Hypertension

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CLINICAL DESCRIPTION

  • Diagnosis is based on a raised blood pressure measured while patient is at rest on at least 3 separate readings
  • Hypertension is generally asymptomatic
  • Essential hypertension is unusual in children and young adults and an underlying cause should be excluded at hospital level
  • Hypertension in children is dependent on the age, sex, and height

 

1 to 13 years

 ≥ 13 years

Normal BP

Systolic (SBP) and diastolic BP (DBP) < 90th percentile

<120/80

Elevated BP (Previously prehypertension)

SBP and/or DBP ≥ 90th percentile but < 95th percentile

SBP 120-129, DBP <80

Stage 1 hypertension

SBP and/or DBP ≥ 95th percentile to < 95th percentile + 12mmHg or 130/80 to 139/89 (whichever is lower)

130/80 – 139/89

Stage 2 hypertension 

SBP and/or DBP ≥ 95th percentile + 12

mmHg or ≥ 140/90 mmHg (whichever is lower)

BP ≥ 140/90

Causes include:

Renal disease (glomerulonephritis, Hemolytic uremic syndrome, renal failure, cystic renal disease)

  • Renovascular (renal artery stenosis)
  • Cardiovascular (coarctation of the aorta)
  • Endocrine (Cushing’s Syndrome, neuroblastoma)

HYPERTENSION IN CHILDRENCLINICAL DESCRIPTION

Refer all children with hypertension to a doctor for management

  • In children, hypertension is defined statistically because BP levels vary with age and outcome. Based data are not available for this population. Hypertension is defined as systolic and /or diastolic pressure levels greater than the 95th percentile for age and gender on at least 3 occasions
  • The upper limit for normal systolic Bp in children greater than 0one year may be calculated as follows:
    • {Age in years x 3} +100
    • Diastolic BP is 2/3 of systolic BP
    • 90% of hypertension in children is caused by renal conditions

The table below shows normative blood pressure levels {systolic/diastolic} in children up to age 5 years. Blood pressures above the 95th percentile indicate hypertension

Age

Mean BP levels

95th Percentile

1-3 days

64/41 {50}

78/52 {62}

1mo -2yr

95/58 {72}

110/71 {86}

2-5yr

101/57 {74}

115/68 {85}

Remember to use the correct cuff size when measuring BP. It should cover 2/3 of the upper arm

Primary hypertension

  • Idiopathic

Secondary hypertension

Renal disease

  • Renal parenchymal disease: glomerulonephritis
  • Polycystic kidney disease
  • Congenital abnormalities of kidney and urinary tract,
  • chronic kidney disease

Renovascular disease

  • Renal artery stenosis
  • Takayasu arteritis

Endocrine

  • Pheochromocytoma
  • Agangliomas 
  • Hyperthyroidism
  • Cushing’s syndrome

Cardiac

  • Coarctation of the aorta

Drugs

  • Steroids

Tumors

  • Wilm’s tumor
  • Neuroblastoma
  • Adrenal carcinoma

CLINICAL FEATURES 

SIGNS AND SYMPTOMS

  • Seizures, claudication, sweating, headache, tachycardia, altered level of consciousness, signs of underlying condition

INVESTIGATIONS

  • Limb BP, Urine dipstick and urinalysis, Urea, electrolytes, and creatinine, FBC, Abdominal ultrasound scan and doppler, ECG, Echocardiography, Fundoscopy, rest of investigations dependent on underlying cause

TREATMENT

NON-PHARMACOLOGICAL

  • Reduce salt intake
  • Regular monitored exercise
  • Weight loss

PHARMACOLOGICAL 

  1. Calcium channel blocker
    1. Nifedipine slow release 0.1-0.25mg/kg 6 hourly PO or
    2. Amlodipine 0.1mg/kg 4 to 6 hourly PO
  2. ACE-Inhibitor
    1. Enalapril 0.1mg/kg PO daily or 12 hourly or
    2. Lisinopril 0.1mg/kg PO daily
  3. Beta Blockers
    1. Propranolol 0.5-1mg/kg 12 hourly

Complications 

  • Hypertensive crises
  • Hypertensive retinopathy
  • Hypertensive nephropathy
  • Hypertensive cardiomyopathy

Referral 

Refer all children with hypertension for diagnostic work up

HYPERTENSION IN ADULTS 

CLINICAL DESCRIPTION

Classification of Adult Hypertension

Type of Hypertension

Systolic Blood Pressure

Diastolic Blood Pressure

Mild

140-159

90-99

Moderate

160-179

100-109

Severe

>180

>110

CLINICAL FEATURES

SIGNS AND SYMPTOMS

  • Usually none
  • Occasionally headaches, palpitations, dizziness, easy fatiguability
  • high Blood pressure ≥ 140/90 mmHg
  • +/-Displaced apex beat
  • Signs pointing to a specific cause for secondary hypertension

