Renal Flashcards
Define acute kidney injury
Drop in kidney function
Rise in serum creatinine
List the NICE criteria for AKI
Rise in Cr of >25micromol/L in 48hrs
Rise in Cr of >50% in 7 days
Urine output <0.5ml/Kg/hr for >6hrs
List some risk factors for AKI
Chronic kidney disease Heart failure Diabetes Liver disease Older age Cognitive impairment Nephrotoxic medication - NSAIDs and ACEi Contrast medium
What causes an AKI
Pre-renal
- Dehydration
- Hypotension
- Heart failure
Renal
- Glomerulonephritis
- Interstitial nephritis
- Acute tubular necrosis
Post-renal
- Stones
- Urethral or ureter strictures
- Enlarged prostate or prostate cancer
What investigations would you do for AKI
Urinalysis - protein and blood (acute nephritis or infection), leucocytes (infection), glucose (DM)
USS - obstruction
Describe the management of an AKI
Prevention - stop nephrotoxic drugs, ensure adequate fluids
Fluid rehydration - IV fluid sin pre-renal
Stop nephrotoxic medications - NSAID, ACEi
Relieve obstruction
List some complications of AKI
Hyperkalaemia
Fluid overload, heart failure, pulmonary oedema
Metabolic acidosis
Uraemia - encephalopathy or pericarditis
List some causes of chronic kidney disease
DM HTN Age related DM Polycystic kidney disease Medication - NSAID, lithium and PPIs
List some risk factors of CKD
Old HTN Smoking DM Nephrotoxic meds
Describe the presentation of CKD
Pruitis Asymptomatic HTN Oedema Loss of appetite Nausea Peripheral neuropathy Pallor Muscle cramps
What investigations would you do for CKD
Estimated glomerular filtration rate (eGFR) - 2 tests 3 months apart
Proteinuria - urine albumin:creatinine ratio (ACR), a result >3mg/mmol is significant
Haematuria - urine dipstick
Renal ultrasound - accelerated CKD, FH of polycystic kidney disease or evidence of obstruction
How is CKD scored?
G score - based on eGFR G1 >90 G2 60-89 G3a 45-59 G3b 30-44 G4 15-29 Gr <15
A score - albumin:creatinine ratio
A1 <3
A2 3-30
A3 >30
What is needed for a diagnosis of CKD
eGFR <60 and Proteinuria
List the complications of CKD
Anaemia Renal bone disease Cardiovascular disease Peripheral neuropathy Dialysis related problems
How is CKD treated
Atorvastatin 20mg - primary prevention CVD
Oral sodium bicarbonate - metabolic acidosis
Iron supplementation and erythropoietin - anaemia
ACEi in HTN
Vit D (alfacalcidol and calcitriol), low phosphate diet and bisphosphonates - bone disease
Dialysis and transplant in end stage renal failure
Describe how CKD causes anaemia
Kidney cells normally produce erythropeotin which stimulates production of new RBC
In CKD, reduced EPO meansd reduced RBC
List the features and X-ray changes of CKD renal bone disease
Osteoporosis
Osteosclerosis - both ends of vertebrae are brighter white
Osteomalacia - centre of vertebrae are less white (rugger jersey sign)
Describe how renal bone disease occurs in CKD
High serum phosphate due to reduced excretion, this stimulates hyperparathyroidism as the parathyroid glands sense this and low calcium and secrete parathyroid hormone to increase osteoclast activity leading to more absorption of the calcium from the bone
Active Vitamin D is essential for calcium absorption and metabolism of Vit D is done by the kidneys
Osteomacia - increased turnover of bones without adequate calcium
Osteosclerosis - osteoblasts respond by increasing their activity to match the osteoclasts by creating new tissue in bone
What blood test shows a pre-renal AKI
Increased Ur:Cr ratio
List the eGFR variables in the Modification of diet in renal disease equation
Creatinine
Age
Gender
Ethnicity
List some indications for dialysis
Acidosis Electrolyte disturbance - severe and unresponsive hyperkalaemia Intoxication Oedema Uraemia - seizures and reduced GCS
What are the indications for long term dialysis
End stage renal failure
Any of the acute indications continuing long term
Name the different types of dialysis
Continuous ambulatory peritoneal dialysis
Automated peritoneal dialysis
