Renal Flashcards
(82 cards)
Where in the kidney is most of the filtered Na reabsorbed?
Proximal convoluted tubule
How does RAAS system work to raise BP?
Renin produced by juxtraglomerular apparatus- triggered by a low BP/decreased Na. It converts angiotensinogen to angiotensin I. ACE converts angiotensin I to angiotensin II which produces aldosterone. This reabsorbs Na and water in the kidney and vasoconstricts to raise the BP.
What is the definition of a stage 1 AKI?
Creatinine rise >26umol/L in 48h or 1.5 x from baseline.
AND Urine output <0.5ml/kg/hour for > 6hours
What is the definition of a stage 2 AKI?
Creatinine rise 2 x baseline AND urine output <0.5ml/kg/hour for >12 hours
What is the definition of stage 3 AKI?
Creatinine rise 3 x baseline AND urine output <0.3ml/kg/hour >24 hours or anuria >12 hours
What are the causes of AKI? And the headings they fall under?
Pre renal:
- Hypovolaemia - dehydration, shock, sepsis
- Heart failure (hypervolaemia)
- Renal artery stenosis
Renal:
- Acute tubular necrosis
- Rhabdomyolysis
- Acute interstitial nephritis- NSAIDs
- Drugs- DAMN- diuretics (furosemide, thiazide, spironolactone- causes a hyperK–> AKI), ACEi, metformin, NSAIDs, contrast, anticonvulsants eg. lamotrigine and valproate, lithium,
- Glomerulonephritis
- Vasculitis
Post-renal:
-Obstruction: ureteric/renal calculi, tumour (bladder/ureter), infection, enlarged prostate
What happens in acute tubular necrosis? What is the cause?
Cause is prolonged hypoperfusion/prolonged use of nephrotoxic drugs. The potassium and hydrogen ions don’t filter through into the urine- so they create an acidosis which causes tubules to die.
What are the causes of rhabdomyolysis?
Prolonged immobilisation after a fall Crush injury Burns Trauma Embolism
What signs may you see in a patient with rhabdomyolysis?
Brown coloured urine, muscle pain, swelling
What investigations would you do in a patient with suspected rhabdomyolysis?
Creatinine kinase- raised
U&Es- AKI?
Phosphate- raised and potassium- raised
How do you treat rhabdomyolysis?
Treat the hyperkalaemia- calcium gluconate and insulin + dextrose
IV fluids
Catheterise
IV sodium bicarbonate
What is the biggest cause of acute interstitial nephritis?
NSAIDs
What are the symptoms to ask about in a patient with an AKI?
Dehydration- oliguria, dizziness, dry mucous membranes
Abdominal pain (loin to groin if stones)
Nausea and vomiting
LUTS symptoms- frequency, hesitancy, straining, urgency- prostate cancer/BPH
Weight loss, night sweats - malignancy
Rashes, joint pains, fevers- renal cause (vasculitis, glomerulonpehritis)
Recent illness
Previous AKI
MEDICATIONS
FMH- kidney failure? Polycystic kidneys?
Sx of hyperkalaemia- muscle cramps/weakness, respiratory distress, decreased reflexes
What investigations would you do in a patient who’s coming in with oliguria, abdominal pain and a raised creatinine? He has been taking ibuprofen for his back pain for a year now and sometimes takes too much.
Suspecting AKI
- urine dip and MC&S (rule out urinary sepsis): if renal cause- protein and blood
- Bloods- FBC (infection), U&Es (monitor creatinine, dehydrated?), LFTS, CRP, clotting, Na and K (hypo Na, hyper K), Ca, phosphate, creatinine kinase
- ECG- hyperkalaemia (kidneys usually reabsorb Na and excrete K)
- May do ABG for hyperkalaemia
- If suspected obstruction- USS KUB - anuria
- Later on- Autoimmune profile (anti-dsDNA-SLE, ANCA- granulomatosis with polyangiitis, anti-GBM- good pastures)
What would you treat a patient who was in AKI? and hyperkalaemia?
Catheterise - monitor fluid balance
Stop nephrotoxic drugs
Regular U&Es - daily
Treat cause:
- Pre renal: IV fluids- monitor, IV Abx - sepsis
-Obstruction: USS KUB and may need nephrostomy
-Hypervolaemia (HF)- fluid restrict and IV furosemide
- Treat hyperkalaemia- IV 10ml of 10% calcium gluconate, IV insulin (actrapid) + dextrose, nebs salbutamol
If a patient was in AKI- when would you refer for dialysis/to the renal team?
Refractory hyperkalaemia Refractory pulmonary oedema Severe metabolic acidosis Uraemia complications- encephalopathy, pericarditis, seizures Drug overdose
What is the definition of CKD?
Imapired kidney function for >3 months (based on abnormal kidney results- proteinuria) or eGFR <60ml/min/1.73m2.
Name 5 causes of CKD?
Glomerulonephritidies- IgA nephropathy, membranous, SLE
Diabetes
Hypertension
AKI
Obstruction- stones, prostatic hyperplasia
Polycystic kidney disease
Pyelonephritis
What would you ask in a history in a patient with CKD?
Symptoms- changes in urine output? Abdominal pain? LUTS symptoms- frequency, urgency, hesitancy, poor steam? signs of overload- SOB, ankle oedema. Uraemic symptoms- confusion, vomiting, asteriks tremor, seizures
Cause- well controlled diabetes? well controlled HTN? recent UTI?
Medication review
What would you look for on examination in a patient with CKD?
Uraemia- yellow skin, flapping tremor,
Pallor - anaemia
Fluid overload (complication of CKD) - ankle oedema, consolidation in lungs
Ballotable kidneys- polycystic kidneys
What investigations would you do in a patient with CKD?
Urine dip- proteinuria, haematuria?
Albumin: creatinine ratio
Bloods- FBC- anaemia?, U&E- monitor regularly, clotting, glucose, low calcium & high phosphate, high PTH (tertiary hyperPTH- if CKD stage 3 higher), iron studies (needs to be done before giving EPO)
USS kidneys - usually small in CKD
How would you treat a patient with CKD?
- How would you treat potential causes?
- How would you limit complications? And what are these?
- How would you treat symptoms eg. anaemia, oedema, acidosis
Treating cause:
- Stop nephrotoxic drugs
- Tighter control of diabetes and HTN
- USS KUB and nephrostomy if obstruction
- Stop smoking, healthy diet- low salt and phosphate
Limiting complications:
- Renal osteodystrophy- check PTH. Tx: vitamin D and calcium supplements. Bisphophonates.
- BP control - ACEi if <55 (best for proteinuria), >55 /black=CCB
- Treat any hyperkalaemia
- Statins- reduce cardiac risk
Treating symptoms:
- Anaemia- IV Fe supplementation + B12, folate. IF this doesn’t work- EPO
- Oedema- fluid restrict, furosemide
- Acidosis- sodium bicarb
What is the last line if all the initial treatments of CKD don’t work?
Renal replacement therapy
What are the 3 types of RRT?
Haemodialysis
Peritoneal dialysis
Transplant