Nephrology Flashcards
Presentation: patient presenting with diarrhoea illness alongside reduced urine output - most likely cause?
Haemolytic uraemic syndrome caused by Shiga toxin (either due to E.coli or Shigella)
Presentation: headache in a patient with Autosomal Dominant Polycystic kidney disease?
Ruptured berry aneurysm (SAH)
What are the two features of AKI?
Raised creatinine
Reduced urine output
How is AKI staged?
AKI 1 -creatinine raised to 1.5-1.9x baseline, urine output <0.5ml/kg/hr for 6 hours
AKI 2 - creatinine raised to 2-2.9x baseline, urine output <0.5ml/kg/hr for 12 hours
AKI 3 - creatinine raised to over 3x baseline, urine output <0.3ml/kg/hr for 24 hours
What are pre-renal causes of AKI?
Pre-renal AKI = due to lack of perfusion to the kidneys
Dehydration
Hypotension
Renal artery stenosis
What are causes of renal AKI?
Acute tubular necrosis
Acute interstitial nephritis
Glomerulonephritis
Rhabdomyolysis
Tumour lysis syndrome
What are causes of post-renal AKI?
Renal calculi
Stricture
Prostate enlargement
Mass
How can you determine the cause of AKI from urine results?
Pre-renal = low urine sodium (high urine osmolality)
Renal = high urine sodium (low urine osmolality)
What drugs are directly nephrotoxic?
NSAIDs
Gentamicin
ACEi/ARBs
Diuretics
Which drugs are not directly nephrotoxic but are renally excreted and should be stopped in AKI?
Lithium
Metformin
Digoxin
What is acute tubular necrosis and what are the main causes?
Damage/necrosis of the renal tubules (renal cause of AKI)
Mainly due to
- Ischaemia (due to sepsis/dehydration)
- Toxins - contrast dye, NSAIDs, Gentamicin
What is seen on urinalysis in acute tubular necrosis?
Muddy brown casts
How is acute tubular necrosis managed?
Stop any nephrotoxic drugs
IV fluids
How can you prevent acute tubular necrosis due to contrast media in patients at risk? Who is at risk?
At risk = known renal impairment, age >70, dehydration, cardiac failure, use of nephrotoxic drugs
Prevention = IV 0.9% NaCl 1ml/kg/hr for 12 hours pre and post contrast
Nephrotoxic drugs should be stopped for 48 hours prior to procedure
How does acute interstitial nephritis present?
AKI and Hypertension
As well as - rash, fever, raised eosinophils
What can cause acute interstitial nephritis?
NSAIDs
Penicillin antibiotics
Rifampicin
Ciprofloxacin
PPIs
Allopurinol
Furosemide
How is acute interstitial nephritis managed?
Stop offending drug
What is Rhabdomyolysis?
Breakdown of muscle which releases breakdown products into the blood
Myoglobin (nephrotoxic)
Potassium
Phosphate
Creatinine kinase (markedly elevated)
What is the most immediately dangerous breakdown product in Rhabdomyolysis?
Potassium - hyperkalaemia can cause cardiac arrhythmias and cardiac arrest
Why does Rhabdomyolysis cause an AKI?
Releases myoglobin into blood
Myoglobin is nephrotoxic
What are causes of Rhabdomyolysis?
Prolonged immobility (e.g. elderly patient falls and spends time on the floor before being found)
Extremely rigorous exercise
Crush injuries
Seizures
How does Rhabdomyolysis present?
Myalgia
Oedema
Fatigue
Confusion
Tea coloured (red brown) urine
What investigations should be done in suspected Rhabdomyolysis?
Creatine kinase will be markedly elevated
Myoglobinurea
U+Es - look for AKI
ECG - look for cardiac arrhythmia caused by hyperkalaemia (widened flattened P wave, tall tented T waves, broad QRS complex)
How is Rhabdomyolysis treated?
Mainstay = IV fluids - 0.9% sodium chloride
Treat hyperkalaemia - insulin + glucose, calcium gluconate (stabilisation of cardiac membranes), potassium
Can give IV Bicarbonate to neutralise the acidity of urine
What ECG changes are seen in hyperkalaemia?
Tall tented T waves
Flattened P waves
Broad QRS complex
What level of potassium warrants urgent treatment?
> 6.5
Or >6 with ECG changes (check ECG first if in between 6 and 6.5)
What warrants dialysis in hyperkalaemia?
If severe hyperkalaemia associated with AKI
Non-responsive to treatment
What is the difference between nephritic syndrome and nephrotic syndrome?
Nephritic syndrome: haematuria, oliguria, Proteinuria, fluid retention
Nephrotic syndrome: peripheral oedema, massive Proteinuria, low albumin <25, hypercholesterolaemia
What is the main complication of nephrotic syndrome?
