Nephrology Flashcards
(113 cards)
Define Autosomal Dominant Polycystic Kidney Disease
An A. dominant renal condition characterised by the growth of numerous cysts on the kidneys
Leads to progressive kidney damage and CKD
Autosomal Dominant Polycystic Kidney Disease features
Renal:
- Cyst rupture = flank pain and haematuria
- Cyst infection = flank pain, haematuria and urinary symptoms
- HTN
- Slowly progressing CKD
Extrarenal:
- Cysts in other organs = liver, pancreas, spleen
- Intracranial berry aneurysms
- Mitral valve prolapse and aortic regurgitation
- Diverticular disease
Autosomal Dominant Polycystic Kidney Disease investigations
US is primary modality:
- Ages 15-39 = at least 2 renal cysts (uni/bilaterally)
- Ages 40-59 = more than 2 renal cysts bilaterally
- Ages > 60 = more than 4 renal cysts bilaterally
CT/MRI can be used to determine extent of disease
Autosomal Dominant Polycystic Kidney Disease management
- Support of CKD
- Manage HTN
- Tolvaptan has been shown to slow the formation of cysts and decline in renal function
Define Acute Tubular Necrosis
Acute injury to the tubular epithelial cells of the kidneys due to ischaemic events or direct toxicity
Most common cause of renal AKI
What are the causes of Acute Tubular Necrosis?
Ischaemic:
- Hypotension
- Shock
- Direct vascular injury = trauma, surgery
Nephrotoxic:
- Aminoglycosides
- Amphotericin
- Chemo (e.g. cisplatin)
- Antivirals (e.g. tenofovir)
- NSAIDs
- Contrast
- Myoglobin - in rhabdomyolysis
- Haemoglobin - in haemolysis
- Uric acid - tumour lysis syndrome
Acute Tubular Necrosis features
- AKI
- Oliguria
- Uraemia
- Electrolyte imbalances
Acute Tubular Necrosis investigation
- U&Es
- Renal USS to rule out post-renal causes
- Identify nephrotoxic drugs
Acute Tubular Necrosis management
- Correct underlying cause
- Remove nephrotoxic drugs
- Supportive care - may require hemofiltration or haemodialysis
Define Acute Interstitial Nephritis
An interstitial hypersensitivity reaction to certain medications which are not directly toxic, or chronic inflammation
This causes an intrinsic kidney injury and a renal AKI
What are the causes of Acute Interstitial Nephritis?
Drugs:
- Beta lactams
- Cephalosporins
- Fluoroquinolones
- NSAIDs
- Diuretics
- Rifampicin
- Allopurinol
- PPIs
Chronic inflammation:
- Sjogrens syndrome
- SLE
Acute Interstitial Nephritis features
- Rash
- Fever
- Eosinophilia (<10% of cases)
- Progressive AKI, esp following initiation of a new drug
Acute Interstitial Nephritis management
- Discontinuation of causative drug - most AKIs resolve after this
- Glucocorticoids if no improvement after stopping drug
Define Acute kidney injury
Decline in renal function that happens over hours to days.
KDIGO criteria, one of:
- Increase in serum creatinine by >= 26.5 w/in 48 hrs
- Increase in serum creatinine by >= 1.5x the baseline w/in the last 7 days
- Urine output < 0.5 ml/kg/h for 6 hours
What are the causes of pre-renal AKIs?
Most common, occur due to decreased renal perfusion;
- Hypovolaemia (dehydration, haemorrhage, GI loss, burns)
- Renovascular disease (renal artery stenosis)
- Medications to reduce blood pressure or renal blood flow (NSAIDs, ACEi, ARBs, diuretics)
- Hypotension due to reduced CO
What are the causes of renal AKIs?
Occur due to structural damage to the kidneys:
- Glomeruli = glomerulonephritis, nephrotic syndrome
- Tubules = ATN, rhabdomyolysis
- Interstitium = Acute interstitial nephritis
- Renal vessels = renal vein thrombosis, vasculitis
What are the causes of post-renal AKIs?
Occur due to obstruction to urinary flow anywhere along the urinary tract:
- Luminal = ureteric stones or blocked catheter
- Intramural = ureteral/ureteric stricture, ureteric carcinomas
- External compression = abdo/pelvic tumour, BPH)
What are the stages of AKI?
Stage 1 - any of:
- Creatinine rise of 26 or more w/in 48 hrs
- Creatinine rise to 1.5-1.99x baseline w/in 7 days
- Urine output < 0.5 mL/kg/hr for > 6 hours
Stage 2 - any of:
- Creatinine rise to 2-2.99x baseline w/in 7 days
- Urine output < 0.5 mL/kg/hr for > 12 hours
Stage 3 - any of:
- Creatine rise to 3x baseline or higher w/in 7 days
- Creatinine rise to 354 or more, with either an acute rise of 26 or more w/in 48 hrs or 50% rise w/in 7 days
- Urine output < 0.3 mL/kg/hr for 24 hours
- Anuria for 12 hrs
AKI features
Asymptomatic and only seen on blood tests
Most symptoms occur due to uraemia:
- N&V
- fatigue
- Confusion
- Anorexia
- Pruritus
- HTN
- Bladder distention
- Signs of underlying cause
AKI investigations
Bedside:
- Urinalysis
- ECG
- Blood gas
Bloods:
- U&Es
- FBC
- LFTs
- Clotting
- Bone profile
- Creatinine kinase
- CRP
- Renal screen
Imaging:
- Bladder scan
- US KUB
- CT KUB
Renal biopsy if cause still unclear
What is done in a renal screen?
- ANA
- DsDNA
- ANCA
- Anti-GBM antibodies
- ESR
- Serum Ig
- Serum electrophoresis
- Serum free light chains
- C3/4 levels
- HIV screen
- Hep B/C serology
AKI management
- Fluid resus
- Medication review, suspend nephrotoxic drugs
- Catheterisation
Renal replacement therapy in the following pts (AEIOU):
- Acidosis (metabolic) = pH < 7.2
- Electrolyte imbalances = resistant hyperkalaemia
- Intoxication = AKI secondary to drugs or poisons
- Oedema = refractory pulmonary oedema
- Uraemia = uraemia encephalopathy or pericarditis
What are the causes of Acute urinary retention?
- Luminal causes = stones, clots, tumours, UTI
- Mural causes = strictures, neuromuscular dysfunction
- Extra-mural causes = abdo/pelvis tumours, retroperitoneal fibrosis
- Neuro = cauda equina, MS
- Obstructive
- Anticholinergics
- Alpha agonists
- Post Op
- Constipation
- Alcohol
Acute urinary retention investigations
- Bladder scan
- Renal US
- DRE
- Urinalysis, urine MC&S
- Post-residual volume
- ## Bloods = FBC, U&Es, CRP