Hypertension: symptoms and causes

What are the symptoms of hypertension?

Often, there are no early symptoms in hypertension, especially if it is mild or moderate.

More common symptoms of hypertension

Some children with hypertension have the following symptoms:

  • headaches that keep coming back or that do not go away
  • vomiting (being sick), especially with a headache
  • blurred (fuzzy) vision.

If your child has any of the above symptoms, take them to your doctor to check their blood pressure as soon as possible.

Less common symptoms of hypertension

A few children with hypertension – especially if it is very high (malignant hypertension) – have the following symptoms:

  • blurred (fuzzy) vision
  • odd feelings/numbness
  • poor coordination, or movement disorders – they may seem clumsy
  • temporary weakness or paralysis (difficulty moving) of one side of the face (this is called Bell’s palsy)
  • seizures (which may also be called fits or convulsions).

If your child has any of the above symptoms, take them to your doctor or call 999 straight away.

Causes of hypertension

Your child’s doctor will try to find out what is causing hypertension in your child, and how severe it is. Hypertension may be primary or secondary. It may also be considered malignant.

Primary hypertension

Sometimes there is no known cause of hypertension. This is called primary hypertension or essential hypertension. It is quite common in older adults, but much less common in children. It may be linked to a eating a high-salt diet, smoking, drinking alcohol or being overweight. There are often no early symptoms.

Secondary hypertension

Sometimes an underlying problem with the kidneys or another part of the body is causing the hypertension. This is called secondary hypertension. It is more common in children. It can be acute (sudden) or long-term.

Acute hypertension

Acute hypertension starts suddenly or gets worse quickly. If your child has acute hypertension, he or she is admitted to the hospital. Your doctor will try to diagnose and treat the condition that is causing the high blood pressure. In some cases, after treatment, the blood pressure gets better over time.

Causes of acute hypertension in children include:

  • structural problems in the urinary system – where one or more parts have not developed normally
  • pyelonephritis – infection in the kidney
  • glomerulonephritis – a group of diseases that affect the kidney filters, the glomeruli
  • a side-effect of some medicines
  • occasionally, problems with the endocrine system (which controls many of the body’s functions), the heart or brain.

Causes of acute hypertension

Structural problems of the urinary system

In some children, one or more parts of the urinary system do not develop, or grow, normally. Children with structural problems are usually born with them, and they are sometimes found on a pregnancy ultrasound scan.

Different problems in the urinary system may cause acute hypertension:

Infection in the kidney

A urinary tract infection (often called a UTI) happens when germs (usually bacteria) get into the urine and travel into the urinary system. In serious cases, this infection can travel into the kidney. This is called pyelonephritis.


Glomerulonephritis is a group of diseases in which the kidney filters, glomeruli, are damaged or inflamed (swollen). Children with this condition have blood and protein in their urine, as well as swelling of the body, especially around their face and legs.

Other problems

Rarely, acute hypertension is caused by other problems:

  • a side-effect of some medicines – for example, a high dose (amount) of steroids, which may be given in hospital
  • a problem with the endocrine system, which is the system of glands that controls many of the body’s functions – for example, a tumour in the adrenal gland, which is the gland that sits on top of the kidney
  • a problem with the heart or the brain.

Long-term hypertension

Hypertension may also be caused by chronic conditions, which start slowly and last a long time, sometimes for life. If your child has a chronic condition that causes hypertension, his or her blood pressure will need to be controlled on a long-term basis. This often means taking medicine. Chronic conditions that cause hypertension in children include:

Scars in the kidneys

Some children have scars in the kidney – this is called renal scarring. Some children are born with these scars and do not have any other symptoms. Other children have urinary tract infections, which are caused by germs in the urine, because of the scars.

Cystic kidneys

Cystic kidneys are kidneys that have cysts on them. Cysts are round swellings that may be filled with a watery liquid. There are different types of diseases that cause cystic kidneys. Diseases that cause cystic kidneys include:

Renovascular disease

In renovascular disease (or renal vascular disease), there is a problem with the blood vessels that carry blood to the kidney. Types of renal vascular disease include mid-aortic syndrome and renal artery stenosis.

Hypertension with chronic kidney disease

Many children with chronic kidney disease have hypertension due to fluid and salt retention (the kidneys cannot remove enough water and salt). If the hypertension is not controlled, this increases the risk of further kidney damage.

Malignant hypertension

Malignant hypertension is very high blood pressure.

Children with malignant hypertension usually have most of the symptoms described in the symptoms section.

These children need quick and intensive treatment to control their blood pressure. They will need to be admitted to a specialist unit in the hospital that treats malignant hypertension.

More information

  • Blood pressure and your child’s health

    Understand more about children's blood pressure, how the kidneys control blood pressure to help make sure it is at a healthy level and how you can keep the whole family's blood pressure in a healthy range.

  • Measuring blood pressure

    Information about how children's blood pressure is measured in clinics, surgeries or hospitals, and when you might be asked to measure blood pressure at home.

  • Glomerulonephritis

    A group of conditions in which the kidneys are inflamed and leak blood and protein into the urine.