Renal and Urology Flashcards
intrinsic causes of AKI
- glomerulonephritis
- acute tubular necrosis (ATN)
- acute interstitial nephritis (AIN), respectively
- rhabdomyolysis
- tumour lysis syndrome
what is the criteria for AKI
- any of the following;
- a rise in serum creatinine of 26 micromol/litre or greater within 48 hours
- a 50% or greater rise in serum creatinine over past 7 days
- a fall in urine output to less than 0.5 ml/kg/hour for more than 6 hours in adults
- 25% fall in eGFR in children / young adults in 7 days.
5 types of drug that should be stopped in aki as they may worsen renal function
- NSAIDs (except if aspirin at cardiac dose e.g. 75mg od)
- Aminoglycosides
- ACE inhibitors
- Angiotensin II receptor antagonists
- Diuretics
three drugs that should be stopped in aki since there is increased risk of toxicity (but won’t worsen the aki itself)
- Metformin
- Lithium
- Digoxin
what are the causes of acute interstitial nephritis
- drugs are by far the most common cause - particularly antibiotics
- penicillin
- rifampicin
- NSAIDs
- allopurinol
- furosemide
- infection
- staphylococci
- Hanta virus
- systemic illness
- sjorgen’s
- sarcoid
- SLE
What is the histology finding in acute interstitial nephritis
marked interstitial oedema and interstitial infiltrate in the connective tissue between renal tubules
what are the clinical features of acute interstitial nephritis
- fever, rash, arthralgia
- eosinophilia
- mild renal impairment
- hypertension
investigation results in acute interstitial nephritis
- sterile pyuria
- white cell casts
how do you differentiate between AKI and CKD
- ultrasound
- most CKD will have bilateral small kidneys apart from
- autosomal dominant polycystic kidney
- amyloid
- early diabetic
- most CKD will have bilateral small kidneys apart from
- hypocalcaemia
- in CKD they are likely to have hypocalcaemia due to lack of vitamin D
what is the most common cause of AKI seen in clinical practice?
acute tubular necrosis
what is the cause of acute tubular necrosis
- there are two main causes
- ischaemia
- shock
- nephrotoxins
- aminoglycosides
- myoglobin secondary to rhabdomyolysis
- radiocontrast agents
- lead
- ischaemia
histopathological features of acute tubular necrosis
- tubular epithelium necrosis: loss of nuclei and detachment of tubular cells from the basement membrane
- dilatation of the tubules may occur
- necrotic cells obstruct the tubule lumen
histopathological features of acute tubular necrosis
- tubular epithelium necrosis: loss of nuclei and detachment of tubular cells from the basement membrane
- dilatation of the tubules may occur
- necrotic cells obstruct the tubule lumen
what are the phases of acute tubular necrosis?
- oliguric phase
- polyuric phase
- recovery phase
what do you find in the urine in acute tubular necrosis
brown granular casts
what are the different stages of AKI
How do you calculate the anion gap?
(sodium + potassium) - (bicarbonate + chloride)
what causes tumour lysis syndrome?
It can occur in the absence of chemotherapy but is usually triggered by the introduction of combination chemotherapy. On occasion, it can occur with steroid treatment alone.
what should be suspected in any patient presenting with an acute kidney injury in the presence of a high phosphate and high uric acid level.
tumour lysis syndrome
how should you protect against TLS
Patients at high risk of TLS should be given IV allopurinol or IV rasburicase immediately prior to and during the first days of chemotherapy.
They should not be given in combination
how do you diagnose tumour lysis syndrome
- Laboratory tumor lysis syndrome: abnormality in two or more of the following, occurring within three days before or seven days after chemotherapy.
- uric acid 25% increase
- potassium25% increase
- phosphate 25% increase
- calcium 25% decrease
- clinical tumour lysis syndrome: you need laboratory TLS and one of the following
- seizure
- arrhythmia
- sudden death
- creatinine 1.5x upper limit of normal
what is the more common type of autosomal dominant polycystic kidney disease, which chromosomes are the mutations on and which presents earlier?
what is the method of screening for relatives of patients with ADPKD and what are the criteria
Ultrasound diagnostic criteria (in patients with positive family history)
- two cysts, unilateral or bilateral, if aged < 30 years
- two cysts in both kidneys if aged 30-59 years
- four cysts in both kidneys if aged > 60 years
what ethnicities are most likely to get BPH
black > white > Asian