Renal Flashcards
When can an official diagnosis of an AKI be made ?
- Rise in serum creatinine of 26 micromol/litre or greater within 48 hours
- 50% or greater rise in serum creatinine known or presumed to have occurred within the past 7 days
- Fall in urine output to less than 0.5 ml/kg/hour for more than 6 hours in adults and more than
What are the pre renal causes of an AKI ?
- Hypovolaemia secondary to D&V
- HF
- Renal artery stenosis
What are the intrinsic causes of AKI ?
- Glomerulonephritis
- Acute tubular necrosis (ATN)
- Acute interstitial nephritis (AIN)
- Rhabdomyolysis
- Tumour lysis syndrome
- HUS
What are the postrenal causes of AKI?
- Kidney stone in ureter or bladder
- BPH
- External compression of the ureter
what are the signs of an AKI?
- Reduced urine output
- Pulmonary and peripheral oedema
- Rise in K+ = arrhythmias
- Rise in urea / creatinine
- Features of uraemia (pericarditis / encephalopathy)
RF for an AKI
- CKD
- Other organ failure/chronic disease e.g. heart failure, liver disease, diabetes mellitus
- History of AKI
- Use of drugs with nephrotoxic potential (e.g. NSAIDs, aminoglycosides, ACEI/ARBs within the past week
- Use of iodinated contrast agents within the past week
- AGge >=65 years
What is acute tubular necrosis and what can it be caused by ?
- Most common cause of AKI
- Necrosis of renal tubular epithelial cells
- Caused by : ischaemia due to hypoperfusion or nephrotoxins
What will be seen on urinalysis in acute tubular necrosis ?
Muddy brown casts
What can cause acute interstitial nephritis ?
- Drugs : acute interstitial nephritis accounts for 25% of drug-induced AKI
- Systemic disease : SLE, sarcoidosis and Sjogrens
- Infection : Hanta virus, staphylococci
What drugs can cause acute interstitial nephritis
- Penicillin
- Rifampicin
- NSAIDs
- Allopurinol
- Furosemide
what will be seen on urinalysis in acute interstitial nephritis
- Sterile pyuria
- White cell casts
4 features of acute interstitial nephritis
- Fever, rash, arthralgia
- Eosinophilia
- Mild renal impairment
- HTN
what medications should be stopped in an AKI
- NSAIDs (except if aspirin at cardiac dose e.g. 75mg od)
- Aminoglycosides
- ACE inhibitors
- Angiotensin II receptor antagonists
- Diuretics
what is involved in the management of AKI
- Careful fluid balance
- Stop any nephrotoxic medications
- Correction of hyperkalaemia if present
Give 5 causes of CKD
- Diabetes
- HTN
- Polycystic kidney disease
- Chronic glomerulonephritis
- Chronic pyelonephritis
what investigations are used to assess CKD
- eGFR
- Proteinuria quantified with urine albumin:creatinine ratio
- Haematuria
- Renal USS
How does nephrotic syndrome present ?
- Oedema
- Possible frothy urine due to the high protein content
How is CKD classified based on eGFR ?
- 1 : Greater than 90 ml/min, with some sign of kidney damage on other tests
- 2 : 60-90 ml/min with some sign of kidney damage
- 3a : 45-59 ml/min, a moderate reduction in kidney function.
- 3b : 30-44 ml/min, a moderate reduction in kidney function
- 4 : 15-29 ml/min, a severe reduction in kidney function
- 5 : Less than 15 ml/min, established kidney failure - dialysis or a kidney transplant may be needed
How is CKD classified based on albumin:creatinine ration ?
- A1 : <3mg/mmol
- A2 : 3-30 mg/mol
- A3 : >30mg/mol
what are the group of features seen in nephritic syndrome
-> Haematuria (blood in the urine), which can be microscopic (not visible) or macroscopic (visible)
-> Oliguria (significantly reduced urine output)
-> Proteinuria (protein in the urine), but less than 3g per 24 hours (higher protein suggests nephrotic syndrome)
-> Fluid retention
what is nephritis ?
Inflammation in the kidney
Primary causes of nephrotic syndrome
- Minimal change disease
- Focal segmental glomerulosclerosis (FSGS),
- Membranous nephropathy.
Most common type of inherited kidney disease
- AD
- PKD1 gene on chromosome 16 (85% of cases)
- PKD2 gene on chromosome 4 (15% of cases)
What is nephrotic syndrome ?
- The basement membrane of the glomerulus becomes highly permeable resulting in significant proteinuria
what are the group of features seen in nephrotic syndrome ?
- Proteinuria (more than 3g per 24 hours)
- Low serum albumin (less than 25g per litre)
- Peripheral oedema
- Hypercholesterolaemia
what is the eGFR based on ?
