Renal Failure and Kidney Anatomy

Renal Failure

• Renal failure occurs in a condition where the kidneys cannot remove metabolic waste from the blood and regulate fluid, electrolytes, and pH balance in extracellular fluids

Anatomy of the Kidneys

• Kidneys are retroperitoneal structures located usually between the transverse processes of T12-L3 vertebrae
• The left kidney is typically more superior than the right
• The upper poles are oriented more medially and posteriorly, as compared to the lower poles
• Kidneys are bean-shaped and normally about 12cm in length, 6cm in breadth, and 3cm in thickness
• Kidneys have anterior and posterior surfaces, lateral (convex) and medial (concave) borders with the hilum in the middle
• Located on the posterior abdominal wall, on both sides of the vertebral column, behind the peritoneum.
• Kidneys lie obliquely, with their upper poles nearer to each other than their lower poles
• The structure of the kidney is composed of a fibrous capsule and a cortex
• The cortex stretches into renal columns between the pyramids
• The Medulla of the kidney showcases pyramids, which are triangular dark striated areas
• The apices of the pyramids are the papillae which open into a minor calyx
• Minor calyces converge to create major calyces that diverge to create the pelvis and ureter
• The nephron serves at the fundamental building block of the kidney
• Human kidneys contain about 1,000,000 nephrons

Function of the Kidneys

• The primary functions encompass filtration and excretion of metabolic waste products, such as urea and ammonium
• Kidneys ensure the regulation of electrolytes, fluids, and maintaining acid-base balance
• Regulation of blood pressure is achieved through the renin-angiotensin-aldosterone system
• Kidneys also manage water reabsorption and maintain intravascular volume

Causes of Kidney Failure

• Kidney failure is often observed in individuals with risk factors from one or more of the following causes
• Reduction of blood flow to the kidneys prompts kidney failure
• Causes of reduced blood flow included: heart attack, heart disease, liver scarring or failure, dehydration, severe burns, allergic reactions, and sepsis
• High blood pressure and anti-inflammatory medications can limit blood flow
• Urine elimination issues occur when the body cannot remove urine, causing toxins build up and overload the kidneys
• Cancers may block the urine passageways, including prostate, colon, and bladder
• Other conditions that may interfere with urination include: kidney stones, enlarged prostate, and blood clots within the urinary tract
• Nerves that control the bladder, when damaged, can lead lead to kidney failure
• Other causes includes; blood clots in or around your kidneys and infection
• Significant accumulation of toxins from heavy metals, drugs and alcohol can also damage kidneys
• Vasculitis (inflammation of blood vessels), Lupis(an autoimmune disease) as well as glomerulonephritis (inflammation of blood vessels) can cause problems
• Hemolytic uremic syndrome can cause breakdown of red blood cells
• Multiple myeloma causes cancer of plasma cells in your bone marrow
• Scleroderma is an autoimmune disease affecting the skin
• Thrombotic thrombocytopenic purpura is a disorder contributing to blood clots in small vessels
• Certain medications and imaging tests may lead to kidney problems like chemotherapy drugs, dyes, certain antibiotics and uncontrolled diabetes

Uremic Symptoms

• Symptoms include: anorexia, nausea, vomiting, weight loss, restless limbs, generalized restlessness, fatigue, weakness, reduced mental acuity/clouding, and a loss of concentration
• Other symptoms commonly relate to pruritus, peripheral dysaesthesia, headaches and also sleep disturbance

Types of Kidney Failure

• Acute renal failure
• Chronic renal failure

Acute Renal Failure

• Acute renal failure (ARF) is a sudden, severe loss of kidney function over hours or days, decreasing the Glomerular Filtration Rate (GFR)
• Although ARF is often a problem seen in hospitalized patients, it may also occur in the outpatient setting
• ARF manifests with oliguria, anuria, or normal urine volume
• Oliguria, or having a urine output of less than 400 mL/day of urine, is the most common clinical situation with ARF
• Rising serum creatinine and blood urea nitrogen (BUN) levels and retention of metabolic waste (azotemia) are caused by ARF

