Paediatric Cystic Fibrosis (CF) - Salt and fluid advice for hot weather

Introduction

This leaflet is designed for families with children with Cystic Fibrosis (CF) and provides advice on salt and fluid in the hot weather.

What is salt?

Salt is a mineral that is made up of sodium and chloride. It has many important functions in the body including how muscles and nerves work and regulate the amount of water in the blood and tissues in the body.

Why children with CF need extra fluid and salt?

CF changes how salt and fluid move through the cells in the body. As a result, patients can lose high levels of salt and fluid through sweating. This increases the risk of dehydration and salt depletion. Patient on CFTR modulators are however less likely to lose as much salt through their sweat. Patients on CFTR modulators might only need additional salt in their diet or salt supplements in very hot weather and/or when they are doing strenuous exercise.

In hot weather children will sweat more, especially if they are running about or doing a lot of exercise. Salt levels in the body can drop quite quickly, which increases the risk of dehydration and salt depletion. Sodium is also particularly important in infancy to help your child grow.

People with CF don’t always feel thirsty, even if their bodies need more fluid. This may be due to the high salt losses through their sweat. This leads to your child not feeling thirsty, even after losing a lot of body fluid. Don’t rely on your child letting you know when they are thirsty. This is especially important in infants and young children. You need to anticipate this and be pro-active about keeping them hydrated.

How are salt levels checked?

Your child might be offered a urine test called a urinary sodium where we check salt levels in the urine. This measures the amount of sodium excreted in your child’s urine. You might be asked to put cotton wool in your infants or young child’s nappy or your child might be asked to collect urine in a pot. These tests are frequently done in infancy as babies with CF are likely to require salt supplementation to help them grow. When your child is older these tests might be performed once a year at annual review and other times in the year if clinically indicated.

Your child will have a sweat chloride performed at CF diagnosis and possibly another time in your child’s life if they have started on CFTR modulators. The sweat test measures the amount of salt (usually measured as chloride) in sweat.

What are the signs of salt depletion or dehydration?

Signs and symptoms of salt depletion or dehydration will vary in severity and your child may not experience them all at the same time.

Specific signs of dehydration in people with cystic fibrosis may include:

• Thick sputum that may be more difficult to clear from your child’s airways.
• Increased risk of gastrointestinal problems such as constipation or Distal Intestinal Obstruction Syndrome (DIOS). DIOS is a condition where the small intestine gets blocked by thickened stool.

When should I seek medical advice?

If your child vomits in the heat, has sunken eyes (dark circles) or is lethargic/floppy it is important to seek medical advice straight away as these may be signs of severe dehydration or heatstroke.

How can I prevent salt depletion in hot weather and/or when doing intense exercise?

These are some of the ways you can help:

• Keep out of the sun between the hours of 11am and 3pm and provide opportunities for rest during the hottest time of the day.
• Encourage your child to play in the shade and wear a hat. Make sure they avoid sunburn using high factor sun cream.
• Ensure your child drinks plenty of fluid.
• You might be advised to give additional salt to your child either in their diet and /or with salt supplements.
• When travelling to very hot dry countries, or when the weather in the UK is particularly hot and dry especially if they are exercising in hot weather, it is vital to give your child additional salt and fluids to ensure the sodium levels remain normal.

Remember: the more your child sweats, the more salt they lose and the more salt they require!

Some medications make the skin more sensitive to sun burn for example Ciprofloxacin and Voriconazole: very high factor sun cream MUST be used.

How can I increase salt in my child’s diet if required?

Try to give naturally salty foods where possible such as: cheese, salted butter, bread, baked beans, fish tinned in brine, smoked fish, olives, some meats for example sausages, bacon, ham, salami, chorizo, MarmiteTM, BovrilTM, Worcestershire sauce, soy sauce, tomato ketchup, gravies and stocks, pickles.

You can add a little extra salt in cooking or at the table

You can include foods with added salt such as: crisps, tinned or dried soup, salted crackers, salted nuts (children over 4 years), pretzels, salted popcorn, Bombay mix, ‘Cheddars’, ‘Pepperami’, sports drinks, packet and processed foods for example ready meals, pizza, Pot Noodles, pasta in sauce.

