Renal Flashcards
What are the mechanisms of anaemia in CKD?
Which of these is the main mechanism?
4 mechanisms:
- Reduces circulating EPO (main mechanism)
- Reduced dietary iron intake
- Toxic effects of uraemia on bone marrow
- Reduced red cell survival
- Low grade haemolysis
What is the mechanism of hypocalcaemia in CKD?
2-fold:
- Reduced 1-alpha-hydroxylation of vit D
- Hyperphosphataemia
What is the mechanism of hyperkalaemia in CKD?
2-fold:
- Metabolic acidosis:
- bicarbonate loss
- reduced ammonia and acid excretion - Decreased GFR
What are the mechanisms of renal osteodystrophy?
- Renal impairment causes reduced 1,25(OH)2 vit D production causes..
- Decreased intestinal calcium absorption, which causes…
- Secondary hyperparathyroidism which leads to bone breakdown
In CKD, what are the effects upon the blood indices?
RBC: anaemia (various mechanisms)
Platelets: thrombocytopenia and platelet dysfunction
WCC: defective granulocyte function
What effect does CKD have upon the lipid profile?
Hypertriglyceridaemia - due to decreased plasma lipoprotein lipase activity.
True/False: CKD is associated with glucose intolerance and tissue insulin intolerance.
True.
For Type 1 RTA, describe the following:
- Site of lesion and mechanism for acidosis
- K level in blood
- pH of urine
- Other features
- DT (alpha intercalated cells) inability to excrete H+ into urine, causing severe acidosis
- Hypokalaemia (K+ absorption is linked to H+ excretion)
- More Alkaline (pH greater than 5.5)
- Nephrocalcinosis due to calcium deposition from alkaline urine - children develop Rickets and adults develop osteomalacia
True/False: Bartter and Conn’s syndromes cause hyperkalaemic and metabolic acidosis.
False.
Both cause hypokalaemia and metabolic alkalosis
What type of donor source in renal transplantation for end-stage renal failure yield improved mortality AND quality of life?
Any - cadaveric or live unrelated donors both lead to improved rates in mortality and QoL.
In which part of the nephron is glucose reabsorbed?
Proximal tubule
Most common cause of nephritis in Australia?
IgA nephropathy
Patient with ESRD on HD for 7 years presents with MULTIPLE non-healing leg ulcers that have developed over 2 months. What is the most likely diagnosis?
Calciphylaxis
25F with SLE presents with worsening renal function and proteinuria. Renal biopsy confirms class III focal proliferative lupus nephritis.
What is the most appropriate drug in addition to steroid therapy?
Mycophenolate.
49F smoker presents with haemoptysis and CXR shows bilateral lower zone infiltrates. She is noted to have AKI and urinalysis shows red cell casts and proteinuria.
What investigation would you order?
What is your concern?
anti-GBM to diagnose Goodpastures syndrome
What is the pathophysiology of Goodpasture’s syndrome?
What is the treatment?
Autoimmune reaction to alpha-3 subunit of type IV collagen.
Rx: steroids + cyclophosphamide + plasmaphoresis
What is the main cause of mortality post renal transplant?
Malignancy
T/F: being female is a risk factor for AKI.
True
Asian patient presents with painless macroscopic haematuria, with a history of intermittent episodes of the same. Patient noted to have macroalbuminuria but no signs of nephrotic syndrome.
Diagnosis?
What would be found on biopsy?
IgA nephropathy - Mesangial IgA deposition
What are 3 rare syndromes that can cause HYPOKALAEMIA?
BGL:
Bartter’s syndrome
Gitelman’s syndrome
Liddle syndrome
Which type of confectionary can cause hypokalaemia?
Liquorice
Which common beverage can cause hypokalaemia?
Coca Cola
What is the utility of the Cockcroft Gault equation?
- Estimates GFR via creatinine clearance
- Used for dosing drugs in patients with renal impairment.
Aside from Creatinine, which 3-4 other parameters are required for calculating the Cockcorft Gault equation?
Sex
Age
Weight
+/-Height
Which 3 types of patients are likely to experience water intoxication?
- Long-distance atheletes - marathon/triathlon
- Psychotic patients
- Ecstacy-taking
What is the maximal rate at which the kidneys can excrete a water load per hour?
1L per hour - beyond this the body retains water.
