Renal medicine Flashcards
ADPKD (Autosomal-Dominant (Adult) Polycystic Kidney Disease)
cause
characterized by cystic dilation of the renal tubular epithelium.
Expanding cysts result in massive bilateral kidney enlargement and destruction of the renal parenchyma beginning at age 20-25 years.
Cysts are found in both the renal cortex and medulla and are filled with fluid that may be clear, turbid or hemorrhagic.
Causes
ADPKD is caused by a mutation in either the PKD1 or PKD2 genes.
ADPKD (Autosomal-Dominant (Adult) Polycystic Kidney Disease)
Clinical features
Clinical Features - Renal
Flank pain.
Renal dysfunction
Hypertension
Haematuria
Microalbuminuria
Clinical Features - Extra-Renal
Extrarenal cysts e.g. liver,pancreas, spleen
Intracranial berry aneurysms commonly at the junction of the anterior communicating artery and anterial cerebral artery
Mitral valve prolapse
Colonic diverticular
Common Causes of Death in Patients with ADPKD
Heart disease
Infection
Subarachnoid haemorrhage due to aneurysm
Intracerebral haemorrhage due to hypertension
most common cause of intrinsic acute kidney injury (AKI).
Acute Tubular Necrosis
Acute Tubular Necrosis
Clinical features
Oliguria
Uraemia
Electrolyte imbalance
Acute interstitial nephritis
Features
Patients with acute interstitial nephritis typically present with delayed (2-40 days) picture of rash, fever, acute kidney injury and eosinophilia after a triggering medication. A subset of patients also report transient arthralgia.
Drug Causes of Acute interstitial nephritis
Antibiotics (e.g. penicillins, sulfa drugs, cephalosporins and quinolones) NSAIDs Diuretics Rifampicin Allopurinol
Classification of AKI
Stage 1: creatinine rise of 1.5x compared to baseline or urine output <0.5 ml/kg/hour for 6 hours.
Stage 2: creatinine rise of 2x compared to baseline or urine output <0.5 ml/kg/hour for 12 hours.
Stage 3: creatinine rise of 3x compared to baseline or urine output <0.3 ml/kg/hour for 24 hours (or anuria for 12
An increased risk of AKI is associated with:
Chronic kidney disease Diabetes with chronic kidney disease Heart failure Renal transplant Age 75 or over Hypovolaemia Contrast administration
Treatment of AKI
A-E approach - make sure patient is stable and doesn’t need any intervention ASAP
The cause should then be identified and treated appropriately:
Pre-renal AKI: give fluids if the patient is hypovolaemic, give intravenous antibiotics if the patient is septic. Stop nephrotoxic drugs.
Renal AKI: A nephrology review is often required to identify less common causes of Acute Kidney Injury
Post-renal AKI: catheterisation and urology review.
The patient should be also monitored carefully with regular observations, fluid status, and measurement of urine output (usually with a catheter) and U&Es.
Indications for Dialysis AKI
Acidosis (severe metabolic acidosis with pH of less than 7.20)
Electrolyte imbalance (persistent hyperkalaemia of more than 7 mM
Intoxication (poisoning)
Oedema (refractory pulmonary oedema)
Uraemia (encephalopathy or pericarditis).
Anti-glomerular basement membrane disease
The pillars of therapy in anti-GBM disease involves:
Removing any circulating antibody
Immunosuppression of the individual with medications so as to stop further production of antibodies
The former is achieved with plasmapheresis which removes the pathogenic circulating antibodies.
Immunosuppression is normally achieved with high dose oral prednisolone or oral cyclophosphamide.
sterile pyuria
Renal tuberculosis Partially treated UTI Drug causes (antibiotics, NSAIDs, PPI, cyclophosphamide) Urinary tract stones Papillary necrosis.
Staging of CKD
Stage 1 CKD if eGFR is >90 ml/min/1.73m2 with demonstrable kidney damage (e.g. haematuria or proteinuria).
Stage 2 CKD if eGFR is 60-89 ml/min/1.73m2 with demonstrable kidney damage (e.g. haematuria, proteinuria, or raised urine albumin/creatinine ratio).
Stage 3 CKD if eGFR is 30-59 ml/min/1.73m2.
