Prader-Willi syndrome and hot weather: Understanding the risks and how to stay safe

People with Prader-Willi Syndrome can be particularly vulnerable during heatwaves because PWS affects the hypothalamus, the part of the brain responsible for regulating body temperature, thirst, hunger, hormone production, sleep, and many automatic body functions.

The combination of impaired temperature regulation, altered thirst responses, co-occurring health conditions like diabetes and obesity and reduced awareness of illness means that some people with PWS may not recognise when they are becoming dangerously overheated, putting them at risk of heatstroke and dehydration

Heatstroke and Heat Exhaustion

People with PWS might not be able to recognise or tell you when they’re too hot, so it's important to monitor them closely during periods of intense heat.

Watch out for red cheeks, lethargy and 'shutdowns', these are all potential signs that the heat is getting to them.

Tips for Keeping Cool:

• Provide regular cool drinks
• Place wet towels or cooling pads on neck, underarms and groin to cool down fast
• Scale back your plans and avoid strenous physical exertion
• Moving someone once they go into shutdown can be very difficult - instead, encourage them to spend time in the coolest part of your house

Dehydration

Dehydration can have serious consequences on temperature regulation, increase fatigue, and affect kidney function. In addition it carries a risk of constipation which brings increased danger for people with PWS.

Getting people with PWS to drink enough water can be a struggle, however, as many people find it tastes unpleasant. In periods of extreme heat, adults can require up to three litres of fluid a day, so if someone with PWS is struggling to drink enough water, a low sugar alternative should be offered.

Medication-related heat risks

Some medications prescribed to people with PWS, such as SSRIs, Antipsychotics, Insulin and Desmopressin can carry additional risks in hot weather.

People on SSRIs or Antipsychotics be closely monitored for symptoms of heat exhaustion and dehydration and follow the advice above to stay safe.

Diabetes

Hot weather can affect both blood glucose levels and how insulin works in the body.

Extreme heat can:

• Cause dehydration, which can affect blood glucose control.
• Increase blood flow to the skin, making insulin absorb more quickly.
• Increase the risk of low blood glucose (hypoglycaemia).
• Make it harder to recognise symptoms of overheating because some symptoms are similar to low blood glucose.
• Damage insulin if it becomes too hot, making it less effective

How to help:

Offering regular drinks

Checking blood sugar more often if possible

Keeping insulin cool

Staying out of the hottest sun

Getting urgent help if the person collapses, has a seizure or becomes confused.

Desmopressin

In hot weather, desmopressin requires special attention because the usual advice to "drink more water" may not always be appropriate.

Drinking too much fluid while taking desmopressin can lead to water intoxication and low sodium levels (hyponatraemia), which can be serious.

 If you or the person you care for is prescribed Desmopressin, you may wish to draw your clinician's attention to this study about the use of Desmopressin in PWS: https://pubmed.ncbi.nlm.nih.gov/34441851/