Comment on the following in a case of Thrombotic Microangiopathy (TMA):
- Hb
- Blood film
- LDH level
- Haptoglobins
- Coombs test
- Platelet count
- Hb - anaemia
- Blood film - schistocytes / fragments
- LDH level - high
- Haptoglobins - low (consumed)
- Coombs test - negative (non-immune)
- Platelet count - low (below 150,000)
Patient has anaemia (low Hb, haematocrit and RCC). These results should be interpreted with other tests, however, comment on the likelihood of intravascular/extravascular haemolysis or non-haemolytic causes in the following haptoglobin levels:
- HIGH reticulocyte count + VERY LOW haptoglobins
- HIGH reticulocyte count + NORMAL/LOW haptoglobins
- NORMAL reticulocytes + NORMAL haptoglobins
- HIGH reticulocyte count + VERY LOW haptoglobins
Intravascular haemolysis
2. HIGH reticulocyte count + NORMAL/LOW haptoglobins Extravascular haemolysis (spleen/liver)
3. NORMAL reticulocytes + NORMAL haptoglobins NOT haemolysis (e.g. marrow failure)
Patient is thought to have TMA (thrombotic microangiopathy), how does one differentiate between TTP (thrombotic thrombocytopenic purpura) and HUS (haemolytic uraemic syndrome)?
ADAMTS-13:
TTP - less than 10% (deficient)
HUS - more than 10% (replete)
What is the pentad of clinical features for TTP (thrombotic thrombocytopenic purpura)?
Do fat registered nurses get TTP?
FAT-RN:
Fever Anaemia (MAHA) Thrombocytopenia Renal problem Neurological problem
Do fat registered nurses get TTP? No, horrible mnemonic, can change it later.
Patient is thought to has HUS (ADAMTS-13 greater than 10%).
How are typical and atypical HUS differentiated?
Diarrhoea:
Typical HUS (infection-induced):
- diarrhoea with shiga-toxin producing infection (E. Coli / EHEC)
- S. pneumonia may also cause typical HUS
Atypical HUS: NO diarrhoea, many DDx.
What is the pathophysiology of the following condition:
- HUS (haemolytic uraemic syndrome)
- aHUS (atypical haemolytic uraemic syndrome)
- TTP (thrombotic thrombocytopenic purpura)
- HUS (haemolytic uraemic syndrome)
- Infection-related (STEC or S. Pneumonia) - aHUS (atypical haemolytic uraemic syndrome)
- Complement alternative dysregulation (uncontrolled) e.g. presence of CFH (complement factor H - inhibitor of alternative pathway)
- Others: CTD, drugs, malignancy - TTP (thrombotic thrombocytopenic purpura)
- ADAMTS-13 deficiency, usually from an auto-antibody
- Deficiency leads to excess ultra-large vWF
What is the treatment of the following 2 types of TMA (thrombotic microangiopathies):
- TTP (thrombotic thrombocytopenic purpura)
- aHUS (atypical haemolytic uraemic syndrome)
- TTP (thrombotic thrombocytopenic purpura)
Plasma exchange - aHUS (atypical haemolytic uraemic syndrome)
Eculizumab (mAb to C5)
What is the MOA of Eculizumab?
Monoclonal Ab to C5 preventing it’s cleavage to C5a (pro-inflammatory) and C5b that forms C5b-9 (membrane attack complex)
What percentage of HUS patients are typical HUS and atypical HUS?
How do they are they different in terms of risk of recurrence?
HUS = 90% aHUS = 10% (increased risk of recurrence)
In order of likelihood what are the 2 most commonest organisms in PD peritonitis?
- Coagulation negative Staphylococcus
2. Gram negative oganism
In pregnant women what type of dialysis yields the best outcomes for the mother and foetus:
- PD
- Intermittent HD (3x per week)
- Daily HD (nocturnal)
Nocturnal daily HD
What are the 5 DDx for haemaglobinuria?
Is rhabdomyolysis one of these (strictly-speaking)?
MS BPT:
- Malaria
- Sickle cell disease
- Burns
- PNH (paroxysmal nocturnal haematuria)
- Thalassaemia
Rhabdomyolysis is strictly-speaking a ‘myoglobulinuria’ (from muscle cells)
What is the conservative treatment of rhabdomyolysis?
IVF and urinary alkalinisation
Patient presents 4 weeks post-renal transplant with a creatinine rise and biopsy reveals peri-tubular capillaritis with neutrophilic infiltrates, glomerulitis and C4d POSITIVE staining. No evidence of tubulitis.
What is the diagnosis and treatment?
Antibody-mediated rejection
1st line treatment:
- plasma exchange / IVIG
- steroids
- antilymphocyte Abs
Adjunctive treatment:
- Rituximab / Bortezomib / Eculizumab
- splenectomy
Patient with presents post-renal transplant with worsening renal function and a biopsy that reveals tubilitis.
What is the diagnosis and treatment?
Tubulitis suggests T-cell mediated rejection - treat with pulse steroids and increasing the Tacrolimus levels.
