Organ failure, including kidney failure, is a hallmark of sepsis. As the body is overwhelmed, its organs begin to shut down, causing even more problems. The kidneys are often among the first to be affected by sepsis.
The National Kidney Foundation has identified sepsis as one of the major causes of acute kidney injury (AKI). Some studies have found that between 32% and 48% of acute kidney injury cases were caused by sepsis.
Sepsis and Kidney
There are two ways the kidneys can be affected by sepsis. The first is if the infection that caused the sepsis begins in the kidney through a kidney infection or a bladder infection that has spread to the kidney. The second is if the series of events from sepsis causes kidney damage.
In sepsis and septic shock ,toxins produced by bacteria can damage the small blood vessels, causing them to leak fluid into the surrounding tissues. This can affect the heart's ability to pump blood to your organs, which lowers your blood pressure and means blood doesn't reach vital organs. Because the blood cannot flow quickly, the oxygen and other nutrients are not delivered effectively to the organs and thereby contributing to organ failure.
Chronic kidney disease is associated with buildup of urea in the blood as Kidneys are not working properly, it leads to fluids and toxins buildup causing the clots to accumulate and slowing down the blood even more.
Signs and Symptoms
A person with Acute Kidney failure may have any of the following symptoms:
Decreased urine output
Shortness of breath
Urine and blood tests tell doctors how well your kidneys are functioning, so many samples are taken during diagnosis and treatment. In sepsis patients, kidney failure can be indicated by a number of different blood test levels, including:
Creatinine: Creatinine is a waste product that is normally filtered out of the blood by the kidneys. In sepsis patients, elevated levels of creatinine may indicate acute kidney injury (AKI), which is a common complication of sepsis.
Blood urea nitrogen (BUN): BUN is a waste product that is produced when the body breaks down protein. Like creatinine, BUN is normally filtered out of the blood by the kidneys. Elevated BUN levels in sepsis patients can be a sign of impaired kidney function.
Potassium: The kidneys play a critical role in regulating the balance of electrolytes, such as potassium, in the body. In sepsis patients with kidney failure, potassium levels may become elevated, leading to a range of symptoms and potentially life-threatening complications.
Fibrinogen: Chronic kidney disease (CKD) patients have increased rates of bleeding as well as thrombosis. Fibrinogen and platelets combine to generate a mature clot, but in CKD platelets are dysfunctional. Therefore, CKD patients have increased clot strength due to elevated fibrinogen levels.
Sodium: Sodium levels may also be affected in sepsis patients with kidney failure. Depending on the severity of the kidney damage, sodium levels may be too high or too low, which can cause a range of symptoms.
Glucose: One cause of kidney failure is diabetes mellitus, a condition characterised by high blood glucose (sugar) levels. Over time, the high levels of sugar in the blood damage the millions of tiny filtering units within each kidney. This eventually leads to kidney failure.
Glomerular filtration rate (GFR): GFR is a measure of how well the kidneys are filtering waste products from the blood. In sepsis patients with kidney failure, GFR may be decreased, indicating impaired kidney function.
Analysis of different biomarkers for kidney dysfunction during sepsis
Creatinine levels in the blood can vary depending on age and body size. A creatinine level of greater than 1.2 for women and greater than 1.4 for men may be an early sign that the kidneys are not working properly. As kidney disease progresses, the level of creatinine in the blood rises. The following chart shows that more percentage of sepsis patients have higher creatinine levels than non sepsis patients putting them at higher risk.
If serum creatinine test results are higher than normal, your doctor may want to run other tests like BUN which tests the amount of urea nitrogen in the blood, fibrinogen etc..If these test results reveals any sign of kidney disease then doctor will decide on the treatment plan.
The chart below shows the BUN and Fibrinogen levels for sepsis and non sepsis patients. It is clear that higher percentage of sepsis patients have high BUN and Fibrinogen levels than non sepsis patients.
Analysis of AKI with respect to age and gender
The following chart shows the sepsis patients with high creatinine, high fibrinogen and high BUN levels with respect to age and gender of the patient respectively. From the chart we can easily analyse that male patients in the range 60 - 70 years have higher values for all three biomarkers. Men may be at increased risk of reaching kidney failure sooner than women because of differences in hormone levels. Higher testosterone levels in men may cause a loss in kidney function. The incidence of end stage kidney disease (ESRD) is 50% higher in adult men than in women
A combination of SOFA score and biomarkers gives a better prediction of septic AKI and in-hospital mortality in critically ill patients. One cause of kidney failure is diabetes mellitus, a condition characterised by high blood glucose (sugar) levels. Over time, the high levels of sugar in the blood damage the millions of tiny filtering units within each kidney. This eventually leads to kidney failure. The following chart shows the SOFA mortality rate for high risk patients who have all three biomarkers (creatinine, fibrinogen and BUN) value in higher range along with high glucose levels. The patients with higher SOFA score along with abnormal biomarkers are more vulnerable to septic shock.
Based on a dataset of hospitalized patients, male sex is associated with an increased incidence of hospital-associated AKI but you can help lower your risk for CKD or keep it from getting worse by eating healthy, being active, and keeping the blood pressure and cholesterol levels in target range. Make sure to take care of your kidneys if you are at risk for CKD (chronic kidney disease). If you have diabetes, get tested for kidney disease once each year. Having your kidneys checked regularly gives you the best chance for finding and treating CKD early.