|Year : 2017 | Volume
| Issue : 3 | Page : 182-186
Dysphagia following acute stroke and its effect on short-term outcome
Sani Atta Abubakar, Bello Yusuf Jamoh
Department of Medicine, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Nigeria
|Date of Web Publication||30-Oct-2017|
Sani Atta Abubakar
Neurology Unit, Department of Medicine, Ahmadu Bello University, Zaria, Kaduna State
Source of Support: None, Conflict of Interest: None
Background: Dysphagia is assciated with numerous medical conditions including stroke, and there are wide variations in reported frequency of dysphagia in stroke survivors in the literature. Dysphagia has been shown to be an important risk factor for aspiration pneumonia and has profound impact on survivors. Aims: This study aims to determine the frequency of dysphagia in stroke survivors and its effects on short-term outcome. Methods: Consecutive patients hospitalised for first-ever acute stroke at Ahmadu Bello University Teaching Hospital Zaria, Nigeria, were prospectively enrolled from April 2015 to January 2017. Stroke severity was assessed using the National Institute of Health Stroke Scale (NIHSS). Water swallowing test was used to screen patients for the presence of dysphagia. This was followed by swallowing provocative test which was aimed at evaluating swallowing reflexes. All the patients were then followed up till day 30. Outcome measures applied were 30-day mortality and functional impairment on the Modified Rankin Scale. Results: Ninety-four patients (53 males and 41 females) with acute stroke were studied. Mean age of patients was 55.51 ± 15.7 years and 32 (34.4%) patients had dysphagia at presentation. Mean NIHSS score of patients with dysphagia was significantly higher than those without dysphagia. Aspiration pneumonia occurred more significantly in those with dysphagia. In multivariate logistic regression, only aspiration pneumonia was independently associated with 30-day mortality. Conclusion: The prevalence of dysphagia in this cohort of stroke patients was 34.4%, and the major independent determinant of 30-day mortality was development of aspiration pneumonia.
Keywords: Acute stroke, dysphagia, outcome
|How to cite this article:|
Abubakar SA, Jamoh BY. Dysphagia following acute stroke and its effect on short-term outcome. Niger Postgrad Med J 2017;24:182-6
|How to cite this URL:|
Abubakar SA, Jamoh BY. Dysphagia following acute stroke and its effect on short-term outcome. Niger Postgrad Med J [serial online] 2017 [cited 2018 Apr 23];24:182-6. Available from: http://www.npmj.org/text.asp?2017/24/3/182/217407
| Introduction|| |
Dysphagia could be defined as any difficulty associated with swallowing. Swallowing consists primarily of four phases; oral preparatory, oral, pharyngeal and oesophageal phases. Stroke commonly affects the first three phases by interrupting the voluntary control of chewing and moving food around the mouth (more common with cerebral lesions) or delay in pharyngeal reflex (more common with brainstem lesions).
Multiple areas of the brain, notably the brainstem, thalamus, basal ganglia, cerebellum and motor and sensory cortices, are concerned with control of spontaneous and involuntary swallowing., Disorders or lesions affecting these areas could lead to abnormal lip closure, in-coordination and delayed or absent triggering of the swallowing reflexes and subsequently disturbances of both oral and pharyngeal stages of swallowing which may manifest as incomplete oral clearance, pharyngeal pooling, regurgitation and aspiration of feeds or secretion.,, Dysphagia is a common complication seen in stroke patients affecting up to 76% of patients; though it is known to resolve in most of those patients within few weeks, it may persist in a fraction for up to 6 months. Dysphagia is usually associated with chest infection, prolonged hospitalisation and increased mortality. Dysphagia has also not only been shown to be a risk factor for aspiration pneumonia but could also lead to malnutrition and dehydration with profound impact on survivors, thus early identification of stroke survivors with dysphagia and prompt intervention may help to reduce morbidity and mortality., Several studies have tried to establish the incidence of dysphagia after stroke with wide variation in published results.,, The aims of the present investigation were to determine the frequency of dysphagia following acute stroke and its effect on 30-day outcome.
| Patients and Methods|| |
Between April 2015 and January 2017, consecutively presenting first-ever acute stroke (both ischaemic and haemorrhagic) patients who fulfilled predetermined inclusion criteria were prospectively enrolled at Ahmadu Bello University Teaching Hospital (ABUTH), Zaria. ABUTH is a tertiary healthcare hospital located in Shika-Zaria, North West Nigeria. The hospital accepts referral from all over the country although majority of the patients come from neighbouring primary and secondary healthcare centres. Patients also come on self-referral. Individuals who fulfilled the pre-determined inclusion criteria were prospectively recruited after giving a well-informed consent. Approval was obtained from ABUTH Health Research Ethics Committee (Ref; ABUTH/HREC/TRG/36 dated 8th May 2012) before embarking on the study. Included in this study were patients who presented within 72 h of onset of symptoms of acute stroke, patients with computed tomography-scan/magnetic resonance imaging-confirmed acute stroke. Excluded from the study were patients with medical disorders such as motor neuron disease, previous stroke, cerebral palsy and chronic obstructive airway diseases that could interfere with swallowing. At presentation, all patients who were recruited had thorough physical and neurological examination by a team of neurologists and information obtained were entered into structured questionnaire designed for the study.
