Renal Flashcards
Name kidney functions
RAAS => regulates blood volume + BP Acid-base balance Electrolyte balance Excretion of water-soluble waste products via filtration Vit D synthesis => 1-alpha-hydroxylase RBC synthetsis => EPO
AKI vs CKI definition
AKI - rapid decline in renal function over hours or days - measured bye urea and creatinine - failure to maintain homeostasis: = oliguria, vol. overload (fluid) = hyperkalaemia (electrolyte) = metabolic acidosis (acid-base) - potentially reversible
CKI
- impaired renal function for >3 months based on:
= abnormal structure/function or
= GFR <60 ml/min for >3 months
= +/- evidence of kidney damage
- usually progressive and irreversible, leads to end-stage renal failure
AKI staging classifications
Stage I
- creatinine increase x1.5
- UO < 0.5ml/kg/hr for 6 hrs
Stage II
- creatinine increase x2
- UO < 0.5ml/kg/hr for 12 hrs
Stage III
- creatinine increase x3
AKI signs
Hypertension
Distended bladder
Dehydration; postural hypotension
Pallor, rash, bruising (vascular disease)
Fluid overload (heart failure, cirrhosis, nephrotic syndrome)
- increased JVP, pulmonary and peripheral oedema
AKI sx
Confusion, dehydration, underlying cause, N&V, oliguria/anuria***
Pre-renal causes of AKI
*due to inadequate perfusion (55% cases)
Hypovolaemia
- renal loss: diuretic overdose, osmotic diuresis (DKA)
- extrarenal: D&V, burns, sweating, blood loss
Systemic vasodilation
- sepsis, neurogenic shock
Decreased cardiac output
- heart failure, MI
Intrarenal vasoconstriction
- cardiorenal syndrome
- hepatorenal syndrome
Renal causes of AKI
*due to cellular damage (35% cases)
Acute tubular necrosis
- ischaemia, drugs, toxins (i.e. paracetamol, NSAIDs, ACEi, contrast, myoglobinuria in rhabdomyloysis)
Glomerulonephritis
- post-infection
Interstitial nephritis
- drugs, immune disorders (SLE), lymphoma, infections, tumour lysis syndrome following chemo, eosinophilia and haematuria
Vessel obstruction
- thrombosis, vasculitis, haemolytic microangiopathy
Post-renal causes of AKI
*due to obstruction (20% causes)
Luminal
- clots, stones
Mural
- strictures, BPH, malignancy
Extrinsic compressions
- retroperitoneal fibrosis
What types of microangopathy may cause AKI?
1) Haemolytic uraemic syndrome (HUS)
2) Thrombotic thrombocytopenic purpura (TTP)
3) Disseminated intravascular coagulation (DIC)
Compare HUS and TTP
HUS
- occurs mainly in children after a bout of gastroenteritis caused by E.Coli 0157:H7
- poor kidney function, haematuria/proteinuria, pain and bloody diarrhoea, low Hb, low plts
TTP
- mainly occurs in women aged 10-50yo that are deficient in protease that weaves vWF (ADAMTS13)
- haemolytic anaemia, thrombocytopenia, ureaemia, fever, neurologic sx (seizures, hemiparesis, decreased consciousness, blurred vision)
Causes of glomerulonephritis
IgA neuropathy
- after URTI, IgA complexes form
Henoch Schonlein Purpura
- purpuric rash, systemic variant of IgA
Goodpasture’s; anti-GBM antibodies
- also bind to alveolar basement membranes => lung haemorrhage
Post-strep GN
- previously healthy person presents post-throat infection
Pauci-immune
- +ANCA bond to neutrophils, activated within glomerular capillaries loops
Nephrotic syndrome summary card
Proteinuria > 3.5g/24hrs
Oedema
Low serum albumin <25g/L
- also see hyperlipidaemia as liver tries to compensate for low albumin by increasing lipids thus in hypercoaguable state
- children: minimal change glomerulonephritis
- adults: membranous glomerulonephritis
- other causes include focal segmental glomerulosclerosis, mesangiocapillary glomerulonephritis, DM, SLE, amyloid, HBV/HCV
Nephritic syndrome summary card
Hypertension, haematuria, oedema, oliguria (<400ml/day)
- Primary causes: IgA nephropathy, mesangiocapillary glomeulonephritis
- Secondary causes: post-strep, vasculitis, SLE, anti-GBM disease, cryoglobulinemia
Ix and mx for glomerulonephritis
Ix: bloods (FBC, U&Es, CRP, complement, autoantibodies), urine, imaging (renal USS +/- renal biopsy)
Mx: treat underlying cause, steroids/immunosuppression, refer to specialist, BP mx <130/80, ACEi/ARB (decrease proteinuria and pressure on renal function as decreases intraglomerular pressure by inhibiting AGII efferent vasoconstriction)
Which nephrotoxic agents cause renal AKIs?
