Patho/Pharm: Exam 3 AKI and CKI (Ch. 28)

what are kidneys for

regulate fluid, balance electrolytes, acid-base balance, excrete metabolic waste products, and produce and secrete hormones

what is acute kidney injury

a broad spectrum of kidney diseases that range from minor changes in renal function to complete renal function

what happens when kidney function is reduced

• sudden loss of kidney function (few hours to few days)

• disruption in fluid, electrolyte, and acid-base balance

• build of nitrogenous waste

• increased BUN

• increased serum creatinine

• decreased glomerular filtration rate

• oliguria

what is the etiology of AKI

• pre-existing conditions: renal impairment, cardiovascular and peripherovascular disease, hypertension, diabetes mellitus, and heart failure

• associated co-morbidities: age and direct damage to kidneys

what is pre-renal AKI

decreased blood flow to the kidneys → reduced filtration

• if it continues, lack of oxygen will damage kidney tissues

• may progress into intra-renal AKI

what clinical manifestations occur in pre-renal AKI

hypovolemia, hypotension, heart failure, renal artery obstruction, fever, vomiting, diarrhea, burns, overuse of diuretics, edema, ascites, drugs (ACE inhbitors, angiotension II blockers, and NSAIDS)

what is instrinsic/intra-renal AKI

caused by direct damage to the kidneys → dysfunction of nephrons and inability to filter blood

• commonly caused by acute tubular necrosis → nephrotoxic insult and ischemic insults; others are autoimmune conditions and severe infections

what is post-renal AKI

a blockage that prevents urine from flowing out of the kidneys → increases pressure in urinary tract

• if relieved early, may see improved function

• if prolonged, permanent damage

what is acute tubular necrosis (ATN)

damage to the tubule in the kidneys that are responsible for filtering waste and reabsorbing fluids

what are the pathophysiological processes involved in ATN

• vascular due to renal blood flow decreased → hypoxia, vasoconstriction

• tubular: inflammation and reperfusion injury

what is the first phase of ATN

prodromal where there is already an initial kidney injury

• normal or declining urine output

• serum BUN and creatinine rise due to inability to excrete

• duration of phase depends on: cause of injury, amount of toxic ingested, and the duration and severity of hypotension

what is the second phase of ATN

oliguric where body retains water and accumulates waste products caused by oliguria and progressive uremia

• as a result of decreased GFR and hypervolemia → S&S of fluid excess, hyperkalemia, uremic syndrome

• dialysis may be needed

what is the third phase of ATN

post-oliguric (diuretic) which marks the beginning of renal recovery where urinate may begin again, but concentration is not fully recovered

• urine volume increases, but tubular function remains impaired and azotemia (high conc. of nitrogenous waste = urea and creatinine) continues → hypokalemia may happen

• fluid volume deficit until kidneys recover

• may last 2 to 10 days, but full recovery takes a year

  • full recovery: creatinine and BUN = normal

  • but degree of renal insufficiency persists

what is chronic kidney disease (CKD)

a progressive and irrevocable loss of functional nephrons → remaining nephrons to compensate (which helps) → over time, workload and pressure causes nephron damage

• progression is often monitor based on increasing severity of disease

• the higher the stage, the worse the GFR and kidney function

what is stage 1 and 2 of CKD

typically asymptomatic patients → difficult to determine length of stage until it is too late → so try to reduce risk factors beforehand

what is stage 3 of CKD

symptoms start to appear and treatment may be needed

what is stage 4 of CKD

when definite diagnosis is determined due to clinical manifestations becoming very apparent → begin planning for dialysis or transplants AND conversation about end-stage renal disease to prepare

what is stage 5 of CKD

when renal replacement therapy is needed due to manifestations of end-stage renal disease → will result in death if not treated