Renal Flashcards
Dent disease
Presentation
Gene
Dent disease is also known as X-linked recessive nephrolithiasis.
Children with Dent disease present with polyuria, microscopic haematuria, proteinuria or kidney stones. 75% of patients develop kidney stones.
Most cases of Dent disease are caused by mutations in theCLCN5genethat inactivates a voltage-gated chloride transporter named CLC-5. Some cases are associated with mutations in theOCRL1gene, which is also the gene mutation associated with Lower oculocerebrorenal syndrome.
Cystinosis
Presentation
Diagnosis
Cystinosis is a lysosomal storage disease. Cysteine accumulates in organs and tissues, leading to severe organ dysfunction.
Children appear normal at birth but present with renal problems at 3-6 months of age. They will often have vitamin D resistant rickets at presentation, secondary to phosphate wasting.
Diagnosis is confirmed by measuring high levels of cysteine in leukocytes or fibroblasts.
Homocystinuria is a different entity but is often confused with cystinosis because of the similar name. Children with homocystinuria have Marfanoid habitus and are prone to thrombotic events but do not usually have renal problems.
Von Gierke disease
Clinical features
Von Gierke disease is also known as glycogen storage disease type 1a.
Clinical features include hepatomegaly, seizures (secondary to hypoglycaemia), renal calculi, poor growth and doll-like facies. It presents in infancy.
Wilson’s disease renal complications
A less well known clinical feature of Wilson disease is that is can lead to distal renal tubular acidosis which results in kidney stones.
Aldosterone.
Action in hypovolemia
Increases reabsorption of Na+ by acting primarily on principal cells in collecting ducts. Responsible for active sodium reabsorption and subsequent water conservation.
Angiotensin II.
Action in hypovolemia
Produces arteriolar constriction and increases SBP and DBP. One of the most potent vasoconstrictors known. Also acts on adrenal cortex to increase secretion of aldosterone.
Anti diuretic hormone
Action in hypovolemia
Causes retention of water by the kidney by increasing permeability of collecting ducts. Therefore urine becomes more concentrated and its volume decreases. Hence, osmolality of body fluid decreases.
Prostaglandin I2
Action in hypovolemia
Unstable cyclooxcygenase metabolite found in vascular endothelial cells. Potent vasodilator and inhibitor of platelet aggregation.
During acute hypovolaemia, produces dilation of the renal afferent arteriole
Thromboxane
Action
Promotes platelet aggregation and vasoconstriction. Activated in acute severe blood loss to contract bleeding vessels and form clot.
Causes of anaemia in chronic renal failure?
Which is the most common?
Decreased EPO production (MC) Iron deficiency Folate deficiency Vit B12 deficiency Decreased erythrocyte survival
Recombinant human EPO therapy reduced need for transfusions
Should also be given Fe supplements
Which embryonic structure develops into the kidney
Metanephros (the most caudal end of the nephrogenic cord)
Antihypertensive - renoprotective and decrease proteinuria
ACEi
UTI in females
Frequency
Bugs
3-5% of girls
first occurs by 5 years age, peak in infancy and during toilet training; 60-80% will develop a second UTI within 18 months.
E.coli, Klebsiella and Proteus
UTI in boys
Frequency
Bugs
1% of boys
most occur during the first 12 months of life, more common if uncircumcised.
E.coli,also gram +ve organisms
Leading cause of renal artery stenosis (RAS)
Associations
Ix
fibromuscular dysplasia is the leading cause.
neurofibromatosis is at increased risk of renal artery stenosis (RAS)
renal arteriography as gold standard. Doppler renal ultrasound may be done as first line but is not as sensitive nor specific.
Vesicoureteric reflux (grading)
1) limited to ureter
2) reflux up to renal pelvis
3) mild dilatation of ureter and pelvicalycael system
4) tortoise ureter with moderate dilatation + blunting of cornices but preserved papillary impressions
5) tortuous ureter with severe dilatation of ureter and pelvicalycael system + loss of cornices and papillary impressions
Triad of nephrotic syndrome
Hypoalbuminemia
Oedema
Hyperlipidemia
Associated with large urinary loss of protein
Prognosis of multicystic dysplastic kidney
Complete cyst regression by 7 in half of patients
15% contralateral VUR
5-10% contralateral hydronephrosis
0.2-1.2% HTN
0.3% Wilms
Most common cause of abdominal mass in newborn
Most accurate measure of GRF
Cr EDTA clearance
(chromium-51 ethylenediaminetetraacetic acid)
(Less cumbersome that gold standard of inulin)
Patient receives IV Cr EDTA and blood radioactivity is measured at 2 and 4 hrs post
Which of the following embryonic structures develops into the kidney?
The metanephros is the most caudal end of the nephrogenic cord and becomes the kidney.
Renin release from juxtaglomerular cells is stimulated by:
Sodium depletion via macula densastimulates renin release.
Where does aldosterone act and what does it do
Targets epithelial cells in distal colon and renal nephron to resorb Na and secrete K
It increases Ba resorption in distal tubule
Formula for fractional excretion of sodium
FENa = (UNa X PCr) ÷ (PNa X UCr)
Delineate cause of renal failure fro FENa
Prerenal <1%
Intrinsic >2% (1-2% probably intrinsic ATN)
Post renal >4%
Horseshoe kidney
Frequency
Complications
Associations
Most common renal fusion anomaly. 1 in 10,000 births.
Occurs week 5-9
80% have hydronephrosis cause by vesicoureteric reflux, ureteropelvic junction obstruction, renal calculi, external compression
20% renal calculi
Increased risk of UTI due to urinary stasis but do not routinely require prophylaxis
Turners syndrome
Laurance-moon-biedl syndrome
Causes of high and normal anion gap acidosis
High anion gap is caused by:
ketoacidosis (diabetic, alcohol, starvation)
lactic acidosis (Type A and B)
renal (uraemia)
toxins (including ethylene glycol and aspirin)
Normal anion gap acidosis is caused by:
renal (renal tubular acidosis, carbonic anhydrase inhibitors)
severe GI losses
