Renal Flashcards
AKI
- criteria
- Sx, conditions, urinalysis and Mx for Pre-renal, renal and post-renal
Criteria needed for diagnosis:
* A rise in serum creatinine of ≥26 µmol/L within 48 hours
* A rise in serum creatinine to ≥1.5 times baseline in the last 7 days
* Urine volume <0.5 mL/kg/hr for >6 hours
PRE-RENAL:
Sx - signs of volume depletion (e.g., hypotension, tachycardia, reduced skin turgor)
Conditions - hypoperfusion, renovasc disease
Urinalysis - hyaline casts
Mx - fluid resus
RENAL:
Sx - oliguria, eosinophiluria, fever, rash, haematuria, flank pain
Conditions - glomerulonephritis,
vasculitis (PAN, TTP),
acute tubular necrosis (ATN),
acute interstitial nephritis (AIN)
Urinalysis - proteinuria, haematuria and RBC casts
Mx - corticosteroids, IV fluids, and cessation of offending drugs (such as gentamicin)
POST-RENAL:
Sx - signs of renal obstruction (distended bladder, incomplete voiding)
Conditions - outflow obstruction (tumours, clots, strictures)
Urinalysis - if kidney stones, haematuria
Mx - remove blockage
Indications for dialysis
Dialysis indications (“AEIOU”):
* Acidosis
* Electrolyte abnormalities (hyperkalaemia)
* Intoxication (e.g., ethylene glycol, lithium)
* Overload (volume)
* Uraemia (pericarditis, encephalopathy, platelet dysfunction)*
Drugs in AKI:
Safe
Worsen renal fucntion
Increased risk of toxicity (but do not worsen AKI)
**Safe: **
* paracetamol
* warfarin
* statins
* aspirin (cardioprotective 75mg)
* clopidogrel
* BBs
should be stopped:*
* NSAIDs
* Aminoglycosides
* ACEi
* ARBs
* Diuretics **
**May be stopped: **
* metformin
* digoxin
* lithium
Nephrotic syndrome
- features
- causes
- risk of thrombosis
- Mx
Clinical features:
* Massive proteinuria (>3.5 g/24 hr)
* Hypoalbuminaemia (<30 g/L)
* Oedema
* Hyperlipidaemia (accelerated atherosclerosis)
Common causes of nephrotic syndrome:
* Minimal change disease (most common in children, associated with recent infections)
* Focal segmental glomerulosclerosis (most common in Afro-Caribbean adults, presents with hypertension)
* Membranous nephropathy (associated with malignancies, autoimmune diseases, hepatitis B/C)
* Diabetic nephropathy (complication of diabetes)
* Lupus nephritis (with haematuria and proteinura)
* Amyloidosis (associated with multiple myeloma or chronic inflammatory disease)
Thrombosis risk is increased due to the loss of antithrombin III, protein C, and protein S in urine.
Treatment approach includes treatment of underlying disease and symptoms:
* Lifestyle—Fluid restriction
* Medical—Steroids and immunosuppressant, diuretic, ACEI, statin, antibiotic (infection risk), hypercoagulability treatment.
**Renal artery stenosis **
- causes
- Sx
- examinations
- investigations
- Mx
Most common causes:
* Atherosclerotic disease (90% of cases)
* Fibromuscular dysplasia (10% of cases) is angiopathy of medium-sized vessels resulting in areas of stenosis and aneurysm (in carotid, vertebral, and renal arteries)
* Takayasu’s arteritis in Southeast Asia/East Asia
Common presenting symptoms:
* >55 years old
* Accelerated or difficult-to-control secondary hypertension due to RAAS activation
* Decrease in renal function with ACEI or ARBs
* Flash pulmonary oedema in absence of decreased cardiac output
Examination findings: Abdominal bruit heard over the epigastrium or flank
Initial investigation:
* Duplex ultrasound should be ordered to assess the velocity and severity of stenosis (>50% reduction in vessel diameter)
* Ultrasound, however, cannot confirm diagnosis.
