HCR 240- Human Systems: Human Pathophysiology at Arizona College of Nursing

Pre-renal dysfunction occurs when there is a reduction in blood flow to the kidneys, leading to decreased glomerular filtration rate (GFR). Conditions like hypovolemia (low blood volume) and heart failure (reduced cardiac output) both limit renal perfusion. This results in inadequate filtration of blood without intrinsic kidney damage. If untreated, prolonged pre-renal hypoperfusion can progress to ischemic injury, causing intra-renal (acute tubular necrosis) damage. Restoring perfusion is crucial to prevent permanent renal impairment.

Steatorrhea refers to the presence of excess fat in the stool, making it bulky, pale, foul-smelling, and difficult to flush. It occurs in conditions like Celiac Disease, where damage to the intestinal villi leads to fat malabsorption. Because dietary fats are not properly digested or absorbed, they are excreted in the stool. This symptom is a hallmark of malabsorption syndromes and helps differentiate them from other gastrointestinal disorders.

Cushing’s triad is a classic sign of increased intracranial pressure and includes three key findings: hypertension (with widened pulse pressure), bradycardia, and irregular or slowed respirations (bradypnea). These signs result from brainstem compression that activates the Cushing reflex to maintain cerebral perfusion. Tachycardia, however, is not part of Cushing’s triad and usually suggests another cause, such as pain, anxiety, or hypovolemia, rather than elevated intracranial pressure.

The cerebellum is responsible for coordination, balance, and fine motor control. Damage to this region after a stroke typically results in ataxia, characterized by unsteady gait, difficulty maintaining posture, and impaired coordination of voluntary movements. Other signs may include dizziness and tremors. In contrast, language difficulties are associated with damage to Broca’s or Wernicke’s areas in the cerebrum, and memory issues are linked to temporal lobe dysfunction, not cerebellar injury.

SIADH (Syndrome of Inappropriate Antidiuretic Hormone Secretion) is most consistent with this presentation. It causes water retention, hyponatremia (sodium level 90), low urine output, and fluid overload. The link to small cell lung cancer, which often secretes ectopic ADH, strongly supports this diagnosis. The patient’s rapid weight gain, high BP, low sodium, and inability to urinate are hallmark features of SIADH, where excess ADH leads to dilutional hyponatremia and fluid retention.

A hemorrhagic stroke occurs when a cerebral blood vessel ruptures, leading to bleeding (hematoma) within the brain tissue. The CT scan confirming a hematoma indicates bleeding, not blockage, which differentiates it from an ischemic event. Common symptoms include sudden paralysis, slurred speech, facial droop, and loss of gag reflex, all caused by increased intracranial pressure and tissue damage from bleeding.

Hepatitis B (HBV) is a viral infection transmitted through contact with infected blood, semen, or other body fluids, as well as through sexual contact and perinatal exposure. Laboratory testing can detect hepatitis B surface antigen (HBsAg) or antibodies to confirm infection. A highly effective vaccine is available for prevention, unlike hepatitis C, for which no vaccine exists. Chronic HBV infection can lead to cirrhosis, liver failure, or hepatocellular carcinoma if untreated.

Pyuria, the presence of white blood cells (pus) in the urine, is a key diagnostic indicator of pyelonephritis. It reflects inflammation and infection of the renal pelvis and kidney tissue. Pyuria typically accompanies bacteriuria and is detected through urinalysis or urine culture. This finding confirms an upper urinary tract infection and helps guide antibiotic therapy. Persistent pyuria suggests ongoing infection or incomplete treatment response.

Acute glomerulonephritis is an inflammatory condition of the glomeruli often following a streptococcal infection. The inflammation leads to fluid retention due to decreased glomerular filtration rate (GFR), resulting in facial and periorbital edema, especially noticeable in the morning. Other classic symptoms include hematuria (tea-colored urine), mild to moderate hypertension, and oliguria. Polyuria and hypotension are not typical findings, while green-tinged urine is unrelated to this condition.