Water swallowing test was used to screen patients for the presence of dysphagia. Patients were asked to first drink 5 ml of water and then 50 ml of water. Stuporous patients (i.e., those with an National Institute of Health Stroke Scale (NIHSS) score of 2 for the item 'level of consciousness') and patients with impaired sensorium (i.e. those 'who are not alert and require repeated stimulation to attend') were excluded. Patients who drank water without cough or wet/hoarse voice were considered normal. This was followed by swallowing provocative test which was aimed at evaluating swallowing reflexes. In this test, we injected 0.4 ml of distilled water followed by 2 ml into suprapharynx through a small nasal catheter. This test was judged to be normal according to Teramoto and Fukuchi , if the latency of swallowing after either of the water injections was <3 s.
Stroke severity was determined at presentation using the NIHSS. The NIHSS is a 15-item impairment scale which provides a quantitative measure of a key component of standard neurological examination. Patients were examined daily throughout their hospital stay for clinical progress and presence of pneumonia and other post-stroke complications.
The diagnosis of pneumonia was based on the presence of three or more of the following variables; fever (38°C), productive cough with purulent sputum, abnormal respiratory examination (tachypnoea [respiratory rate ≥22 breaths/min], tachycardia, inspiratory crackles, bronchial breathing), abnormal chest radiograph, arterial hypoxaemia (PO2, 9.3 kPa) and isolation of a relevant pathogen (positive Gram stain or culture). Outcome variables evaluated included 30-day mortality, presence of pneumonia and functional outcome. The functional outcome was assessed at 30 days' post-stroke using Modified Rankin Scale, this is an observer-rated global measure of disability assessing any limitation in the patient's social role. It is rated from 0 (no symptoms) to 5 (severely disabled or bedridden). Patients with score of 0–3 were categorised as having good outcome (not disabled) and those with score of 4–5 as disabled.
Statistical analysis was done using Statistical Package for the Social Sciences for Windows version 20.0 (IBM, Armonk, NY, USA). Means and standard deviations were generated, continuous variables were compared using the Student's t-test while Chi-square test was used to compare categorical non-continuous variables and in cases where this was not applicable, Fisher's exact test was used. Multiple logistic regression analysis was used to determine the effect of dysphagia on outcome in the presence of other variables. P ≤ 0.05 was considered statistically significant.
| Results|| |
The study was conducted between April 2015 and January 2017 and enrolled a total of 105 consecutively presenting and consenting acute stroke patients. Six patients presented for care a week after onset of symptoms of acute stroke and five had depressed sensorium and were excluded. Thus, a total of 94 patients comprising 53 males and 41 females were studied. The mean age of the patients was 55.5 (±15.7) years with systemic hypertension being the most common modifiable risk factor followed by diabetes mellitus [Table 1].
A total of 32 (34.04%) patients had dysphagia at presentation: 2 (2.1%) had odynophagia, choking while feeding occurred in 24 (25.5%) and drooling of saliva and aspiration occurred in 16 (17.0%) and 12 (12.8%) patients, respectively. The mean NIHSS (measure of stroke severity) score was significantly higher in people who had dysphagia compared to those without dysphagia, but outcome in terms of 30-day mortality was not statistically different between the groups [Table 2]. A total of 15 (16.0%) patients had complete resolution of their dysphagia within 5 days of onset of stroke while additional 15 (16.0%) were free of dysphagia about 20 days of onset of stroke but 2 (2.1%) were discharged to rehabilitation unit with nasogastric tube. There was no statistically significant association between the duration of dysphagia and 30-day mortality (χ2 = 0.062, df = 3). Ten (31.3%) of the 32 patients with dysphagia developed aspiration pneumonia, but only 2 (0.032%) of the 62 patients without dysphagia developed aspiration pneumonia. The difference was statistically significant (P< 0.0001) [Table 2]. Of 94 patients who were recruited, 25 (26.0%) developed one form of complication or the other, ranging from seizures in 9 (9.6%), depressive symptoms in 6 (6.4%), pressure sores in 9 (9.6%) and sepsis in 11 (11.7%) patients. In a multivariate logistic regression analysis, the major independent determinants of 30-day mortality were aspiration pneumonitis and presence of complications and not dysphagia [Table 3].
