Nutrition and gastrostomy
Motor neurone disease (MND) is a progressive and terminal disease that results in degeneration of the motor neurones, or nerves, in the brain and spinal cord.
Monitoring nutritional intake and weight is important. Unintentional weight loss and risk of malnutrition can result from:
- cognitive impairment
- respiratory insufficiency
- constipation and fatigue
- physical difficulties buying, preparing and eating foods.
Functional consequences of weight loss/malnutrition include:
- increased muscle wasting due to muscle catabolism
- increased respiratory muscle weakness
- decreased physical strength and mobility
- impaired immune function, which can increase susceptibility to opportunistic infections
- decreased tissue viability
- increased discomfort sitting or lying due to weight loss and loss of tissue ‘padding’ over bony protuberances
- decreased morale and quality of life.
Involvement of a speech and language therapist and a dietitian is essential at an early stage to assess, monitor and review the individual’s nutritional intake and to provide practical oral and non-oral dietary advice to enable nutritional needs to be met.
Advice may include:
- fortification to improve food quality
- recipe ideas to increase variety
- practical solutions to ease food preparation and physical eating and drinking difficulties (in association with an occupational therapist)
- recommending prescribed nutritional supplements
- discussing gastrostomy.
As swallowing problems progress, alternative feeding methods should be discussed with the person with MND. Exploring pros and cons will enable the individual to make an informed choice.
The following may be used to ‘top-up’ oral intake, to meet full nutritional and dehydration needs and to administer medications:
- Nasogastric tubes (NGT)
- Percutaneous Endoscopic Gastrostomy (PEG)
- Radiologically Inserted Gastrostomy (RIG)
- Per-oral Image-guided Gastrostomy (PIG)
With RIG, the feeding tube is inserted under x-ray guidance. PIG is a hybrid of PEG and RIG but at present is not widely available.
A nasogastric tube can be used in the short-term to build up someone who is malnourished or dehydrated, and who wants to proceed with gastrostomy, or it may be used for a longer period. This method may be used in people for whom other types of gastrostomy are not appropriate, or may be preferred by some. It is often considered less comfortable than gastrostomy tube placement.
PEG is the preferred method of gastrostomy when someone has good respiratory function, or PIG/RIG when there is significant compromise of respiratory function.
The optimal timing of gastrostomy is likely to be when someone has lost around 5% of their body weight (from measurement taken at diagnosis). Earlier placement of a gastrostomy tube is recommended, even if it isn’t used straight away, as when needed, it can improve/maintain quality of life.
Someone considering a gastrostomy needs to be aware of the level of support needed to manage living with this intervention. For example, who will manage the feeds in the community. If it is a family member, this person will need to understand what is involved and how often feeds should be administered, to ensure they can physically manage. If care support is needed, arrangements need to be made at an early stage. Not everyone with MND will choose this type of intervention and their decision should be respected. Gastrostomy may be included in an Advance Decision to Refuse Treatment (ADRT).
Sphincter muscles are not normally affected by MND. Changes in bowel function are usually the result of:
- forced inactivity
- reduced peristalsis
- low fluid intake
- reduced fibre intake
- weakness of pelvic floor and abdominal muscles
- use of analgesics.
- Maintain hydration and assess fibre intake.
- Use of softeners and stimulants may help. Liquid versions are available that can be given via a feeding tube.
- Use of suppositories, enemas or manual evacuation may be necessary on occasions.
- Remedies such as bulking agents and fruits with a high sorbitol content (eg prunes) are also readily available.
Diarrhoea may be due to constipation with overflow.