Overview of Intrinsic ARF
Acute renal failure that is not caused by prerenal or postrenal factors is categorized as intrinsic acute renal failure. This type involves damage or injury within both kidneys. Intrinsic ARF accounts for approximately 40% of the cases of acute renal failure.
Causes of Intrinsic ARF
The causes can be classified as follows:
- Vascular disease
- Diseases of tubules and interstitium (space between parts of tissue)
- Amyloidosis (deposition of proteins in kidney tissues)
- Interstitial nephritis (associated with allergy or infection)
- Acute tubular necrosis
- Ischema (lack of blood flow to an organ)
Nearly 90% of intrinsic ARF cases are caused by ischemia or toxins, both of which lead to acute tubular necrosis (ATN). Ischemic ARF is associated with reduced blood flow to the kidneys (renal hypoperfusion), which leads to tissue death and irreversible kidney failure. Ischemic ARF occurs most frequently when there is hemorrhage (blood loss), trauma, or sepsis (severe infection), and in patients undergoing major cardiovascular surgery.
Many types of medication can cause nephrotoxic intrinsic ARF, and the effect seems to be dose related. Most cases occur in the elderly and in patients with chronic renal failure (CRF). Toxins taken into the body that can trigger intrinsic ARF include the following:
- Antibiotics (e.g., acyclovir, roscarnet)
- Chemotherapeutic drugs (used to treat cancer, e.g., cisplatin, ifosfamide)
- Radiocontrast dyes (used in imaging procedures)
Some toxins are released by tissues as a result of injury or are created by electrolyte imbalance. Some endogenous toxins that trigger nephrotoxic ARF include the following:
- Rhabdomyolysis (release of myoglobin in the urine resulting from the destruction of muscle tissue) caused by the following:
- Intoxication (e.g., alcohol, cocaine)
- Traumatic crush injury
- Hypercalcemia (high level of calcium in the blood) caused by the following:
- Deposition of calcium in tissue
- Vasoconstriction (reduced diameter of blood vessels)
Both ischemic and nephrotoxic ARF cause acute tubular necrosis (ATN), but ATN is less pronounced in nephrotoxic ARF.
Allergic interstitial nephritis can be triggered by several different types of drugs. The most common are:
- antibiotics (e.g., penicillin, cephalosporins) and
- nonsteroidal anti-inflammatory drugs (e.g., acetaminophen, ibuprofen).