Renal Pathology 1 Flashcards
Label structures:
Outline the Renin-angiotensin system.
When blood volume is low, juxtaglomerular cells in the kidneys secrete renin directly into circulation.
Juxtaglomerular cells → Renin → (Angiotensin → Angiotensin I) → Angiotensin II → Adrenal gland → Aldosterone
- Angiotensin II causes ADH release from posterior pituitary, and arteriolar vasoconstriction.
- Aldosterone causes K+ excretion and water retention.
- Leads to an increase in blood volume
What tests can be done to test renal function? [6]
- Blood Urea: (normal blood level = 7-21 mg/dl) Urea is a waste product formed in the liver from ammonia. Ammonia is a toxic compound produced during protein-catabolism. Urea is normally excreted from blood by kidney. It is raised in renal failure.
- Creatinine : (normal blood level = 0.6 to 1.2 mg/dl) Creatinine is a waste product of muscle metabolism. It is produced at a constant rate and filtered freely by the glomeruli without reabsorption. Therefore, creatinine levels in the blood are increased when there is reduced glomerular filtration. Plasma creatinine is not a sensitive test, and about 60% of the renal capacity is usually lost before levels become abnormal.
- Proteinuria: Normally, protein is not found in urine when a routine dipstick test is performed. When albumin is present in the urine it is the sign of renal disease.
- Albumin Creatinine Ratio: The albumin creatinine ratio is done to compare the amount of albumin that is passing into the urine as compared to the amount of creatinine present. This ratio remains unaffected by any kind of variation in the concentration in urine. The normal ratio of albumin to creatinine is seen to be around less than 30 mg/g of creatinine. Greater the ratio, more albumin in the urine.
- Serum electrolyte: routinely measured electrolytes are sodium, potassium, chloride and bicarbonate. Abnormal blood levels of any of these may be due to a kidney problem.
- Blood in the urine: presence of erythrocytes in the urine is a sign of renal disease.
What are the 3 spatial categories for causes of acute renal failure?
- Prerenal
- Intrarenal
- Postrenal
Define azotaemia.
(azo-: containing two adjacent nitrogen atoms between carbon atoms)
Azotaemia is a medical condition characterized by abnormally high levels of nitrogen-containing compounds, such as urea and creatinine.
What causes prerenal azotaemia?
Prerenal azotaemia is caused by a decrease in cardiac output, resulting in inadequate blood supply to the kidneys. There is no inherent kidney disease.
What causes renal azotaemia?
Renal azotaemia (acute renal failure) typically leads to uremia. It is an intrinsic disease of the kidney, generally the result of renal parenchymal damage. Causes include glomerulonephritis, acute tubular necrosis, or any other kind of renal disease.
What causes postrenal azotaemia?
Postrenal azotaemia:
Blockage of urine flow in an area below the kidneys results in postrenal azotemia. It can be caused by blockage of the ureters by stones, pregnancy, compression of the ureters by cancer, prostatic hyperplasia, or blockage of the urethra by stone.
Define oligouria.
Oligourea is defined as excretion of less than 300 ml of urine/day.
Causes:
- hypotension
- obstruction of urine outflow
- renal failure
Define uremia.
Uremia: Azotaemia + signs and symptoms
Uremia is a term used to loosely describe the illness accompanying kidney failure (also called renal failure). Here urea, creatinine and other waste products are retained in the blood, along with symptoms such as loss of appetite with nausea, vomiting, pericarditis. Symptoms like lethargy, confusion, coma indicate a progression of the final stages of uraemia.
Define dysuria.
Dysuria is defined as pain, burning, difficulty, or discomfort related to urination. Causes include, stone and/or infection in the urinary tract.
Define renal colic.
Renal colic is a very severe pain that can present suddenly and without warning. It is usually caused by stones in the kidney, renal pelvis or ureter. The pain is caused by dilatation, stretching and spasm of the ureter.
Define polyuria.
Polyurea is persistent large increase in urine output. It may be due to excess intake of water, or increase excretion of solute, as in hyperglycemia and glycosuria or defective renal concentration ability.
Define proteinuria.
Proteinuria (protein in the urine) is the most common sign of renal disease. Most reagent strips can detect 20mg/dl or more in urine. These tests primarily detect albumin and are insensitive to globulin. Causes include: glomerulonephritis, eclampsia, diabetes, SLE etc
Define haematuria.
Haematuria is the presence of erythrocytes in the urine. It can be a sign that there is a kidney stone or a tumor in the urinary tract.
Label:
What are the main structures in the nephron? What are their functions?
