Renal Flashcards
Sequence of Potter syndrome?
Pulmonary hypoplasia Oligohydraminios Twisted face Twisted skin Extremity defects Renal failure
What is oligohydraminos?
Causes?
Compression of developping fetus with limb deformities, facial anomalies (low set ears, retrognathia, flattened nose)
Compression of chest and lack of amniotic fluid aspiration into the fetal lungs
Can cause pulmonary hypoplasia
Causes: ARPKD (polycystic kidney disease) Obstructive uropathy bilateral renal agenesis Chronic placental insufficiency
Horeshoe kidney?
Inferior poles of the kidney are fused
Kidney’s function normally
Associated with hydronephrosis (uretropelvic obstruction, renal stones, infection, and chromosomal abnormality)
Associated with Turner’s syndrome, trisomies 13, 18, 21 and renal cancer
Unilateral renal agenesis?
Ureteric bud fails to develp and induce differentiation of metanephric mesenchyme
Complete absense of kidney and ureter
Often diagnosed with ultrasound prenatally
Multicyctic dyplastic kidney?
Ureteric bud fails to differentiare
Creates non functioning kidney consisting of cysts and connective tissue
What is duplex collecting system?
Bifurcation of ureteric bud before it enters the metanephric blastema
Y shaped bifid ureter
Strongly associated with vesicouretal refluc and ureteral obstruction
Increase risk of UTI
Congenital solitary functioning kidney?
Born with only one functioning kidney
Majority asymptomatic with compensatory hypertrophy of the contralateral kidney
Anomalies of the contralateral kidney are common
Which kidney taken during transplant?
Left kidney is taken, because it has a longer renal vein
Afferent vs efferent?
Afferent is arriving
Efferent is exiting
What is the renal blood flow?
Renal artery—segmental artery—interlobar artery—arcuate artery—interlober artery—afferent arterirole —-glomerus—-efferent arteriole—vasa rectal —peritubular capillaries—venous outflow
What is the course of the ureters?
Pass under uterine artery or under vas deferens (retroperitoneal)
Gynecological procedures (ligation of uterine or ovarian vessels) may damage ureter
Cause ureteral obstruction or leak
What are the percentage of the body composions?
(the percentage of body weight of a person)
60% total body water
40% ICF
20% ECF
Plasma volume can be measuredby radiolabeling albumin
Extracellular volume can be measured by insulin or mannitol
Glomerular filtration barrier?
responsible for filtration of plasma according size and net charge
Composed of fenestrated capillary endothelium
Fused basement membrane with heparin sulfate epithelial layer (negative charge and size barrier)
Epithlial layer consisting of podocyte foot processes (negative charge barrier)
What happens in the glomerular filtration barrier during nephrotic syndrome?
Albuinuriea
Hypoproteinemia
Generalized edema
Hyperlipidemia
How to calculate renal clearnace?
Cx (clearance of X)
Ux (urine concentration)
Px (plasma concentration)
V (urine flow rate)
If Cx < GFR (net resoprtion of X)
If Cx > GFR (net tubular secretion of X)
Cx = GFR no net secretion or absorption
How to calculate the volume ofplasma from which the substance is completely cleared per unit of time:
Cx= UxV/Px
What is a normal GFR?
How is GFR affected by stages of the kidney disease?
Normal GFR is 100 ml/minute
Incremental reduction of GFR that define stages of chronic kidney disease
Note: creatinine clearance is an approximate measure of GFR (slightly overestimates GFR because creatinine is moderately secreted by renal tubules
What is effective renal plasma flow?
Can be estimated using para-aminohippuric acid (PAH) clearence because between filtration and secretion, there is 100% secretion of all PAH that enters the kidney
eRPF = Upah x V/Ppah = Cpah
r
What is the renal blood flow?
RBF= RPF/ (1-Hct)
What is the plasma blood flow?
1-hematocrit
How does the eRPF compare to the renal plasma flow ?
The eRPF (effective renal plasma flow) underestimates the true renal plasma flow.
How to calculate filtration fraction?
FF= GFR/RPF (RPF is effective renal flow)
Normal FF is 20%
Effect GFR, RPF, and FF with afferent arteriole constriction?
GFR decreases
RPF decreases
No change in the FF (because FF is equal to GFR/RPF
Effect on GFR, RPF and FF if efferent arteriole constriction?
Increase GFR
Decrease RPF
Increase in FF
Effect of GFR, RPF abd FF increase plasma concentration?
Decrease GFR
No change in RPF
Decrease in FF
Effect on GFR, RPF and FF decrease in plasma?
