Passmed Renal Flashcards
What is a test for renal function?
Inulin which is wholly filtered in the glomerulus and not secreted or excreted.
How can systemic lupus affect the kidneys?
Autoimmune complex deposition affects the glomerulus and causes diffuse proliferative glomerulonephritis, with wire-loop glomerular lesion with proteinuria on histopathological testing. It is managed by treating the underlying hypertension and steroid therapy to reduce immune response.
How can systemic lupus be detected on examination?
Autoimmune complex deposition affecting the glomerulus and causes proliferative wire-loop glomerular lesion with proteinuria on histopathological testing. It is managed by treating the underlying hypertension, steroid therapy to reduce immune response and
How does diabetes affect the kidneys?
Non-enzymatic glycation results in nodular glomerulosclerosis and hyaline arteriosclerosis.
What is the most common cause of acute kidney injury?
Acute tubular necrosis, which is typical following dehydration and loss of perfusion to the kidneys. Dysfunction of the renal cells results in dark concentrated urine. A hallmark of acute tubular necrosis is muddy brown granular casts because of the loss of the cells. Treatment is typically addressing Hypovolemia and correcting electrolyte imbalances.
What are the causes of acute tubular necrosis?
-> Shock due to ischaemia or sepsis
-> Use of Nephrotoxins like aminoglycosides, myoglobin, radio-contrast agents or lead.
In acute tubular necrosis, there is an oliguria phase, polyuria phase and recovery phase.
What is the risk with correction of low sodium?
“Low to high, the brains will die”
Osmotic demyelination syndrome, where fluid shifts from the cells to extracellular space causes damage to myelin of neural cells, causing dysphagia, seizure, dysarthria and motor abnromalities.
What is the risk with correction of hypernatremia?
“High to low the brain will blow”
Rapid drops in serum osmolality will cause fluid to deposit in the extracellular space.
What is Goodpasture’s syndrome?
Type 2 hypersensitivity where antibodies attack the glomerular basement membrane and lung membranes, causing haemoptysis and haematuria.
Which glomerulopathies are mediated by immune complexes?
Systemic lupus erythematous
Post-streptococcal glomerulonephritis
Which glomerulopathies are mediated by immune complexes?
Systemic lupus erythematous
Post-streptococcal glomerulonephritis
What occurs after parathyroidectomy?
Removal of the parathyroid glands results in severe hypocalcaemia known as hungry bone syndrome due to a shift from osteoclasts activity to osteoblast activity
What are the features of post-streptococcal glomerulonephritis?
Immune complex deposition of IgG, IgM and C3 in the glomeruli with endothelial profileration by neutrophils, granular appearance on immunofluoresence and a subepithelial hump which results in nephritic syndrome with haematuria and proteinuria, which occurs 7-14 days following an infection with a group B streptococcus pathogen and commonly affects young children.
Which medications should be stopped during an acute kidney injury?
ACE inhibitors
NSAIDs
Diuretics
What is the implication with the use of lithium?
Diabetes insipidus which targets the collecting duct by desensitising the body’s response to ADH.
What is the most common cause of nephrotic syndrome in children?
Minimal change disease, where there is T cella and cytokine mediated damage to the basement membrane, resulting in an increased glomerular permeability to albumin. It is typically managed with corticosteroids and
How does raised pH affect levels of potassium?
Alkalosis indicates that there is a higher concentration of H+ ions in the cell which causes the loss of potassium levels intracellularly.
What are the causes of hyperkalemia?
Metabolic acidosis
Rhabdomyolysis
AKI
Addison’s disease
Large blood transfusion: donated blood may be high in K+ that induces loss of in vivo K+ via the urine
Why does Addison’s disease result in hyperkalemia?
Destruction of the adrenal glands results in undersecretion of aldosterone, which prevents the excretion of K+ into the urine and promotes the loss of Na+ and H20.
What is the specific gravity of urine?
Concentration of solutes in the urine.
Which factors affect the clearance of a drug?
Diffusivity across the membrane and tubular reabsorption/secretion.
Which cells make up the juxtaglomerular apparatus?
Juxtaglomerular cells
Extraglomerular mesangial cells
Macula dense cells
What is the role of the juxtaglomerular cells?
Specialised smooth muscle cells found in the afferent arteriole which release renin as part of the RAAS system, and are involved in delivering blood to the glomerulus.
What is the role of the macula densa?