Causes of Acute Renal Failure

• Prerenal failure comes from volume depletion resulting from hemorrhage, renal losses (diuretics/osmotic diuresis) as well as Gastrointestinal losses (vomiting, diarrhea, nasogastric suction)
• Impaired Cardiac function may cause kidney failure which comes from myocardial infarction, heart failure, dysrhythmias, cardiogenic shock
• Vasodilation may cause kidney failure which stems from sepsis, anaphylaxis, and antihypertensive medications that will cause vasodilation
• Prolonged renal ischemia contributes to Intrarenal failure due to pigment nephropathy that has a breakdown of blood cells containing pigments
• Nephrotoxic agents can potentially lead to intrarenal failure such as Aminoglycoside antibiotics (gentamicin, tobramycin), Radiopaque contrast agents, Heavy metals (lead, mercury), Solvents/chemicals (ethylene glycol/carbon tetrachloride/arsenic), Nonsteroidal anti-inflammatory drugs (NSAIDs), and Angiotensin-converting enzyme inhibitors (ACE inhibitors) will lead to failure
• Infectious processes and urinary tract obstructions can cause acute renal failure

Chronic Renal Failure

• Chronic renal failure, or End-Stage Renal Disease (ESRD), is a progressive, irreversible deterioration in renal function

Stages of Chronic Renal Disease

• Stage 1: There is a reduced renal reserve, characterized by a 40 to 75% loss of nephron function, patients often have no symptoms
• Stage 2: Renal insufficiency occurs with 75 to 90% of nephron function is lost, and serum creatinine and blood urea nitrogen levels increase. This stage also has a loss in the ability to concentrate urine and anemia. Patients may also have polyuria and nocturia.
• Stage 3: This is also known as End-stage renal disease or ESRD, it occurs when less than 10% nephron function remains and all normal regulatory/excretory/hormonal functions of the kidney are severely impaired. Increased creatinine and blood urea nitrogen as well as electrolyte imbalances are seen here. Here, patients will need dialysis and many uremic symptoms may be reversible

Diagnosing Kidney Failure

• Several test can use to determine kidney failure such as
• Urinalysis: Doctors can test a urine sample to test for abnormalities such as sugar or excessive amounts of cellular casts
• Urine volume measurements: One of the simplest tests to help diagnose kidney failure, low urinary output may suggest a urinary blockage due to multiple illnesses and injuries

Blood Samples

• Blood tests can measure substances that are filtered by the kidneys
• Specific conditions such as blood urea nitrogen (BUN) and creatinine (Cr) are checked
• Acute kidney failure is indicated by a rapid increase in these levels

Imaging

• Imaging tools such Ultrasound and CT scans can provide images of the kidneys and urinary tract for abnormalities

Treatment of Kidney Failure

• Since medications are removed from the blood during hemodialysis, dosage changes are necessary
• Protein-Bound Metabolites of drugs are not removed during dialysis
• Patients receiving dialysis, all medications and their dosages must be carefully evaluated

Dialysis

• Dialysis is meant to remove fluid and uremic waste products from the body if the kidneys can’t
• It is also used to treat patients with edema, hepatic coma, hyperkalemia, hypercalcemia and hypertension
• Dialysis does not cure kidney failure, but extends life in regularly scheduled appointments

Types of Dialysis

• Acute Dialysis is indicated when there is a high and rising level of serum potassium, fluid overload or impending pulmonary edema, increasing acidosis, pericarditis and severe confusion
• Chronic dialysis is indicated in chronic renal failure, known as end-stage renal disease (ESRD), in instances like and uremic signs, nausea and vomiting, severe anorexia, increasing lethargy, mental confusion
• Patients with no renal function can be maintained by dialysis

Prevention methods

• Quit Smoking and Alcohol consumption
• Lose Weight if Overweight or Obese
• Follow a healthy diet and lower salt intake