Stage 4 CKD if eGFR is 15-30 ml/min/1.73m2.
Stage 5 CKD if eGFR is <15 ml/min/1.73m2.
The complications of chronic kidney disease (CKD) can be understood by considering the key functions of the kidney.
Waste excretion - Uraemia and hyperphosphataemia
Regulation of fluid balance - Hypertension and peripheral/pulmonary oedema.
Acid-base balance - Metabolic acidosis.
Erythropoietin production - Anaemia.
Activation of vitamin D - Hypocalcaemia.
nephritic syndrome
haematuria and non-nephrotic range proteinuria (+/++ on the urine dipstick). Hypertension is also more common.
conditions that can cause a nephritic picture
SHARP AIM
SLE Henoch-Schönlein purpura Anti glomerular basement membrane (GBM) disease (AKA goodpasture's disease) Rapidly Progressive glomerulonephritis (GN) Post-streptococcal GN Alport's synrome IgA nephropathy (AKA Berger's disease) Membranoproliferative GN
Clinical Features of
IgA nephropathy
Clinical Features
Typically patients present with recurrent gross or microscopic haematuria following (12-72h) an upper respiratory tract infection.
Mild proteinuria may also be present. On examination, hypertension may be present. Rare cases may present with rapidly progressive GN where they rapidly progress to acute renal failure.
Slow progression to chronic renal failure occurs in 15 - 40% of patients.
cause of nephrotic syndrome
Minimal Change Glomerulonephritis
Associated with upper respiratory tract infection
Biospy: normal light microscopy, fusion of podocytes on electron microscope
Treat with steroids
1% go on to have end-stage renal failure
cause of nephrotic syndrome
Membranous nephropathy
Associated with cancers (Lung, Colon Breast), infections (SLE, thyroid disease), infections (Hepatitis B) and drugs (Penicillamine and Gold)
Biopsy: subepithelial immune complex deposits
40% have spontaneous remission
cause of nephrotic syndrome
Focal segmental glomerulosclerosis
Focal segmental glomerulosclerosis
More common in Afro-caribbean population
Associated with Berger’s disease, sickle cell, HIV
Biopsy: focal scarring, IgM deposition
Treat with steroids or cylophosphamide/ciclosporin
30-50% progress to end stage renal failure
cause of nephrotic syndrome
Membranoproliferative/Mesangiocapillary
Less common
May present as both nephrotic or nephritic
Associated with Hepatitis B, Hepatitis C and Endocarditis
50% progress to End-Stage Renal Failure
Post-streptococcal glomerulonephritis
Poststreptococcal GN is a type of glomerular nephritis that occurs 1-2 weeks after a streptococcal throat infection or 2-6 weeks after a streptococcal skin infection.
Patients typically present with sudden onset of haematuria, oliguria, hypertension and oedema (normally periorbital, due to salt retention in the loose skin).
This is a typical nephritic syndrome presentation.
Post-streptococcal glomerulonephritis
Investigations
First line investigation in these patients would involve a urinalysis and microscopy, culture and sensitivities (MC&S).
Urinalysis is typically positive for protein or blood or both. Urine MC&S would likely show presence of red blood cells (normally dysmorphic, which suggests bleeding from the glomerulus), white blood cells (neutrophil infiltration is one of the mechanisms of damage in nephritic syndrome) and associated casts.
Blood tests should include Full blood count (FBC) to look for raised white cells, suggestive of an infective process, Urea and Electrolytes (U&Es) which can suggest acute kidney injury.
Immunoglobulins, complement (low C3 levels commonly found) and autoantibodies (such as raised anti-streptolysin titre, raised DNAse B titre) can help delineate an autoimmune process. Blood cultures are also indicated in patients with fever. Imaging is rarely helpful. The gold standard method for diagnosis is renal biopsy.
rapidly progressive glomerulonephritis (RPGN)
Definition
RPGN is a spectrum of conditions associated with severe glomerular injury.
It is characterised by a nephritic picture associated with a rapid and progressive loss of renal function.
Patients are often significantly oliguric. It can be broadly grouped into 3 types.
rapidly progressive glomerulonephritis (RPGN) type 1
Anti-Glomerular Basement Membrane (GBM) antibody disease.
