Fever And Stroke: What's The Connection?

Fever is a common complication after a stroke, with up to 50% of hospitalized stroke patients developing a fever. The fever usually occurs within the first two days after a stroke and is associated with a poor prognosis. The cause of post-stroke fever is not always clear, but it is often the result of an infection or central fever, which is caused by immune system activation or the effect of the brain lesion on thermoregulatory centers. Infections after a stroke are common, with a reported prevalence of up to 30%, and are associated with higher morbidity and mortality.

Fever is a common complication after a stroke

Fever is a common complication following a stroke, with between 40% and 61% of hospitalised stroke patients developing a fever. The fever usually occurs within the first two days of a stroke, and 15% of patients with a fever develop it on the first day.

Fever after a stroke is associated with poor outcomes, with patients with a fever far more likely to die within the first 10 days after a stroke than those with lower temperatures. Animal studies have shown that a rise in body temperature after cerebral ischemia causes more extensive brain damage, and that hyperthermic ischemic rats tend to remain unresponsive and die soon after ischemia.

The cause of a fever after a stroke is often an infection, with aspiration pneumonia being the most common cause. However, a fever after a stroke can also be endogenous, caused by the immune system activation or the effects of the brain lesion on thermoregulatory centres.

The treatment of a fever after a stroke is complex and often ineffective. Oral antipyretics such as acetaminophen are only marginally effective in lowering body temperature and may have unintended adverse consequences. Nonpharmacological approaches to cooling, such as blankets and intravascular catheters, have been more effective in achieving normothermia, but it is unclear whether stroke outcomes can be improved.

Infections are a common cause of fever after a stroke

Fever after a stroke is a common occurrence, with approximately 50% of patients hospitalized for stroke developing a fever. In fact, a fever occurring after a stroke is associated with poor outcomes. In most cases, the cause of a fever after a stroke is an infection.

One study examined 119 patients hospitalized after an ischemic stroke, and found that 25% of these patients had a fever within 24 hours of experiencing stroke symptoms, and 32% had a body temperature higher than 37.5°C within 48 hours after an ischemic stroke. The probable causes of fever within 48 hours after an ischemic stroke included pneumococci, streptococci, Escherichia coli, enterococci, or parainfluenza virus and influenza virus type A. The study concluded that most fevers (83%) could be explained by infectious or chemical aspiration pneumonia.

Another study found that fever in the first 7 days of hospitalization occurred in 43% of stroke patients, and that the onset of fever occurred in the first 2 days in 64% of febrile patients. The study also found that fever was an independent predictor of poor outcome during the first month after a stroke.

In summary, infections are a common cause of fever after a stroke, and the development of a fever after a stroke is associated with a worse prognosis.

Fever after a stroke is associated with poor outcomes

Animal studies show that a rise in body temperature after experimentally induced cerebral ischemia produces more extensive brain damage, and that hyperthermic ischemic rats tend to remain unresponsive and die soon after ischemia. When brain temperature was elevated to 40°C for 3 hours within 24 hours after middle cerebral artery occlusion, the resulting cortical infarct volume enlarged dramatically (~6.4-fold), as did the total infarct volume (3-fold). In addition, neurobehavioral recovery in animals with fever was worse compared with animals with normal body temperatures.

In most cases, infection is the cause of fever after a stroke. In a study of 119 patients hospitalized after an ischemic stroke, 25% of these patients had a fever (temperature > 38°C) within 24 hours of experiencing stroke symptoms, and 32% had a body temperature higher than 37.5°C within 48 hours after an ischemic stroke. The probable causes of fever within 48 hours after an ischemic stroke included pneumococci, streptococci, Escherichia coli, enterococci, or parainfluenza virus and influenza virus type A. The authors concluded that most fever (83%) can be explained by infectious or chemical aspiration pneumonia.

High body temperature after a stroke is linked to initial stroke severity, lesion size, mortality, and neurological outcome

Fever is a common complication after a stroke, with approximately 40% to 61% of patients experiencing it. High body temperature after a stroke is linked to several factors and outcomes. Firstly, it is associated with the initial severity of the stroke. Animal studies have shown that elevated body temperature after experimentally induced cerebral ischemia results in more extensive brain damage. The relationship between fever intensity and stroke outcome is strongest within the first 24 hours, with earlier fever development indicating worse cerebral damage.

Secondly, high body temperature after a stroke is linked to lesion size. Fever can cause the transformation of ischemic penumbra into infarction and increase blood-brain barrier breakdown, resulting in larger lesion sizes.

Thirdly, elevated body temperature is correlated with mortality. Patients with fever after a stroke are more likely to die within the first 10 days than those with lower temperatures. High body temperature is also associated with higher morbidity and mortality rates compared to normothermic patients.

Lastly, high body temperature after a stroke is associated with poor neurological outcomes. Animal studies suggest that elevated temperatures worsen neurobehavioral recovery, and clinical data supports the correlation between high body temperature and poor neurological outcomes.

In summary, high body temperature after a stroke is linked to initial stroke severity, lesion size, mortality, and neurological outcome. These correlations emphasize the importance of monitoring and managing body temperature in stroke patients to potentially improve outcomes.

Treatments for fever after a stroke include oral antipyretics and nonpharmacologic approaches to cooling

Fever is a common complication after a stroke, with approximately 50% of patients hospitalized for stroke developing a fever. Oral antipyretics and nonpharmacologic approaches to cooling are the main treatments for fever after a stroke. However, it is important to note that oral antipyretics, such as acetaminophen, have only marginal effectiveness in lowering body temperature and may have unintended adverse consequences. Therefore, nonpharmacologic approaches to cooling, such as the use of cooling blankets or intravascular catheter-based heat exchange systems, have been found to be more effective in achieving normothermia. Nonetheless, it is still unclear whether these treatments can improve stroke outcomes.

When treating fever after a stroke, it is recommended to use body temperature as a biomarker and to aggressively investigate for an infectious etiology. Additionally, it is crucial to monitor for any signs of infection and start tailored antibiotic treatment if necessary. The early and prophylactic use of antibiotics should be approached with caution, as it can lead to an increase in antibiotic-resistant bacteria. Furthermore, care must be taken not to exceed the maximum recommended dose of acetaminophen, as it can cause hepatic toxicity.

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