- Serum creatinine
- Age
- Gender
- Ethnicity
4 extra-renal manifestations of ADPKD
- Cerebral aneurysms
- Hepatic, splenic, pancreatic, ovarian and prostatic cysts
- Mitral regurgitation
- Colonic diverticula
6 complications of ADPKD
- Chronic loin/flank pain
- Hypertension
- Gross haematuria can occur with cyst rupture (usually resolves within a few days)
- Recurrent urinary tract infections
- Renal stones
- End-stage renal failure occurs at a mean age of 50 years
Presentation of ARKPD
- Picked up on antenatal scans with oligohydramnios
- Leads to pulmonary hypoplasia and resp failure shortly after birth
- Dysmorphic features (underdeveloped ear cartilage, low set eats, flat nasal bridge)
Chromosome involved in ARPKD
mutation in the polycystic kidney and hepatic disease 1 (PKHD1) gene on chromosome 6
what can be given to slow the development of cysts and progression of renal failure in ADPKD
Tolvaptan (vasopressin receptor antagonist)
Causes of hyperkalaemia
D : Drugs (ACEI, ARB, NSAID, aldosterone antagonist)
R : Renal failure
E : Endocrine (Addison’s)
A : Artefact
D : DKA / DI
what 5 conditions can cause hyperkalaemia
Acute kidney injury
Chronic kidney disease (stage 4 or 5)
Rhabdomyolysis
Adrenal insufficiency
Tumour lysis syndrome
what ECG changes are seen in hyperkalaemia
Tall peaked T-waves
Flattening or absence of P waves
Prolonged PR interval
Broad QRS complexes
when do people require urgent treatment for hyperkalaemia
ECG changes
Serum potassium above 6.5 mmol/L
what is the treatment for hyperkalaemia
- Insulin and dextrose infusion and IV calcium gluconate
what is rhabdomyolysis and 5 possible causes
-> Skeletal muscle breakdown
- Prolonged immobility
- Extreme rigorous exercise
- Crush injuries
- Seizures
- Statins
What chemicals are released from muscle in rhabdomyolysis and why is this dangerous
Myoglobin = AKI
Potassium = arrythmias / arrest
Phosphate
Creatine kinase
7 signs and symptoms of rhabdomyolysis
Muscle pain
Muscle weakness
Muscle swelling
Reduced urine output (oliguria)
Red-brown urine (myoglobinuria)
Fatigue
Nausea and vomiting
Confusion (particularly in frail patients)
Diagnostic blood test for rhabdomyolysis
-> Creatinine kinase (CK) : remains elevated for 1-3 days
what will a urine dipstick show in rhabdomyolysis
- Positive for blood due to presence of myoglobin (red-brown colour to urine)
Mainstay of treatment for rhabdomyolysis
- IV fluids to correct hypovolaemia and filter breakdown products
what is HUS and the usual trigger ?
- Thrombosis in small blood vessels
- Triggered y shiga toxins for E.coli O157 or Shigella
Who does HUS usually affect and what increases the risk of it ?
- Children following an episode of gastroenteritis
- Abx and anti-motility medication (e.g. loiperamide)
what triad is seen in HUS ?
- AKI
- Thromboytopenia (formation of blood clots)
- Microangiopathic haemolytic anaemia
what is the presentation of HUS ?
- Diarrhoea from gastroenteritis, turns blood in 3 days
- After a week, Sx of HUS develop :
Fever
Abdominal pain
Lethargy
Pallor
Reduced urine output (oliguria)
Haematuria
Hypertension
Bruising
Jaundice (due to haemolysis)
Confusion
How is HUS managed
-> Medical emergency = admit and treat :
Hypovolaemia (e.g., IV fluids)
Hypertension
Severe anaemia (e.g., blood transfusions)
Severe renal failure (e.g., haemodialysis)
Correction of hypokalaemia due to diarrhoea
IV sodium chloride with IV potassium chloride at 10mmol/hour
Secondary causes of nephrotic syndrome
- DM
- SLE
- Amyloidosis
- Infections (HIV, hepatitis B and C), - Drugs (NSAIDs, gold therapy).
Common presentation of amyloidosis
- 50-65 yr old
- Worsening SOB and weakness
- Loss of renal function & proteinuria
- Massive hepatosplenomegaly
Results in keeping with a diagnosis of acute tubular necrosis
- Raised urinary sodium
What urea to creatinine ratio would suggest a pre renal cause of an AKI
Urea rise»_space;» Creatinine rise
- Urea : creatinine ratio of >100
- In pre renal causes, blood flow to kidney is reduce and so kidneys reabsorb more water and solutes including urea
New onset chest pain on a background of CKD with raised urea
Pericarditis caused by uraemia