Renal Flashcards
how do you tell the difference between acute tubular necrosis and prerenal uraemia?
in prerenal uraemia the kidneys hold on to sodium to try and preserve volume. Therefore test urinary sodium
Prerenal uraemia responds to fluid challenges (ATN doesn’t)
what is a significant albumin:creatinine ratio?
non-diabetics >30 is clinically significant
in diabetics ACR >2.5 in men and 3.5 in women is significant
what is nephrotic syndrome?
proteinuria
hypoalbuminaemia
peripheral oedema
pathology of MGN?
causes of membranous glomerulonephritis?
immune complex formation in the glomerulus -> inflammation and nephrotic syn
idiopathic infection - malaria, hep B malignancy - lung ca, lymphoma, leukaemia drugs - gold, penacillamine, NSAIDS SLE
management of membranous glomerulonephritis
immunosuppression - corticosteroids + other (eg chlorambucil)
antihypertensives (ACEi for proteinuria)
?anticoagulant
PCKD type 1 inheritance
auto dominant chromosome 16
0.1% of caucasians
what’s the pathology in Alport’s syndrome?
what’s the inheritance?
defect in gene for type 4 collagen, leading to defective glomerular basement membranes
X-linked dominant
features of Alport’s syndrome
presents in childhood sensorineural deafness microscopic haematuria progressive renal failure and episodic frank haematurea ocular pathology
features of Goodpasture’s syndrome
pulmonary haemorrhage
rapidly progressive glomerulonephritis (IgG)
what is Goodpasture’s syndrome
HLA association
autoimmune antibodies to type 4 collagen in BM (anti GBM antibodies) (type 2 hypersensitivity) HLA DR2 (narcolepsy and goodpastures)
Ix and Mx of goodpasture’s syndrome
renal biopsy - linear IgG deposits
transfer factor - raised due to pulmonary haemorrhage
plasma exchange, steroids, cyclophosphamide
how do you calculate the anion gap?
what is normal?
(Na + K) - (Cl + HCO3) (cations(+) - anions(-))
normal 10-18
causes of a metabolic acidosis with normal anion gap
GI bicarb loss: diarrhoea, fistula etc
renal tubular acidosis
Addison’s disease (no aldosterone)
drugs eg acetazolamide
causes of a metabolic acidosis with raised anion gap
lactate: shock, hypoxia, metformin
ketones: DKA, alcohol,
urate: renal failure
acid poisoning; salicylate, methanol
variables in eGFR calculation
CAGE creatinine age gender ethnicity
what are the eGFR boundaries for CKD staging?
1: >90
2: 90 - 60
3a: 59 - 45
3b: 44 - 30
4: 29 - 15
5: <15
action of Spironolactone and eplerenone
where does it act?
aldosterone antagonist (eplerenone more selective) acts on the distal convoluted tubule
What is Henoch-Schonlein Purpura?
features?
IgA mediated vasculitis
usually in children post infection
palpable purpuric rash on buttocks and extensor surfaces, IgA nephropathy (haematuria, RF - resolves), abdo pain, poly arthritis
What is the composition of a staghorn calculus?
risk factors?
Struvite (triple phosphate)
form in alkaline urine so proteus and ureaplasma urealyticum infections (which produces ammonia) predispose to their formation.
Features of haemolytic uraemic syndrome
Mx
triad:
acute renal failure
thrombocytopenia
microangiopathic haemolytic anemia
generally seen in young children after E.coli 157:H7
Supportative, plasma exchange if severe with no diarrhoea
Type 1 renal tubular acidosis pathology? causes? features? Mx
unable to make acidic urine in distal CT (pH >5.5)
idiopathic, SLE, Sjogren’s syn
metabolic acidosis, hypokalaemia, renal stones
Mx: correct K then give bicarbonate 1-3mmol/kg/day
Type 2 renal tubular acidosis
pathology?
causes?
features?
Inability to reabsorb HCO3 in PCT
Fanconi syn, Wilsons, cystinosis, idiopathic
hypokalamia, osteomalacia
Type 4 renal tubular acidosis
pathology?
causes?
features?
decreased aldosterone -> decreased NH3 excretion
hypoaldosteronism, diabetes
hyperkalaemia
Where do renal cell carcinomas originate from?
PCT