Increase in GFR
No change RPF
increase FF
Effect on GFR, RPF, FF with constriction of ureter?
Decrease in GFR
No change in RPF
Decrease FF
Effect on GFR, RPF, FF with dehydration?
GFR decreases
RPf descreases
Increase FF
Normal range of glucose in the plasma levelÉ
Range is 60-120 mg per dl
Glucose should be completely resorbed in proximal convoluted tubule by Na+/glucose
At what glucose level does the transporters become saturated?
200 mg/dl
(this is when glucosuria begins) when all of the transporters are saturated
What happens to glucose during pregnancy?
Normal pregnancy decreases the ability of PCT to resorb glucose and amino acids
Leads to glucosuria and aminoaciduria
The proximal collecting tubule has a decreased ability to reasbosrb glucose
what does the proximal collecting tubule do?
Resorbs: Glucose Amino acids HCO3 Na Cl PO3 K H20
What does thin descending loop of Henle show?
Passively resorbs H2O via medullary hyetonicity (makes urine hypertonic)
what does thick ascending loop of Henle show?
Reorbs: Na K Cl Mg and Ca
Does NOTabsorb H2O
early Descending collecting tubule?
Resorbs
Na
Cl
Makes uring fully dilute (hypotonic)
what does the collecting tubule do?
Resorbs: Na K H+ regulated by aldosterone
Fanconi defect?
Generalized defect in PCT
Increased excretion of amino acids (glucose, HCO3, Po43 and results in metabolic acidosis
Caused by hereditary defects (wilson disease, tyrosemia, glycogen storage disease, ischemia, multiple myeloma, nephrotoxins, lead poisoning
Barter syndrome?
Resorptive defect in thick ascending loop of Henle
Autosomal recessive
Affects Na/K/Cl
Results in hypokalemia, and metabolic acidosis with hypercalciuria
Gitelman syndrome?
Resorptive defect NaCl in DCT Similar to lifelong thiazide diurectics Autosomal recessive Less severe then Barter syndrome Hypokalemia Hypomagneisum Metabolic alkalosis Hypocalciuria
Liddle syndrome?
Gain of function mutation
Increase Na resorption in collecting tubules
Presents like hyperaldosteronism
Aldosterone is nearly undetectable
Results in HTN Hypokalemia metabolic alkalosis Decrease in aldosterone Treatment: amiloride
Syndrome of Apparent Mineralcorticoid excess?
Hereditary deficiency of 11B-hydroxysteroid dehydrogenase
(usually converts cortisol to cortisone)
Excess cortisol in the cells from enzyme deficiency
Increase mineralcorticoid receptor activity leading to HTN, hypokalemia, metabolic alkalosis
Treatment: corticosteroids —> decreases endogenous cortisol production and decrease mineralcorticoid activation
Cortisol tries to be the same as aldosterone
Relative concentrations along proximal convoluted tubules?
Tubular insulin increases in concentration along proximal collecting tubule due to water absorption
Cl reabsorption occurs at a slower rate then Na+ in early PCT and then matches Na+ resoprtion more distally
Relative concentration increases before it plateaus.
How does the Renin-Angiotensin-aldosterone system work?
renin secreted by the kidneys
Responsible for transforming angiotensinogen to angiotensin I
(ACE) produced by the lung and kidney to tranform angiotensin I to angiotensin II
Angiotensin II affects:
Vasoconstriction which increases the BP
Constricts efferent arteriole of glomerus (increases FF to preserve the renal function) in low volume states
Causes aldosterone secretion in the adrenal gland (increase Na2+ and Na/K) and creates a favorable gradient or Na+ and H20
Causes ADH secretion of the posterior pituitary: Increases aquaporin (increases H2O resoprtion
Increases PCT absorption Na, HCO3 and H20 which can cause contraction alkalosis
Stimulates the hypothalamus leading to thirst
Fucntion of renin?
Secreted by JG cells in response to decrease renal arterial pressure and increase renal sympathetic discharge
Angiotensin II
Affects barorecptors function
Limits reflex bradycardia which would normally accompany the pressor effect
Helps maintain blood pressure and volume
ANP and BNP?
Released from atria ANP
And ventricles BNP in response to increase in volume
Relaxes smooth muscle cells via cGMP (icnrease GFR_ and decrease renin
Dilates afferent arteriole
Constricts efferent arteriole
Promotes natriuriesis
What does ADH do?
Regulates osmolarity
Responds to low blood volume states
What does aldosterone do?
Primarily regulares osmolarity (responds to low blood volume state)
Functions of juxtaglomerular appararus?
