Renal Failure Flashcards
what are the two layers of the interior kidney called?
- outer cortex
2. inner medulla
80% of the nephrons are called what?
cortical as they’re located in the cortex
20% of the nephrons are called what?
juxtamedulla as they’re located in the medulla
describe the structure of the nephron?
- bowman’s capsule surrounding a network of capillaries known as the glomerulus - site of ultrafiltration - (bowman’s capsule and glomerulus form the renal corpuscle)
- fluid flows into proximal tubule then into the loop of Henle.
- FLuid passes into distal tubue
- Distal tubules of up to 8 nephrons drain into a single larger tubule called the collecting duct passing from the corteex into the medulla.
what are the 4 processes of a nephron?
- Filtration
- Excretion
- Reabsorption
- Secretion
how do you calculate the amount of excretion via urine?
(amount filtered) - (amount reabsorbed + amount secreted)
how do you calculate clearance?
(urine conc X urine fow rate) / (plasma conc)
what is the normal creatinine clearance value?
89-137 mL/min
who has a higher GFR, larger or smaller patients?
Larger patients due to having a larger kidney
what is used to compensate for patient size when measuring patient glomerular filtration rate?
the body surface area is taken into consideration
what are the functions of the kidneys?
- Homeostatic regulation of water and ion content of the blood
- Excretion of metabolic waste
- Production of Hormones
what is renal failure?
failure of filtration
what are the kidney disease classifications?
Mild: 60 - 89 mL/min/1.73m2 Moderate: 30 - 59 mL/min/1.73m2 Severe: 15 - 29 mL/min/1.73m2 Kidney failure: <15 mL/min/1.73m2 (The values are GFR)
how can we detect renal failure?
by the presence of urea in blood (uraemia)
what are the types of renal failure?
- Acute renal failure
- Chronic renal failure: long standing loss of renal function
that is usually progressive
what is acute renal function?
Deterioration in renal function that is usually reversible over
a period of days or weeks
what are symptoms of acute renal failure to help with diagnosis?
uraemia (urea in blood) and oligouria (uria in urine)
what are the causes of acute renal failure grouped into?
- pre-renal
- renal
- post renal
what is pre-renal acute injury?
when there is a large fall in blood pressure which can not be compensated for hence reducing glomerular filtration rate causing pre-renal injury
what causes pre-renal acute injury?
impaired perfusion of the kidneys
what conditions cause pre-renal acute injury which can lead to kidney damage and/or chronic renal failure?
• Hypovolaemia • Hypotension • Heart failure(reduced cardiac output) • Vascular disease that limits renal blood flow • Drugs that impair renal autoregulation (NSAIDS, ACE inhibitors)
what causes post-renal acute injury?
obstruction of the urinary tract by (calculus, blood clot or bladder tumour)
what causes renal acute injury?
(Cellular damge/intrinsic) • Renal parenchymal disease - secondary to diseases that affect vascular system • Glomerulonephritis - Autoimmune (e.g. Lupus) • Acute tubular necrosis - caused by renal ischaemia, drugs that cause renal toxicity (aminoglycosides, Li+). - All cause tubule cell injury
what is chronic renal disease?
long standing and progressive decline in renal function
what are the signs and symptoms of chronic renal failure?
• Fluid retention causing swelling in the ankles during day
• Fluid in lungs (pulmonary oedema)
• High blood pressure
• (hyperkalemia) – life threatening emergency since will
impair cardiac function
• Cardiovascular disease – can be secondary to renal disease and vice versa
• Weak bones and an increased risk of bone fractures
• Anemia
• Irreversible damage to your kidneys
what are the causes of renal disease?
- associated with another pathology
- glomerulonephritis
- Interstitial nephritis
- prolonged obstruction of the urinary tract
- vesicoureteral reflux
- recurrent kidney infection
what causes anaemia?
- erythropoietin deficiency
- Substances toxic to bone marrow not excreted
-Incorrect regulation of iron, vitamin B12 and folate levels - Increased red cell destruction and red cell fragility
- ACE inhibitors may cause anaemia by interfering
with erythropoietin release
what causes bone disease?
-kidneys play a role in vitamin D metabolism
-kidney disease leads to reduced production of 1α hydrolase
-this reduces the conversion of 25-(OH)2D3 to more active 1,25-
(OH)2D3
-therefore tthere’s malabsorption of Ca2+ in the gut
-Leads to demineralisation of bone and fibrosis of bone
marrow
-this affects red blood cells
what causes endocrine dysfunction?
- Decreased testosterone production in males
- Decreased estrogen levels in females
- Alterations in thyroid hormone levels
what causes skin disease?
- Retention of nitrogenous waste products leads to pruritis (itching)
- In dialysis patients itching is a sign of incomplete dialysis
what are some Gastrointestinal complications?
- Increased risk of peptic ulceration
- Increased risk of acute pancreatitis
- Constipation and diarrhoea
what are some Metabolic complications?
- Gout - caused by retention of urate which accumulates in joints as crystals
- Severe and very painful arthritis
- Alterations in Insulin metabolism
- Abnormal lipid metabolism (can cause hypercholesterolaemia)
what are the treatment strategies for chronic renal disease?
- controlling blood pressure
- frequent blood tests to monitor electrolyte levels
- ACE inhibitor or ARB or diuretics for lowering blood pressure
- Statins to lower cholesterol
- erythopoietin stimulate RBC production
- Calcium and vitamin D supplements to prevent weak bones and lower risks of fracture
- Low protein to minimize nitrogenous waste products in your blood
