Hypertensive Emergencies

Hypertensive Emergencies Amy Staples, MD, MPH UNM Department of Pediatrics

Outline • Measuring BP • Definition of Hypertension • Etiology of hypertension in kids • When to treat • How to treat

11 yo girl with a sinusitis, HA and BP 124/83 5 yo boy with rash, abd pain, joint pain, tea colored urine and BP 117/81 16 yo athletic boy in clinic for sports PE BP 132/84 HTN Treat ___ ___ ___ ___ ___ ___ Clinical Quiz

3 yo girl with NF, alert and playful; BP 125/77 2 yo girl with nephrotic syndrome admitted for albumin/lasix due to anarsca, with severe HA and seizure, BP 119/76; on admit 93/52 HTN Treat ___ ___ ___ ___ Clinical Quiz

Measuring accurate BP’s • Cuff too small → high reading • Cuff too big → OK reading or no reading (usually not falsely low) • Lower extremities - Normally, BP is 10 to 20 mmHg higher in the legs than the arms • Prefer arm if at all possible • Right arm for comparison with standards

Cuff Size • Bladder width> 40% of mid-arm circumference. • Bladder length80-100% of arm circumference. A. Ideal arm circumference B. Range of acceptable arm circumferences C.Bladder length D. Midline of bladder E.Bladder width F. Cuff width

Oscillometric Devices Measure mean arterial pressure (MAP) and calculates SBP and DBP • The algorithms used are proprietary and NOT standardized • Results can vary widely and they do not always closely match BP values obtained by auscultation • These machines must be calibrated regularly

Manual vs. Automatic • Manual is the gold standard • Oscillometric measurements preferred in infants and ICU settings ONLY • All high readings should be confirmed with a manual

Confirming High BP’s • Repeat BP in both arms and one leg (both not usually necessary) • Repeat 3 times to assure accurate • Dx of HTN requires elevated BP’s on 3 separate occasions

Disappearance of “HTN” with Repeated Measurement

New BP Normals • 4th report on the diagnosis, evaluation and treatment of high blood pressure in children and adolescents • Correlates with the JNC 7 • Uses new growth parameter data from NHANES

Definitions Normotensive • Average SBP and DBP <90th % for age, sex and height Pre-hypertension • Average SBP or DBP >90th but <95th percentile (OR >120/80) Hypertension • Average SBP and/or DBP >95th percentile for age, sex and height on 3 separate occasions • Stage 1: 95th-99th percentile + 5 mmHg • Stage 2: >99th percentile + 5 mm Hg

How to use the tables • Need: • Age, gender, height percentage • BP charts

7 yo boy Ht 75%tile 50% 99/58 90% 113/73 95% 119/80 99% 127/88 http://www.cc.nih.gov/ccc/pedweb/pedsstaff/bptable1.PDF

BP tables for Infants *Task Force on Blood Pressure Control in Children. Report of theSecond Task Force on Blood Pressure Control in Children—1987.Pediatrics.1987;79:1–25(PR)

Urgency vs. Emergency • Urgency – severely elevated BP with no current evidence of secondary organ damage, although if left untreated, target organ injury may result imminently →Decrease BP Soon • Emergency – severely elevated BP with evidence of target organ injury → Decrease BP Immediately • Target organs – CNS, heart, kidney, eye Constantine and Linakis, Pediatric Emergency Care, 2005

Severe Hypertension “Hypertension that represents a threat to life or to the function of vital organs” OR Severe hypertension is when your blood pressure goes up too! Adelman, et al. Pediatric Nephrology, 2000

Etiology of Hypertension Constantine and Linakis, Pediatric Emergency Care, 2005

Miscellaneous Causes • Endocrine • Hyperthyroid • Pheochromocytoma • Elevated ICP/CNS disease • Drug use (cocaine, ecstasy) • Medication (abrupt withdrawal) • Exercise • Traction • Hypovolemia

Overall • 15-20% Essential Hypertension • 80-85% Secondary Hypertension • 60-80% Renal • 8-10% Renovascular • 2% Coarctation

Which hypertensive patients need immediate treatment? • Severe HTN • Malignant HTN - >30% above 95% • Moderate – Severe HTN - >99% with target organ damage • Symptomatic HTN • Target Organ Damage

Complications of Severe HTN Retinopathy 27% Encephalopathy 25% LVH 13% Facial palsy 12% Visual changes 9% Hemiplegia 8% Deal, et al. Arch Dis Child, 1992

Clinical Signs of Malignant HTN • Eyes • Retinal hemorrhages, exudates and papilledema • Malignant Nephrosclerosis • ARF, Hematuria, Proteinuria • Hypertensive Encephalopathy • Headache, nausea, vomiting • Restlessness, confusion  seizures, coma • MRI (T2-weighted images) ; • Edema of the white matter of the parieto-occipital regions: posterior leukoencephalopathy

