National Physical Therapy Examination (NPTE) Practice Exam

What does dark purplish-blue discoloration of the skin indicate in a patient with peripheral vascular disease?

1. Reflex vasoconstriction due to cold response

2. Pathology involving the liver

3. Tissue hypoxia or hematologic pathology

4. Normal response to pressure on the skin

The correct answer is: Tissue hypoxia or hematologic pathology

Dark purplish-blue discoloration of the skin in a patient with peripheral vascular disease indicates tissue hypoxia or a hematologic pathology. In conditions like peripheral vascular disease, blood flow to the extremities is compromised due to narrowed or blocked arteries. This insufficient blood supply leads to a lack of oxygen reaching the tissues, resulting in hypoxia, which can manifest as discoloration of the skin. Additionally, hematologic issues that affect the blood's ability to transport oxygen, such as anemia or sickle cell disease, can also contribute to similar discoloration due to the inadequate delivery of oxygenated hemoglobin to the tissues. The presence of this distinctive color change serves as a clinical sign that reflects the underlying pathology related to blood flow and oxygen delivery. In contrast, reflex vasoconstriction in response to cold would typically cause pallor or initial vasoconstrictive responses rather than dark purplish-blue discoloration. Pathologies involving the liver may present with other symptoms such as jaundice or ascites, not specific discoloration related to peripheral vascular disease. Lastly, a normal response to pressure on the skin would not typically produce a dark purplish-blue coloration; it would usually resolve quickly once the pressure is relieved. Therefore, the most accurate interpretation