What is stroke?
A stroke or cerebrovascular accident (CVA) is defined as a loss of function caused by a disruption of the blood supply to a part of the brain. This can lead to brain damage and possibly death (RCP, 2012).
There are two main causes of strokes:
Prevalence of stroke
There are approximately 152,000 cases of stroke in the UK per year, more than one every 5 minutes. It is estimated that there are approximately 1.1 million stroke survivors living in the UK. Stroke incidence is approximately 25% higher in men than women. However, although stroke incidence is higher for men, there are more strokes in women since women generally live longer than men (Stroke Association Statistics, 2013)
Stroke remains the fourth most common cause of death in the UK, after cancer, heart and respiratory disease, accounting for more than 55,000 deaths in 2010 (Townsend et al, 2012), with implications on healthcare resources (RCP Audit, 2010). One in five strokes is fatal. Stroke causes about 7% of deaths in men and 10% in women.
In Ireland, there are approximately 10,000 strokes each year. Of these, five out of six strokes happen in people over the age of 60. Each year, approximately 2,000 Irish people die from stoke which accounts for more deaths than breast cancer, prostate cancer and bowel cancer combined. An estimated 30,000 people are living in the community with disabilities as a result of a stroke. This makes stroke the third biggest cause of death in Ireland and the biggest cause of acquired disability (Irish Heart Foundation, 2014).
Malnutrition is prevalent in stroke patients
The overall prevalence of malnutrition in stroke patients ranges from 6.1% to 62% (Foley et al. 2009a). A recent study carried out in UK hyper acute stroke units found that the prevalence of patients at high risk of malnutrition is 29% (Gomes et al. 2014). This value agrees with the proportion of stroke patients at risk of malnutrition previously reported by Stratton and colleagues of 30% for those in the acute and community setting (Stratton et al. 2003).
Dysphagia and dehydration
There are a number of clinical consequences of stroke, one of which is dysphagia (difficulty swallowing). Dysphagia is common following stroke and it is present in 40-50% of patients who survive the first few days (Stroke Association, 2012; Bogaardt et al. 2009). Dysphagia after stroke may involve difficulties with both the oral and pharyngeal phases of swallowing and increases the risk of respiratory complications and aspiration pneumonia (Sura et al. 2012) and mortality (Singh & Hamdy 2006).
It can add an average of 1.6 days to a typical hospital stay (Cichero & Altman, 2012) and prolong length of stay 13 days due to associated complications such as infections e.g. pneumonia, urinary tract infections (Ingeman et al.2011).
Dysphagia is also a strong predictor of malnutrition risk (Sura et al. 2012) and dysphagic stroke patients are 2.4 times more likely to be malnourished compared with those who have normal swallowing (p <0.008) (Foley et al. 2009b). The serious consequences of malnutrition and dysphagia in stroke mean that it is extremely important to identify those patients who are at risk.
Dysphagia has also been associated with dehydration; it is estimated that 62% of stroke patients suffer from dehydration at some point during their admission (Rowat et al. 2012). Patients often limit their drinking, probably due to concerns about choking and may need enteral or intravenous fluids to meet their requirements (Vivanti et al. 2009). Dehydration is a predictor of poor outcomes including discharge to long term-care (Lakshminarayan et al. 2010; Finlayson et al. 2011, Crary et al. 2013).
Identifying Malnutrition and Dysphagia in Stroke
The NICE Clinical Guideline for Stroke (NICE CG68, 2008) and the Royal College of Physicians (RCP) National Clinical Guideline for Stroke (RCP, 2012) support the identification and management of malnutrition and dehydration in stroke patients. They recommend that:
Early assessment of nutritional risk, with appropriate nutritional management, may improve survival of stroke patients (Yoo et al. 2008). Delays in assessment, treatment and rehabilitation of stroke patients will increase the risk of secondary complications, hinder recovery, increased likelihood of malnutrition and dehydration, and lead to long-term disability or even death.
The Evidence for Nutrition Intervention
Texture modification of food and fluids is widely used for the management of dysphagia (Stoke Association, 2012). Guidelines have been produced based on best available current evidence and a consensus of expert opinion, which support the use of thickeners to thicken fluid and foods (Dysphagia Diet Food Texture Descriptors, 2012; Irish Consistency Descriptors for Modified Fluids and Fluids Consensus Document 2009).
There is evidence to suggest that increasing the bolus viscosity improves swallowing function in neurological patients (including stroke survivors) which can lead to a significant reduction in aspiration (Clavé et al. 2006). Food and fluids need to be modified with a thickener to a consistency which provides patients with best control over the rate at which foods and fluids pass through the pharynx (Thomas and Bishop, 2007). If consistency recommendations are not followed, patients may consume food/fluids which they do not have sufficient control over and thus put them at risk of aspiration (Garcia et al. 2010).
Modified texture diets are often nutritionally deficient due to the need to add liquid to reduce the consistency of the meal for certain consistencies (Wright et al. 2005; Foley et al. 2006; Keller et al. 2012). If these diets, which are deficient in energy and protein, are administered for prolonged periods without appropriate nutrition support, they in themselves can lead to dehydration and malnutrition.
A randomised control trial by Ha et al. examined whether individualized nutrition support (including ONS in the acute stage of stroke) could prevent or minimize weight loss at 3 months in patients at risk of malnutrition. The nutritional intervention provided was energy- and protein fortified meals, or ONS (0.8-1.5 kcal/ml, 0.04-0.1 g/ml protein), or enteral tube feeding (1-4 kcal/ml) based on nutritional needs. The study showed that weight loss (≥5%) was significantly lower in patients receiving ONS during the first week in hospital (p = 0.013). Moreover, there is a trend towards decreased weight loss at 3 months with ONS however this was not statistically significant (Ha et al. 2010a). Energy and protein supplementation (via fortified diet, ONS or ETF) was also linked with a significant improvement in handgrip strength (Ha et al. 2010b).
Nutritional Management of Stroke Patients
When managing people with stroke, ONS, ETF, texture modified diets and thickened fluids should be considered as per NICE CG32 and RCP guidelines (NICE, 2006; RCP, 2012).
There are a variety of products which may be suitable for patients following a stroke. These include enteral tube feeds for patients who are unable to meet their nutritional requirements through oral diet alone or have an unsafe swallow; powdered thickeners for patients who require texture modified food or fluids and/or pre thickened oral nutritional supplements for those that are at nutritional risk and oral nutritional supplements patients who can tolerate normal consistency fluids but require nutritional support.
The management of stroke patients by a multidisciplinary team, which includes a Speech and Language therapist and Dietitian, is key to successful outcomes for the stroke patient with dysphagia.
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