If advised, how can I give salt supplements to my child?

Salt supplements are very effective in the following circumstances: in hot weather; during intense exercise/ exercise lasting more than one hour; if you are going abroad to a hot country; if your child is showing signs of salt depletion or if they are clearly sweating a lot - for example you can see white salt marks on their pillow/salt crystals in their hairline.

The following are available and the CF team will give advice on these if needed:

• Oral Rehydration Solution (ORS) such as Dioralyte sachets: can be purchased over the counter. Many chemists and supermarkets have their own brand of ORS which are often cheaper than Dioralyte. Make up one sachet mixed in 200ml water (boiled, cooled water if under six months). Once made up this can be kept in the fridge for 48 hours. Usually available in neutral and blackcurrant flavour.
• 30% sodium chloride solution: Available from your GP on repeat prescription. This can be given using a small mouth syringe or can be mixed in small amount of milk or apple puree just before a feed.
• Slow Sodium tablets: Available from your GP on repeat prescription. These release salt gradually and should be swallowed whole.

Supplements should be given throughout the day and it is important your child also drinks plenty of fluid.

Please contact your CF team for specific doses and information on salt supplements.

How much fluid does my child need?

Fluid requirements vary depending on age and weight. Children with CF tend to require more fluid than other children.

As a guide, aim for at least the following amount of fluid per day:

• 1 – 3 years - 1200ml (2½ pints) - 5 Cups (each cup being about 250ml)
• 3 – 5 years - 1500ml (3 pints) - 6 Cups
• 5 – 10 years - 1800ml (3½ pints) - 7 Cups
• > 10yrs 2300ml - (4½ pints) - 8 – 10 cups

When would my child need more fluid?

• Illness and chest infections – if your child is unwell, they may require increased fluid to cover losses caused by sweating and having a raised body temperature.
• Hot weather and hot rooms – your child is more likely to become dehydrated in hot weather, both in the UK and when on holiday abroad. Air-conditioned rooms and hot rooms may also cause them to feel more dehydrated.
• Exercise – if your child sweats during exercise then they are more likely to become dehydrated, even if the exercise is low intensity.
• Raised blood glucose levels – if your child has CF-related diabetes and it is not well controlled, they may lose fluid when their blood glucose level is high.

What are good sources of fluid?

• Water
• Fruit juice/smoothies (diluted for younger children)
• Diluted squash
• Oral Rehydration Solution
• Isotonic sports drinks (in small amounts)
• Milky drinks such as milk, milkshakes, hot chocolate, Ovaltine, Horlicks etc
• Avoid caffeinated drinks such as cola, tea, and coffee in hot weather or for young children or choose decaffeinated versions of the above.

Some foods are also good sources of fluid such as ice lollies, ice cream, cucumber, melon, watermelon, yoghurts, custard, fruit purees and soups.

Practical tips for staying hydrated

• Try offering your child chilled drinks which may encourage fluid intake.
• Use a bigger glass or cup or bottle so your child will automatically drink more.
• Consider buying a bottle with measurements on the side of the bottle to monitor how much your child is drinking.
• Add fresh or frozen fruit slices such as lemon, berries, lime or orange to water to add flavour.
• Try adding sparkling water or soda water to squash or cordial for an alternative fizzy drink.
• Always have a water bottle when out and about to encourage fluid intake or consider buying an insulated cup if your child prefers hot or chilled drinks.
• Offer drinks with all meals and snacks.
• Encourage the school or nursery to allow your child to drink throughout the day and to carry a drink with them if able to do so. If your child struggles to drink water please ask the school or nursery to be flexible and to allow your child to drink non-water drinks if needed. We would be happy to support you if you are having some difficulties with this.

Practical tips for staying hydrated

Please contact your CF Team. If you are travelling to a hot country, it is important to let them know as soon as possible so that they can arrange salt supplements to be prescribed by your doctor.