Renal Flashcards
What is renal function?
How much blood flow goes through the glomerulus = Glomerular filtration rate. Should be >90ml/mom
Endogenous marker is blood urea and serum creatinine (this is dependent on age/sex/weight/muscle mass).
Can give EDTA to clinically assess
What conditions raises blood urea levels?
GI bleeds, hepatic function and nutrition states
What is normal urea:creatinine ratio?
40:1 to 100:1
What does metformin predispose for in poor kidney function patients?
lactic Acidosis
Features of AKI?
Fluid -> oliguria, volume overload
Electrolyte - > hyperkalae,ia
Acid-base -> metabolic acidosis
Measured by urea or creatinine
Potentially reversible
CKD features?
Impaired renal function for >3 months.
Abnormal structure/function or GFR <60ml/min for >3months
+/- evidence of idney damage
usuualy progressive and irreversible
Symptoms of AKI?
Underlying cause
Oliguria/anuria
N+V
SOB
Dehydration
Confusion (encephalopathy from uraemia)
Signs of AKI?
HTN, distended bladder, dehydration (postural hypotension)
Fluid overload e.g. HF, cirrhosis, nephrotic syndrome) = raised JVP, pulmonary and peripheral oedema
Pallor, rash and bruising from vascular disease
How to classify AKI?
Stage 1: 1.4x rise in Creatinine to baseline of urine <0.5ml/kg/hr for >6hours
Stage 2: 2x Cr rise r urine output the same for >12hours
Stage 3: 3x Cr rise of <0.3ml/kg/hour for >24hrs or anuria>12hours
RFs for AKI?
Hypovolaemia
CKD, diabetes, HF, renal transplant, ?75YO, contrast administration
Pre-renal causes of AKI?
40-70% AKI= reduced urine output and raised urea:creatinine ratio
Hypovolaemia: either renal loss from diruetic overuse or extrarenal loss e.g. V+D, burns, sweating and blood loss
Systemic vasodilation e.g. Sepsis and neurogenic shock
Decreased CO e.g. MI or HF
Intrarenal vasoconstriction
Renal AKI causes?
Tubular = acute tubular necrosis
Glomerular = glomerulonephritis
Interstitial = iterstitial nephritis
Vascular = vessel obstruction e.g. thrombosis, vasculitis and haemolytic microangiopathy
What can cause acute tubular necrosis?
Paracetamol, NSAIDs, ACEi, contrast and myoglobinuria in rhabdomyolysis
What causes intrarenal vasoconstriction in pre-renal AKI?
Renal artery stenosis, fibromuscular dysplasia, cardiorenal syndrome, hepatorenal syndrome,
NSAIDS, ACEi and ARB
How to manage pre-renal AKI?
NEWS and identify causitive problem e.g. hypovolaemia and monitor fluid balance, K+, lactate and daily creatinine
Bolus and maintenance fluid
Stop nephrotoxic meds and change medications that are renal excreted
e.g. metformin and LMWH
Avoid contrast
What drugs can commonly cause AKI?
Abx such as aminoglycosides e.g. gentamicin and amikacin
What causes Acute Tubular Necrosis (ATN)?
> 50% of renal causes of AKI
Renal tubular epithelial cell injury due to ischaemia from shock/sepsis or nephrotoxic agents
What Exogenous substances causes ATN?
NSIADS, aminoglycosiides, amphotericin B, contrast media, calcineurin inhibitors, cisplatin
What endogenous substances cause ATN?
Myoglobiunuria (rhabdomyolysis), haemoglobinuria, crystals (uric acid) e.g. gout, and myeloma (IgG light chains)
Features of ATN?
Urine = muddy brown granular casts, myoglobiunuria and haemoglobiunrura
Features of raised AKI: e.g. urea, creatinine, potassium and metabolic acidosis
Urea:creatinine ratio <40:1
Indicators of rhabdomyolysis?
Raised CK, hypocalcaemia and elevated phosphate
Hyperkalaemia management?
Escalate + ABCDE
Continuous cardiac monitoring + IV acess and redo bloods
Review drugs e.g. stop neprotoxic
10ml 10% calcium gluconate IV over 10 mins
100ml 20% dextrose with 8U insulin over 15mins
Nebulised salbutamol 5-10mg
Sodium bicarbonate to correct acidosis
ECG changes in hyperkalaemia?
Tall tented T wave, small absent p wave, broad QRS, increased PR interval, sine wave, bradycardia
What is glomerulonephritis and what can it causes?
Inflammation of the glomeruli and nephrons.
Can cause increase in BP to malignant HTN
Urine dipstick can show blood and protein
Decreased renal function due to loss of filtering capacity
Features of nephrotic syndrome?
Proteinuria?3.5mg/24hours
Hypoalbunaemia <25g/L
oedema
Hyperlidaemia +-hypercoagulative state
features of nephritic syndrome?
Hypertension
haematuria + red cell casts
Oedema
Oliguria and progressive renal impairment
Primary Causes of nephrotic syndromer?
Minimal changes disease
Membranous nephropathy
Focal segmental glomerulosclerosis
Secondary causes of nephrotic syndrome?