|Table 2: Clinical characteristics of the patients stratified by presence or absence of dysphagia|
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|Table 3: Determinants of 30-day mortality using binary logistic regressions|
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| Discussion|| |
The baseline clinical characteristics of this cohort of stroke survivors were similar to the characteristics described earlier at the same study site, region  and other parts of Nigeria. The patients were predominately middle aged (55.5 years) with slight male predominance (M: F =1.3:1) as is the case in most studies in Sub-Saharan Africa.,
Our study revealed that about one-third of this cohort of stroke patients had dysphagia at presentation. The reported frequency of dysphagia in the literature is variable, with values ranging from 13% to 94% of acute stroke sufferers.,, This variability in reported frequency could be due to several factors; first the methods used in the identification of dysphagia play a great role, as assessment of swallowing may either be at the bedside using simple bedside clinical examination (water swallowing test) or through instrumental investigation (video fluoroscopy). Bedside clinical evaluation has been the cornerstone for assessing swallowing in most hospitals as is the case in our study. Bedside evaluation is simple and easily performed. Instrumental evaluation using video fluoroscopy remains the goal standard with better sensitivity and specificity, but requires lots of expertise and is not convenient for routine practice; second, the variability in frequency of dysphagia may be due to timing of assessment, that is, time interval between stroke (ictus) and evaluation for dysphagia. This is because recovery could have taken place at the time of some evaluation. This is corroborated by our results as up to 16% of patients with dysphagia recovered within 5 days of onset of stroke. Why do some patients develop dysphagia post-stroke and others do not? The reasons are not quite clear; however, results of series of experiment by Hamdy et al. using transcranial magnetic stimulation suggested that there is bilateral representation of midline swallowing muscles in the motor cortex in asymmetric manner. This has led to the hypothesis that some individuals have a 'dominant' swallowing hemisphere and acute stroke involving this dominant swallowing hemisphere which perhaps may result in dysphagia.
One important finding of our study is that the presence of dysphagia increased the risk of aspiration pneumonia, the odds ratio was 13.6 (confidence interval [CI]: 2.79–67.1). Several studies have also correlated clinical dysphagia with increased risk of aspiration pneumonia.,, Our study also revealed that overall 12.8% of all stroke patients developed aspiration pneumonia which is similar to 12% to 30% reported in the literature.,, Aspiration pneumonia is common in stroke patients and particularly in patients with dysphagia and may have some bearing on stroke-related morbidity and mortality. The overall 30-day mortality in this study was 13.8%, while the 30-day mortality among patients with dysphagia and those without dysphagia was 18.75% and 11.29%, respectively, this was not statistically significant (odds ratio: 1.8; CI = 0.55–5.9). The implication of this is that, even though dysphagia remains common in acute stroke, if detected early and properly managed, aspiration could be prevented or at least minimised. In this study, those patients who were found to have dysphagia on admission were kept on nil per oral till dysphagia resolved except in a few in whom we had to pass nasogastric tube. This finding is not in keeping with findings by Arnold et al. where patients with dysphagia had 8.5-fold increased risk of death as compared to those without dysphagia. Our 30-day mortality of 13.8% is higher than 8.1% reported in a series of ischaemic stroke  but much lower than 40% reported earlier in South West Nigeria, the difference could probably be explained by the difference in the study design. The presence of complication adversely affected outcome in this study. About 26.0% of our patients have one form of complication or the other which is similar to findings by Watila et al. in North East Nigeria. Aspiration pneumonia is common in patients with dysphagia and was an independent determinant of 30-day mortality.
This study appears to have raised some questions about the effect of dysphagia on acute stroke outcome and effect of dysphagia complicated with aspiration on acute stroke outcome. Our study revealed that mere presence of dysphagia at presentation has less bearing on 30-day mortality, but aspiration pneumonia remains an independent determinant of 30-day mortality. Hence, clinicians should routinely evaluate stroke patients for the presence of dysphagia so as to promptly treat. We acknowledge the modest size of the sample studied and indicated that our findings though preliminary in nature provide a thrust for larger and more elaborate multicentric study.
| Conclusion|| |
We have demonstrated that dysphagia is common in acute stroke and adversely affects functional outcome in terms of morbidity. Development of complication including aspiration pneumonia was an independent determinant of 30-day mortality and not the presence of dysphagia.
We wish to thank Prof. MS Isa and Dr. OR Obiakor for their support and encouragements.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]