Hypertension in the oncology patient
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Hypertension can occur for a variety of reasons. Probably the commonest reason in children (particularly adolescents) is high dose steroid treatment. This often needs treatment but is rarely an emergency. Management of hypertension should be discussed with the paediatric oncologist and often the paediatric nephrologist as well. Drug doses as listed in the dosage table.
Hypertension is a common sign in paediatric oncology
Borderline hypertension can be managed in a "wait and watch" fashion, whereas marked hypertension ( > 99th centile) may need to be managed urgently in view of the risk of hypertensive encephalopathy.
Causes of Hypertension
Hypertension is most often a result of:
- Wilms tumour compressing the normal kidney and inducing reno-vascular hypertension.
- Neuroblastoma - chronic hypertension is usually secondary to kidney compression as for Wilms tumours. Hypertensive crises may be induced by massive release of catecholamines, e.g., during surgery/biopsy of a neuroblastoma.
- Brain tumours and raised intracranial pressure.
- Therapy-induced - steroid, CSA, tumour lysis syndrome.
Use the Blood Pressure Tables and judge a patient hypertensive if systolic and/or diastolic pressure > 95th%tile for age, sex and height. BP consistently above the assigned level should be treated. For full BP ranges and 95 centile levels in children, see:
Treatment of Hypertension
Choice of therapy depends on the severity of the hypertension and its underlying cause.
The paediatric nephrologist should be contacted for advice on a patient requiring treatment for hypertension; it is mandatory they are consulted urgently in the event of a hypertensive crisis.
Many children with severe hypertension at presentation have extracellular fluid depletion, the administration of diuretics at that point is contraindicated because severe hypotension may ensue. Unless saline overload is obvious, it is safer to reserve diuretics until the hypertensive state is stabilised.
The first step is to consider the underlying cause:
- If there is fluid overload, then decrease IVF therapy.
- For raised ICP, start mannitol and dexamethasone.
- If renal compression is the cause then anti-hypertensive therapy will be needed until tumour bulk can be reduced by medical or surgical means.
- If the cause is drug therapy then check for toxicity e.g., cyclosporin, or support with antihypertensives over the treatment course e.g., steroids.
Treatment of moderate to severe Hypertension
Children with moderate to severe hypertension should be discussed with the renal team. They can usually be managed effectively with the stepwise introduction of:
- Oral labetolol (1-2 mg/kg BD initially which can increase to 10
mg/kg (max 600 mg) QID)
if BP not controlled add
- Oral frusemide
Hypertensive Crisis/Acute Hypertensive Encephalopathy
This is: "A severe elevation of BP associated with a clinical
picture of progressive and rapid CNS, visual, myocardial,
haematological or renal deterioration."
This scenario is usually encountered when the BP is particularly high but can also be seen when the BP appears only moderately elevated and
- the patient is suffering from tumour lysis syndrome
Under these circumstances, the aetiology is usually fluid overload due to continuing hyperhydration in the face of worsening renal function. Treatment should be discussed with the renal team and usually involves diuretics.
- post-stem cell transplant thrombotic thrombocytopenic purpura
(TTP) syndrome develops.
TTP is a microangiopathy with intravascular coagulation due to "endothelial inflammation" as a result of disordered immune mechanisms. Recognised early by raised reticulocytes, raised LDH and increased % fragmented RBCs. Patients then develop low Hb and refractory thrombocytopenia. Haematuria and proteinuria may develop if the kidneys are involved in the thrombotic microangiopathy.
Under both these circumstances, patients may rapidly develop posterior leucoencephalopathy syndrome.
Treatment of Hypertensive Crisis/Acute Hypertensive Encephalopathy
- Discuss with the paediatric nephrologist.
- Drugs with a rapid action are necessary but require a titrated continuous infusion and careful administration to prevent sudden hypotension resulting in end organ damage.
- Labetalol and sodium nitroprusside are both effective. Labetalol is easier to administer as Na+ nitroprusside needs to be administered in ICU.
- Avoid simultaneous administration of oral hypotensive agents or diuretics in the initial management of hypertensive crisis; these are best reserved until the blood pressure is safely controlled.
- Do not aim for a normal blood pressure but rather to lower to
safe levels (e.g., in adults a diastolic of 100mmHg is the aim).
The target BP must be clearly defined at the start of treatment.
for girls, and BP for boys.)
BP should be decreased:
- in the first 6 hours by not more than one-third of the total reduction planned
- by a further one third over the next 12-36 hours
- and the final third over the next two days.
- An IV line must be available throughout so that saline or plasma can be administered if the BP drops unexpectedly. A central line is also valuable to monitor the CVP for detection of volume overload or depletion, however, the usual oncology lines are generally not suitable for this purpose.
- In the event of a convulsion, diazepam and a loading dose of phenytoin should be administered intravenously in addition to steps being taken to reduce blood pressure by IV Labetalol.
Posterior Leucoencephalopathy Syndrome
The features of this syndrome may develop as part of a hypertensive crisis and are characterised by sudden onset of:
- reduced level of consciousness
- cortical blindness
- MRI changes particularly affecting the occipital lobes.
Symptoms and signs often reverse as rapidly as they appear.
Hypertension in Neuroblastoma Patients
In preparation for surgery, hypertension should be treated with labetolol. However, chronic hypertension is probably due to renal compression rather than catecholamine excess and may require treatment with an ACE-inhibitor. See the drug dose table below.
Drug Dose Table
Click on link to view Drug Dose table. Includes information on Labetalol infusion.
Kaelber and Pickett. Pediatrics 123(6) 2009 p972-974 The Fourth report on the diagnosis, evaluation and treatment of high blood pressure in children and adolescents. Pediatrics 2004; 104:555-576
Christchurch hospital Blue Book for the management of common medical conditions 2009 13th edition.
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- Date last published: 01 December 2010
- Document type: Clinical Guideline
- Services responsible: National Child Cancer Network
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