kidney and urinary tract disorders
Acute Kidney Injury
Diagnosis of Acute Kidney Injury
Blood and urine tests Imaging tests A disorder must affect both kidneys to cause kidney failure. The doctor evaluates whether the person has acute kidney injury and, very importantly, its cause. The physical examination findings may help doctors identify the cause of the acute kidney injury. For example, an enlarged bladder may indicate obstruction of the urinary tract causing hydronephrosis. Blood tests that measure levels of creatinine andureanitrogen in the blood are needed to confirm the diagnosis. A progressive daily rise in creatinine indicates acute kidney injury. The level of creatinine is also the best indicator of the degree or severity of kidney function decline. The higher the level, the more severe the decline in kidney function is likely to be. Other blood tests detect metabolic imbalances that occur if the decline in kidney function is severe, such as an increase in blood acidity ( Acidosis , which means low bicarbonate level), a high potassium level ( Urine tests, such as urinalysis and measurement of certain electrolytes (sodium, potassium, calcium, phosphate), may enable doctors to determine whether the cause of kidney injury is insufficient blood flow to the kidneys, damage to the kidneys, or urinary obstruction. Imaging of the kidneys using Ultrasonography or X-rays of the arteries or veins that lead to and from the kidneys ( Angiography ) may be done if obstruction of blood vessels is the suspected cause. However, angiography is done only when other tests do not provide enough information, because angiography uses an intravenous contrast agent that contains iodine, which carries a risk of additional kidney damage. Magnetic resonance angiography (MRA) can provide information similar to that provided by angiography. However, MRA has traditionally used gadolinium, a substance that, in people who have severely reduced kidney function, rarely causes a disorder that triggers production of scar tissue in the body (nephrogenic fibrosing dermopathy). The risk of this condition decreased with the newer gadolinium formulations, so MRA could be a good option after discussion with the health care team. If other tests do not reveal the cause of kidney injury, a Kidney biopsy may be necessary to determine the diagnosis and the prognosis. 