What is the probable condition of a patient showing signs of responding only to painful stimuli and having constricted pupils?

The condition described, where a patient responds only to painful stimuli and has constricted pupils, is indicative of a narcotic overdose. Narcotics, also known as opioids, include substances such as morphine, heroin, and prescription pain medications. One of the hallmark signs of opioid overdose is the presence of "miosis," or constricted pupils. Additionally, altered levels of consciousness are common, with patients often being responsive only to vigorous stimuli.

In contrast, other conditions such as hyperglycemia, cardiac arrest, and alcohol intoxication present with different clinical signs. Hyperglycemia typically leads to symptoms such as excessive thirst, frequent urination, and fatigue rather than altered consciousness and pupil changes. Cardiac arrest would usually present with unresponsiveness and lack of pulse, rather than just responding to painful stimuli. Alcohol intoxication can lead to altered mental status, but it usually does not cause the specific combination of constricted pupils and a response strictly to painful stimuli that are characteristic of narcotic overdose.