A client reports seeing flashes of light and a curtain moving across their field of vision.
The nurse suspects retinal detachment.
Which pathophysiologic process is responsible for this condition?
Inflammation of the optic nerve causing vision loss.
Degeneration of the lens leading to impaired light refraction.
Separation of the retina from the underlying choroid.
Increased intraocular pressure compressing the optic nerve.
The Correct Answer is C
Choice A rationale
Optic neuritis involves inflammation of the optic nerve, frequently associated with multiple sclerosis. While it results in vision loss and pain with eye movement, it does not typically manifest as flashes of light or the classic curtain sensation. The pathophysiology is demyelination rather than mechanical separation. Consequently, the clinical presentation differs significantly from the sudden mechanical detachment of the sensory retina from the vascular supply provided by the underlying choroid layer.
Choice B rationale
Cataracts involve the progressive degeneration and clouding of the crystalline lens, which impairs light refraction and causes blurred vision. This is a slow, degenerative process related to protein aggregation within the lens fibers. It does not involve the sudden vitreous traction or retinal tearing associated with flashes of light. Pathophysiologically, lens opacity blocks light transmission to the retina but does not cause the retina itself to physically peel away from its anatomical base.
Choice C rationale
Retinal detachment occurs when the thin layer of light sensitive tissue, the neurosensory retina, physically pulls away from the retinal pigment epithelium and the underlying choroid. The choroid provides essential oxygen and nutrients; without this contact, photoreceptors begin to die. The flashes of light, or photopsia, result from vitreous traction on the retina, while the curtain effect represents the actual physical separation and loss of visual field in the detached area.
Choice D rationale
Increased intraocular pressure is the hallmark of glaucoma, where the compression of the optic nerve leads to progressive peripheral vision loss. Normal intraocular pressure ranges from 10 to 21 mmHg. When pressure exceeds these limits, it causes mechanical and ischemic damage to the nerve fibers. However, this condition does not typically cause the sudden onset of flashes or the sensation of a moving curtain, which are indicative of an acute rhegmatogenous or tractional event.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice B rationale
Anxiety-induced hyperventilation leads to an excessive elimination of carbon dioxide via the lungs, resulting in respiratory alkalosis. The blood gas values show a pH of 7.48, which is above the normal range of 7.35 to 7.45, and a PaCO2 of 30 mmHg, which is below the normal range of 35 to 45 mmHg. The elevated HCO3 of 29 mEq/L, compared to the normal 22 to 26 mEq/L, indicates a partially compensated or mixed alkalotic state.
Choice A rationale
Renal failure typically results in metabolic acidosis because the kidneys are unable to excrete hydrogen ions or reabsorb sufficient bicarbonate. This would present with a pH below 7.35 and a low HCO3 level. In this specific case, the pH is alkaline at 7.48 and the bicarbonate is elevated at 29 mEq/L, which contradicts the expected findings of renal insufficiency. Lab values for chronic kidney disease often reflect high creatinine and urea rather than primary respiratory alkalosis.
Choice C rationale
Severe diarrhea causes a significant loss of bicarbonate from the lower gastrointestinal tract, leading to metabolic acidosis. The expected arterial blood gas results for this condition would include a pH lower than 7.35 and a bicarbonate level lower than 22 mEq/L. Since the client has an alkaline pH and high bicarbonate, diarrhea is an unlikely cause. Metabolic acidosis usually triggers compensatory hyperpnea, but the primary pathology here is alkalosis rather than an acidic state.
Choice D rationale
Opioid overdose causes central nervous system depression, leading to hypoventilation and respiratory acidosis. This condition results in the retention of carbon dioxide, causing the PaCO2 to rise above 45 mmHg and the pH to drop below 7.35. The clients current blood gas profile shows a low PaCO2 and a high pH, which is the exact opposite of what occurs during respiratory depression. Opioids decrease the respiratory rate and depth, leading to hypercapnia rather than hypocapnia.
Correct Answer is C
Explanation
Choice A rationale
Increased bicarbonate excretion would be an appropriate compensation for metabolic alkalosis, not metabolic acidosis. In metabolic acidosis, the body is experiencing a deficit of base or an excess of hydrogen ions. The renal system attempts to compensate by retaining bicarbonate and excreting hydrogen ions to raise the pH. Excreting more bicarbonate would worsen the acidic state by further depleting the body of its primary buffer system, leading to a dangerous drop in pH.
Choice B rationale
A decreased respiratory rate would lead to the retention of carbon dioxide, which combines with water to form carbonic acid. This process increases the concentration of hydrogen ions in the blood, leading to respiratory acidosis. If a client is already in metabolic acidosis, slowing the breathing would be a maladaptive response that causes a combined acid-base disorder. Respiratory compensation for an acidic state must involve increasing the removal of volatile acids to normalize blood pH.
Choice C rationale
In metabolic acidosis, the body compensates by increasing the respiratory rate and depth, often referred to as Kussmaul respirations. This physiological response facilitates the rapid removal of carbon dioxide from the lungs. Since carbon dioxide acts as a volatile acid in the bloodstream, lowering its partial pressure helps to increase the overall pH back toward the normal range of 7.35 to 7.45. This respiratory compensation occurs quickly to offset the primary metabolic imbalance.
Choice D rationale
Oxygen saturation is a measure of the percentage of hemoglobin binding sites occupied by oxygen and is not a direct compensatory mechanism for acid-base imbalances. While severe acidosis can shift the oxyhemoglobin dissociation curve and affect how easily oxygen is released to tissues, a decrease in saturation does not serve to neutralize excess hydrogen ions. Compensation involves specific adjustments in the partial pressure of carbon dioxide or the concentration of bicarbonate to stabilize pH levels.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.