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
RCC associations/RFs
smoking
Von-Hippel-Lindau disease
tuberous sclerosis
RCC features
loin pain, haematuria, abdo mass left varicocele (left testicular vein occlusion) endo: may secrete PTH, erythropoetin, renin, ACTH
Mx of RCC
5 yr survival?
nephrectomy even if mets as these may regress
- C/I if bilateral tumours or poor renal function
small molecule kinase inhibitors
interferon alpha and IL-2
no benefit in radio/chemotherapy
5yr survival - 60-70% without mets, 5% with mets
features of minimal change glomerulonephritis
pathology
T-cell and cytokine BM damage leads to loss in electrostatic charge, increased permeability to albumin
Sx: nephrotic syn, normotensive
renal biopsy - fusion of podocytes
Mx of minimal change glomerulonephritis
prognosis
oral prednisolone
1/3rd have single episode
1/3rd have infrequent recurrences
1/3rd have frequent relapses, which stop before adulthood
features of IgA nephropathy
deposits of IgA immune complexes
positive immunoflorescence for IgA and C3
typically in young males, following an URTI
as seen in Henoch Schoelein Purpura
most common organism infecting peritoneal dialysis
staph epidermis
Mx of renal stones
diclofenac/naproxen analgesia alpha blockers (tamsulosin) to aid stone passage stones <5mm will pass spontaneously
imaging of choice for renal stones
non contrast CT (99% reliability)
xray KUB shows 60% of stones
Membranous glomerulonephritis:
presentation
prognosis
proteinurea/nephrotic syn, CKD
1/3rd resolve, 1/3rd respond to cytotoxics, 1/3rd develop CKD
Diffuse proliferative glomerulonephritis
presentation
disease association
classical post-strep nephritis in children
presents as nephritic syn (haematuria, proteinurea, HTN, uraemia) or AKI
most common renal disease in SLE
Minimal change disease
presentation
causes
Mx
child with nephrotic syn (80%)
causes: Hodgkin’s, NSAIDs,
good response to steroids
Focal segmental glomerulonephritis
presentation
causes
proteinurea / nephrotic syn / CKD
may be idiopathic or 2ndary to HIV, heroin
Rapidly progressive glomerulonephritis
presentation
causes
rapid onset AKI
causes: Goodpastures, ANCA positive vasculitis
both can be managed by plasma exchange
Mesangiocapillary glomerulonephritis
associations
type 1: cryoglobinaemia, Hep C
type 2: partial lipodystrophy.
most common type of renal stone
calcium oxalate (40%) - radio-opaque note urate and xanthine stones are radiolucent (can't be seen on xray)
causes of nephrogenic diabetes insipidus
genetic
hypercalcaemia, hypokalaemia
demeclocycline (reduces response to ADH), lithium
sickle cell disease, obstruction, pyelonephritis
Indications for emergency renal replacement therapy
hyperkalaemia refractory to medical management
refractory volume overload
severe metabolic acidosis
uraemic pericarditis
how do you treat hyperphosphataemia?
sevelamer - a phosphate binder
Indications for spironolactone
ascites (cirrohsis -> 2ndary hyperaldosteronism therefore high doses 100-200mg needed) HF (NYHA stage 3-4) nephrotic syn (proteinurea, hypoalbuminaemia, oedema) Conns syn. (too much aldosterone)
What is the usual precipitating factor for mesangioproliferative (IgA) nephropathy?
upper respiratory tract infection 2-3 days prior
What are the microscopic findings in chronic glomerulonephritis?
glomeruli filled with hyaline (homogenous pink substance) with dilation of the remaining tubules.
What age group are affected by renal artery stenosis?
how should it be managed?
hypertension in young adults (30s)
AVOID ACEis
