Paediatric Renal 1 Flashcards
When do nephrons finish growing?
- Formation of nephrons 36-40 weeks gestation
- GFR per 1.73m^2 is improving until age 2/3rd year
- Functional maturation with tubular growth and elongation 1st 10 years
What mutation is implicated in Alport Syndrome?
- Mutations in Type IV collagen
- Lots of different genes
What are the causes of acute nephritis in childhood?
- Post-infectious
- Vasculitis (HSP), rarely SLE, Wegener granulomatosis, microscopic polyarteritis, polyarteritis nodosa
- IgA nephropathy and mesangiocapillary glomerulonephritis
- Anti-GBM disease (Goodpasture syndrome) – very rare
What is the expected time course to resolution of the signs / findings of acute glomerulonephritis?
- gross haematuria 2-4 weeks
- hypertension 4-6 weeks
- low C3 8-12 weeks
- proteinuria 6/12 (may be intermittent for up to 1 year)
- microscopic haematuria up to 2 years
What infectious diseases are associated with secondary membranous nephropathy?
- Congenital syphilis
- Chronic hepatitis B
- Malaria
What renal disease is most likely to present with renal vein thrombosis?
- nephrotic syndrome - specifically membranous nephropathy
Anion gap formula:
Na - (bicarb + chloride)
Normal is 8-12
What are the increased anion gap causes of metabolic acidosis?
M — Methanol U — Uremia D — Diabetic ketoacidosis P — Paracetamol, Propylene glycol, Paraldehyde I — Infection, Iron, Isoniazid (lactic acidosis in overdose), Inborn errors of metabolism L — Lactic acidosis E — Ethylene glycol, ethanol S — Salicylates
What are the normal anion gap causes of metabolic acidosis?
Addisons (adrenal insufficiency)
Bicarbonate loss (GI or Renal)
Chloride excess
Diuretics (Acetazolamide)
What is the aetiology of Goodpasture disease?
Pulmonary haemorrhage and glomerulonephritis due to antibodies to certain epitopes of Type IV collagen
What are the most common causes of HUS?
- Western countries - verotoxin or Shiga-like toxin producing E. coli (STEC), 0157:H7 in Europe/Americas
- Asian subcontinent/southern Africa- toxin of Shigella dysenteriae type 1
What are non-gut bug infectious causes of HUS?
- Neuraminidase (Strep pneumoniae)
- HIV
- Apparently diptheria can
Chemotherapy causes of renal Fanconi syndrome?
- Cisplatin
- Ifosfamide
Why can Cr be low (overestimate GFR)?
Decreased muscle mass = decreased Cr
Increased tubular secretion in CKD, nephrotic syndrome
How much does tubular secretion contribute to renal Cr clearance?
~10-15% (normal circumstances - in CKD etc. may well be higher percentage affecting estimated GFR)
Cystatin C can be influenced by what factors?
Steroid use and thyroid function
What is the name of the lethal ciliopathy with
- occipital encephalocele
- enlarged cystic kidneys
- postaxial polydactyly
Meckel-Gruber syndrome
A child presents with kidney stones, low K and Cl, metabolic alkalosis, FTT with tubular dysfunction, What syndrome is most likely?
- Bartter - similar to having frusemide!!
- Na-K-Cl cotransporter in loop of Henle
- Urinary calcium excretion is normal-high since calcium reabsorption in the thick ascending limb requires normal sodium chloride reabsorption
What are the genes encoding nephrin and podocin?
NPHS1 is nephrin
NPHS2 is podocin
Which gene is most implicated in congenital nephrotic syndrome?
NPHS1 nephrin (40-80%) NPHS2 podocin is as well, but is more likely to be steroid resistant childhood nephrotic syndrome.
How do you treat rickets in primary RTA?
- Bicarbonate first
- Then phosphate and vitamin D
Renin release is stimulated by…
Low sodium - macula densa detects low sodium with hypovolemia.
Tacrolimus side effects include…
Everything has GI side effects Important: High BSL, diabetes Nephrotoxicity with hyperkalemia Neurotoxicity with parasthesia, LESS likely to cause high cholesterol
Excretion of excess sodium when the dietary intake of salt is high is primarily driven by:
ANP/ANF
Which RTA gives you HYPERkalemia?
RTA 4
Which syndromes are associated with Wilms tumour?
- WAGR (Wilms tumour, Aniridia, GU malformation, retardation)
- Denys-Drash syndrome
- Beckwith-Wiederman / hemihypertrophy
- Frasier syndrome (kidneys and genitalia)
- Simpson-Golabi-Behmel syndrome (overgrowth)
How much should your BP dip overnight?
10%
What is the most common inherited cause of Fanconi syndrome?
Cystinosis
What is the typical phenotype of Fanconi?
- Fanconi is RTA 2
- Growth failure, <1yo
- Polyuria/polydipsia
- Rickets
- Bloods show hyperchloraemic metabolic acidosis with hypokalemia and hypophosphataemia
- urinary acidification with glycosuria, aminoaciduria, hyperphosphaturia
A fair-skinned 18 month old presents with fevers, polyuria, growth failure since 6/12, and not walking. She has been previously treated for constipation which was thought to have caused her to vomit. On further questioning, Mum says she seems unable to see very well and does not like going outside to play. You think she has…
Cystinosis - build up of cystine which can’t get out of the lysosomes. Brain, eyes, liver and kidney!
If younger BOY, he could have Lowe syndrome which is congenital cataracts, mental retardation/behavioural issues, and Fanconi syndrome.
Which gene is associated with Lowe syndrome?
OCRL1 gene, which encodes the phosphatidylinositol polyphosphate 5-phosphatase protein.
X-linked recessive
A 3 week old baby boy is noted to have cataracts, has only just regained birth weight, is floppy and seems to pass a lot of urine. He has heavy proteinuria and mild glycosuria on dipstick. What renal associated syndrome could he have?
Lowe syndrome - cataracts, progressive growth failure, hypotonia, and Fanconi syndrome with significant proteinuria
- Blindness and renal insufficiency
- Characteristic behavioral abnormalities are also seen, including tantrums, stubbornness, stereotypy (repetitive behaviors), and obsessions.
- Kidneys show nonspecific tubulointerstitial changes.
- Thickened GBM and change in proximal tubule mitochondria also seen.
What is the difference between RTA 1 and 2?
- RTA 1 = distal, can’t get rid of acid
- RTA 2 = proximal, can’t keep bicarbonate
- Kidney stones and calcium in urine with distal RTA
What do you see in bloods and urine with Renal Fanconi?
- RTA2 - proximal
- Bloods show normal anion gap, hyperchloraemic metabolic acidosis with hypokalemia and hypophosphataemia
- urinary acidification with glycosuria, aminoaciduria, hyperphosphaturia
What do you see in bloods and urine with RTA 1?
- RTA1 - distal
- Bloods show normal anion gap metabolic acidosis, varying electrolytes but usually normal
- Calciuria, pH>5.5, stones
NB severe recessive form gives hyperchloremic metabolic acidosis (sometimes bicarb<10), hypokalemia, stones
What is MOSTLY re absorbed in the proximal tubule?
- glucose and AA
- phosphate
- citrate
- 2/3 salt and H20
What does the distal tubule re absorb?
- calcium
- bicarbonate
- some salt and water (ADH receptor 2 lives here)