This is characterised by linear deposits of IgG in the basement membrane seen on immunofluorescence.
In a subset of these patients, these anti-GBM antibodies cross react with antigens on the alveolar basement membrane.
This can produce pulmonary haemorrhage associated with renal failure, the typical picture associated with Goodpasture’s syndrome.
rapidly progressive glomerulonephritis (RPGN) type 2
Immune complex deposition disease.
This is a complication of any of the immune complex nephritic diseases.
This includes post-streptococcal GN, Lupus nephritis, IgA nephropathy, Henoch-Schonlein purpura.
Type II RPGN is typically characterised by a granular pattern of staining on immunofluorescence studies, this granular pattern is typical for immune complex deposition.
rapidly progressive glomerulonephritis (RPGN) type 3
Pauci-immune disease
This is typically defined by the lack of anti-GBM antibodies or immune complexes by immunofluorescence and electron microscopy.
Type III RPGN is typically mediated by circulating antineutrophil cytoplasmic antibodies (ANCAs).
Granulomatosis with Polyangiitis
Wegener’s granulomatosis features
The majority of patients with GPA are ANCA positive.
The majority of those patients are positive for cANCA (anti-PR3).
GPA is characterised by the triad of necrotising granulomatous upper airway and lower airway lesions, systemic vasculitis and pauci-immune GN.
Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss) features
The majority of patients with EGPA are ANCA positive.
The majority of these patients are positive for pANCA (anti-MPO).
EGPA is characterised by allergic asthma and eosinophilia.
Complications of peritoneal dialysis
Complications of peritoneal dialysis include peritoneal dialysis peritonitis.
This is typically caused by Staphylococcus epidermidis.
The patient presents with abdominal pain, fever, and a cloudy dialysis bag.
The peritoneal dialysis fluid should be sent for culture.
Management is with intraperitoneal and systemic antibiotics.
Other complications of peritoneal dialysis include catheter malfunction, obesity (due to absorption of glucose from the dialysate fluid),
and hernias.
Complications of Haemodialysis
Cardiovascular disease
Fistula complications: stenosis, aneurysm, infection, steal syndrome, heart failure
Hypotension
Amyloidosis (secondary to build up of B2 microglobulin)
Dialysis disequilibrium syndrome (acute cerebral oedema due to rapid extraction of osmotically active substances)
Contraindications to renal transplant
Active infections
Cancer
Severe co-morbidity
Initial Investigations Prior to Transplant (renal)
Virology status: CMV, HCV, HBV, HIV, VZV, EBV
Tuberculosis testing
ABO and HLA haplotype
Renal artery stenosis
worsening renal function after starting on an ACE inhibitor.
refractory hypertension in the outpatient setting.
flash’ pulmonary oedema with no evidence of cardiac dysfunction
What is the most common cause of idiopathic nephrotic syndrome in adults?
Focal segmental glomerulosclerosis
Renal biopsy shows diffuse proliferative necrotising crescentic glomerulonephritis
Microscopic polyangiitis (MPA). The majority of patients with MPA are ANCA positive. The majority of these patients are positive for pANCA (anti-MPO). MPA is characterised by RPGN, pulmonary infiltrates and often in combination with central nervous system or musculoskeletal system abnormalities.
Should be stopped in AKI as may worsen renal function
- NSAIDs (except if aspirin at cardiac dose e.g. 75mg od)
- Aminoglycosides
- ACE inhibitors
- Angiotensin II receptor antagonists
- Diuretics
May have to be stopped in AKI as increased risk of toxicity (but doesn’t usually worsen AKI itself)
- Metformin
- Lithium
- Digoxin
se of 0.9% Sodium Chloride for fluid therapy in patients requiring large volumes
= risk of hyperchloraemic metabolic acidosis
CKD with raised A;C ratio should be given?
ACEi
enal failure, sensorineural hearing loss and ocular abnormalities develop in a child
Alports
maximum recommended rate of potassium infusion via a peripheral lin
10 mmol/hour,
Membranous glomerulonephritis histology:
basement membrane thickening on light microscopy
subepithelial spikes on sliver stain
positive immunohistochemistry for PLA2
