A stroke occurs when blood flow to the brain is interrupted, causing brain cells to die. This injury often results in various physical and cognitive impairments. Dysphagia, or difficulty swallowing, is a common complication that significantly impacts recovery. This condition arises because the stroke damages brain regions controlling the complex muscle movements involved in swallowing. Identifying and managing swallowing difficulty is an immediate concern for medical teams in the first hours and days after a stroke.
Prevalence of Acute Post-Stroke Dysphagia
The number of people who experience swallowing difficulty immediately following a stroke is substantial, affecting a large minority to a majority of patients. Overall, the pooled prevalence of post-stroke dysphagia has been estimated at approximately 46.6% across various studies. However, the specific rate depends heavily on the type of stroke and the method used for diagnosis.
Estimates of dysphagia prevalence typically fall within a wide range of 30% to over 80% in acute stroke patients. A key factor influencing these statistics is the stroke type: hemorrhagic strokes show a higher prevalence (around 58.8%) compared to ischemic strokes (closer to 43.6%).
The diagnostic method employed also causes variation. If dysphagia is identified using simple bedside screening tests, the prevalence may be reported lower (37% to 45%). Conversely, when more sensitive instrumental assessments, such as videofluoroscopy or endoscopy, are used, the reported prevalence can climb much higher (64% to 78%). The rate is highest within the first 48 to 72 hours following the stroke.
Defining the Acute Phase
The “acute phase” generally refers to the initial period immediately following stroke onset, typically spanning the first hours, days, and up to the first two weeks. Swallowing function is assessed as soon as the patient is medically stable, often within the first 24 hours of hospital admission.
This initial timeframe is characterized by neurological instability and swelling in the brain tissue, which contributes to the severity of symptoms like dysphagia. The swallowing difficulty during this phase is often transient, meaning it is not permanent for most people. A large proportion of these acute cases resolve spontaneously as the brain begins its process of natural recovery.
Studies show that between 73% and 86% of those with acute dysphagia recover their swallowing function within the first one to two weeks. This rapid improvement explains why the number of people with persistent or chronic dysphagia—swallowing difficulty that remains six months after the stroke—drops significantly. Chronic prevalence generally falls between 11% and 50%.
Critical Risks Associated with Acute Dysphagia
Immediate identification of swallowing difficulty in the acute phase is necessary because of serious and life-threatening complications. The most common immediate danger is aspiration, the entry of food, liquid, or saliva into the airway and lungs. Aspiration is a strong precursor for developing aspiration pneumonia, a severe pulmonary infection that significantly increases mortality and extends the hospital stay.
Dysphagia is associated with a seven-fold increase in the risk of aspiration pneumonia compared to patients without swallowing difficulty. A significant number of aspiration events are “silent,” meaning the patient does not cough or show outward signs of distress.
Beyond respiratory complications, acute dysphagia also puts patients at risk for dehydration and malnutrition. These complications may necessitate alternative feeding methods like nasogastric tube placement. Systematic dysphagia screening protocols upon hospital admission are directly linked to a lower risk of pneumonia, reduced mortality, and shorter hospital stays.