Renal Medicine Flashcards
How do you tell the difference between AKI and dehydration on bloods?
AKI - creatinine will be much higher than urea
Dehydration - urea will be much higher than creatinine
How do you tell the difference between AKI and CKD?
CKD patients will have bilateral small kidneys except those with:
- ADPKD
- Early diabetic nephropathy
- Amyloidosis
- HIV nephropathy
What is a common cause of fragility fractures?
CKD induced secondary hyperparathyroidism
What is a common cause of drug-induced AKI?
Acute interstitial nephritis
What drugs cause acute interstitial nephritis?
- Antibiotics including penicillin, rifampicin
- NSAIDs
- Allopurinol
- Furosemide
Causes of acute interstitial nephritis?
drugs; systemic disease eg. SLE, scaroidosis, Sjogrens; infection eg. Hanta virus, staphlococci
What does histology show for acute interstitial nephritis?
marked interstitial oedema and interstitial infiltrate in connective tissue between renal tubules
Acute interstital nephritis Ix?
sterile pyuria and white cell casts
How are diabetic patients screened for diabetic nephropathy?
albumin:creatinine ratio (ACR) in early morning specimens
What are the ECG changes of hypokalaemia?
U waves
T wave flattening
ST segment changes
What is the most common cause of nephrotic syndrome with malignancy?
Membranous nephropathy
What would biopsy show for someone with membranous nephropathy?
subepithelial immune complex deposits
What drugs should be withheld with AKi?
- Diuretics
- Aminoglycosides (gentamicin) and ACE/ARB
- Metformin
- NSAIDs
DAMN AKI
What drug is most commonly used to decrease phosphate levels?
Sevelamer - a non calcium based binder which binds to dietary phosphate and prevents it being absorbed
How can stages 1 and 2 of CKD be diagnosed?
GFR range PLUS if kidney tests must be abnormal
What are causes of focal segmental gomerulosclerosis?
idiopathic
secondary to other renal pathology e.g. IgA nephropathy, reflux nephropathy
HIV
heroin
Alport’s syndrome
sickle-cell
What is the risk of using 0.9% NaCl fluid therpay in patients who need large volumes?
Hyperchloremic metabolic acidosis
What can alcohol bingeing lead to?
ADH suppression in the posterior pituitary leading to polyuria as well as hypernatremia
What is the classic triad for HUS?
- AKI
- Haemolytic anaemia
- Thrombocytopenia
What organism typically causes HUS?
E coli
What medication should be used as an alternative to spironolactone for patients with gynaecomastia?
Eplerenone
How does membranous glomerulonephritis present on histology?
basement membrane thickening on light microscopy
subepithelial spikes on sliver stain
positive immunohistochemistry for PLA2
What is hyperacute transplant rejection?
Rejection within minutes to hours
What is the cause of hyper acute transplant rejection?
pre-existing antibodies against ABO or HLA antigens
What type of hypersensitivity reaction of hyper acute transplant rejection?
Type 2
Why does rhabdomyolysis cause renal failure?
Tubular cell necrosis
What is the prognosis for HSP?
Full renal recovery
What is the diuretic of choice in ascites?
Spironolactone
When is a renal biopsy indicated for those with minimal change disease?
If the response to steroids is poor
What HLA subtype is the most important for transplants?
HLA-DR
What are the side effects of EPO?
- Accelerated hypertension
- Bone aches
- Flu like symptoms
- Skin rash
What medication can be used for recurrence of hyperkalaemia?
Calcium resonium
How does acute tubular necrosis respond to fluid challenge?
Poorly
What is prerenal uraemia?
Where the kidneys hold onto sodium to preserve volume
Prerenal uraemia vs ATN?
- Prerenal responds well to fluid challenge
- Urine osmlaitity will be raised
- Urine sodium will be low
Why should metformin be stopped in AKI?
Due to increased risk of toxicity
How does anti-GBM disease present?
- Haemoptysis
- AKI/proteinuria/haematuria
What is the most common cause of refractory HTN?
Renal artery stenosis secondary to atherosclerosis
eGFR is an inaccurate in which patients?
Those with extreme muscle mass
What investigation is needed for patients with AKI of unknown aetiology?
US
Patients with HSP require what to monitor for renal involvement?
BP and urinalysis
Patient presents with grey/brown tinge to the skin along with history of CKD?
Urea build up within the blood
Management of lupus nephritis?
Cyclophosphamide and methylprednisolone
What are the indications for acute haemodyialysis?
AEIOU
Acidosis
Electrolyte disturbance e.g. hyperkalaemia
Intoxication i.e. drug overdose
Oedema
Uraemia symptoms e.g encephalopathy
What is causes of sterile pyuria (white cells in urine with negative culture)
- Renal TB
- Partially treated UTI
- Drugs including NSAIDs, Abx
- Urinary tract stones
- Papillary necrosis
Schisotchtes on blood film?
