Urethral stricture in the context of "Stenosis"

Acute kidney injury (AKI), previously called acute renal failure (ARF), is a sudden decrease in kidney function that develops within seven days, as shown by an increase in serum creatinine or a decrease in urine output, or both.

Causes of AKI are classified as either prerenal (due to decreased blood flow to the kidney), intrinsic renal (due to damage to the kidney itself), or postrenal (due to blockage of urine flow). Prerenal causes of AKI include sepsis, dehydration, excessive blood loss, cardiogenic shock, heart failure, cirrhosis, and certain medications like ACE inhibitors or NSAIDs. Intrinsic renal causes of AKI include glomerulonephritis, lupus nephritis, acute tubular necrosis, certain antibiotics, and chemotherapeutic agents. Postrenal causes of AKI include kidney stones, bladder cancer, neurogenic bladder, enlargement of the prostate, narrowing of the urethra, and certain medications like anticholinergics.

Urinary retention is an inability to completely empty the bladder. Onset can be sudden or gradual. When of sudden onset, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include loss of bladder control, mild lower abdominal pain, and a weak urine stream. Those with long-term problems are at risk of urinary tract infections.

Causes include blockage of the urethra, nerve problems, certain medications, and weak bladder muscles. Blockage can be caused by benign prostatic hyperplasia (BPH), urethral strictures, bladder stones, a cystocele, constipation, or tumors. Nerve problems can occur from diabetes, trauma, spinal cord problems, stroke, or heavy metal poisoning. Medications that can cause problems include anticholinergics, antihistamines, tricyclic antidepressants, cyclobenzaprine, diazepam, nonsteroidal anti-inflammatory drugs (NSAID), stimulants, and opioids. Diagnosis is typically based on measuring the amount of urine in the bladder after urinating.