Nephrology Flashcards
What are the two causes of diffuse proliferative glomerulonephritis?
- Post strep (children)
- SLE
What is nephrotic syndrome?
Glomeruli leak protein into urine (>3g/24h)
- Hypoalbuminia
- Hyperlipidaemia
- Albuminuria
- Oedema - typically legs, feet or ankles. Less commonly, face.
What is the most common cause of nephrotic syndrome in adults?
Children?
Adults: Focal segmental glomerulonephritis
Children: Minimal change glomerulonephritis
What is the difference between nephrogenic and cranial diabetes insipidus?
Treatment?
Cranial: Body produces insufficient ADH (vasopressin) - Treat with synthetic, i.e. Desmopressin
Nephrogenic: Kidneys unable to respond to ADH. Treat with thiazide diuretics
How do you calculate volume of maintenance fluids for children?
First 10kg: 100mL/kg per 24 hours
Next 10kg: 50mL/Kg
Anything over 20kg: 20mL/kg
What are the adult requirements for maintenance fluids?
25-30ml/kg/day fluid
Approx 1mmol/kg/day of potassium, sodium and chloride
50-100g/day glucose to limit starvation ketosis.
So typically:
25-30ml/kg/day NaCL 0.18% in 4% glucose (cont 30ml/L each and 40g glucose/L) with 27 mol/L K on day 1.
What would renal failure, sensorineural hearing loss and ocular abnormalities in a child make you think of?
Alport syndrome (esp male: x-linked dominant)
What is the screening test for adult polycystic kidney disease?
US abdo
Diagnostic criteria: (with +ve family hx)
- 2 cysts if <30
- 2 cysts in both kidneys if 30-59
- 4 cysts in both kidneys if >60
Why does nephrotic syndrome predispose to venous thromboembolism?
Loss of antithrombin-III, proteins C and S and an associated rise in fibrinogen levels predispose to thrombosis.
Why do you do a CK following a fall and a long lie?
Rhabdomyolysis - death of muscle fibres -> renal failure (myoglobinuria -> tubular cell necrosis)
In terms of mx of hyperkalaemia, which drug(s):
- Stabilise the cardiac membrane?
- Shift K into the intracellular compartment?
- Remove K from body?
- Stabilise the cardiac membrane: IV calcium gluconate
- Shift K into the intracellular compartment: Combined insulin/dextrose infusion; nebulised salbutamol
- Remove K from body:
Calcium resonium
Loop diuretics
Dialysis
What would you expect on a blood gas in sepsis?
Often have raised lactate -> metabolic acidosis with raised anion gap
What are the causes of high anion gap metabolic acidosis?
Mneumonic
M ethanol U raemia D KA P ropylene glycol I soniazid/iron L actate (shock, hypoxia, burns, metformin) E thylene glycol S alicylates
What are the causes of metabolic acidosis with a normal anion gap?
= hyperchloraemic metabolic acidosis
- GI HCO3 loss (diarrhoea, ureterosigmoidostomy, fistula)
- Renal tubular acidosis
- Acetazolamide
- Ammonium chloride injection
- Addison’s
What are the pre-renal causes of AKI?
Kidney function is normal, but reduced perfusion. Patients with CKD have impaired compensation so can develop acute-on-chronic failure easily.
- Blood loss
- Low arterial blood pressure - HF/sepsis
- ACE-i, ARBs and NSAIDs
- Dehydration (vomiting, diarrhoea)
- Severe burns
- Pancreatitis, liver disease -> fluid shift
What are the intrinsic causes of AKI?
- Acute tubular necrosis = most common in hospital. (nephrotoxic meds, hypotension, trauma, contrast agents, rhabdomyolysis)
- Glomerular (SLE, systemic sclerosis, Goodpasture, Wegners, arthritis, hep C, HIV)
What are the post-renal causes of AKI?
Prostatic hypertrophy
Kidney stones
Ca: prostate, cervix, colon
What is the triad of haemolytic uraemic syndrome?