What are other complications?
Increased risk of VTE due to loss of Antithrombin III
AKI, CKD, end stage renal disease
What is the most common cause of nephrotic syndrome in children? What is seen on renal biopsy? How is it managed?
Minimal change disease
Renal biopsy shows fusion of podocytes and effacement of foot processes (on electron microscopy only - light microscopy is normal)
Treated with oral prednisolone
What might you want to let someone know who has had minimal change disease?
Majority of people have at least one more episode
What is the most common cause of nephrotic syndrome in adults?
Membranous glomerulonephritis
What is the difference between IgA Nephropathy and post-strep glomerulonephritis?
IgA nephropathy - usually within 1-2 of infection, mainly macroscopic haematuria (but can also be proteinuria)
Post-strep glomerulonephritis - 1-2 weeks post-infection, can be both haematuria + proteinuria, low complement C3 levels
Anti-streptolysin O
How does membranous glomerulonephitis present and how is it seen on renal biopsy?
Nephrotic syndrome
Renal biopsy - thickened basement membrane, igG and complement deposits on basement membrane –> “Spike and dome appearance”
Which antigen is associated with membranous glomerulonephritis?
PLA2
How is membranous glomerulonephritis treated?
ACEi/ARB
What is rapidly progressive glomerulonephritis?
Presents with very acute illness - rapid loss of renal function
Histology - epithelial crescents
Often secondary to Anti-GBM (Goodpasture’s) or GPA Granulomatosis with Polyangiitis (Wegener’s)
What is Anti-GBM disease (Goodpasture’s)? How does it present?
A rare type of small vessel vasculitis
Pulmonary haemorrhage (presents with Haemoptysis)
Rapidly progressive glomerulonephritis (Proteinuria, haematuria)
What is seen on renal biopsy in anti-GBM disease?
Linear IgG deposits on basement membrane
Epithelial crescents
(Same as what is seen in rapidly progressive glomerulonephritis)
How can you differentiate between Anti-GBM and GPA?
Anti-GBM = Haemoptysis, rapidly progressive glomerulonephritis, Anti-GBM antibodies
GPA = glomerulonephritis, Haemoptysis, epistaxis, sinusitis, saddle shaped nose deformity, associated with cANCA
What is Henoch Schonlein Purpura? How is it managed?
IgA mediated small vessel vasculitis
Usually seen in children following an URTI
Palpable purpuric rash on the buttocks and limbs
Abdominal pain
Polyarthritis
Features of IgA nephropaty - haematuria, Proteinuria
Management is supportive
What are complications of chronic kidney disease?
Anaemia (normocytic) - due to decreased erythropoietin production
Bone disease - kidney does not convert vitamin D to active form (decreased calcium absorption), and stops excreting phosphate
Low calcium and high phosphate leads to increased PTH production (secondary hyperparathyroidism)
Increased PTH causes bone disease - osteomalacia
Hypertension
How is anaemia in CKD treated?
Erythropoietin
Treat iron deficiency prior to giving erythropoietin
How is renal bone disease treated?
Reduced dietary phosphate
Active forms of vit D
Phosphate binder e.g. Sevelamar/Calcium acetate/Calcium carbonate
Bisphosphonates
What Spinal X-ray changes can be seen in chronic kidney disease?
Spinal x-ray =
sclerosis of both ends of vertebra (denser white)
Osteomalacia in centre of vertebra (less white)
How is hypertension in chronic kidney disease treated?
ACE inhibitors
Monitor serum potassium - CKD with ACEi can cause hyperkalaemia
A decrease in eGFR of up to 25% and an increase in creatinine of 30% after starting ACEi = acceptable
How is CKD staged?
1 - >90 (plus evidence of renal disease - Proteinuria, albumin:creatinine ratio >30)
2 - 60-89
3a - 45-59
3b - 30-44
4 - 15-29
5 - <15
What is the most common cause of CKD in the UK?
What are other causes?
Diabetic nephropathy
Hypertension
PKD
Glomerulonephritis
Pyelonephritis
How is diabetic nephropathy diagnosed?
Monitor early morning albumin:creatinine ratio
If abnormal - conduct 1st pass urine for Proteinuria
How are kidneys seen on X-ray in CKD?
Small and scarred
In diabetic nephropathy- can be large
What is the string of beads sign?
Seen in fibromuscular dysplasia
String of beads appearance to renal artery on angiogram
Fibromuscular dysplasia = cause of renal artery stenosis
What are the two types of ADPKD?
PKD1 - chromosome 4
PKD2 - chromosome 16
What is the diagnostic criteria for Polycystic kidney disease?
Age below 30 - two cysts (can be in one kidney or two)
Age 30-60 - two cysts in both kidneys
Age over 60 - four cysts in both kidneys
How does Polycystic kidney disease present?