NSAIDs Contrast agents Aminoglycosides (gentamicin, streptomycin) ACEi, ARBs Urate crystals Myoglobin from rhabdomyolysis
How does myeloma cause renal AKI?
Myeloma leads to monoclonal paraprotein production
This is deposited in the distal tubules as casts of free light chains of paraprotein precipitates, causing inflammation
Ix for AKI
Dipstick testing
Microscopic examination = urine MCS, protein CR, 24hr urine
Proteinuria quantification
Electrolyte estimation
What do urine dipstick results suggest?
Haematuria
- renal: pyelonephritis, glomerulonephritis, carcinoma, trauma
- extrarenal: cystitis/prostatitis/utheritis, stones, trauma (catheter), bladder/prostate/urethra cancer
Proteinuria
- nephrotic syndrome, DM
Glucose
- DM
Ketones
- starvation, diabetic ketoacidosis
Urobilinogen
- pre-hepatic jaundice
Complications of AKIs
Uraemia, volume overload, hyperkalaemia, hyperphosphataemia, metabolic acidosis, chronic progressive kidney disease
Mx of AKIs
General
- stop nephrotoxic drugs (incl. metformin if GFF <30)
Underlying cause
- pre-renal: correct volume depletion with appropriate fluids, Abx if sepsis, inotropes if signs of shock
- post-renal: catheretise and imaging of renal tract and urology referral
- renal: refer early to nephrology
Manage complications
- pulmonary oedema, ureaemia, acidaemia (50-100ml of 8.4% IV sodium bicarbonate with central line infusion over 15-30mins)
Renal replacement therapy
- haemodialysis and haemofiltration
Causes and classification of CKD
Diabetes, hypertension, atherosclerosis, chronic glomerulonephritis, infective/obstructive uropathy, adult polycystic kidney disease
Staging: I. damage, normal GFR >/= 90 II. damange, mild GFR 60-89 III. moderate low GFR 30-59 IV. severe low GFR 15-29 V. end-stage renal disease <15 (or dialysis)
Signs and sx of CKD
Peripheral vascular disease, peripheral oedema, HTN, pallor (ACD), excoriation marks (uraemia), skin pigmentation (uraemia), renal bone disease, signs of underlying disease (i.e. SLE)
Often asymptomatic, anorexia, N&V, fatigue, pruritus, peripheral oedema, muscle cramps, pulmonary oedema, sexual dysfunction
Ix for CKD
Bloods
- increased urea + creatinine (U&E), normocytic anaemia, glucose (DM), secondary hyperPTH (if severe), GFR, low calcium, high phosphates, high ALP in renal bone disease
Urine
- dipstick, MCS, protein:Cr ratio
Imaging
- USS (size/anatomy/corticomedullary differentiate + eliminate obstruction)
- CKD small kidneys but can be enlarged in infiltrative disorders
CXR
- pericardial effusion, pulmonary oedema
Mx of CKD
1) Limiting progression/complications
= BP <130/80 or <125/75 if diabetic
= tight glucose control if DM
= diet with help of MDT: low protein, potassium and phosphate food
= smoking cessation, wt loss
= renal osteodystrophy: calcichew (Ca2+ supplement), calcium acetate (phosphate binders), cinacalcet (calcimimetic to decrease PTH)
2) Symptom control
= anaemia; human EPO may be required
= acidosis; sodium bicarbonate supplements
= oedema; loop diuretics, restriction of fluids
3) Preparation for renal replacement therapy
= haemodialysis; vascular access required
= transplantation; gold standard, major surgery with life-long immunosuppression
Pathogens that cause UTIs
Common: E. Coli (gram-negative anaerobic) Staph saprophyticus (gram-positive coccus) Proteus mirabilis Enterococci
Immunocompromised:
Klebsiella
Candida albicans
Pseudonomas aeruginosa
RFs for UTIs
