Renal Flashcards
AKI
- acute reversible reduction in renal function
- GFR declines -> failure to maintain fluid, electrolyte, acid-base homeostasis
- reduced UO, fluid overload, rise in K, urea, creat
AKI Dx criteria
- Rise in creatinine >25umol/L in 48hrs
- Rise in creatinine >50% in 7d
- UO less than 0.5ml/kg/hr over >6hrs
stages of AKI?
1 - increase >26 mol/L within 48 hrs or 1.5 to 1.9 x reference creatinine.
Urine output <0.5 mL/kg/hr for > 6hrs
2 - increase 2 to 2.9 x reference creatinine
UO <0.5 mL/kg/ hr for > 12 hrs
3 - increase ≥3 X reference creatinine or
increase 354 μmol/L or commenced on renal replacement therapy (RRT) irrespective of stage
UO <0.3 mL/kg/ hr for > 24 hrs or anuria for 12 hrs
AKI causes ?
Pre-renal causes = Insufficient blood supply (hypoperfusion) to kidneys reduces the filtration of blood. Due to:
- Dehydration
- Shock (e.g., sepsis or acute blood loss)
- Heart failure
Renal causes are due to intrinsic disease in the kidney. Due to:
- Acute tubular necrosis
- Glomerulonephritis
- Acute interstitial nephritis
- Haemolytic uraemic syndrome
- Rhabdomyolysis
Post-renal causes = obstruction to the outflow of urine away from the kidney, causing back-pressure into the kidney and reduced kidney function = obstructive uropathy.
Obstruction may be caused by:
- Kidney stones
- Tumours (e.g., retroperitoneal, bladder or prostate)
- Strictures of the ureters or urethra
- Benign prostatic hyperplasia (benign enlarged prostate)
- Neurogenic bladder
AKI Px
- asym
- reduced UO
- pulm / peripheral oedema
- arrhythmias
- uraemia - pericarditis / encephalopathy
- sx of cause
AKI Ix
- U/E
- urine dip
- fluid balance
- renal USS
AKI Mx
- tx cause
- IV fluids
- stop worsening meds
- adjust renally-excreted meds
- tx electrolytes
- dialysis
what is Acute tubular necrosis (ATN)?
- death of renal tubular epithelial cells
- ischaemic - hypoperfusion - shock, sepsis
- nephrotoxins - eg gentamicin, radiocontrast, rhabdo (myoglobin)
how does ATN present?
- AKI
- muddy brown casts in urine
Acute interstitial nephritis (AIN) - causes Px and ix?
- Acute inflammation of renal tubule-interstitium
Cause - meds
- systemic disease, eg SLE, sarcoidosis
- infection
Px
- fever, rash, arthralgia
- eosinophilia
- mild renal impairment, HTN
Ix
- urine - sterile pyuria, white cell casts
Tubulointerstitial nephritis with uveitis (TINU)
- usually young females
Px
- fever, wt loss, painful red eyes
Ix
- urinalysis - leucocytes + protein
CKD
Chronic kidney function reduction - permanent + progressive
causes of CKD?
- diabetic nephropathy
- HTN
- Meds - NSAIDs, lithium
- glomerulonephritis
- PKD
- chronic pyelonephritis
CKD Dx criteria
> 3mo of either:
- eGFR <60
- urine albumin:creatinine ratio (ACR) >3mg/mmol
CKD classification by eGFR
1 - >90
2 - 60-89
3a - 45-59
3b - 30-44
4 - 15-29
5 - <15
CKD Px
- asym
- fatigue
- pallor
- foamy urine - proteinuria
- nausea
- anorexia
- pruritis - uraemia
- oedema
- polyuria
- HTN
- N+V
- peripheral neuropathy - vit/mineral imbalance
CKD Ix
- ECG - K
- Bloods - U/E, phosph, Ca, FBC
- urine albumin:creatinine ratio (ACR)
- urine dip + MC+S
- renal USS
- BP, HbA1c, lipids
- Kidney Failure Risk Equation
- Kidney biopsy
CKD Mx
- tx cause
- ACEi / ARB
- SGLT-2 inhibitor - dapagliflozin
- exercise, wt loss, stop smoking
- atorvastatin
- ESRF - dialysis, renal transplant
- review meds
CKD Cx
- anaemia
- CKD mineral and bone disorder (CKD-MBD)
- metabolic acidosis - oral sodium bicarb
- CV disease
- uraemia - lethargy, itch, anorexia, confusion, pericarditis
- peripheral neuropathy
- ESRF
Anaemia in CKD
- lack of EPO production -> fewer RBCs
- normocytic, normochromic
Mx
- oral / IV iron
- EPO
CKD -MBD Ix and Mx?
