Individuals with diabetes, a minor injury to the foot can cause major complications due to:

Choice A reason: The most obvious and common clinical manifestation of kidney stones is severe pain, often described as excruciating and colicky. This pain is typically located in the back or side, just below the ribs, and may radiate to the lower abdomen and groin. The pain occurs as the stone moves through the urinary tract, causing irritation and blockage. This intense pain is often what prompts individuals to seek medical attention and is a hallmark symptom of kidney stones.

Choice B reason: Tachycardia, or an increased heart rate, may occur as a secondary response to the severe pain caused by kidney stones, but it is not the primary clinical manifestation. Tachycardia can be a symptom of many other conditions and is not specific to kidney stones.

Choice C reason: Hypertension, or high blood pressure, is not a direct manifestation of kidney stones. While there may be some association between kidney stone disease and hypertension, the primary symptom of kidney stones is pain, not elevated blood pressure.

Choice D reason: Edema, or swelling, is not a typical clinical manifestation of kidney stones. Edema is more commonly associated with conditions such as heart failure, kidney disease, and certain vascular disorders. Kidney stones primarily cause pain and urinary symptoms rather than generalized swelling.

Choice A reason: Most patients with CNS tumors do not develop metastatic disease. Central nervous system (CNS) tumors, including brain tumors, typically do not metastasize outside the CNS. Instead, they grow and exert pressure on adjacent brain structures, leading to neurological symptoms.

Choice B reason: While brain tumors can be very deadly, the TNM classification system is not avoided due to the lethality of the tumors. The main reason for not using the TNM system is because the classification criteria do not align well with the unique aspects of brain tumors.

Choice C reason: Tumor size is less relevant than the location and histology for brain tumors. The location of the tumor within the brain and its histological characteristics (e.g., type, grade, and molecular features) are more critical for prognosis and treatment planning. Brain tumors can cause significant clinical issues even when small, depending on their location.

Choice D reason: Brain tumors can have a poor prognosis, but this is not the reason the TNM classification is not used. The classification system's limitation is primarily due to the fact that brain tumors' behavior and treatment considerations depend more on their location and histological features than on tumor size, nodal involvement, and metastasis, which are the focus of the TNM system.