Female >>> male Sexual intercourse Exposure to spermicide Pregnancy Menopause Immunocompormised Catheritisation UT obstructon UT malformation
Ix for UTIs
Urine dipstick: + nitrates
MSU for urine MCS: WBC, provide colony forming unti, sensitivity
Bloods: FBC, CRP, U&Es
Complicated UTI: renal USS/IV urography
Mx for UTIs
Uncomplicated
- cefalexin 500mg 3 days or nitrofurantoin 500mg 7 days
- cefalexin; co-amoxiclav if pregnant
Male
- 7 day course of cefalexin/ciprofloxacin 500mg
Pyelonephritis/urosepsis
- co-amoxiclav 1-2mg IV +/- amikaxin or gentamicin first 1-2 days
Polycystic kidney disease summary card
ADPKD 1 and 2
- adult onset one occurs 30-60yo
- hx: acute loin pain, stone formation, sx of renal failure, abdo discomfort, FHx of berry aneurysms (SAH)
- o/e: HTN, renal enlargement, abdo pain +/- haematuria
- ix: haematuria, increased Hb, damaged U&Es, abdo USS, MRI angiography if 1st-degree SAH + ADPKD
Renal cell carcinoma summary card
Associated with von Hippel-Lindau syndrome
Tumours include von Grawitz, hypernephroma
- presents: fevers, night sweats, polycythaemia, varicocoele (due to invasion of left renal vein)
- triad: haematuria, abdo mass, loin pain
- RFs: male, old, HTN, smoking, obesity, dialysis, vHL, tuberous sclerosis
- ix: RBCs in urine, increased BP, filling defect + calcification via CT/MRI, Iv urogram, ALP (bone mets), polycythaemia or IDA, cannon ball mets (lungs)
Renal artery stenosis summary card
Hypoperfusion activation leads to RAAS therefore increased BP, contributing to fibrosis, glomerulsclerosis and renal failure
- atherosclerosis (80% cases), fibromuscular dysplasia (10% cases, young females with string of beads on imaging)
- abdominal and carotid or femoral bruits, weak leg pulses, flash pulmonary oedema, worsening renal function after ACEi/ARB in bilateral RAS, increased BP refractory to tx
- ix: USS kidney size, CT angiogram of MR angiogram; risk of contrast nephrotoxicity caution, digital subtraction renal angiography (gold standard)
A 34-year-old man, Ross, has lost a significant amount of blood following a motorbike accident.
His blood test results include a serum urea of 20.2 mmol/L, a creatinine of 220 μmol/L, a potassium of 5.7 mmol/L and a sodium of 137 mmol/L.
Urine electrolytes and osmolarity are normal. A CT scan confirms that there was no damage to the kidneys during the accident.
What is the most likely impression?
A Pre-renal AKI 2°to hypovolaemia
B Pre-renal AKI 2° to coarctation of aorta
C Post-renal AKI 2° to prostatic hypertrophy
D Renal AKI 2° to glomerulonephritis
E Haemolytic uraemic syndrome
A Pre-renal AKI 2°to hypovolaemia
An 65-year-old, Nancy had seen her GP after straining her back while lifting a heavy box.
She was prescribed a course of diclofenac.
Five days later, she presents to the emergency department feeling generally unwell and slightly confused. Blood tests confirm that she is in acute renal failure.
What is the most likely impression? A Pre-renal AKI 2°to hypovolaemia B Acute tubular necrosis C Interstitial renal failure 2° to glomerular nephritis D Interstitial renal failure 2°to NSAIDs E Analgesia nephropathy
E Analgesia nephropathy
A 25-year-old man, Harry presents to the emergency department complaining of severe loin pain and vomiting.
He has had three episodes of this pain today, each lasting 10 minutes.
On examination, he is pale, sweaty and tender in his right loin. A urine dipstick shows 3+ blood, 1+ protein, no nitrites and no leucocytes.
What is the best investigation to reach a diagnosis?