Microangiopathic haemolytic anaemia -> HUS
Epithelial crescents in the glomeruli?
Rapidly progressing glomerulonephritis
What investigation should be done with all patients with AKI of unknown aetiology?
Renal US within 24 hours
Management of low urine output post surgery?
Fluid challenge - give bolus of NaCl
How should severe hyperkalaemia be managed?
Urgent discussion with nephrology/critical care
Pulmonary oedema with AKI needs what?
Haemodialysis
Cause of normal anion gap metabolic acidosis
Renal tubular acidosis
Causes of CKD
DM, Hypertension , glomerulonephritis, renovascular disease,
pyelonephritis, polycystic kidney disease, obstructive uropathy.
Signs of CKD on examination
purpura, bruising, brown discolouration of
nails, evidence of excoriation, peripheral oedema, hypertension,
pericardial rub, evidence o f pleural effusions, proximal myopathy,evidence of preparation for renal replacement therapy
How does haemodialysis work?
Blood and dialysis fluid flow either side of a semipermeable
membrane, molecules diffuse down their concentration gradients, plasma biochemistry changes to become more like the dialysis fluid.
What is the management of renal stones?
<5mm - wait and watch if asymptomatic
5mm - 10mm - Shockwave lithotripsy
10mm-20mm - Lithrotripsy / Ureteroscopy
>20mm - percutaneous nephrolithotomy
What is the management of ureteric stones?
If <10mm - shockwave lithotripsy +/- alpha blockers
If >10mm - Ureteroscopy
Which chromosome is affected in ADPKD?
16
Full house immunoflueoresence pattern on renal biopsy?
Lupus nephritis
How would Goodpastures present on biopsy?
Crescent formation and linear deposition of IgG antibodies across the glomerular basement membrane (anti-GBM antibodies)
What are C/I to renal biopsy?
- HTN
- CKD wit small kidneys
- Abnormal coagulation studies
Dietary advice for nephrotic syndrome
Restrict salt intake, normal protein intake
AKI + Haemoptysis + Lung changes?
Think Goodpastures
What are causes of rhabdomyolysis?
- Prolonged immobilisation
- Crush injuries
- Seizures
- Post surgery
- Medications such as statins
Period of hypotension followed by renal impairment with urinary casts
Acute tubular necrosis
How to calculate anion gap?
(sodium + potassium) - (bicarbonate + chloride)
Normal = 8-14
What are causes of normal anion gap metabolic acidosis?
- Diarrhoea
- Renal tubular acidosis
- Addisons
What are causes of raised anion gap metabolic acidosis?
- Shock
- DKA/Alcohol
- Acid poisoning e.g salicylates
How to work out pre, renal and post renal cause of AKI?
Urea / (creatinine(umol)/1000
Pre renal - >100
Renal/Normal - 40 - 100
Post renal - <40
What is in indication for chronic kidney disease over acute?
Hypocalcaemia
Acute interstitial nephritis vs acute tubular necrosis?
AIN is an inflammatory process so white cells will be in the urine whereas ATN is not therefore no white cells in urine
Tubulointerstitial nephritis with ueveitis?
usually young females; fever, weight loss and painful red eyes; urinalysis= +ve leukocytes and protein
Diarrhoea causes what?
Hypokalaemia metabolic acidosis
Eosinophilic casts are an indication of what?
Acute interstitial nephritis
What does proteinuria indicate in the context of AKI?
Intrinsic renal AKI cause
Anyone with severe hyperkalaemia / ECG changes for hyperkalaemia?
IV 10mls of 10% Calcium Gluconate
Insulin/Dextrose
What must be assessed in someone with bilateral calculi?
Renal function
HIV nephropathy causes what?
Focal segmental glomerulosclerosis -> causes nephrotic syndrome
Rapidly progressing glomerulonephritis is associated with what?
Goodpasture’s
GPA
What can invalidate an EGR?
Eating red meat
AKI values
Creatinine
Stage 1 - 1.5-1.9x baseline / Increased by 26 umol+ in 48hrs / urine output <0.5mls/kg >6 hours
Stage 2 - 2 - 2.9x baseline / urine output <0.5mls/kg >12 hours
Stage 3 - 3x baseline / urine output <0.3mls/kg >24 hours
What are the 4 variables in the MDRD equation to work out estimated EGFR in patients with CKD?
Creatinine
Age
Gender
Ethnicity
Addisons causes what?
Hyperkalaemic metabolic acidosis
Patients with CKD and ACR >30 should be started on what?
ACE + Statin
Hereditary haemochromatosis can cause what?
Cranial diabetes insipidus
fever + rash + renal dysfunction
Acute interstitial nephritis
Urine osmolality >500 + urine sodium < 20
Pre renal uraemia
Urine osmolality < 350 + urine sodium > 40
Acute tubular necrosis
Brown granular casts are a sign of what?
Acute tubular necrosis
What is the most common viral infection in solid organ transplant patients?
CMV
What is the treatment for acute clot retention in urethra?