Haemodialysis
Describe peritoneal dialysis
Peritoneal membrane as the filtration membrane
Dialysis solution containing dextrose is added to the peritoneal cavity
Ultrafiltation occurs across the membrane in to the dialyisis solution, the solution is then taken away
Tenckhoff catheter - plastic tube into peritoneal acity - insert and remove the fluid
Continuous ambulatory - dilayisis solution is in the peritoneum at all times
Automated dialysis - peritoneal dialysis at night, machine continuously replaces fluid in abdomen overnight to optimise ultrafilttayion - takes 8-10hrs
List some complications of peritoneal dialysis
Bacterial peritonitis
Peritoneal sclerosis
Ultrafiltration failure - absorb the dextrose instead
Weight gain
Psychosocial effects
Describe haemodilayisis
Blood filtered by machine 4hrs a day for 3 days a week
Good access - tunnelled cuffed catheter or arteriovenous fistula
Describe tunnelled cuffed catheter
Tube inserted into the subclavian or jugular vein with a tip that sits in the superior vena cava or right atrium
2 lumens - blood exits (red) and blood enters (blue)
Dacron cuff - surrounds catheter - promotes healing and adhesion of tissue to the cuff making ti permanent and providing a barrier to infection
What are the complications of a tunnelled cuffed catheter
Infection
Blood clots
Describe an AV fistula
Artificial connection between an artery and a vein
Bypass the capillary system and allows blood to flow under high pressure from the artery directly into the vein
Permanent easy access blood vessel with high pressure arterial blood flow
Surgical operation and 4week to 4 month maturation period without use
Formed between artery and vein in patients forearm (radio-cephalic, brachiocephalic, brachiobasilic)
What do you look for when examining AV fistula
Skin integrity
Aneurysms
Palpable thrill - fine vibration felt over anastomosis
Machinery murmur on auscultation
List some AV fistula complications
Aneurysms Infection Thrombosis Stenosis STEAL syndrome High output HF
Describe STEAL syndrome
Inadequate blood flow to the limb distal to the AV fistula - steals blood from distal limb - causes distal ischaemia
Describe High output HF in terms of AV fistula
Blood is flowing quickly through the fistula - rapid flow of blood to heart increasing pre-load and leading to hypertrophy and HF
What must you never take blood from
AV fistula
What type of scar is seen in renal transplant?
Hockey stick
How are patient and donor kidneys matched
HLA - A, B and C on chromosome 6
How are kidneys transplanted
Patients own kidneys are left in situ
Donor vessels are connected with external iliac vessels
Donor ureter is anastomosed directly with the patients bladder
Donor kidney is placed anterior in the abdomen and can be palpated in the iliac fossa area
Describe the usual immunosuppressant regime post renal transplant
Tacrolimus
Mycophenolate
Prednisolone
Possibly cyclosporine, sirolimus and azathioprine
List the complications relating to renal transplant
Transplant rejection
Transplant failure
Electrolyte imbalances
List the complications related to the immunosuppressants used in renal transplant
Ischaemic heart disease T2DM Infection Unusual infections - PCP, CMV, PJP, TB Non-Hodgkin lymphoma Skin cancer
What is nephritic syndrome
Group of symptoms suggesting
inflammation of the kidney
What features occur in nephritic syndrome
Haematuria - micro/macroscopic
Oliguria
Proteinuria <3g/24hrs
Fluid retention
What are the features of nephrotic syndrome
Peripheral oedema
Proteinuria >3g/24hr - frothy urine
Serum albumin <25g/L
Hypercholesterolaemia - predisposing to thrombosis, HTN
Sometimes low total thyroxine may be seen
What is nephrotic syndrome
A way of saying there is some kidney disease but not specifying the cause
What is glomerulonephritis
Umbrella term applied to conditions that cause inflammation of or around the glomerulus and nephron
How are most types of glomerulonephritis treated?