A Cystoscopy B KUB X-ray C Renal tract ultrasound scan D CT-KUB E MSU for MCS
D CT-KUB
A 40-year-old man, Gareth, presents with a 2-week history of coughing up blood.
He is found to have 2+ of protein in his urine on dipstick analysis. Blood tests show a urea of 9.5 mmol/L and a creatinine of 148 μmol/L.
Further tests confirm that he is positive for the anti- glomerular basement membrane antibody
What is the most likely diagnosis A IgA nephropathy B Membranous glomerulonephritis C Rapidly progressive glomerulonephritis D Minimal-change glomerulonephritis E Goodpasture’s syndrome
E Goodpasture’s syndrome
*type II hypersensitivity reaction
A 25-year-old man, Timothée, presents with facial and ankle swelling. He is found to have 3+ of protein in his urine on dipstick analysis. Blood tests reveal an albumin of 16 g/L.
What is the most likely diagnosis A IgA nephropathy B Membranous glomerulonephritis C Rapidly progressive glomerulonephritis D Minimal-change glomerulonephritis E Goodpasture’s syndrome
B Membranous glomerulonephritis
2/7 dysuria + frequency + offensive urine
Which renal ix should you do?
MSU for MCS
Severe loin pain, vomiting
Haematuria dipstick
Which renal ix is most sensitive to pick up diagnosis?
Non-contrast CT-KUB
Recurrent UTI, FTT, baby FHx of vesico-ureteric reflux
Which renal ix should you do?
USS of renal tract
India + weight loss + night sweats, UD: blood, leukocytes (sterile pyuria)
Urine sample: no growth (-ve culture)
Which renal ix should you do?
3 early morning urine samples for Microscopy, culture, ZN staining
Transplanted kidney worsening renal function over 2/52, pain around area,
Transplant 4/12 ago
Which renal ix should you do?
Renal biopsy
Muddy brown cast + high creatinine
High urine sodium, low urine osmolality
Low urine:serum urea ratio
Low urine:plasma osmolarity ratio
Diagnosis?
Acute tubular necrosis
Unwell after ACEi
Bilateral renal bruits, Hx of IHD
Diagnosis?
Pre-renal acute renal failure 2° renal artery stenosis
Esoinophilic cast, urine dip: protein+blood
Old man, CAP, penicillin Tx, dysuria, back pain
Diagnosis?
Acute interstitial nephritis
Bladder palpable up to umbilicus + unable to pass urine + man
Diagnosis?
Post-renal AKI 2° to prostatic hypertrophy
D&V + high urea + creatinine + K+
Normocytic anaemia + fractionate RBC (film)
Escherichia coli O157:H7 stool
Diagnosis?
Haemolytic uraemic syndrome
HUS + Fever + neurological manifestations
Diagnosis?
TTP
24 years of rheumatoid + develop peripheral oedema
Proteinuria 3+ urine
Cause?
Amyloidosis
Bone pain, lethargy, poor renal function
Monoclonal band on serum electrophoresis
Monoclonal globulin protein in urine
Cause?
Multiple myeloma
Crohn’s, poor renal function, proteinuria
Stain +ve with congo red – renal Biopsy
Cause?
Amyloid A amyloidosis
T1DM albuminuria, previous dipstick normal
Cause?
Diabetic microalbuminuria
Collapse following stroke: High urea + creatinine, K+, High CK, urine dark red
Cause?
Rhabdomyolysis
4M, facial swelling, 3+ proteinuria, low albumin
Diagnosis and what would microscopy show?
Minimal change glomerulonephritis
Electron microscopy: Fusion of podocytes
25M, facial swelling, 3+ proteinuria, low albumin
Diagnosis?
Membranous glomerulonephritis
+ve anti-GDM antibodies
Diagnosis?
Goodpasture’s syndrome
7M 2/7 after URTI hematuria, flank pain
Biopsy: Proliferative glomerulonephritis with antibody deposition
Diagnosis?
IgA nephropathy (Berger’s disease)
15F, 2/52 post-tonsilitis, dark urine, puffy
High titres of anti-streptolysin O antibody
Diagnosis?
Post-strep glomerulonephritis
A 75 year old man is admitted with community acquired pneumonia.
On examination, his abdomen is soft and non-tender. The bladder is not palpable. A urinary catheter bag at the bedside contains a small amount of concentrated urine. He has dry mucous membranes, reduced skin turgor and his JVP is not visible.