Continuous bladder irrigation via a 3 way urethral catheter
What is a drug cause of nephrogenic diabetes insipidus?
Lithium - desensitizes the kidneys ability to respond to ADH in the collecting ducts
Granulomatosis with polyangiitis is associated with what?
Rapidly progressing glomerulonephritis
Young female patient with AKI after starting ACE?
Fibromuscular dysplasia
What is the daily maintenance fluids requirement?
25-30ml/kg/day
Haemodialysis can cause what?
A falsely low HbA1c
What is monitoring for ACE inhibitors?
Increase in creatinine up to 30% is acceptable
If K+ > 6 - stop ACE and switch to alternative
Why do you get kidney stones in PKD?
Cysts block collecting ducts leading to urinary stasis and stone formation
What part of nephron does RCC affect?
PCT
What are risk factors for RCC?
- Smoking
- Male
- Increasing age
- HTN
- FH
- Obesity
Symptoms of chronic renal failure?
- Anaemia
- Fatigue
- Vomiting
- Bone pain
- SOB
- Fluid overload
Complications of haemodialysis?
- Hypotension
- Thrombosis
- Infection
- Blockage
Complication of peritoneal dialysis?
- Peritonitis
- Obesity
- Hernias
- Loss of membrane function
Where does sodium reabsorption take place?
PCT
Anti-GBM has antibody against which type of collagen?
Type 4
What kind of reaction is IgA nephropathy?
Type 3
What can be given for calcium stones due to hypercalcicuria?
- Potassium citrate
- Thiazide diuretics (increase distal tubular reabsorption)
Most common cause of death in patients with CKD on harm-dialysis?
IHD
What is a complication UTI?
UTI in the presence of an abnormal urinary tract
What is the pathophysiology of IgA nephropathy?
IgA immune complex deposit in the mesangial cells
haemoptysis + haematuria
Think Good pastures
Sickness, headache, vomiting and drowsiness after haemodialysis?
Disequilibrium syndrome caused by rapid changes in plasma osmolality and cerebral oedema
Causes of raised CK?
- Burns
- Myositis
- Seizures
- Influenza
- Duchennes muscular dystrophy
What gene is responsible for PKD?
PKD1
What are complications of PKD?
- Renal failure
- HTN
- Renal calculi
- Cyst infection
- Hepatic cysts
What is screening of ADKPD for relatives?
Abdo US scan for first degree relatives
subepithelial ‘humps’ on electron microscopy
Post strep glomerulonephritis
A high urea can indicate what gastro pathology?
Upper GI bleed
What is a classic sign of renal artery stenosis?
- Worsening renal function after starting an ACE
- Refractory HTN
Which UTI medication can cause rise in creatinine?
Trimethoprim
What is a good marker prognosis in IgA nephropathy?
Macroscopic haematuria
Muddy brown casts
ATN
rash, eosinophilia and acute renal impairment
AIN
Most common component of renal stones?
Calcium oxalate
What is the most common cause of AKI?
Pre-renal causes
Management of acute upper urinary tract obstruction
Nephrostomy
fever, arthralgia, rash and eosinophilia in a setting of decreased renal function; HTN
Acute interstitial nephritis
When can a diagnosis of CKD be made?
When EGFR <60 on 2 tests which are 3 months apart
UTI + haematuria?
Must send MSU
Trimethoprim can cause a falsely low what?
eGFR
thickened glomerular basement membrane with IgG and C3 subepithelial deposits
Membranous nephropathy
Treatment of HTN in someone with IgA nephropathy?
ACE inhibitors
Headache and tremor can be signs of what?
Calcineurin inhibitors (tacrolimus) toxicity
Why are patients with nephrotic syndrome susceptible to clots?
Loss of antithrombin III and plasminogen via the kidneys
Periureteric fat stranding on CT KUB can indicate what?
Spontaneously passed calculus
Stag horn calculi are made of what?
Struvite (magnesium ammonium phosphate)
What is a vitamin D supplement which is used in end stage renal disease?
Alfacalcidol -> does not require activation in the kidneys
anti-MPO antibodies are indicative of what?
Microscopic polyangiitis
What are the types of renal tubular acidosis?
1 - inability to generate acid urine causing hypokalaemia (causes include RA, Sjogrens, SLE)
2 - decreased bicarb resorption causing hypokalaemia (causes include Wilsons)
4 - reduced aldosterone causing hyperkalaemia (causes include diabetes)
Crescent formation on biopsy with rapid decrease in EGFR?
Membranoproliferative glomerulonephritis
When is acute vs chronic rejection following transplant?
Acute - within first 6 months
Chronic - >6 months
Gold standard imaging for suspected renal cancer?
CT Abdo with contrast
Abx for UTI in egfr <45
Trimethoprim
What is the most common complication of haemodialysis?
Dialysis-induced hypotension
Worsening renal function with dark brown urine
ATN
Gentamicin can cause what?
ATN