- high serum phosph, low vit D, low serum Ca
- kidneys secrete less phosphate, vit D not activated by kidneys (Ca not reabsorbed by kidneys, nor absorbed by gut), PTH secreted due to low Ca, increased bone turnover, osteosclerosis
Ix
- spinal XR - rugger jersey spine
Mx
- low phosph diet
- phosph binders - Ca based / can use sevelamer
- active vit D - calcitriol
- Ca in diet
- bisphosphonates for osteoporosis
Haemodialysis
- regular filtration of blood through dialysis machine
- blood access via AV fistula / tunnelled cuffed catheter
- anticoagulate with citrate / heparin
Indications for short-term dialysis
A - acidosis - severe, not responding to tx
E - electrolyte abnormalities - eg tx-resistant hyperkalaemia
I - intoxication - OD
O - oedema - severe, unresponsive pulmonary oedema
U - uraemia sx - seizures, coma
Peritoneal dialysis
- filtration in pt’s abdo - inject dialysis solution into abdo cavity, draws waste products from blood, then drain
- continuous ambulatory / automatic (at night)
Cx
- peritonitis - add vanc / teic + ceftazidime to dialysis fluid
Renal transplant
- donor kidney matched based on HLA type A,B,C
- take life-long immunosuppression
Renal transplant rejection
- Hyperacute (mins-hrs) - T2 hypersensitivity - pre-existing ABs - widespread thrombosis of graft vessels - take graft out
- Acute graft failure (<6mo) - cytotoxic T cells, reversible with steroids, immunosuppressants
- Chronic graft failure (>6mo) - AB / cell mediated
Glomerulonephritis
- inflammation of glomeruli
Nephritic syndrome
- inflammation of kidneys - haematuria, oliguria, proteinuria <3g/24hrs, fluid retention/oedema
Nephrotic syndrome
- damage to podocytes, GBM highly permeable to protein
- proteinuria >3g/24hrs, low albumin <25g/L, peripheral oedema
- leads to - thrombosis, HTN, high cholesterol, CKD, infection risk, hypocalcaemia
Nephritic syndrome causes
- IgA nephropathy
- post-strep
- anti-GBM
- ANCA-associated vasculitis
- Rapidly progressive glomerulonephritis (RPGN)
- Lupus nephriti
Nephrotic syndrome causes
- minimal change disease
- Focal segmental glomerulosclerosis (FSGS)
- membranous nephropathy
- Membranoproliferative glomerulonephritis
- HSP
- diabetic nephropathy - scarring from high BMs
- infection - HIV
IgA nephropathy / Berger’s disease - Px, ix and Mx
- deposition of IgA immune complexes -> inflammation
Px
- pt in 20s, URTI a couple of days ago
- macroscopic haematuria - coca cola urine
Ix
- U/E
- urine dip, MC+S
- renal USS / CT / ?biopsy
Mx
- isolated - no tx
- persistent proteinuria - ACEi
- falling eGFR - corticosteroids
Post-strep glomerulonephritis - Px, Ix and Mx?
- 1-3wks after GAS (b haemolytic - often S pyogenes of tonsils)
- immune complexes, ABs, complement get stuck in glomeruli -> inflammation
Px
- tonsillitis
- headache, malaise
- brown urine
- oedema
- decreased UO
- HTN
Ix
- FBC, U/E
- ASO - anti-streptolysin O titre - for strep infection
- throat swabs, urinalysis, ?renal biopsy
Mx
- penicillin for throat
- worsening renal function - anti-HTN, diuretics
Anti-GBM disease / Goodpastures - Px, Ix and Mx?