Bloods: Creatinine 362μmol/L (120μmol/L – 1 month ago)
What is the most appropriate immediate management option? A IV fluids B IV furosemide C USS kidneys D Urgent urology referral E Haemodialysis
A IV fluids
A 67 year old man presents with a long history of fatigue, nausea and poor appetite. He has a past medical history of type 2 diabetes mellitus and hypertension. You suspect this patient’s presentation is due to chronic kidney disease.
Which of the following can be used to stage chronic kidney disease? A Blood pressure B Haemoglobin C Creatinine D Potassium E HbA1c
C Creatinine
to calculate GFR
A 32 year old woman is feeling tired for the past 3 days. Over this time she has noticed that has only passed small amounts of concentrated urine. She is normally fit and well. She was successfully treated with oral antibiotics for a sore throat 2 weeks ago.
Blood pressure: 145/95mmHg Urine dipstick: protein 1+, blood 2+
What is the most likely diagnosis? A Acute tubular necrosis B Acute interstitial nephritis C Glomerulonephritis D Pyelonephritis E Urinary tract calculus
C Glomerulonephritis
post-strep
A 45 year old woman has noticed that her face and legs have become swollen gradually over the last 6 months. She has no past medical history and takes no regular medications.
Blood pressure: 120/80mmHg Urine dipstick: protein 3+, blood neg
What is the most likely diagnosis? A Acute tubular necrosis B Acute interstitial nephritis C Glomerulonephritis D Pyelonephritis E Urinary tract calculus
C Glomerulonephritis
membranous glom. most common reason for nephrotic syndrome in adults
A 45 year old woman is found to be hypertensive. Her mother was recently admitted to hospital for a subarachnoid haemorrhage and has been on haemodialysis since the age of 50.
On examination: Bilateral palpable abdominal masses.
Urine dipstick: leukocytes neg, nitrites neg, blood +
What is the most likely diagnosis? A Glomerulonephritis B Primary (essential) hypertension C Conn’s syndrome D Polycystic kidney disease E Renal artery stenosis
D Polycystic kidney disease
A 69 year old man with known coronary artery disease and peripheral vascular disease presents with an acute kidney injury. Ramipril has recently been started for resistant hypertension.
What is the most likely underlying diagnosis? A Renal artery stenosis B Renal cell carcinoma C Phaeochromocytoma D Conn’s syndrome E Cushing’s syndrome
A Renal artery stenosis
A 36 year old woman presents with a 2 day history of fever and right-sided back pain. She also describes pain on passing urine. She is normally fit and well.
On examination: Right-sided costovertebral angle tenderness. HR 110bpm, Temp 39.2ºC
Urine dipstick: leukocytes ++, nitrites ++, blood +
What is the most likely diagnosis? A Lower urinary tract infection B Acute pyelonephritis C Urinary tract calculus D Glomerulonephritis E Acute tubular necrosis
B Acute pyelonephritis
A 66 year old male smoker presents with a 3 month history of dull left flank pain. No significant past medical history or family history.
On examination: Left-sided palpable abdominal mass.
Urine dipstick: leukocytes neg, nitrites neg, blood +
What is the most likely diagnosis? A Acute pyelonephritis B Urinary tract calculus C Glomerulonephritis D Renal cell carcinoma E Polycystic kidney disease
D Renal cell carcinoma
What AKI does the pt have if the following is found:
a) brown cell casts in urine,
b) white cell casts in urine,
c) eosinophilia in renal biopsy?
a) Acute tubular nephritis (85% cause of intrinsic AKIs)
b) Infective acute interstitial nephritis (likely pyelonephritis - UTI sx)
c) Non-infective acute interstitial nephritis (likely acute hypersensitivity - reaction to drugs, also has a rash)
Compare nephritic and nephrotic syndrome
Nephritic (think nephritis, inflammation, something disrupting glomerulus so blood getting out) P roteinuria H aematuria A zotemia (high urea) R ed cell casts O liguria H ypertension
Nephrotic (think nephrosis, structural problem, something in glomerulus) H ypoalbuminaemia E dema L ipid abnormalities P roteinuria
Key causes of AKIs
Sepsis
Toxicity
Obstruction
Parenchymal disease
