Which individual risk factor contributes to impaired glucose regulation?

Choice A rationale

Autonomic dysreflexia is a medical emergency occurring in spinal cord injuries at T6 or above, triggered by noxious stimuli like a full bladder. The resulting massive sympathetic discharge causes severe vasoconstriction and hypertension. The body attempts to compensate via the vagus nerve, causing vasodilation above the level of the injury. This results in a severe, pounding headache due to the rapidly increasing intracranial pressure and dilated cephalic vessels. Blood pressure must be monitored and triggers removed immediately.

Choice B rationale

Hyperkalemia is a serum potassium level > 5.0 mEq/L and is not a specific manifestation of autonomic dysreflexia. The condition is driven by a paroxysmal autonomic nervous system reflex rather than a sudden shift in electrolytes. While spinal cord patients are at risk for various metabolic issues, an acute episode of autonomic dysreflexia is characterized by cardiovascular symptoms like extreme hypertension and bradycardia, not by the specific elevation of potassium ions in the bloodstream.

Choice C rationale

Hypotension is not expected during autonomic dysreflexia; in fact, the condition is defined by sudden and severe hypertension. Patients with high-level spinal cord injuries often have a low baseline systolic blood pressure (90 to 110 mmHg). During an episode, the blood pressure can spike 20 to 40 mmHg above baseline, which is significantly high for these individuals. Hypotension is more likely seen in neurogenic shock, which involves a loss of sympathetic tone shortly after injury.

Choice D rationale

Diarrhea is not a symptom of autonomic dysreflexia. Conversely, gastrointestinal issues such as fecal impaction or constipation are actually common triggers for the condition. The distended bowel acts as the noxious stimulus that sends afferent signals to the spinal cord, initiating the uninhibited sympathetic reflex below the level of the lesion. The manifestations of the reflex itself are primarily vascular and autonomic, including sweating, flushing, and hypertension, rather than changes in bowel motility.

Choice C rationale

A pulmonary embolus is an obstruction in the pulmonary vasculature, typically caused by a blood clot, but it can also be composed of fat, air, or amniotic fluid. This blockage prevents deoxygenated blood from reaching the alveolar-capillary membrane for gas exchange. The most common source is a deep vein thrombosis from the lower extremities that breaks loose and travels to the lungs. This condition causes a ventilation-perfusion mismatch, leading to hypoxemia and potential right heart strain.

Choice A rationale

A pneumothorax is defined by the presence of air in the pleural space, which is the area between the visceral and parietal pleura. This accumulation of air disrupts the negative pressure required for lung expansion, leading to a partial or total collapse of the lung. While it causes sudden respiratory distress similar to an embolism, it is a structural problem involving air outside the lung tissue rather than a vascular blockage within the pulmonary arterial system.

Choice B rationale

Pulmonary hypertension is characterized by abnormally high blood pressure within the pulmonary arteries, often defined as a mean pulmonary artery pressure > 20 mmHg at rest. While a large or chronic pulmonary embolus can lead to pulmonary hypertension by increasing resistance to blood flow, the term describes the hemodynamic state of elevated pressure rather than the actual physical mass or clot that causes an acute blockage. It involves remodeling of the vessel walls over time.

Choice D rationale

Pulmonary edema refers to the accumulation of excess fluid in the alveoli and interstitial spaces of the lungs. It is most commonly caused by left-sided heart failure, where high pulmonary venous pressure forces fluid into the air sacs. This interferes with gas exchange and causes severe dyspnea. Unlike a pulmonary embolus, which is a discrete blockage within a vessel, pulmonary edema is a diffuse fluid distribution issue that impairs the oxygenation capacity of the lung parenchyma.