- small vessel vasculitis - ABs attack glomerulus + pulm basement membranes
Px
- rapid onset AKI, proteinuria, haematuria
- URTI sx first
- SOB, raised RR, crackles, cough, fatigue
- haemoptysis
Ix
- renal biopsy
- anti-GBM ABs in blood
Mx
- intubation, ventilation, haemodialysis
- plasma exchange
- immunosuppression - steroids / cyclophosphamide
ANCA-associated vasculitis
- small-vessel vasculitis
Ix
- p-ANCA / MPO antibodies - microscopic polyangiitis
- c-ANCA / PR3 antibodies - granulomatosis with polyangiitis
Mx
- immunosuppression, steroids
Rapidly progressive glomerulonephritis (RPGN)
- rapid loss in kidney function
- associated with Goodpasture, SLE, microscopic polyangiitis
Px
- haematuria, proteinuria, HTN, oliguria
Ix
- biopsy - glomerular crescent formation
Lupus nephritis
- SLE that can lead to ESRF, glomerulonephritis + sclerosis
Mx
- tx HTN
- glucocorticoids + immunosuppression
Minimal change disease
- most common cause nephrotic syndrome in children
- no specific cause, no change in biopsy
Mx
- steroids
Focal segmental glomerulosclerosis (FSGS)
- a common cause of nephrotic syndrome in adults, also causes CKD
Causes
- idiopathic, renal pathology, HIV, heroin, Alport’s, sickle cell
Ix
- renal biopsy - sclerosis, effacement of foot processes
Mx
- steroids +/- immunosuppression
Membranous nephropathy
- most common cause nephrotic syndrome in adults
- Immune complexes (IgG, complement) deposit in GBM -> thickening, proteinuria
- idiopathic, malignancy, SLE, drugs, RA, infections
Ix
- renal biopsy
Mx
- ACEi/ARB
- immunosuppression + corticosteroid
Membranoproliferative glomerulonephritis / mesangiocapillary glomerulonephritis (MCGN)
- <30yo, immune complex deposits + mesangial proliferation
Px
- nephrotic sx, haematuria, proteinuria
Mx
- poor prognosis
- steroids may help
HIV - nephrotic syndrome
either from infection / tx itself
5 features
- Massive proteinuria -> nephrotic syndrome
- Normal / large kidneys
- FSGS, capillary collapse on renal biopsy
- Elevated urea, creatinine
- Normotension
Renal tubular acidosis (RTA)
metabolic acidosis due to pathology in kidney tubules
Type 1 RTA
- distal tubule cannot excrete H+
Causes
- SLE, genetic, Sjogren, PBC, hyperthyroid, sickle cell, Marfan’s
Px
- failure to thrive (children)
- recurrent UTIs
- rickets / osteomalacia
- muscle weakness
- arrhythmias (low K)
Mx
- oral bicarb
Type 2 RTA
- proximal tubule cannot reabsorb bicarb
Causes
- genetic, multiple myeloma, Fanconi’s syndrome
Mx
- oral bicarb
Type 3 RTA
mix of type 1+2
Type 4 RTA
- low aldosterone / impaired function - normally reabsorbs Na, secretes K + H+
- K and H+ retained in blood
Causes
- adrenal insufficiency, diabetic nephropathy, ACEi, spironolactone
Mx
- tx cause
- fludrocortisone
- oral bicarb
- hyperkalaemia tx
Rhabdomyolysis
- breakdown of skeletal muscle - releases myoglobin, K, phosph, CK
Causes
- long lie, vigorous exercise, crush injuries, seizures, statins, ecstasy, McArdle syndrome
Rhabdo Px
- muscle pain, weakness, swelling
- oliguria
- myoglobinuria - red/brown urine
- fatigue
- N+V
confusion
Rhabdo Ix
Bloods - CK, U/E, Ca (myoglobin binds to Ca)
- urine dip - blood
- ECG
Rhabdo Mx
- IV fluids
- hyperkalaemia mx
- IV sodium bicarb
- IV mannitol - increase UO, reduce oedema
