Acute kidney injury (AKI) signifies a sudden, severe decline in kidney function. This deterioration prevents the kidneys from adequately filtering waste products from the blood. Recognizing the various factors that increase the likelihood of developing AKI is important due to its potential for serious health consequences.
Chronic Health Conditions
Long-standing medical conditions can increase an individual’s susceptibility to AKI. Pre-existing chronic kidney disease (CKD) makes the kidneys more vulnerable, as their filtering capacity is already compromised. Diabetes, characterized by persistently high blood sugar levels, can progressively damage the small blood vessels throughout the body, including the filtering units within the kidneys. This vascular injury makes the kidneys less resilient to acute insults.
Heart failure, where the heart struggles to pump blood, leads to reduced blood flow to various organs, including the kidneys. This decreased perfusion can starve kidney tissues of oxygen and nutrients, making them prone to injury. Impaired liver function in liver diseases can disrupt fluid balance, influence blood pressure regulation, and hinder the body’s ability to eliminate toxins. These systemic effects can indirectly strain kidney health and increase AKI risk.
Certain cancers can directly affect kidney tissue or impair kidney function. Also, specific cancer treatments, such as chemotherapy drugs, are nephrotoxic, directly damaging kidney cells. Lupus, an autoimmune disease, involves the immune system attacking the body’s own tissues. This inflammation can directly damage the kidneys, making them more susceptible to acute injury.
Acute Illnesses and Events
Sudden medical events or severe conditions can trigger AKI. Insufficient fluid intake or excessive fluid loss, dehydration, reduces blood volume and flow to the kidneys. This diminished perfusion can rapidly impair kidney function, as the kidneys require adequate blood supply to operate. Sepsis, a severe response to an infection, involves widespread inflammation and low blood pressure. This systemic shock impairs blood flow to organs, including the kidneys, leading to their dysfunction.
Hypovolemia, low blood volume from severe bleeding, burns, or extreme vomiting and diarrhea, similarly reduces the amount of blood reaching the kidneys. Without sufficient blood volume, the kidneys cannot maintain their filtering capacity, increasing AKI risk. Severe systemic infections, such as COVID-19, can directly damage kidney cells through inflammatory processes or indirectly contribute to AKI by inducing sepsis.
Blockages in blood vessels supplying the kidneys can cut off their blood supply. Conditions like atherosclerosis, causing narrowing of the renal arteries, can lead to such obstructions. Blood clots forming within or traveling to the renal arteries can also block blood flow to parts of the kidney, leading to rapid tissue damage and loss of function.
Medications
Certain medications can directly harm the kidneys, contributing to AKI. Nephrotoxic drugs, known for their kidney-damaging potential, can induce injury. Non-steroidal anti-inflammatory drugs (NSAIDs), used for pain and inflammation, can constrict blood vessels leading to the kidneys, reducing blood flow and impairing filtration, especially with pre-existing kidney conditions.
Some antibiotics, such as aminoglycosides, can accumulate within kidney cells and damage the tubular structures responsible for reabsorbing water and solutes. This cellular toxicity disrupts normal kidney function and can lead to AKI. Contrast dyes, administered during medical imaging procedures such as CT scans and angiograms, are also nephrotoxic. These dyes can cause cellular damage and alter blood flow within the kidneys, leading to a decline in kidney function.
Demographic and Situational Factors
Demographic and situational factors also influence an individual’s risk for AKI. Kidneys experience a gradual decline in function with advanced age, making older individuals more susceptible to injury. Older adults also often have multiple underlying health conditions, such as hypertension or diabetes, which further increase their vulnerability.
Obesity is associated with conditions like type 2 diabetes and high blood pressure, both direct risk factors for kidney disease and AKI. Increased metabolic demands and systemic inflammation linked to obesity can also indirectly strain kidney function. Individuals of Black race experience a higher prevalence of conditions such as hypertension and diabetes, which contribute to chronic kidney disease and an elevated risk for AKI. Genetic predispositions may also play a role in this increased susceptibility.
Being admitted to an intensive care unit (ICU) elevates the risk of AKI. Critically ill patients often have multiple organ failures, are reliant on mechanical ventilation or other life support systems, and are exposed to many medications, some of which may be nephrotoxic. The severity of their illness, coupled with complex medical interventions, creates a challenging environment for kidney function.