- AKI
- Microangiopathic haemolytic anaemia
- Thrombocytopenia
Causes of haemolytic uraemic syndrome?
- Post-dysentery (E.coli) = most common
- Tumours
- Pregnancy
- Ciclosporin
- COCP
- SLE
- HIV
Most common in children.
What is seen on FBC in haemolytic uraemic syndrome?
Anaemia
Thrombocytopaenia
Fragmented RBC
Which type of cancers are renal transplant patients are risk of?
SSC particularly
Also lymphoma and cervical.
What are the 4 main symptoms of nephritic syndrome?
- Haematuria
- Proteinuria
- HTN (mild)
- Low urine volume
What are the 3 primary and 5 secondary causes of nephrotic syndrome?
1:
- Minimal change glomerulonephritis
- Focal segmental glomerulonephritis
- Membranous glomerulonephritis
2:
- SLE
- Hep B and C
- HIV
- DM
- Malignancy
What are the 5 causes of nephritic syndrome?
- Post-strep glomerulonephritis
- IgA nephropathy
- Rapidly progressive glomerulonephritis (Goodpastures or vasculitic)
- Membranoproliferative glomerulonephritis (SLE, Hep B/C)
- Henoch-Schonlein purpura
What is the main cause of death in patients on haemodialysis?
IHD
What are urine eosinophilic casts indicative of?
Tubulointerstitial nephritis (often due to drug reactions)
What 3 drugs would you stop in AKI due to increased risk of toxicity?
- Metformin (risk of lactic acidosis)
- Lithium
- Digoxin
What 5 classes of drugs would you discontinue in AKI as they may worsen renal function?
- NSAIDs (except aspirin at cardioprotective dose - 75mg)
- Nephrotoxic abx, especially gent and nitro.
- ACE-i
- Angio II R antag
- Diuretics
What would you expect in terms of urine and plasma osmolality in diabetes insidious?
High plasma osmolality (hence why patient feels thirsty)
Low urine osmolality
How do you confirm a diagnosis of diabetes insidious?
Water deprivation test.
Normal patients would produce small quantity of conc urine to maintain normal plasma osmolarity.
In DI there is a rise in plasma osmolarity with the production of low osmolarity (dilute) urine. If you then give ADH, Cranial will produce conc urine, nephrogenic will have no response.
What would be the differential for HTN with low K?
How would you tell them apart?
Conn’s, Cushing’s, renal artery stenosis, Liddle’s.
Do renin and angiotensin levels:
- Cushing’s and Conn’s = high aldosterone, low renin
- Renal A stenosis: high both
- Liddle’s: low both
What would you switch a patient to if they developed gynaecomastia with spironolactone?
Eplerenone
Which antibiotics are most likely to cause an intrinsic AKI?
Penicillins Cephalosporins Aminoglycosides - Gent Vancomycin Quinolones
What is the gold standard for bladder cancer diagnosis?
Cystoscopy
What are the features of Henock-Scholein purpora?
IgA mediated vasculitis, usually seen in children following an infection.
- Palpable purpuric rash (+localised oedema) over buttocks and extensor surfaces of arms and legs
- Abdo pain
- Polyarthritis
- Features of IgA nephropathy (haematuria, renal failure)
What is the most common causative organism in peritonitis as a complication of peritoneal dialysis?
Staph epidermis
Staph aureus is also common
What is the most common viral infection in solid organ transplant recipients?
Mx?
CMV
Ganciclovir
How does muscle mass affect eGFR?
Can be inappropriately low in body builders.
What type of diuretic would you use to prevent re-accumulation of ascites following drainage?
Spironolactone (aldosterone antagonist - acts in collecting duct). Add a loop if no response.
What are the variables used in Modification of Diet in Renal Disease (MDRD) estimation of eGFR?
CAGE: Creatinine Age Gender Ethnicity
What is the maximum infusion rate in potassium replacement therapy?
Why do you dilute it in high volumes of saline?
20mmol/hr
High concentrations can be phlebitic
What drugs can cause nephrogenic DI?