INVESTIGATIONS

  • FBC, Urinalysis, Blood urea, electrolytes, and creatinine, Blood glucose, Serum lipids, Serum uric acid, Chest X-ray, 12-lead ECG
  • Ultrasound scan of kidneys and adrenals (in suspected secondary hypertension) 
  • Echocardiogram

TREATMENT

NON-PHARMACOLOGICAL

  • Reduce salt intake
  • Stop smoking
  • Regular monitored exercise
  • Lose weight
  • Avoid excessive alcohol consumption
  • Prevent complications (stroke, heart failure, Myocardial infarction, chronic kidney disease etc.
  • Explain to the patient that treatment should be regular (every day), closely monitored and generally must be taken for life
  • Lifestyle changes mentioned above

PHARMACOLOGICAL 

  • Use the following stepped treatment approach with the medicines in this order unless there are specific contraindications, co- morbidities, or side- effects

Note: Consider medicine treatment for mild hypertension only if the above general measures are unsuccessful

Stepped anti-hypertensive treatment approach

Step 1: 

  • Hydrochlorothiazide 25 mg each morning, increasing the dose is not advised. Explain to the patient that treatment must be regular (every day), closely monitored and generally must be taken for life
  • Alternatively, give Bendrofluazide 5mg daily or Indapamide 2.5mg daily

Note: Avoid in pregnancy feeding and breastfeeding

Step 2: 

  • Give Hydrochlorothiazide 25mg once daily and Amlodipine 5- 10mg once daily
  • Where Amlodipine is not available Nifedipine 10-20mg slow-release tablets once or twice a day can be used.

Step 3: 

  • Give Hydrochlorothiazide 25mg once daily, Amlodipine 5-10 mg once daily and Enalapril 10- 20mg once daily (increase dose slowly)
  • Where Enalapril is not available Captopril 12.5-50mg (start with low dose) every 8 hours or lisinopril 10mg od can be used.
  • Best to start with a lower dose of Enalapril 5mg and increase to 10mg after observation of the BP response over a few days.
  • Avoid Enalapril and Captopril in pregnancy and breast-feeding

Step 4: 

  • Give Hydrochlorothiazide 25mg once daily and Amlodipine 5- 10mg once daily (or Nifedipine 10-20mg), Enalapril 10-20mg once daily and Atenolol 50-100mg once daily
  • Where Atenolol is not available Propranolol 40mg - 80mg every 8 hours can be used (start with low dose) or Carvedilol 12.5mg bd (and increase to 25mg bd if need be) or Nebilong 5-10mg daily.

Step 5: 

  • Refer to Medical Specialist

Note: Side-effects may outweigh benefits. In patients with severe hypertension or complications {heart failure, renal   failure} start medicine treatment immediately. 

  • In patients without co-morbidity, aim for a BP of around 140/90 and aim around 130/80 if co-morbidity (Diabetes, chronic kidney disease)
  • For patients taking ART, because of the interactions between Calcium Channel Blockers, and NNRTIs, please consider Enalapril or Atenolol before a Calcium Channel Blocker.
  • If not tolerating ACE inhibitors give ARBs e.g. Losartan 50-100mg daily or Telmisartan 40-80mg daily

Compelling indications for the choice of antihypertensives 

  • Left ventricular hypertrophy: ACE-I or ARB, CCB preferably Amlodipine.
  • Microalbuminuria: ACE-I or ARB.
  • Renal dysfunction: ACE-I or ARB; Caution- if eGFR <15min/ml without renal replacement therapy.
  • Previous stroke: Any of the first-line drugs, especially ACE-I.
  • Coronary artery disease (Angina/Myocardial infarction): ACE-I or ARB, Beta-blocker, CCB.
  • Heart failure: ACE-I or ARB, Cardio-selective B-Blockers- bisoprolol, metoprolol, carvedilol; Loop diuretics, Spironolactone in advanced heart failure.
  • Peripheral artery disease: CCB, ACE-I or ARB. Diabetes mellitus: ACE-I or ARB.
  • Atrial fibrillation: ARB or ACE-I or B-blockers

 Compelling Contraindications.

  • Gout: Thiazide diuretics.
  • Asthma: Beta-blockers.
  • AV block (2nd and 3rd degree): Beta blockers and calcium channel blockers.
  • Bilateral renal artery stenosis and hyperkalemia: ACE Inhibitor and ARBs

Referral Criteria:

Refer the following categories of hypertensive patients to an appropriate specialist: 

Note

  • Those not achieving the target blood pressure (BP) level after several months of treatment
  • Those on three or more anti-hypertensive drugs yet have poor BP control y Those with worsening of BP over a few weeks or months.
  • Those with plasma creatinine levels above the upper limit of normal.
  • Those with multiple risk factors (diabetes, dyslipidemia, obesity, family history of heart disease).
  • Those not on diuretics but have persistently low potassium on repeated blood tests.