Immunosuppression
Blood pressure control by blocking the RAAS - ACEi or ARBs
What is the most common cause of nephrotic syndrome in children
Minimal change disease
What is the most common cause of nephrotic syndrome in adults
Focal segmental glomerulosclerosis
Describe IgA nephropathy (Berger’s disease)
Most common cause of primary glomerulonephritis
Peak age = 20s
Histology shows IgA deposits and glomerular mesangial proliferation
Macroscopic haematuria following URTI
Describe membranous glomerulonephritis
Most common cause of glomerulonephritis overall
Bimodal peak in age - 20s and 60s
Histology shows IgG and complement deposits on the basement membrane
Majority are idiopathic (70%)
Can be secondary to malignancy, RA, drugs (NSAIDs)
Describe post streptococcal glomerulonephritis
Patients <30yo
Present 1-3 weeks after streptococcal infection (tonsillitis, impetigo)
Nephritic syndrome
Full recovery
Describe Goodpasture’s syndrome
Anti-GBM antibodies attack glomerulus and pulmonary basement membranes - anti-GBM antibodies
Glomerulonephritis and pulmonary haemorrhage - AKI and haemoptysis
Describe granulomatosis with polyangiitis (Wegener’s syndrome)
Vasculitis associated with ANCA antibodies
Wheeze, sinusitis and saddle shaped nose
Describe rapidly progressive glomerulonephritis
Often presents secondary to Goodpasture syndrome
Presents with very acute illness with sick patients but responds well to treatment
What might significant renal impairment after starting an ACE i suggest
Bilateral renal artery stenosis
or fibromuscular dysplasia in young female patient
What does rhabdomyolysis cause in the kidneys
Acute tubular necrosis
What picture does acute interstitial nephritis cause
Allergic type - raised urinary WCC, IgE and eosinophils alongside renal impairment
What is the difference between type 1 and type 2 hepatorenal syndrome
Fast onset in Type 1
Slow onset in type 2 `
What antibodies is membranous glomerulonephritis associated with
PLA2R
What can be found in the urine in acute tubular necrosis
Granular, muddy brown urinary casts
Describe diabetic nephropathy
Chronic exposure to high levels of glucose lead to damage and scarring of the glomerulus - glomerulosclerosis
Proteinuria is a key feature - damage allows protein to be filtered from the blood to the urine
Describe the screening for diabetic nephropathy
Albumin:creatinine ratio - early morning specimen
U&Es
Describe the management of diabetic nephropathy
ACEi
Optimise blood sugar levels
What is interstitial nephritis and what are the two types
Inflammation of the interstitium - space between the cells and tubules
Acute interstitial nephritis
Chronic tubulointerstitial nephritis
Describe acute interstitial nephritis and its management
AKI and HTN
- rash
- eosinophilia
- fever
Acute inflammation of the tubules and interstitium - hypersensitivity reaction to - drugs and infection
Reverse the underlying cause and steroids may help
What is chronic tubulointerstitial nephritis
Chronic inflammation of the tubules and interstitium - CKD
Autoimmune, infectious, iatrogenic and granulomatous disease causes
Management - reverse underlying cause and steroids
Describe acute tubular necrosis
Death of the epithelial cells of the renal tubules
Most common cause of AKI
Describe the prognosis of acute tubular necrosis
7-12 days to recover as epithelial cells are able to regenerate
What causes acute tubular necrosisi
Toxins Ischaemia Shock Dehydration Sepsis Radiology contrast dye Gentamicin NSAIDs
What is found in the urine of someone with acute tubular necrosis
Muddy brown casts - pathognomonic
Renal tubular epithelial cells in the urine
How is acute tubular necrosis treated
Supportive management
IV fluid
Stop nephrotoxic medications
Treat complications
Describe type 1 renal tubular acidosis
Pathology in the distal tubule - unable to excrete hydrogen ions
Hyperventilation - compensate for metabolic acidosis Hypokalaemia CKD Bone disease Failure to thrive Urinary pH high
How do you treat type 1 renal tubular acidosis
Oral bicarbonate
Describe type 4 renal tubular acidosis
Reduced aldosterone Most common cause of renal tubualr acidosis Adrenal insufficiency Medications such as ACEi and spirnolactone or systemic conditions - SLE, DM, HIV Hyperkalaemia High chloride Metabolic acidosis Low urinary pH
How is type 4 renal tubular acidosis managed
Fludrocortisone
Sodium bicarbonate and treatment of hyperkalaemia
What is type 2 renal tubular acidosis associated with
Osteomalacia
Hypokalaemia
List the triad of haemolytic uraemic syndrome
