What situation(s) may cause metabolic acidosis? Select all that apply.

Choice A rationale

Hypertension increases the risk for inadequate perfusion by causing structural changes in the blood vessels, such as thickening and loss of elasticity. High pressure damages the endothelial lining, leading to atherosclerosis. This narrowing of the arteries restricts the delivery of oxygenated blood to vital organs and tissues. Over time, chronic hypertension can lead to heart failure, where the pump becomes too weak or stiff to maintain adequate systemic circulation, further compromising overall tissue perfusion.

Choice B rationale

Advanced age is a significant risk factor for inadequate perfusion due to the natural physiological changes in the cardiovascular system. As people age, their arteries tend to become stiffer and less compliant, a process known as arteriosclerosis. Additionally, the heart muscle may become less efficient, and there is often a decrease in capillary density. These changes collectively reduce the body's ability to adjust blood flow in response to metabolic demands, increasing the vulnerability to ischemic events.

Choice C rationale

Tobacco use is a major contributor to poor perfusion because nicotine is a potent vasoconstrictor that immediately reduces blood flow. Furthermore, the chemicals in tobacco smoke cause chronic inflammation and oxidative stress, which accelerate the development of atherosclerotic plaques. Smoking also increases the level of carbon monoxide in the blood, which binds to hemoglobin and reduces the amount of oxygen available for tissue delivery. This combination of vessel narrowing and reduced oxygen capacity severely impairs perfusion.

Choice D rationale

Hyperlipidemia, specifically high levels of low-density lipoprotein cholesterol, leads to the formation of plaques within the arterial walls. This process, atherosclerosis, progressively narrows the lumen of the vessels, reducing the volume of blood that can pass through. If a plaque ruptures, it can cause an acute blockage, leading to a myocardial infarction or stroke. Even without rupture, the chronic narrowing ensures that tissues downstream receive insufficient blood flow, especially during periods of increased physical activity.

Choice E rationale

Diabetes mellitus impairs perfusion through both macrovascular and microvascular complications. Chronic hyperglycemia damages the basement membrane of small blood vessels and promotes systemic inflammation. This leads to peripheral vascular disease and neuropathy. The impaired circulation is often most evident in the extremities, where decreased blood flow and nerve damage increase the risk of ulcers and infection. Diabetes also accelerates atherosclerosis in larger vessels, further compromising the delivery of oxygen and nutrients to the entire body.

Choice A rationale

Euphoria is the intense feeling of pleasure, excitement, or happiness often sought by individuals with substance use disorders. It results from the rapid release of dopamine within the brain reward system, specifically the nucleus accumbens. This neurochemical surge alters the perception of reality, providing an emotional high that reinforces the repetitive behavior of drug ingestion. This process is the primary driver behind the initial development of psychological dependence and continued drug seeking.

Choice B rationale

This description refers to the loss of control, a hallmark of addiction where the prefrontal cortex fails to regulate impulsive behaviors. While euphoria may motivate the initial use, the inability to stop despite prior intentions is a behavioral manifestation of impaired executive function. It highlights the transition from voluntary use to compulsive use. Euphoria is the subjective emotional state, whereas this choice describes the behavioral failure to adhere to self-imposed limits on substance consumption.

Choice C rationale

This statement defines craving, which is a powerful and overwhelming desire for the substance. Cravings are often triggered by environmental cues associated with past use and are linked to the amygdala and hippocampus. While euphoria is the positive reinforcement felt during use, craving is the motivational state that occurs in its absence. Cravings persist even when the individual is aware of the significant negative social, physical, and legal consequences resulting from their addiction.

Choice D rationale

This explains withdrawal, a physiological response occurring when a substance is discontinued after a period of prolonged use. The body adapts to the presence of the drug to maintain homeostasis; once the drug is removed, the system becomes overactive or depressed, leading to physical illness. Withdrawal is often the opposite of euphoria, characterized by dysphoria and physical pain. It is a sign of physical dependence rather than the pleasurable high described as euphoria.