Abdominal pain
Early satiety
Hypertension
CKD
Hepatomegaly
Diverticulitis
Ovarian cysts
How is Polycystic kidney disease managed?
Tolvaptan
Only needed if patient has reached CKD 2/3
What are extra-renal manifestations of Polycystic kidney disease?
Liver cysts (Hepatomegaly)
Berry aneurysms (can present as SAH if rupture)
How is Polycystic kidney disease screened for in family members?
Abdominal ultrasound
What is haemolytic uraemic syndrome?
Triad of AKI, Haemolytic anaemia and low platelets
Haemolytic anaemia will cause raised bilirubin due to breakdown
Firstly a diarrhoea illness
Then around 5 days later - reduced urine output, abdominal pain, confusion, oedema, hypertension, bruising, vomiting
Treatment is supportive
What is the most common type of renal cell carcinoma?
Adenocarcinoma (Clear cell)
What is the classic triad of symptoms seen in renal cell carcinoma?
Haematuria
Flank pain
Palpable mass
What is the 2WW criteria for suspected renal cancer?
> 45 plus visible unexplained haematuria
What is the most common place for renal cell carcinoma to metastasise?
Lung (seen as cannonball metastases)
What are causes of metabolic alkalosis?
Vomiting
Diuretics
Hypokalaemia
Primary hyperaldosteronism
Cushing’s
What are causes of metabolic acidosis? (raised anion gap vs. normal anion gap)
Raised anion gap = sepsis, shock, DKA, alcohol, aspirin, methanol
Normal anion gap = diarrhoea, renal tubular acidosis, Addison’s
How is the anion gap calculated? What is a normal anion gap?
(Sodium+potassium) - (bicarbonate+chloride)
Normal anion gap = 8-14
What is Alport’s syndrome?
X-linked recessive condition
Microscopic haematuria
Progressive renal failure
Bilateral sensorineural deafness
Protrusion of lens surface
Retinitis pigmentosa
Presentation: renal failure + deafness +/- vision problems?
Alports syndrome
What is seen on renal biopsy in Alport’s syndrome?
Longitudinal splitting of the lamina densa
Basket-weave appearance
What is the NICE criteria for AKI?
Rise in creatinine of ≥ 25 micromol/L in 48 hours
Rise in creatinine of ≥ 50% in 7 days
Urine output of < 0.5ml/kg/hour for > 6 hours
What is renal tubular acidosis? What is the normal function of the renal tubules?
Metabolic acidosis due to a pathology of the renal tubules
Renal tubules maintain hydrogen and bicarbonate ion balance to maintain normal pH
What is type 1 and type 2 renal tubular acidosis? What lab results are seen?
Type 1 = distal tubule fails to excrete hydrogen ions
Type 2 = proximal tubule fails to reabsorb bicarbonate ions
Lab results = HYPOkalaema, metabolic acidosis, low urinary pH
What are causes of type 1 renal tubular acidosis?
Genetic
SLE
Sjorgen’s syndrome
Hyperthyroidism
Sickle cell anaemia
Marfan’s
How does type 1 renal tubular acidosis present?
In children - failure to thrive
Hyperventilation (compensation for metabolic acidosis)
CKD
Osteomalacia
What is the treatment for type 1 and type 2 renal tubular acidosis?
Oral bicarbonate
Hypokalaemia does not need to be treated - oral bicarbonate will fix it
Which type of renal tubular acidosis is associated with Fanconi syndrome?
Type 2 renal tubular acidosis
What is the most common type of renal tubular acidosis?
Type 4
What is type 4 renal tubular acidosis? What are causes/?
Reduced aldosterone which leads to reduced ammonium excretion by the proximal tubule
Due to…
Adrenal insufficiency
ACEi
Spironolactone
SLE
HIV
What lab results are seen in type 4 renal tubular acidosis?
HYPERkalaemia
Metabolic acidosis
High chloride
Low urinary pH
How is type 4 renal tubular acidosis managed?
Fludrocortisone
Oral bicarbonate
Hyperkalaemia management
What tests do you want to do in ?Rhabdomyolysis
Blood tests- FBC, U+E, Myoglobin, CK
ECG - due to potential raised potassium
What is seen on urinalysis in acute interstitial nephritis?
Sterile pyuria
White cell casts
What is sterile pyuria and what are causes?
Raised white cells in urine but Negative urine culture
Renal tuberculosis
Partially treated UTI
Acute interstitial nephritis
Urinary tract stones
How can you differentiate heart failure from nephrotic syndrome?
Both will have oedema
Nephrotic syndrome will have massive proteinuria
Heart failure will have little/no proteinuria
What are indications for acute dialysis?