Haemolytic anaemia
Low platelets
AKI
What is the usual trigger for HUS
Shiga toxin
What is haemolytic uraemic syndrome
Thrombosis in small blood vessels
Which bacteria produce the shiga toxin
Ecoli 0157
Salmonella
What may increase the risk of HUS
Use of antibiotics and anti-motility medications - loperamide
Describe the presentation of haemolytic uraemic syndrome
Blood diarrhoea with Ecoli gastroenteritis
5 days later HUS symptoms - Reduced urine output Haematuria or dark brown urine Abdo pain Lethargy and irritability Confusion HTN Bruising
How is HUS managed
Supportive care with antihypertensives, blood transfusions and dialysis
What is the prognosis of HUS
70-80% make full recovery
10% mortality
Self limiting
What is seen on blood film in HUS
Fragmented red blood cells
What is rhabdomyolysis
Skeletal muscle tissue breaks down and releases myoglobin, potassium, phosphate and creatine kinase
What can rhabdomyolysis cause
Hyperkalaemia - arrhythmia
Myoglobin - AKI
What are the causes of rhabdomyolysis
Prolonged immobility
Extremely rigorous exercise
Crush injury
Seizures
List the signs and symptoms of rhabdomyolysis
Muscle aches and pains Oedema Fatigue Confusion Red-brown urine
List the investigations for rhabdomyolysis
Creatine kinase - rises for 12hrs and then remians elevated 1-3 days after before gradually falling
Myoglobinuria - red-brown urine and positive blood on dipstick
U&Es - Hyperkalaemia
ECG - hyperkalaemia
Describe the management of rhabdomyolysis
IV fluids
IV sodium bicarbonate to make the urine more alkaline, reduce toxicity of myoglobin
IV mannitol to increased GFR and reduce oedema, treat hypovolaemia prior to this
Treat complications
List some conditions which cause hyperkalaemia
AKI CKD Rhabdomyolysis Adrenal insufficiency Tumour lysis syndrome Blood samples may haemolyse on way to lab giving false hyperkalaemia
Which medications cause hyperkalaemia
Aldosterone antagonists - spironolactone and eplerenone
ACEi/ARB
NSAIDs
K+ supplements
Give the ECG signs of hyperkalaemia
Tall tented T waves
Flattening or abscence of the P waves
Broad QRS complexes
How is hyperkalaemia managed
Insulin (actrapid 10 Units)
Dextrose (50ml of 50% dextrose)
Calcium gluconate - stabiliose the cardiac muscle cells and reduces risk of arrytmia
Other drugs - nebulised salbutamol, IV fluids, oral calcium resonium, sodium bicarbonate, dialysis
How does Insulin and dextrose cause a lowering of potassium
Drives carbohydrates into the cells and takes potassium with it
What is polycycstic kidney disease
Multiple fluid filled cysts
Reduced kidney fuction
What are the two types of polycystic kidney disease
Autosomal dominant (most common) - PKD-1 Chromosome 16
Autosomal recessive - PKD2 chromosome 4
List some extra-renal manifestations of polycystic kidney disease
Cerebral aneurysms
Hepatic, splenic, pancreatic, ovarian and prostatic cysts
Cardiac valve disease - MR
Colonic diverticulum
Aortic valve dilation
Describe the complications of polycystic kidney disease
Chronic loin pain Hypertension CVD Gross haematuria Renal stones End stage renal failure
What drug can be given in polycystic kidney disease to slow the development of cysts and progression of renal failure in autosomal dominant polycystic kidney disease
Tolvaptan - vasopressin receptor antagonist
List some causes of nephritic syndrome
Post-streptococcal glomerulonephritis - weeks after strep infection
IgA nephropathy -days after URTI
Rapidly progressive glomerulonephritis - Wegener’s (haemoptysis, saddle nose and sinusitis), Goodpasture’s (renal and haemoptysis, antiGBM), SLE
List some causes of nephrotic syndrome
Minimal change disease (most common in children)
Focal segmental glomerulosclerosis (most common in adults)
Membranous glomerulonephritis
What is seen on histology in membranous glomerulonephritis
Thickened membrane
Sub epithelial spikes
What is seen on histology in IgA nephropathy
Mesangial proliferation and complement deposition
What is seen on histology in rapidly progressive glomerulonephritis
Cresenteric glomerulonephritis
What is seen on histology in goodpastures
IgG on basement membrane
Describe the presentation of acute interstitial nephritis
High eosinophils - allergic picture
High WCC in urine
Why might renal function worsen following initiation of ACEi or ARBs
Bilateral renal artery stenosis
List the features of nephritic syndrome
Proteinuria <3g/L
Haematuria
Fluid retention
Oliguria
List the features of nephrotic syndrome
Proteinuria >3g/L
Hypoalbuminemia
Peripheral oedema
Hypercholesterolaemia
