Acute Kidney Injury
Definition
Sudden Reduction in renal function, leading to the retention of products normally excreted by the kidney
Prerenal
Inadequate delivery of blood to kidney to be filtered
Causes
Intravascular volume depletion: Vomiting, diarrhea, diuretics, cirrhosis, medications
Decreased cardiac output
Renal Arterial disease
Prsentation
Signs of intravasular volume depletion
Benign urine sediment
Oliguria
Renal
Cessation of renal function as a result of disease of the kidney
Acute Tubular Necrosis
Acute interstitial nephritis
Causes
Ischemic
Nephrotoxic
Prolonged prerenal injury
Anitbiotics
Cisplatin
IV contrast dye
NSAIDS
Calcineurin inhibitors
Hemoglobin
Myoglobin
Pathophysiology
Tubular Injury causes epithelial Cells to break down
Tamm-Horsfall mucoprotein is secreted by cells in ascending loop of henle
Formation of casts due to myoglobin and other metabolic products in distal tubules/collecting ducts of nephron
TGF Function
NaCl resoption is impaired so MD sees higher NaCl
Activation of TGF
Afferent arteriolar vasoconstriction
Reduction of GFR, and tubule flow rate
Recovery
More likely to reocver if baseline is normal
Mortality associated with ATN
Presentation
AKI 1-2 weeks following exposure
Fever
Rash
Eosinophiia
Urinalysis showing WBCs, RBCs, WBC casts
Causes
Drugs
Antibiotics
PPI
Nsaids
Phenytoin
Allopurinol
Ranitidine
Infection
EBC
CMV
Legionella
Bucella
Mycoplasma
Glomerularnephritides
Examples
Vasculitis
IgA nephropathy
Presentation
Systemic symptoms
Rapid rise in creatinine
HTN
Urinalysis showing RBC, RBC casts, protein
Post-renal
Causes
Congenital
Posterior urethral valves, meningomyelocele
Tumour
Prostate CA, Bladder CA, Cervical CA
Urologic
Papillary necrosis
Bilateral kidney stones
Bladder stones
Strictures
Neurogenic Bladder
Retroperitoneal fibrosis
Hyperkalemia
Maintenance of excretion is impaired when GFR decreases
Normal Function
Reabsorption in proximal tubule
Secretion in the cortical collecting
K+ is freely filtered across glomerulus
Treatment
Dialysis
Indications
A -Acidosis
E - Electrolyte
I - Intoxication
O - Overload
U - Uremia