DM - glomerulosclerosis
SLE
Amyloid
Primary causes of nephritic syndrome?
Membranoprolifertive (MPGN) Raid progressive (RPGN) with types: 1=Anti-GBM (goodpastures) 2=Immune complex deposition 3= pauci immune
Thin BM disease
Alports syndrome
Secondary causes of nephritic syndrome?
Post-streptococcal IgA nephropathy (bergers) HSP Small vessel vasculitiis SLE Anti-GBM disease
Cryoglobineamia (IgM secondary to MM, CLL and waldenstroms)
What is minimal change disease?
Affects youn population with normal biopsy ecept electron = podocyte effacement
Associated with Hodgkins lymphoma
Steroid responsive
Features of membranouse nephropathy
?
100% nephrotic
Granular IC depositon with spike and dome pattern on microscopy
Primary= autoimmune (ab for PLA2R)
Secondary = Malignancy, drugs and infection e.g. HEPB/C and SLE
What drugs can cause secondary membranous nephropathy
?
Gold, penicillamine and captopril
What is FSGS?
Nephrotic
Focal scarring with IgM deposition
In Afro-caribbeans
Heroin, HIV and HIV-associated hephropathy
Bisphosphonate use e.g. Pamidronate
Differences in diabetic and amyloid nephropathy?
Nephrotic
Congo red staining = aple green birefringence for amyloid
Diabetic = Nodular glomerulosclerosis and Kimmelstiel-Wilson nodules
What us MPGN?
nephrotic + nephritic
Immune complex associated with deposition causing mixed nephritic
Type 1 = Hep C>B
Type 2 = C3 nephritic factor (low C3)
Presents tram tacking appearence and mesangial proliferation on microscopy
What is IgA nephropathy?
Days after URTI causes deposition of complexes and episodic macroscopic haematuria
Nephritic syndrome
What is Henoch Schonlein Purpura?
Nephritic
variant of IgA nephropathy
Systemic vasculitis and depostion = purpuric rahs and arthralgia
What is post-strep GN?
1-2 weeks after throat or skin infection causes IgA depostion and high ASOT with Low C3
‘smoky urine’
What are the Rapidly progressive GN?
Nephritic syndromes
Anti-GBM goodpastures
Immune complex deposition
Pauci immune
GFeatures of Anti-GBM type 1 RPGN?
Haematuria, haemopysis, proteinuria young M>F
Auto-abs to Type 4 collahen so linear stain
Features of Type 2 immune complex mediated RPGN?
Any immune complex deposition = granular pattern
SLE< IgA nephrotpathy and HSP
Features of Pauci-immune Type 3 RPGN?
Negtaive stain and ANCA associated
cANCA = ENT+lungs+kidneys = granulomatous polyangiitis
pANCA=asthma+eosinophilia+mononeuritis multiplex and purpura = eosinophilic granulomatosis with polyangiitis [purpura = microscopic polyangiitis]
What drugs cause glomerular damage?
Rifampicine, dapsone, penicillins, isonazid
What drugs cause post-renal tubular blockage?
Aciclovir and sulphonamides
What drugs cause acute interstitial nephritis?
Penicillins, anti-Tb therapy, sulphadiazine and cephalosporins
Symptoms of CKD?
Often asymptomatic.
Severe = anorexia, N+V, fatigue, pruritis, peripheral oedema, msucle cramps, pulmonary oedema, sexual dysfunction
Signs of CKD?
Underlying disease e.g. SLE
Skin pigmentation and excoriations from uraemia, pallor, HTN, peripheral oedem,a peripheral vascular disease and renal bone disease
Consequences of CKD?
Progressive failure of homeostatic = acidosis and hyperkalaemia
Progressive hormonal failure = anaemia and renal bone disease e.g. osteomalacia
CVD = vascular calcification, uraemic cardiomyopathy
Uraemia, encephalopathy and death
CKD Ix?
bedside: BP, dipstick urine, fundoscopy, ECG for cardiac changes
Bloods: bicarb for metabolic acidosis, U&Es, Hb for renal normocytic anaemia, PTHCa/phosphate studies
BM and HbA1c
Imaging: USS and CXR, biopsy if no diagnosis
CKD management?
1) limit progression
2) symptom control
3) Prep for renal replacement therapy
How to limit CKD progression?
BP target so lifestyle and drugs
Tight sugar control
decreased CVS risk
Diet to reduces phosphate and salts
How to symptom control for CKD?
Human EPO or iron for anaemia
Sodium bicarb for acidosis
Loop diuretics and fluid restriction for oedema
HTN treatment
Phosphate binders for hyperphosphataemai e.g. sevelamer
HypoCaHyperPth e.g. cholecaliferol, alfa, cincacimet
How to renal replacement therapy for CKD?
Haemodialysis, peritoneal dialysis and renal transplant
Indications for urgent haemodialysis?
AEIOU Refractory Acidosis Refractory hyperkalaemia (electrolytes) Drug OD (ingestion) Refractory pulmonary oedema Uraemia with complications