Jg secrete renin in response to decrease in renal blood pressure and increase in sympathetic tone
Macula densa cells sense decrease in NaCl delivery to DCT
Increase renin release
Cause efferent arteriole vasconstiction
Increase GFR
Mechanisms that cause shift of K out of the cell, and cause hyperkalemia?
Digitalis (blocks the Na/K ATPase HyperOsmolairty Lysis of cells (crush inhury, rhabdomyolysis, tumor lysis syndrome Acidosis B Blocker High Blood sugar (insulin deficiency)
Process that shifts K into the cells causing hypokalemia?
Hypo-osmolarity
Alkalosis
B-Adrenergc (Na/K ATP ase)
Insulin (Increases Na/ K ATPase)
effects of low/ high Na?
Low:Nausea, Malaise, stupor, coma and seizures
High serum concentration: irritability, stupor, coma
High/low K?
Low: U waves are flattened T waves on ECG
High serum: wide QRS and peaked T waves on ECG, arrythmias, muscle weakness
High/Low Ca?
Low: tetany, Seizures, QT prolongation, Twitching (Chvostek sign)
Spasm(Trousseau’s sign)
High: Stones (renal)
Bones (pain)
Groans (abdominal pain)
Thrones: (increase in urinary frequency)
Pyschiatric overtones (anxiety, altered mental status)
Calciuria
High/low Mg 2?
Low: Tetany
Torsards
Hypokalemia
High: Decrease in Deep tendon reflexes Lethargy Bradycardia Hypotension Cardiac arrest Hypocalcemia
High/low phosphate?
Low:
Bone loss
Osteomalacia (adults)
Rickets (children)
High:
Renal stones
Metastatic calcifications
Hypocalcemia
What are features of Barter syndrome?
No change in blood pressure
Increase plasma renin
Increase in aldosterone
Increase in urine Ca
What are the features of Gitelman syndrome?
No change in blood pressure Increase in plasma renin Increase in aldosteron Decrease in serum Mg Decrease in urine Ca
Features of Liddle Syndrome?
Increase blood pressure
Decrease in renin
Decrease in aldosterone
Features of SIADH?
Increase in blood pressure
Decrease in plasma renin
Decrease in aldosterone
Primary hyperaldosterone (Conn syndrome)
Increase in blood pressure
Decrease in plamsa renin
Increase in aldosterone
Features of Renin-secreting tumor?
Increase in blood pressure
Increase in plasma renin
Increase in aldosterone
What is metabolic acidosis?
Decrease in pH
Low Co2
Low HCO3
Compensation with hyperventilation
Metabolic alkalosis?
Increase in pH
Increase in PCO2
Increase in HCO3
Compensation with hypoventilation
Respiratory acidosis?
Decrease in pH
Increase in PCO2
Increase in HCO3
Increase renal absoprtion of HCO3 (resorption is delayed)
Respiratory alkalosis?
Increase in pH
Decrease in PCO2
Decrease in HCO3
Compensatory: Decrease in renal HCO3 (resorption is delayed)
What are the steps of interpreting acid/base equations?
1) Look at the pH (less then 7.35 is acidic) and more the pH 7.45 is basic
2) Look at the PCO2 (is it more of left then 35)
3) Look at if the HCO3 is going in the same direction
What are functions of erythropoeitin?
Released by intersitial cells on the peritubular capillary bed in response to hypoxia
Stimbulates RBC production in the bone marrow
Can be supplemented in chronic kidney disease
Function of caciferol?
Proximal collecting cells convert 25-OH vitamin D3 to 1.25-(OH)2 vitamin D3 (calcitriol, active form)
Functions of prostaglandins?
Paracrine secretion vasodilates the afferent arteriorles to increase renal blood flow
NSAIDs will block renal protective prostaglandin synthesis leading to constriction of afferent arterirole and decrease GFR
This may result in acute renal failure in low renal blood flow states
Functions of dopamine?
Secreted by proximal collecting tubule cells
Promotes naturesis
At low doses dilates interlobular arteries, afferent arterioles and efferent arterioles
Increase in renal blood flow
Little or no change in GFF
At higher doses acts as vasoconstriction
Function of parathyroid hormone on the kidney?
Secreted in response to
Decrease in plasma Ca
Increase in plasma PO4
Decrease in 1.25 OH2D3
Causes: Increase in CA absorption (DCT) Decrease in PO4 resorprtion PCT Increase in 1.25 D3 production Increase in Calcium and PO4 absortion from the gut (v ia vitamin D)
What does aldosterone do?
Secreted in response to decrease in blood volume via AT II
Increase in plasma K
Causes increase in Na reabsorption
Increase in K secretion
Increase in H+ secretion