Severity in OPQRSTUV refers to how intense the pain is. The letter S stands for Severity, and you’re asking the patient to rate the pain’s intensity, typically on a numeric scale from 0 (no pain) to 10 (worst imaginable pain). This intensity measure is what guides how aggressively to treat and how to monitor response over time. The other parts of OPQRSTUV describe different aspects: onset tells when the pain began, provocation/palliation covers what worsens or relieves it, quality describes the character (sharp, dull, throbbing), region/radiation notes where it is and whether it spreads, time captures duration and pattern, and understanding/impact relates to how the pain affects daily activities or the patient’s comprehension of it.

Visceral pain is pain that arises from internal organs. It is usually deep, crampy, and poorly localized, so it can be difficult to pinpoint exactly where it hurts. This diffuse quality comes from how the nerves from internal organs share pathways with other nerves in the spinal cord, leading the brain to perceive the pain as coming from a broader area or sometimes at a distant site (referred pain). This description fits the option that defines visceral pain. In contrast, pain from the skin is typically sharp and well localized (somatic). Nerve-damage pain is often burning and neuropathic in nature. Pain from bones tends to be dull but is generally somatic and more localized than visceral pain.

Opioid-induced hyperalgesia is a paradoxical increase in pain sensitivity that develops with sustained or high-dose opioid exposure. Instead of the pain relief you’d expect from more opioid, the person experiences amplified pain or newly heightened sensitivity (including allodynia, where normally non-painful stimuli hurt). This is different from tolerance, where more opioid is needed to achieve the same relief; with hyperalgesia, higher opioid doses can worsen the pain. Mechanistically, the pain amplification involves central sensitization in the spinal cord, activation of NMDA receptors, and glial-driven neuroinflammation that enhances nociceptive signaling and disrupts normal pain modulation. Clinically, OIH may present as pain spreading beyond the original injury and escalating despite rising opioid doses, which can be mistaken for tolerance. Managing OIH focuses on reducing the opioid-related contribution to pain and using multimodal strategies. This often means tapering or rotating opioids, avoiding further dose escalation, and adding nonopioid analgesics and adjuvants (such as NSAIDs, acetaminophen, gabapentinoids, antidepressants), regional anesthesia, and nonpharmacologic therapies. NMDA receptor–mediated pathways can be targeted with agents like ketamine; methadone’s NMDA antagonism may help in some cases. Overall, recognizing OIH prevents unnecessary increases in opioid exposure and guides a shift toward strategies that dampen central sensitization while controlling pain.

The main concept is that pain assessment includes a dimension called quality, which describes the sensory character of the pain. This is how the patient communicates what the pain feels like—descriptors such as sharp, dull, burning, throbbing, or electric help differentiate the type of pain and guide treatment. Onset answers when the pain begins, such as sudden or gradual. Timing refers to how the pain occurs over time (constant, intermittent, nocturnal). The option that doesn’t fit is the one that isn’t a standard descriptor of pain’s character. So describing the pain’s quality is the correct way to convey what the pain feels like.