Prader-Willi Syndrome (PWS) is a rare genetic, lifelong, multi system, multistage spectrum condition. It is complex and needs a multidisciplinary response. Patients have an atypical presentation, and have a different response to hospitals and medication than the general population. Note: Refer also to our resource ‘Recommended hospital admissions policy’.

PWS is present from birth. It is caused by an abnormality on chromosome 15. This causes malfunctioning of the hypothalamus and other aspects of the brain and muscles. Each person living with PWS is an individual and may not experience all characteristics of the syndrome.

The main characteristics of PWS are:

• Hyperphagia – often beginning around 2-4 years but can commence much later.
• Hypotonia – from birth.
• Hypogonadism – from birth.
• Short stature, compared with other family members (less evident if the person is receiving growth hormone treatment).
• Delay in and difficulties with emotional and social development.
• Developmental delay/learning disabilities ranging from severe to borderline. A minority of people with PWS do not have a general learning disability. Most have specific difficulties such as slower processing of verbal information, etc.
• Challenging behaviours, (PWS behavioural phenotype), regardless of whether the person has a learning disability.
• A significant number of individuals living with PWS also have Autism Spectrum Disorder.

If the PWS patient is to be admitted, refer to the Admissions Policy developed by the Metabolism & Obesity Services and Prader-Willi Syndrome Clinic Royal Prince Alfred Hospital, NSW, Australia. [Add link when PDF is added to site]

Unusual features and potential risks in PWS

A high pain threshold, poor temperature regulation and lack of vomiting associated with hypothalamic dysfunction can mean that a serious medical problem may present in an unusual way and so could be overlooked.

Abnormal body composition affecting medication

Individuals living with PWS have reduced lean tissue and increased adiposity. This may affect dosages of medication, which may need to be less than usual. Psychotropic medications must always be started at very low doses. Medications that have antidiuretic effects may cause water intoxication. Low sodium is also a risk.

Body temperature abnormalities

An individual living with PWS may be unaware when they are too hot or too cold or may eat or drink very hot food or liquids. Hyper and hypothermia have been reported. Hyperthermia may occur during minor illness and after anaesthesia. Fever may be absent despite serious infection. In cases of hypothermia, the patient may not report feeling cold. Baseline temperature may be below 37.8C.

High pain threshold

Most people living with PWS have a high pain threshold and hence underreport pain. This may mask fractures, acute abdominal conditions, serious infections and internal injuries. Individuals may have difficulties localising pain.

Lack of vomiting

Vomiting rarely occurs in PWS. The presence of vomiting, particularly when the individual has a history of never or very rarely vomiting, may signal a life-threatening illness (see below). Emetics may be ineffective.

Severe gastric distension with ischaemia

This is a life-threatening situation that may also result in stomach rupture. The person with PWS may present with abdominal distension, pain and/or vomiting but may only complain of mild abdominal discomfort. This gastric inflammation with necrosis has often been seen in individuals with PWS who have had a recent binge eating episode and whose weight is generally under control.

Gastroparesis

Many individuals also have gastroparesis, which can become dangerous if overeating occurs or has occurred. This is more common in adults but may affect some children.

Loss of appetite

People living with PWS will usually eat even when ill, due to hyperphagia. Loss of appetite should be viewed as possibly symptomatic of a serious disorder. However, some individuals may refuse food as a controlling behaviour.

Skin lesions – picking and bruises

Many individuals living with PWS pick at small wounds or spots, intensifying and increasing the wound, and thus the potential for infection. This can complicate the healing of IV sites and incisional wounds. It is common for individuals to have sores caused by their own skin-picking. They may bruise easily. Appearances may wrongly lead to suspicion of abuse.

Tendency to psychosis

There have been a few anecdotal reports of teenagers and adults living with PWS experiencing psychotic episodes during hospital stays. If parents and carers report worsening differences in behaviour, seek psychiatric help.

Confabulation

People living with PWS are poor reporters of their own health and ailments. They may even deliberately lie (ie confabulate) to health professionals.

Before any important decisions are taken, the facts need to be verified by a person who knows the patient well and gives frequent, close support to the patient.

General care while the person is in hospital

Informed consent (adolescents and adults)

Anxiety is common in both adults and adolescents and individuals benefit from receiving clear information about what is going to happen next. Even those with higher functioning levels may become anxious or confused about proposed treatments, e.g., insertion of IV lines. This might trigger challenging behaviour. They will require a calm, patient, timely and understanding approach. Inpatient assistance from the disability liaison nurse if possible, collaborating with the family  (or NDIS disability support staff) works best. In some cases, Guardianship and Administration powers may have been granted by the courts to empower a nominated adult to make decisions regarding treatment for the adult living with PWS. The NDIS Nominee, often a parent may also need to be included,  especially upon discharge so that the right transport and service support is in place.