All children, young adults, and pregnant women with elevated BP

HYPERTENSIVE EMERGENCY IN CHILDREN

CLINICAL DESCRIPTION

Hypertensive emergencies encompass a spectrum of clinical presentations in which uncontrolled blood pressures lead to progressive or impending end-organ dysfunction.

CLINICAL FEATURES 

SIGNS AND SYMPTOMS

  •  Encephalopathy, convulsions, Posterior reversible encephalopathy syndrome (PRES), Visual disturbances, retinal hemorrhages, blindness

INVESTIGATIONS

  • As per hypertension protocol

TREATMENT

NON-PHARMACOLOGICAL

  • Neuroprotective measures
    • Nurse head at 30 degrees
    • Treat seizures
    • Maintain normoglycemia
    • Give oxygen
    • Keep temperatures normal

PHARMACOLOGICAL 

  • Assess and manage Airway, Breathing, Circulation and Disability
  • Reduce BP slowly in order to prevent stroke, retinal and spinal cord infarction
    • one third of the total desired reduction in the first 12 hours
    • the next one third in 12 to 36 hours
    • last one third between 36 and 72 hours
  • Hypertensive encephalopathy: Give Hydralazine 0.15 mg/kg slow IV
    • repeat every 30-90 minutes as required
    • maximum dose: 1.7-3.6 mg/kg in 24 hours
    • long term management of hypertension would depend on the cause hence these patients need to be referred for proper management.
  • Labetalol
    • Loading dose 0.25mg/kg IV
    • Then continuous infusion of 0.25mg-3mg/kg/hour
  • Sodium Nitroprusside 0.5-8mcg/kg/min continuous infusion
  • If patient has oedema add frusemide 1-5mg/kg IV/PO 6 to 12 hourly

Complications 

  • Stroke
  • Hypertensive crises
  • Hypertensive retinopathy
  • Hypertensive nephropathy
  • Hypertensive cardiomyopathy

Referral

Refer all patients with hypertensive emergency

HYPERTENSIVE EMERGENCY IN ADULTS

CLINICAL DESCRIPTION

A severe and potentially life-threatening increase in blood pressures (BP) which may result in an acute stroke, retinopathy (grade 3-haemorrhage or 4-papilloedema), subarachnoid hemorrhage, seizures (hypertensive encephalopathy), heart attack, acute dissection of the aorta, heart failure, renal damage, or eclampsia (during pregnancy). The underlying cause may be primary hypertension; however, secondary causes of hypertension must be excluded. In adult patients this often occurs with a BP > 180/120 mmHg, while in children this may occur at lower BP levels.

CLINICAL FEATURESSIGNS AND SYMPTOMS 

  • Encephalopathy, convulsions, retinal hemorrhages, or blindness
  • Symptoms and signs of heart failure/stroke/heart attack/renal failure/aortic dissection

INVESTIGATIONS

  • FBC, Urinalysis, Urea, electrolytes, and creatinine, Cardiac enzymes (CK-MB, AST, CK, LDH, troponin, BNP) for acute coronary syndrome, Chest X-ray, 12-lead ECG, Echocardiogram and kidney Ultrasound, Brain CT scan (for stroke), Chest CT scan with angiography (for suspected aortic dissection)

TREATMENT

  • Reduce the blood pressure in a controlled manner to avoid impaired auto-regulation of cerebral blood flow.
  • Manage target organ damage accordingly
  • Control seizures if present
  • Only use parenteral therapy in:
    • malignant hypertension with heart failure
    • hypertensive encephalopathy
    • eclampsia
    • hypertension and dissecting aneurysm of the aorta

Note: Intravenous rapid lowering of blood pressure has several risks and should be done under close monitoring only, preferably in a high or intensive care setting. It is only indicated in hypertensive emergencies mentioned above.

NON-PHARMACOLOGICAL

  • Appropriate positioning of patient if unconscious (to keep airway patent), raise head of bed if in heart failure

PHARMACOLOGICAL 

  • Give Hydralazine 5-10 mg IM/IV. Repeat up to every 1 hour as necessary.
  • Alternatively, Labetalol, IV, Adults 20-50 mg STAT. (over a 2-minute period). Repeat at 10-minute intervals, if necessary, to a max. of 200 mg
  • If no IV drugs and patient fully awake give Nifedipine 20mg slow release po
  • If heart failure: add Frusemide 40 mg IV stat

Sub-lingual nifedipine (10 mg) should be avoided due to the unpredictable response of the blood pressure. If parenteral drugs are unavailable, then slow release nifedipine 20mg orally can be used.