Eyes Papilledema, blurred optic disk, hemorrhages

Hypertensive Encephalopathy • Failure of autoregulation Shifted baseline Flynn, Ped Neph 2009; 24, 1101-1112

Hypertensive Encephalopathy • Headache, nausea, vomiting • Restlessness, confusion → seizures, coma • Posterior Leukoencephalopathy

Posterior Leukoencephalopathy T1 weighted images – normal appearing T2 weighted images – occipital hyperintensity

Severe Hypertension • Treatment Goals • Prevent adverse events • Reduce BP in controlled manner • Preserve target organ function • Minimize complications of therapy

Severe Hypertension • Treatment Risks • Rapid reduction of BP can lead to complications • Risk of hypoperfusion (ischemia) secondary to autoregulation • Medication side effects may have adverse effects depending on cause of hypertension (e.g. ACEi)

How Much Just Enough Depends on Acute vs. Chronic

How Much • Reduce by 25% of the planned reduction over 8-12 hrs • Another 25% over the next 8-12 hrs • Final 50% over the next 24 hrs • Planned reduction – goal is to the 95-99% for age and height If Unsure, slower is safer

What to do 1st • Monitor, Monitor, Monitor • Need cardiopulmonary monitoring • Need continual BP monitoring (frequently cycling cuff vs. arterial line) • Decide oral vs. IV • Oral OK if asymptomatic • IV necessary if acute target organ damage is present or imminent

IV Medication Rapid Action Titratable Easy to adjust the dose Requires IV access PO Medication Don’t need an IV Harder to control effects Absorption variable Slower kinetics can make titrating more difficult Oral vs. IV

First Line PO Isradipine Nifedipine IV Nicardipine Nitroprusside Labetalol Second Line PO Clonidine IV Hydralazine Enalaprilat Fenoldopam What to choose

Isradipine • Ca channel blocker (Inhibit Ca++ entry into smooth muscle cells → vasodilitation) • Onset of action 30-60 minutes • Side Effects: peripherial edema, flushing, nausea, headache, tachycardia • 0.05-0.1 mg/kg/dose q 4-6 hrs • 2.5 mg and 5 mg tab, 1mg/1ml suspension Nifedipine – 0.1-0.25 mg/kg q 4-6 hours (10 mg tab available) Onset of action 15-30 min

A note on Short acting Ca Channel Blockers • In adults with severe elevations in BP, Nifedipine has been associated with*: • Cerebral ischemia • Myocardial ischemia • Symptomatic hypotension • Preexisting MI, CAD, and hypovolemia predispose to these events. • In children Nifedipine / Isradapine have not been associated with cerebral or myocardial events. † *Grossman E, JAMA 1996;276:1328-31 †Sinaiko AR, NEJM 1997;336:1675

Nicardipine • Ca channel blocker • Onset of action within minutes • Side Effects: same as isradipine • 1-3 mcg/kg/min continuous infusion

Nitroprusside • Direct arteriolar/venous dilator (via nitric oxide donation) • Onset of action within seconds • Side Effects: cyanide/thiocyanate toxicity • 0.5-1 mcg/kg/ min initially, titrate to max 10 mcg/kg/min • Must monitor cyanide levels if used for >24 hrs

Labetalol • Mixed alpha/beta blocker • Onset of action 5-10 min • Side Effects: bronchospasm, contraindicated in asthma, cardiogenic shock, pulmonary edema, or heart block • 0.2-0.3 mg/kg/dose q 10-20 min (max dose 20mg) can be converted into a drip

Enalaprilat • ACE inhibitor (prevents the vaso-constrictive and Na retaining effects of the RAS) • Onset of action 15 min, long duration of action • Side Effects: risk of decreased GFR • 0.005-0.01 mg/kg/dose • Use in cases of severe renin mediated HTN

Hydralazine • Direct arteriolar vasodilator • Side Effects: may cause Lupus-like syndrome • Can be given PO, IV, IM • 0.1 - 0.5 mg/kg q 4-6 hr (max 20 mg/dose)

Case # 1 11 yo girl with a sinusitis, HA and BP 124/83 Ht 75th% Blood Pressures 50% -105/62 95% -122/80 99% -128/87 Diagnosis Pain, repeat when well, no treatment

Case # 2 5 yo boy with rash, abd pain, joint pain, tea colored urine and BP 117/81 Ht 25th% Blood Pressures 50% - 93/52 95% - 110/71 99% - 118/79 Diagnosis GN, treat with medication, likely Ca channel blocker

Case # 3 16 yo athletic boy in clinic for sports PE BP 132/84 Ht 90th% Blood Pressures 50% - 119/67 95% - 137/86 99% - 144/94 Diagnosis Possibly Pre HTN, need repeat measurements and TLC

Hypertensive Emergencies