Which of the following immunosuppressants are teratogenic and therefore shoulde be avoided in pregnancy:
- Mycophenolate Mofetil (MMF)
- Azathioprine (AZA)
- mTOR inhibitors (Sirolimus / Everolimus)
MMF and mTOR inhibitors
AZA is not.
Belatacept is used as an immunosuppressant in post-renal transplantation.
What is the MOA of Belatacept?
Fusion protein = CTLA4 + IgG1
Inactivates T-cells
Belatacept is used as an immunosuppressant in post-renal transplantation.
T/F: Belatacept is associated with better GFR and patient survival in recipients of kidneys from standard criteria donors at 3 and 7 years.
True
Belatacept is used as an immunosuppressant in post-renal transplantation.
What are the 2 potential complications of its usage?
- Acute rejection more likely
2. Post-transplant lymphoproliferative disorder (overactivation of T-cells)
How is anion gap calculated?
What is the norma range?
What is the normal range if K is not included in calculations?
AG = Na + K - Cl - HCO3
Normal range (including K) = 16 - 20
Normal range (excluding K) = 12 - 16 (USE this one is AG quoted)
DDx for HAGMA?
Give short and super-long mnemonic
LTKR: lactate, toxins, ketones, renal failure
CAT-MUDPILES:
C: Cyanide, carbon monoxide
A: Alcoholic ketoacidosis
T: Toluene
M: Methanol, metformin U: Uraemia D: Diabetic ketoacidosis P: Paracetamol, pyroglutamic acid, propylene glycol I: Iron, isoniazid L: Lactate (numerous causes) E: Ethanol, ethylene glycol S: Salicylates
DDx for NAGMA?
Give short and long mnemonic
ABCD: A: Addisons B: Bicarb loss (GI or renal, includes RTA) C: Chloride D: Drugs (e.g. acetazolamide, acids)
HARDUP: H: Hyperchloraemia A: Acetazolamide, Addison’s disease R: Renal tubular acidosis D: Diarrhoea, ileostomies, fistulae U: Ureteroenterostomies P: Pancreatoenterostomies
How is urine anion gap calculated?
What is the utility of urine anion gap?
How is it interpreted?
Urine AG = Na + K - Cl
Utility:
- Indicated in NAGMA
- Differentiates renal (RTA) cause vs. Diarrhoea
Interpretation:
Negative = diarrhoea
Positive = RTA
A positive urine anion gap suggests RTA (types I, II or IV).
When might the urine anion gap be negative in type II RTA (proximal)?
Type II RTA (proximal) at baseline or with acid load will yield a NEGATIVE urine anion gap
What is the clinical significance of urinary pyroglutamic acid test in a septic elderly patient with high anion gap with paracetamol exposure?
Paracetamol exposure may cause HAGMA with pyroglutamic acidaemia due to deranged glutathione metabolism.
Patient has metabolic alkalosis. You are keen to do a urinary chloride to elucidate.
What 5 DDx should be excluded prior to embarking upon this?
PHARM:
Penicillin IV Hypercalcaemia Alkali-loading alkalosis Refeeding alkalosis Milk-alkali syndrome
Patient has metabolic alkalosis. You are keen to do a urinary chloride to elucidate.
You have excluded (PHARM): Penicillin IV, Hypercalcaemia, Alkali-loading alkalosis, Refeeding alkalosis, Milk-alkali syndrome
You note a LOW urinary chloride of less than 20 mEq/L.
What are your 3 DDx?
GDH:
Gastric secretions (e.g. vomiting)
Diuretic use
Hypercapnoea
Patient has metabolic alkalosis. You are keen to do a urinary chloride to elucidate.
You have excluded (PHARM): Penicillin IV, Hypercalcaemia, Alkali-loading alkalosis, Refeeding alkalosis, Milk-alkali syndrome
You note a HIGH urinary chloride of greater than 20 mEq/L but NO hypertension.
What are your 4 DDx?
Bartter’s syndrome (mimics loop)
Gitelman’s syndrome (mimics thiazide)
Diuretic use (loop / thiazide)
Low Mg or K
Patient has metabolic alkalosis. You are keen to do a urinary chloride to elucidate.
You have excluded (PHARM): Penicillin IV, Hypercalcaemia, Alkali-loading alkalosis, Refeeding alkalosis, Milk-alkali syndrome
You note a HIGH urinary chloride of greater than 20 mEq/L WITH hypertension. Plasma renin is HIGH.
What are your 3 DDx?
Diuretic use
Renal artery stenosis
Renin-secreting tumour
Patient has metabolic alkalosis. You are keen to do a urinary chloride to elucidate.