AEIOU
Acidosis (severe metabolic acidosis with pH of less than 7.20)
Electrolyte imbalance (persistent hyperkalaemia with ECG changes)
Intoxication (poisoning)
Oedema (refractory pulmonary oedema not responding to medication)
Uraemia (symptomatic uraemia - encephalopathy or pericarditis)
Which autoantibodies are raised in Anti-GBM disease?
Type IV Collagen autoantibodies
What are physical signs of haemolytic uraemic syndrome?
Jaundice (due to haemolysis)
Bruising(due to low platelets)
Abdominal tenderness
Who is at risk of AKI?
Chronic kidney disease
Diabetes with chronic kidney disease
Heart failure
Renal transplant
Aged 75 or over
Hypovolaemia (dehydration)
Contrast agent
What autoantibodies are raised in post-strep glomerulonephritis?
Anti-streptolysin O antibodies
What is seen on electron microscopy in IgA Nephropathy?
IgA deposition in the mesangium
What is seen on electron microscopy in Post-strep Glomerulonephritis?
IgG and C3 sub epithelial deposition
What is seen on electron microscopy in Membranous nephropathy?
Spike and dome appearance
What is seen on electron microscopy in minimal change disease?
Effacement of foot processes
Fusion of podocytes
If AKI is associated with proteinuria, what is the most likely cause? (Renal, pre-renal or post-renal)
Renal AKI
Urinary sodium - pre renal vs renal AKI
Pre-renal = Low urinary sodium
Renal = High urinary sodium
Urine osmolality - pre renal vs renal AKI
Pre-renal = high urine osmolality
Renal = Low urine osmolality
Serum urea:creatinine ratio - pre renal vs renal AKI
Pre-renal = Raised urea:creatinine ratio
Renal = Normal urea:creatinine ratio
How can you treat steroid resistant nephrotic syndrome?
Tacrolimus/Ciclosporin/Cyclophosphamide
What are risks of oral corticosteroids in children?
Poor growth
Obesity
Osteoporosis
DM
Behavioural disturbances
What are the two main causes of renal artery stenosis?
Atherosclerosis
Fibromuscular dysplasia
What does worsening renal function after starting an ACEi suggest?
Bilateral renal artery stenosis
What is the gold standard diagnostic investigation for renal artery stenosis?
Renal angiography
Also renal ultrasound (first line)
How is renal artery stenosis managed?
Transluminal angiography +/- stenting
What is an acceptable rise in creatinine after starting an ACEi?
<30% rise
Which type of renal replacement therapy is used in AKI?
Haemofiltration
What are complications of haemodialysis?
Site infection Endocarditis Cardiac arrhythmia Air embolus Anaphylactic reaction Amyloidosis Hypertension Disequilibration syndrome (Acute cerebral oedema - headache+drowsy)
What are complications of peritoneal dialysis?
Peritonitis Catheter infection Catheter blockage Constipation Fluid retention Hyperglycaemia Hernia Back pain Malnutrition
What is the most common organism which causes peritonitis due to peritoneal dialysis?
Staph epidermis
What are complications of renal transplant?
DVT/PE Opportunistic infection Malignanies - lymphoma/skin cancer Bone marrow suppression Urinary tract obstruction CVD Graft rejection
What are the different types of renal transplant rejection?
Hyperacute rejection = minutes to hours
Due to antibodies
Graft must be removed
Acute rejection = less than 6 months
Mismatched HLA
May be reversible with immunosuppressants
Chronic graft rejection = more than 6 months
Due to fibrosis
Which autoantibody is raised in post-strep glomerulonephritis?
Anti streptolysin O
What are causes of focal segmental glomerulonephritis?
HIV
Heroin
Alport’s syndrome
Sickle cell disease
Which valvular abnormality is associated with polycystic kidney disease?
Mitral valve prolapse
What is the definitive diagnosis of acute interstitial nephritis?
Kidney biopsy - will show eosinophils, lymphocytes and plasma cells
urinalysis will show sterile pyuria
What is a risk of giving someone too much sodium chloride?
Hypercholeraemic metabolic acidosis
How do you screen for diabetic nephropathy?
Measure albumin:creatinine ratio - microalbumnaemia is the first sign of diabetic nephropathy
If abnormal - do a first pass morning urine sample for proteinuria
How is diabetic nephropathy managed?
ACEi/ARB
When to give calcium gluconate for hyperkalaemia?
> 6.5 or ECG changes
What factor in U+Es points towards dehydration being a cause of AKI?
Urea proportionately higher than the creatinine
Hypernatraemia
What is Fanconi syndrome?
Generalised reabsorptive disorder of renal tubular transport in the proximal convoluted tubule resulting in:
type 2 (proximal) renal tubular acidosis polyuria aminoaciduria glycosuria phosphaturia osteomalacia