Lower calorie diet

Severe obesity can be caused by the combination of hyperphagia and hypotonia. However, in individuals whose access to food has been well controlled, obesity may not be evident. In all cases, however, energy intake should be around two thirds of the average for the individual’s age group, whilst maintaining a balanced, nutritious diet. The input of a dietitian may be required.

Restrict/support access to food

Hyperphagia causes food-seeking and food-stealing behaviour. Ensure that the individual with PWS is not left alone with food or drinks trolley or drinks vending machines, nor has access to other patients’ food and plates. Be aware that an individual may say that they have not had a meal when they have already eaten.

Comprehension and language – receptive and expressive ability

Many people living with PWS can give the impression that they understand everything said to them. This is not always the case. Others may have articulation problems or dyspraxia and hence be difficult to understand. Children and adults may interpret information literally. Keep instructions clear and simple. Use visual aids to help with both comprehension and communication. Give them plenty of time to process information and respond.

Time frames

Be very clear about time frames. If you say you will be back in a few minutes, make sure you do so. Not sticking to times given can result in a rapid increase in anxiety and escalating challenging behaviour.

Parental or support worker support

Individuals require structure to their lives and can find unexpected events or change difficult. The hospital environment can be very stressful for them. Parental, carer, or NDIS worker support and access may be needed much more frequently than usual, especially for adults in wards with restricted visiting times.

For children, take parental advice about their child’s routines and expectations particularly about food. Small deviations in expectations around food can have significant consequences. Take parents’ lead on ways of reducing anxiety and responding to any behavioural difficulties. The hospital’s Disability Liaison Officer should be involved.

Behavioural and emotional outbursts

Children and adults with PWS are prone to emotional lability and outbursts. The reasons for an outburst are not always clear but may include hunger, tiredness, uncertainty, unexpected events, conflict, assumed but unmet expectations, etc. Parent or carer/support worker guidance can help to minimise these.

Treatment

Anasthesia

Recovery from anaesthesia can be affected by muscle to fat body composition. Anaesthesia recommendations for patients living with PWS can be found at: https://www.orphananesthesia.eu/en/rare-diseases/published-guidelines/prader-willi-syndrome.html

Cortisol levels

Individuals living with PWS are probably more likely that the rest of the population to have cortisol deficiency. If there is clinical suspicion of cortisol deficiency during acute illness, immediately take a blood sample to check serum cortisol level. This can then be used to help with diagnosis even if you need to start hydrocortisone as an emergency. Please discuss results with your local endocrinology team.

Medication

People with PWS may have abnormal reactions to standard doses of medication (see Body Composition above).

Hormone replacement

Growth hormone (GH) replacement and other hormones are often used in patients living with PWS. If felt necessary, GH can be temporarily stopped during an acute illness without any likely acute adverse consequences. Patients and families may however wish to continue GH to help maintain routine. Please discuss any questions or concerns with your local endocrinology team.

Oxygen levels

Oxygen levels may be normally lower than usual. Obese patients who have been chronically hypoxic may not tolerate fully corrective use of oxygen and are likely to start retaining CO².

Additional Information

The danger of obesity in PWS – http://pwsausa.org/wp-content/uploads/2015/10/ObesityStillKills.pdf

Psychiatric alert for Prader-Willi syndrome – www.pittsburghpartnership.com/handouts/Psychiatric%20Alert%202009.pdf

Medical Alerts Booklet for Australia [add link when PDF on site]

Websites with extensive information about PWS

PWS Australia – www.pws.org.au

PWSA UK – www.pwsa.co.uk

International Prader Willi Syndrome Organisation has Medical Alerts in several different languages – Medical Alerts Booklet – IPWSO

PWSA USA – www.pwsausa.org

PWSA is in contact with medical specialists with an expertise in PWS. Please do not hesitate to contact us for further information at social@pws.org.au

Thank you to….

PWSA UK for the original source material, including the following for their help:

• Dr Nicola Bridges, Consultant Paediatric Endocrinologist, Chelsea and Westminster Hospital
• Dr Anne Livesey, Consultant Community Paediatrician, Sussex Community Trust. (Brighton PWS Multidisciplinary Clinic)
• Dr Tony Goldstone, Consultant Endocrinologist, Imperial College Healthcare NHS Trust
• Manjeet Singh Riyat, Consultant in Emergency Medicine, Royal Derby Hospital