* Angiography is the GOLD STANDARD
Most appropriate management:
* Optimising vascular risk factors (smoking cessation, diabetes control, statins, and adequate antihypertensive therapy)
* Avoid nephrotoxic agents (e.g., ACEI, ARBs, NSAIDs)
* Angioplasty (stenting) for flash pulmonary oedema or hypertension refractory to medical management
ADPKD
- investigation
- Mx
investigation:
* Renal ultrasound to detectrenal cysts
* However, it is usually limited to detected cysts ≥10 mm
* screening relatives
* FBC may show raised Hb due to excess erythropoietin.
Management:
* Lifestyle—Renoprotective measures (e.g., diet, exercise, cessation of smoking)
* Medical—Tolvaptan (slows cyst growth and delays ESRF), ACEI/ARB, antibiotics (UTI and infected cysts)
Management of end-stage/severe ADPKD:
* Dialysis
* Kidney transplant
Acute interstitial nephritis
- Sx
- Drug causes
- Investigations
- Investigation for definitive diagnosis
- Mx
Sx:
fever, rash, arthralgia
eosinophilia
mild renal impairment
hypertension
Drug causes:
* Antibiotics, especially beta-lactams
* Diuretics
* NSAIDs
* PPIs, H2 antagonists (cimetidine and ranitidine)
* Allopurinol
* Phenytoin
Investigations:
*U&E may show AKI with elevated serum creatinine.
* FBC: Raised eosinophils
* Urinalysis: Sterile pyuria (absence of RBCs excludes acute glomerulonephritis), heavy proteinuria with nephrotic syndrome
* Kidney ultrasound may show large swollen kidneys, to exclude hydronephrosis from post-renal cause.
Investigation to confirm diagnosis: A biopsy of the kidney is needed to provide information on the severity of disease, clues to possible aetiology, and prognosis.
Mx:
* Lifestyle—Discontinue the triggering medication and provide supportive care.
* Medical—Corticosteroids may be associated with greater recovery of kidney function.
Anti-GBM disease (Goodpastures)
- Sx
- Investigations
- Management
**Symptoms: **
* pulmonary haemorrhage
* glomerulonephritis (proteinuria + haematuria)
**Investigations: **
* renal biopsy shows IgG deposits
* raised transfer factor secondary to pul haemorrhage
**Management: **
* plasma exchange
* steroids
* cyclophosphamide
Focal segmental glomerulosclerosis (FSGS)
- causes
- symptoms
- investigation
- management
Causes: idiopathic,HIV, heroin, Alports, sickle-cell
Sx:
- oedema
- ascites
- proteinuria
Investigation:
- renal biopsy shoes effacement of foot processes
Mx:
- steroids +/- immunosurpressants
What is the fluid maintenance in children?
AKI vs CKD
Most patients with CKD have bilaterally small kidneys
Hypocalcaemia is also suggestive of CKD over AKI
Chronic kidney disease
- stages
Maintenance fluids:
- water
- potassium, sodium & chloride
- glucose
- water: 25-30ml/kg/day
- K+: 1mmol/kg/day
- glucose: 50-100g/day
Alports syndrome:
* Sx
* Diagnosis
Results in an abnormal GBM mutation (X-linked dominant)
Sx:
* microscopic haematuria
* progressive renal failure
* bilateral sensorineural deafness
* lenticonus: protrusion of the lens surface into the anterior chamber
* retinitis pigmentosa
* renal biopsy: splitting of lamina densa seen on electron microscopy
Diagnosis:
* renal biopsy - basket weave
Renal transplant: causes of reaction
- hyperacute (minutes to hours)
- acute graft failure (<6 months)
- chronic (>6 months)
- hyperacute: pre-existing antibodies against ABO or HLA antigents
- acute: mismatched HLA. cytotoxic T cells.
- chronic: antibody and cell mediated mechanisms cause fibrosis to the transplanted kidney