Lithium
Demeclocycline
What is the treatment for urinary retention due to clots?
Continuous bladder irrigation via a 3-way urethral catheter
How would you differentiate ATN and pre renal AKI?
Pre-renal: Kidneys hold on to Na to preserve volume, so urine sodium <20. Would also respond to fluid challenge.
What is the normal outcome following minimal change nephropathy?
Full recovery, but likely (2/3) recurrent episodes.
What is the main concern with painless visible haematuria?
Bladder ca - Refer urgently
What drugs can commonly cause haematuria?
NSAIDs Captopril Cephalosporins Cipro Furosemide
What are the risk factors for renal tract ca?
Smoking
Chronic analgesic use
Toxin exposure
What is the empirical treatment of UTI in adult, non-pregnant women?
Trimethoprim or Nitrofurantroin or Amox.
E. Coli
What are the 3 criteria for diagnosing AKI?
- Rise in creatinine >26 in 48hrs
- Rise in creatinine >1.5x baseline (use best figure in last 3/12)
- Urine output <0.5ml/kg/h for 6 consecutive hours
How might you avoid AKI in a patient going for a contrast scan?
1L Normal saline over 12 hours pre- and post-procedure
How do you define chronic kidney disease?
Impaired renal function for >3 months based on abnormal structure or function
or
GFR <60ml.min for >3 months
What are the 5 main/groups of causes of CKD?
- Diabetes (2>1)
- Glomerulonephritis: commonly IgA
- Unknown, up to 20% present with no obvious cause and shrunken kidneys you wouldn’t biopsy
- HTN or renovascular disease
- Pyelonephritis and reflux nephropathy
What is the commonest cause of inherited CKD?
Adult polycystic kidney disease
Who would you screen for CKD?
- Diabetics
- HTN
- IHD, PVD, CVD
- Structural renal disease, known stone or BPH
- Recurrent UTIs or childhood history of vesicouteric reflux
- SLE
- FHx end-stage disease
What is the target BP in CKD?
<130/80
or
<125/75 if diabetic
What is the mx of diabetic kidney disease?
ACE-i or ARB even if BP normal
What would you suspect if iron/B12/folate and subsequent erythropoietin therapy failed to resolve anaemia?
Red cell aplasia - refer to haem.
How do you mx oedema in CKD?
Loop diuretics e.g. furosemide.
Fluid and sodium intake restriction.
How might you treat acidosis in CKD?
Consider sodium bicarb supplements - improves symptoms and may also slow progression. Caution as sodium load may increase BP.
How do you treat restless legs/cramps in CKD?
Check ferritin (low levels -> worse symptoms)
- Clonazepam
- Gabapentin
When might you use haemofiltration rather than haemodialysis?
What is the difference?
In critically ill patients - less haemodynamic instability as the filtrate is replaced with equal amount of fluid. Not used routinely as takes much longer.
What is the annual mortality in dialysis? Why?
Around 20%
MI and CVA
Also high mortality if sepsis develops.
What is the difference between nephrotic and nephritic syndrome in terms of:
BP
Urine
GFR
NephOtic:
- BP: Normal, mild inc
- Urine: PrOtein
- GFR: Normal, mild dec
Nephritic:
- BP Mod-severe inc
- Urine: Haematuria
- GFR: Mod-severe dec
What would be a typical patient with IgA nephropathy?
- Young man
- Episodic haemautria
- NephrItic syndrome
- Rapid recovery between attacks
What would you see on renal biopsy in IgA and Henoch-Schonlein purpura?
Mesangial proliferation
IgA and C3 deposits
(HSP is a systemic variant of IgA - can also see deposition in skin)
What is Goodpasture’s disease/Anti-glomerular basement membrane disease due to?
Caused by auto-antibodies to type IV collagen.
T4 collagen also found in lung so pulmonary haemorrhage can occur, especially in smokers
Is Goodpasture’s nephritic or nephrotic?
Nephritic, but also haematuria.