Renal disease and drug handling Flashcards
What is the difference between acute kidney disease and chronic kidney disease?
Acute Kidney Disease is an abrupt deterioration in kidney function, usually occurring over hours or days, and is typically reversible over a short period (days to weeks). It can be caused by pre-renal, post-renal, or parenchymal issues like acute tubular necrosis.
Chronic Kidney Disease is a progressive and long-standing decline in kidney function lasting more than 3 months. It is often non-reversible and can result from causes such as congenital or inherited diseases, glomerular diseases, and vascular diseases.
How do acute kidney injury and chronic kidney disease relate to each other?
Acute kidney injury and chronic kidney disease can form a continuum, where an initial kidney injury can lead to persistent renal damage, eventually resulting in chronic kidney disease. Acute kidney injury is defined by an abrupt decline in kidney function over 7 days or less, while chronic kidney disease persists for more than 90 days.
What are the common causes of glomerular disease?
Glomerular disease is often caused by immunologically mediated inflammatory injury. Other contributing factors include secondary mechanisms such as fibrin deposition, platelet aggregation, free radical-induced damage, haemodynamic changes, and systemic diseases like lupus.
What is the difference between nephrotic and nephritic glomerular disease?
Nephrotic disease is characterized by the presence of large amounts of protein in the urine.
Nephritic disease involves both protein and blood in the urine.
How does hypertension affect kidney function?
Hypertension can both cause and result from kidney disease. In essential hypertension, blood vessels and kidneys remodel over time, contributing to further damage. In renal hypertension (or renovascular disease), kidney disease activates the renin-angiotensin-aldosterone system, leading to salt and water retention, which worsens kidney function.
What are the common tests used to measure kidney function?
Serum urea and serum creatinine are commonly used, though not the most reliable.
Urine albumin to creatinine ratio (ACR) helps assess kidney function.
Creatinine clearance can estimate the glomerular filtration rate (GFR).
The most reliable method, though less commonly used, is inulin clearance to check GFR.
What is creatinine clearance, and how is it measured?
Creatinine clearance is a measure of kidney function that can be determined by collecting a person’s urine over 24 hours and measuring the amount of creatinine in the sample. This method, while precise, is inconvenient. The GFR can also be estimated through a single blood creatinine level using formulas that consider age, sex, weight, and ethnicity.
What issues arise when using drugs in patients with renal impairment?
In patients with reduced kidney function, drugs can present issues like:
Toxicity due to reduced renal excretion of drugs or their metabolites.
Increased sensitivity to certain drugs even when elimination is unimpaired.
Poor tolerance to drug side effects.
Reduced effectiveness of some drugs when kidney function is impaired.
What classes of drugs should people with renal impairment avoid?
People with renal impairment should avoid the following drugs:
NSAIDs (e.g., ibuprofen) which can reduce glomerular filtration rate by causing vasoconstriction of the afferent arteriole.
Chemotherapeutic drugs like aminoglycosides and amphotericin B.
Calcineurin inhibitors, ACE inhibitors, and Angiotensin 2 receptor blockers which can impair renal function.
Loop and Thiazide diuretics, penicillins, and cephalosporins.
Methotrexate, warfarin, and anticholinergic drugs.
Why are ACE inhibitors potentially harmful to patients with renal impairment?
ACE inhibitors can be harmful because they block the effect of angiotensin 2, which normally helps maintain glomerular filtration rate during low renal perfusion. This can lead to acute renal failure in patients with compromised kidney function.
What is the role of the renin-angiotensin-aldosterone system in renal hypertension?
In renal hypertension, kidney disease can activate the renin-angiotensin-aldosterone system (RAAS), leading to the retention of salt and water. This process increases blood volume, which raises blood pressure and further exacerbates kidney damage.
What is the significance of measuring the urine albumin-to-creatinine ratio (ACR)?
The urine albumin-to-creatinine ratio (ACR) is an important test for assessing kidney function. It helps detect early kidney damage by measuring the amount of albumin (a protein) relative to creatinine in the urine. An elevated ratio indicates kidney dysfunction.
What is acute tubular necrosis (ATN), and how is it related to acute kidney disease?
Acute tubular necrosis (ATN) is a form of parenchymal damage in which the tubular cells of the kidneys die, leading to a decline in renal function. It is a common cause of acute kidney injury, typically caused by ischemia (lack of blood flow) or toxins.
What are some common causes of end-stage kidney disease?
The three most common causes of end-stage kidney disease are:
Glomerular diseases, which damage the kidney’s filtering units.
Hypertension, which can cause gradual damage to the kidneys’ blood vessels.
Vascular diseases, which affect the blood supply to the kidneys.
How does dehydration lead to acute kidney disease?
Dehydration reduces blood volume, leading to decreased renal blood flow. This results in reduced glomerular filtration rate (GFR), which can cause an abrupt decline in kidney function, leading to acute kidney disease.
How does lupus contribute to glomerular disease?
Lupus is an autoimmune disease that can cause inflammation throughout the body, including the kidneys. In lupus, the immune system attacks the glomeruli, leading to glomerular disease, which can present as either nephrotic or nephritic syndrome.
What is the importance of measuring inulin clearance in kidney function testing?
Inulin clearance is the most reliable method for measuring glomerular filtration rate (GFR) because inulin is neither reabsorbed nor secreted by the kidneys. It provides a precise measurement of kidney function but is less commonly used due to the complexity of the test.
What are the potential consequences of reduced renal function when using NSAIDs?
NSAIDs can lead to reduced glomerular filtration rate by causing afferent arteriole vasoconstriction, impairing blood flow to the kidneys. This can worsen renal function, especially in individuals with existing kidney disease, and may lead to acute kidney injury.
How does hypertension contribute to kidney disease over time?
Chronic high blood pressure (hypertension) can cause damage to the blood vessels in the kidneys, leading to glomerulosclerosis (scarring of the kidney’s filtering units). Over time, this damage reduces the kidneys’ ability to filter waste and excess fluid, potentially leading to chronic kidney disease.
Why should the dose of medications be adjusted in patients with renal impairment?
In patients with renal impairment, the kidneys are less able to excrete drugs and their metabolites, which can result in drug toxicity. Adjusting the dose or selecting alternative medications helps avoid adverse effects and ensures that the medication remains effective without causing harm to the kidneys.