Cells lining the thick ascending limb of the loop of Henle which detects Na and Cl levels in the limb lumen and influences the release of renin in the juxtaglomerular cells.
Which HLA is most important for matching?
HLA-DR, followed by HLA-B and HLA-A.
Where is the majority of water reabsorbed in the kidneys?
Proximal tubule.
What is the normal anion gap?
Acidosis, where pH is less than 7.35 and is not accompanied by an increased anion gap and characterised by high levels of chloride ions. This occurs due to:
Renal tubular acidosis
Acetazolamide (carbonic anhydrase inhibitor)
Addison’s disease
What causes the raised anion gap in acidosis?
Higher level of ketones from alcohol and diabetic ketoacidosis
Renal failure
Acid poisoning
Increase in lactate levels due to shock or hypoxia
What are the histological features of minimal change disease?
Fusion of podocyte cels and effacement of foot processes
What is the effect of ACE inhibitors on potassium?
Rise in potassium.
What
What
What
What is the ascending limb of the loop of Henle permeable to?
Sodiuma and chloride ions, and where the majority of magnesium absorption occurs in the kidneys.
What is the descending limb of the loop of Henle permeable to?
Water
What are the risk factors for developing renal stones?
Hypercalcaemia
Reduced urine output
What is a staghorn calculus?
Kidney stone formed in the shape of the renal pelvis viewed through X-ray in the form of struvite, which typically occurs due to an upper respiratory tract infection where bacteria release urea that forms ammonium.
What is the clinical presentation of kidney sotones?
Unilateral renal colic pain from loin to groin which fluctuates in severity, with patients experiencing nausea, vomiting and reduced urine output. There is likely to be haematuria and symptoms of sepsis if infection is present.
Why do renal stones cause sepsis?
Renal stones block the flow of urine and cause kidney infection.
Which type of kidney stones cannot be seen on x-ray?
Uric acid stones, which can only be viewed through non-contrast CT scans.
What are the most common types of kidney stones?
1) Calcium stones, calcium oxolate and calcium phosphate
2) Uric acid stones
3) Struvite stones
4) Cystine stones
Why do calcium stones form?
Why do Uric acid stones form?
Intake of food high in purines from animal proteins like organ meats
High BMI
High intake of salt and sugar and history of diabetes
Why do cystine stones form?
Inherited defect in the transport of cystines that ends to excessive excretion in the kidneys.
What are horseshoe kidneys?
Abnormality of kidney development where the inferior poles of the kidney are fused, and become trapped under the inferior mesenteric artery that prevents its ascent.
What is the management of hypocalcaemia?
IV calcium gluconate
Vitamin D supplements
Oral calcium supplements
What are the features of hyperkalemia on an ECG?
Small/absent P waves
Broad QRS complexes with sinusoidal waveform (S shape)
Tall tented T waves
What is pre-renal uraemia?
Generalised term to describe pre-renal kidney injury as a result of reduced perfusion to the kidneys.
Urine sodium and fractional sodium is low, with a raised serum urea-creatinine ratio and a low plasma osmolality, with a high specific gravity of urine.
The renal cells are functional and able to continue to reabsorb urea.
There is a low urine gravity.
What are the features of intra-renal uraemia?
Renal cells are non-functional which reduces urea and sodium reabsorption, that leads to high urine osmolality, high fractional Na+ and urea excretion.
There is a normal urea to creatinine ratio, and high urine plasma osmolality.
There is a low urine gravity.
What is involved in the pathogenesis of membranous glomerulonephritis?
Membranous glomerulonephritis is one of the most common conditions where antibodies are generated against phospholipase A2
What is osmotic diuresis?
Solutes which increase osmotic pressure and induce water loss through urine via a diuretic effect. This include glucose and urea.
What can be given to correct hyperphosphataemia?
Salbutomol causes a short term reduction in potassium by shifting ions from the extracellular to the intracellular compartment.
Calcium resonium which increases potassium excretion by preventing enteral absorption.
What is used to measure renal blood flow in patients?
Para-amino hippurate clearance to measure renal flow.
What causes sterile pyuria?
Urethritis from chlamydia
Renal stones
Appendicitis
Bladder/Renal cancer
What are hyaline casts?
Formed of Tamms-Horsfall protein found in normal urine during exercise, loop diuretics and during times of stress.
What causes brown granular casts in urine?
Acute tubular necrosis.
