheral vasodilation and is particularly useful in hypertensive emergencies with increased sympathetic tone or when rapid titration is needed
Dosage: Initial bolus of 1-2 mcg/kg/min
Maintenance infusion: 1-6 mcg/kg/min (titrated to effect)
Contraindications: Severe aortic stenosis, caution in patients with heart failure
Advantages: No negative inotropic effect, useful in hypertensive emergencies with suspected intracranial hemorrhage or aortic dissection.
Surgical Management:
Surgical intervention may be required for specific underlying causes of hypertensive emergency, such as repair of coarctation of the aorta, resection of a pheochromocytoma or neuroblastoma, or management of a ruptured aortic aneurysm
However, surgical management is typically delayed until the patient is hemodynamically stabilized and blood pressure is controlled with medical therapy.
Supportive Care:
Close neurological monitoring for signs of intracranial hemorrhage or edema
Management of fluid and electrolyte balance
Sedation and analgesia as needed
Respiratory support if indicated (e.g., mechanical ventilation for pulmonary edema or altered mental status)
Strict intake and output monitoring
Management of underlying comorbidities.
Complications
Early Complications:
Cerebral edema and stroke (ischemic or hemorrhagic)
Myocardial infarction or acute heart failure
Acute kidney injury
Pulmonary edema
Hypertensive encephalopathy
Retinal hemorrhages
Aortic dissection.
Late Complications:
Chronic kidney disease
Long-term cardiovascular sequelae (e.g., left ventricular hypertrophy, accelerated atherosclerosis)
Visual impairment
Cognitive deficits
Persistent organ dysfunction.
Prevention Strategies:
Prompt recognition and aggressive management of elevated blood pressure in at-risk pediatric patients
Careful titration of antihypertensive medications to avoid rapid drops in blood pressure and resulting hypoperfusion
Management of underlying causes of secondary hypertension
Regular monitoring of blood pressure in children with known risk factors
Patient and family education regarding adherence to treatment.
Prognosis
Factors Affecting Prognosis:
The presence and severity of target organ damage at presentation
The underlying cause of the hypertensive emergency
The speed and effectiveness of blood pressure control
The presence of comorbidities
The patient's age and overall health status.
Outcomes:
With prompt and appropriate medical management, many children with hypertensive emergencies can achieve a good outcome, with resolution of acute symptoms and preservation of organ function
However, significant morbidity and mortality can occur if diagnosis and treatment are delayed, or if extensive target organ damage is present
Long-term follow-up is essential to monitor for sequelae.
Follow Up:
Regular follow-up with a pediatric nephrologist and/or cardiologist is recommended
Serial monitoring of blood pressure, renal function, cardiac function, and neurological status
Further investigation and management of the underlying cause of hypertension
Long-term antihypertensive therapy may be required in many cases.
Key Points
Exam Focus:
Hypertensive emergency is defined by severe BP elevation PLUS target organ damage
Aim for gradual BP reduction (20-25% MAP first hour)
Labetalol and Nicardipine are primary IV agents in PICU
Know their contraindications and typical dosing
Consider underlying causes of secondary hypertension.
Clinical Pearls:
Always use appropriately sized cuffs for accurate BP measurement in children
Document BP in all four limbs if coarctation is suspected
Titrate IV infusions slowly to avoid cerebral hypoperfusion
Monitor urine output closely as an indicator of renal perfusion
Early consultation with pediatric critical care and relevant subspecialties is vital.
Common Mistakes:
Treating severely elevated BP without evidence of target organ damage as an emergency
Overly aggressive BP reduction leading to hypoperfusion
Using inappropriate cuff sizes leading to inaccurate readings
Not considering and investigating underlying causes of secondary hypertension
Incorrect dosing or administration of IV antihypertensive agents.