You have excluded (PHARM): Penicillin IV, Hypercalcaemia, Alkali-loading alkalosis, Refeeding alkalosis, Milk-alkali syndrome
You note a HIGH urinary chloride of greater than 20 mEq/L WITH hypertension. Plasma renin is LOW and plasma aldosterone is LOW.
What are 5 DDx?
Cushing's syndrome 11- or 17-Hydroxylse deficiency 11-beta-HSD deficiency Liddle's syndrome Liquorice
Patient has metabolic alkalosis. You are keen to do a urinary chloride to elucidate.
You have excluded (PHARM): Penicillin IV, Hypercalcaemia, Alkali-loading alkalosis, Refeeding alkalosis, Milk-alkali syndrome
You note a HIGH urinary chloride of greater than 20 mEq/L WITH hypertension. Plasma renin is LOW and plasma aldosterone is HIGH.
What is the diagnosis?
Primary hyperaldosteronism
What are the DDx for Primary hyperaldosteronism
Adrenal carcinoma / adenoma
Bilateral adrenal hyperplasia
Glucocorticoid remedial hypertension
Patient has metabolic alkalosis, HIGH urinary Cl (greater than 20 mEq/L) and HIGH urinary K with normal BP.
You suspect Bartter’s or Gitelmans syndrome. Which urine electrolyte is useful to differentiate?
Urine calcium:
Bartter = HIGH (remember frusemide used in treatment of hypercalcaemia)
Gitelman = LOW
What is the leading cause of death in patients with haemodialysis in Australia?
Withdrawal of treatment.
What are the likely target Ag with the following patterns of staining:
- p-ANCA (perinuclear)
- c-ANCA (cytoplasmic)
- p-ANCA - MPO
- c-ANCA - PR3
Remember: Your grandpa need CPR (GPA, c-ANCA, PR-3)
MPO = myeloperoxidase PR3 = proteinase 3
What type of ANCA Ab targets (MPO vs. PR3) are likely to be following vasculitic conditions:
- GPA (wegener’s)
- MPA
- EGPA (churg strauss)
- GPA (wegener’s) - PR3
- MPA - MPO
- EGPA (churg strauss) - either (MPO > PR3)
Which drugs can cause drug-induced MPO-ANCA vasculitis?
HPC: Hydralazine, PTU, Carbimazole
What is the most important risk factor for CV events post-renal transplant?
HTN
Give the diuretic that acts on the following sites in the nephron:
- PCT
- Descending L of H
- Ascending L of H
- DCT
- CCD
- PCT = Acetozolamide
- Descending L of H = Osmotic diuretics (Mannitol)
- Ascending L of H = Loop diuretic (Frusemide)
- DCT = Thiazide (HCT)
- CCD = K-sparing diuretics (Spironolactone)
What is the composition of most kidney stones?
Calcium oxalate
Give the DDx for a hyperosmotic hyponatraemic patient (2) - i.e. >295
MH:
- Mannitol
- Hyperglycaemia
Give the DDx for a iso-osmotic hyponatraemic patient (4) - i.e. 280-295
PLUT:
Protein high
Lipids high
Urea high
TURP - post-TURP
Give the 4 DDx for a hypo-osmotic hyponatraemic patient (i.e. < 280) with the following:
- High urine osmolality ( >100)
- Low urinary sodium (<40)
What 3 investigations would help differentiate?
Sodium retention + Water retention
HHCN:
- Hypovolemia
- HF
- Cirrhosis
- Nephrotic syndrome
Ix: LFT / TTE / 24 urinary protein
Give the 5 DDx for a hypo-osmotic hyponatraemic patient (i.e. < 280) with the following:
- High urine osmolality ( >100)
- High urinary sodium (>40)
Sodium wasting and Water retention
CT-MR-S:
- Cerebral salt wasting (hypovolemic / high UO)
- Thyroid low (hypothyroidism)
- MC deficiency
- Renal sodium loss (TPPC: TZD / Polyuric phase of ATN / Post-obstructive diuresis / CKD)
- SIADH (euvolemic / low UO)
Give the 4 DDx for a hypo-osmotic hyponatraemic patient (i.e. < 280) with the following:
- Low urine osmolality (<100)
- Low urinary sodium (<40)
Sodium retention + Water wasting
BIMP:
- Beero potomania
- IVF (inappropriate)
- Malnutrition
- Polydipsia
Give the 4 DDx for a hypo-osmotic hyponatraemic patient (i.e. < 280) with the following:
- Low urine osmolality (<100)
- High urinary sodium (<40)
Sodiu wasting + Water wasting
Renal sodium loss (PPA):
- Polyuric phase of ATN
- Post-obstructive diuresis
- AKI