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

Clinical Quiz 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 ___ ___

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

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 length 80-100% 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

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

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 Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure

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 the Second 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

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

Etiology of Hypertension Newborn Early Childhood (Infant-6 yo) School Age (6-12 yo) Adolescence Renal vein thrombosis Coarctation Renal artery stenosis Congenital renal anomalies Renal parenchymal disease Renovascular disease Essential hypertension Some debate over the actual frequency of renal disease vs. renovascular disease (which is more common in 2 middle age groups) Some include BPD in newborns Constantine and Linakis, Pediatric Emergency Care, 2005

Miscellaneous Causes Endocrine Elevated ICP/CNS disease 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

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

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

Papilledema, blurred optic disk, hemorrhages Eyes Papilledema, blurred optic disk, hemorrhages 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 Edema of the white matter in the parieto-occipital regions

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

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) Ischemic event in the kidney in RAS and ACE use

Depends on Acute vs. Chronic How Much Just Enough Depends on Acute vs. Chronic

How Much If Unsure, slower is safer 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

Oral vs. IV 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

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

Nifedipine – 0.1-0.25 mg/kg q 4-6 hours (10 mg tab available) 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

Case # 4 3 yo girl with NF, alert and playful BP 125/77 Ht 25% Blood Pressures 50% - 88/48 95% - 105/66 99% - 113/74 Diagnosis NF (possible associated renal artery stenosis), Stage 2 HTN, treat with medication, renal vascular imaging

Case # 5 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 Ht – 75th% Blood Pressures 50% - 89/46 95% - 107/64 99% - 114/71 Diagnosis Acute HTN with end organ involvement, stop albumin, give lasix, consider IV therapy if sz continues

Flynn, Ped Neph 2009; 24, 1101-1112