Nephrology Flashcards
Differences in urine microscopy comparing Acute tubular necrosis and acute interstitial nephritis?
ATN demonstrates muddy brown casts and/or tubular interstitial cells
Low grade haematuria and pyuria are typical of AIN; white cell casts and urinary eosinophils are suggestive of AIN but not diagnostic.
What does FeNa over 2% more suggestive of?
Either excess sodium is lost due to tubular damage, or the damaged glomeruli result in hypovolemia resulting in the normal response of sodium wasting
ADH is released by the posterior pituitary in response to what?
How big or little the cells are - in response to plasma osmolality
How does vasopressin work?
Binds to tube receptor, increases cAMP and increases aquaporins leading to increased reabsorption of water
What is the gene and mode of inheritance of diabetes insipidus?
AVPR2 gene - X linked recessive (mothers may be mildly symptomatic)
Can also be related to Aquaporin 2 upregulation - Autosomal
How does Fanconi syndrome present?
Limited reabsorption in phosphate (rickets), bicarb, water, Hypouricaemia, Amnicoaciduria
What does carbonic anhydrase in the renal tubules do?
It breaks down H2CO3 into CO2 + H20 and this allows passive transfer of CO@ and H20 into the basolateral cell
What drugs can cause Fanconi syndrome?
Gentamicin, Cisplatnisum, Ifosphamide
What are some inherited causes of Fanconi syndrome?
Cystinosis, Dent’s and Lowe’s syndrome
What are the two main electrolytes absorbed in the PCT?
Na and HCO2
Whats a normal anion gap?
Na + K) - (Cl+HCO3
7-13
SLCA4 gene can cause
Distal RTA (type I)
Major way of differentiating distal and proximal RTA?
Distal - urine PH alkalotic and hypercalcuria
Proximal - normal pH
Distal RTA is more likely to be genetic cause - what other features might you seen
Sensorineural hearing loss
What is the major electrolyte anomaly that helps differentiate Type IV RTA?
High Potassium
Hypokalamia, hypochloraemia and metabolic alkalosis?
Barrter’s Syndrome
Where is the anomaly in Barrter’s syndrome?
Impairment in Na+ and Cl- reabsorption in the thick ascending limb of loop of Henle.
Often anomaly in NKCC2 transporter associated with SLC12A1
You urinate sodium and chloride; in response renina nd aldosterone is secreted and you urinate more K+ in response to losing Na+
Barter’s syndrome is like effect from which diuretic?
Frusemide
Frusemide blocks NKCC2 chanel
In Frusemide, complication is
Hypochloraemic, hypokalaemic, Hypercalciuric
How do you treat Bartter’s syndrome?
You can treat with anti-prostaglandins (NSAIDS - indomethacin)
What are potassium sparing diuretics?
Spironlactone and Amiloride
What are the renal actions of prostaglandins?
- Increase renal blood flow
- Increase GFR
- Decrease sodium reabsorption at TAL/LoH
- Increase renin secretion
- Increase water excretion
Where is the pathology with Gitelman syndrome?
Diminished NaCl transport in the distal CT (like thiazides)
What is the 2 major serum anomaly and 1 major urine anomaly that may help you differentiate Barrters syndrome and Gitelman?
Gitelman you have low serum Mg and Low serum K+ and different to Bartters - in Gitelman you have low Urine Ca
NCCT gene associated with ______ syndrome
Gitelman syndrome
Angiotensin more so acts to constrict ________
whereas prostaglandins act to dilate the _____
Angiotensin more so acts to constrict Efferent artieroles
whereas prostaglandins act to dilate the Afferent arterioles
Aldosterone acts to do what?
It’s main action is to bind to the mineralocorticoid receptor (in the collecting duct); Causes production of ENaC (epithelial sodium channels) and also increases the Na-K-ATPASE channel and also increases excretion of potassium
How does Spironlactone and Amilaride work?
Spironlactone - works to block the Mineralocorticoid steroid receptor
Amilaride acts to block ENac
What is Liddle syndrome genetically?
Causes gain of function of ENaC (keeps it on)
Autosomal dominant
How does Liddle’s present?
Hypokalamia, low plasma renin and aldosterone levels, hypertension and metabolic alkalosis
Thus which antihypertensive does Liddle’s syndrome react well too?
Amiloride - because it blocks the ENaC
Which diuretic blocks the NKCC2?
Frusemide
Which diuretic blocks the NCCT?
Thiazide
What are the three most common types of stones?
1) Calcium Oxalate (50-65%)
2) Calcium Phosphate (14-30%)
3) Struvite (Magnesium, ammonium phsophate) 13%
Which stone is radiolucent on XRAY?
Uric acid
Although Cysteine and Xanthine stones stones are slightly opaque and can be difficult to see
Low citrate, low urine volume and pancreatic insufficiency is a risk factor for which type of stone?
Calcium Oxalate