Acute Renal Failure Flashcards
acute renal failure (ARF) - define
clinical syndrome characterised by the sudden onset of haemodynamic, filtration and excretory failure of the kidneys, subsequent accumulation of metabolic (uraemic) toxins and dysregulation of fluid, electrolyte and acid-base balance.
CKD vs ARF
ARF potentially reversible if diagnosed early
renal ultrasound + PE differs (CKD in worse body condition)
chronic weight loss + PU/PD vs toxins
oliguria - define
low output of urine
anuria - define
no output of urine
Clinical presentation – History
often non-specific malaise, lethargy, weakness, anorexia, vomiting, diarrhoea known toxin ingestion altered urine output signs of concurrent disease
Clinical presentation – PE
dehydration oral ulceration/uremic odour hypothermia bradycardia/tachycardia swollen, painful kidneys – or normal signs of concurrent disease
causes of azotemia
High production nitrogenous waste substances (pre-renal)
Low GFR (dehydration/shock)
Reduced renal perfusion (pre-renal)
Intrinsic or functional renal disease (renal)
Urinary obstruction (post-renal)
Reabsorption urine escaped from urinary tract (post-renal)
pre-renal vs renal - SG
pre-renal - >1.035 cat, >1.030 dog
renal - <1.030 dog normally betwen 1.007-25
pre-renal vs renal - urine sodium conc
pre-renal - 20 mmol/l
pre-renal vs renal - urine sediment
pre-renal - unremarkable
renal - infl + casts
pre-renal vs renal - dipstick findings
pre-renal - none
renal - glucosuria (sometimes)
pre-renal vs renal - response to fluids
pre-renal - dramatic
renal - minimal
pre-renal vs renal - hypovolaemia/dehydration
pre-renal - dramatic
renal - minimal
interstitial nephritis - pyelonephritis - causes
ascending infection most common
may be PU/PD, not always azotaemic
may be asymptomatic
consider breaches of UT defences
anatomical-ectopic ureters, perineal urethrostomy
medical-diabetes, renal disease, nephroliths, iatrogenic-catheters, steroid therapy
interstitial nephritis - pyelonephritis - treatment
treat aggressively
culture urine, empiric antibiotic therapy initially
re-culture on treatment, continue for 4-6 weeks
re-culture 1-2 weeks post-treatment
interstitial nephritis - pyelonephritis
infection of renal pelvis + medulla
interstitial nephritis - pyelonephritis - clinical signs
systemic illness, fever, renal pain, nephromegaly
PU/PD if e.coli is infecting organism
clinical signs may be absent
interstitial nephritis - pyelonephritis - diagnosis
presumptive based on cultures from LUT
imaging
interstitial nephritis - leptospirosis
zoonotic
infection by an serovar of leptospira bacteria
interstitial nephritis - leptospirosis - concurrent diseases
hepatic necrosis, icterus, vasculitis, thrombocytopaenia
interstitial nephritis - leptospirosis - diagnosis
showing high antibody titre to a non-vaccinal serovar
interstitial nephritis - leptospirosis - treatment
Penicillin G or amoxycillin (acute tx.)
Doxycycline to clear carrier status
tubular necrosis - toxins - other
hypercalcaemia raisins/grapes (dogs) ethylene glycol plants (especially lilies in cats) myoglobin/haemoglobin, heavy metals, pesticides/herbicides, snake venom
tubular necrosis - toxins - drugs
Antimicrobials Chemotherapeutics NSAIDs ACE-inhibitors IV Contrast agents
tubular necrosis - ischaemia - causes
↓ Intravascular volume, hypotension
Vascular disease (thrombosis, vasculitis)
↓ Effective Intravascular volume
sepsis
Drugs (Cyclosporine, NSAiDs, ACE-inhibitors)
aquired ARF - causes
advanced age fever dehydration cardiac disease pre-existing renal disease anaesthesia/surgery administration of potentially nephrotoxic drugs
treatment
prevent continued toxin exposure/give antidotes for toxins
treat primary underlying disease
correct ECF deficits + dehydration
correct potassium + acid-base balances
incr urine output
control vomiting + nutritional requirements
renal replacement therapy
increasing urine output
Does not equate with GFR
Easier to maintain patient
Diuretics - furosemide, mannitol
Vasoactive agents - dopamine, diltiazem
interstitial nephritis - leptospirosis - clinical signs
fever, muscle pain, vomiting and diarrhea, loss of appetite, lethargy, depression, and blood in the urine.
jaundice - hepatitis - destruction of liver cells by the bacteria.
Blood clotting problems
rare cases, leptospirosis can also cause respiratory distress and acute pulmonary (lung) hemorrhage.