Polycystic kidney disease (PKD)
- genetic condition - multiple cysts develop throughout kidneys
- autosomal dominant (more common) / recessive
- PKD1 on ch16 (codes for polycystin 1) / PKD2 on ch4 (polycystin 2)
- progressive loss of renal function - from mechanical compression, apoptosis, fibrosis
ADPKD Px
- HTN
- recurrent UTIs
- flank pain
- haematuria
- palpable kidneys
- renal impairment
- renal stones
Extra-renal
- liver cysts - hepatomegaly
- berry aneurysms
- CVS - mitral valve prolapse, valve incompetence, aortic dissection / root dilatation
- other cysts - pancreas, spleen
- diverticular disease
ADPKD Ix
- abdo USS
- genetic testing
- MR angiography - of head
ADPKD Diagnostic criteria (if positive FHx)
- 2 cysts, uni/bilateral, if <30yo
- 2 cyst in both kidneys if 30-59yo
- 4 cysts in both kidneys if >60yo
ADPKD Mx
- tolvaptan
- ACEi for HTN
- aspiration / surgery for cyst drainage
- dialysis - for ESRF
- renal transplant
- avoid NSAIDs, anticoags, contact sports
- genetic counselling
ARPKD
- mutation in PKHD1 gene on ch6
- often identified on antenatal scans, with oligohydramnios
- dysmorphic features
- ESRF before adulthood
alport syndrome
- genetic condition - defect in gene for type 4 collagen -> abnormal GBM
- x-linked dominant
Px
- px in childhood
- microscopic haematuria
- progressive renal failure
- bl sensorineural deafness
- retinitis pigmentosa
- lenticonus - protrusion of lens surface into anterior chamber
Ix
- molecular genetic testing
- renal biopsy - splitting of lamina densa on electron microscopy
Fanconi syndrome
- reabsorptive disorder of renal tubular transport in PCT -> T2 RTA, polyuria, glycosuria….
Causes
- cystinosis, Sjogrens, multiple myeloma, nephrotic syndrome, Wilson’s
Renal artery stenosis (RAS)
- narrowing of one / both renal arteries
Causes
- atherosclerosis, fibromuscular dysplasia
Patho
- kidney hypoperfused, RAAS activated, chronic HTN
RAS Px
- HTN
- CKD
- pulm oedema
- bruits on auscultation
RAS Ix
- Doppler US kidneys
- captopril challenge test (not useful)
- renal artery arteriogram
RAS Mx
- diuretics
- anti HTN
- surgery - angioplasty +/- stenting
- nephrectomy
Contrast media nephrotoxicity
- 25% increase in creatinine <3d after IV contrast
RFs
- renal impairment, >70yo, dehydration, HF, nephrotoxic drugs
Mx
- 0.9% NaCl 1ml/kg/hr for 12hrs pre/post procedure
- sodium bicarb
Renal papillary necrosis
- coagulative necrosis of renal papillae
Causes
- severe acute pyelonephritis, diabetic nephropathy, obstructive nephropathy, NSAIDs, sickle cell anaemia
Px
- visible haematuria
- loin pain
- proteinuria
Ix
- urinalysis, cytology
- bloods
- CT, contrast…
- cystoscopy, ureteroscopy
Mx
- supportive
- tx cause
amyloidosis?
- deposition of amyloid fibrils -> tissue/organ dysfunction
- can affect kidneys, heart, nerves, gut, vascular
- familial variant - autosomal dominant
Px
- renal disease - massive proteinuria
- hepatomegaly
- HF
- glove + stocking polyneuropathy
- GI malabsorption, macroglossia
- periorbital purpura
- fatigue, wt loss, bruising, SOB, oedema
Ix
- biopsy - of tissue - congo red staining (apple-green birefringence)
- serum amyloid precursor (SAP) scan
Mx
- optimise nutrition
- chemo + pred
- tx conditions
- familial - liver transplant
