Referred Pain Flashcards
Pain definition
Unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage
Pain pathways
Sensation picked up by peripheral nociceptors and then relayed to the posterior horn of the spinal cord
Travels in the spinothalamic tract to reach the contralateral cortex (through thalamus)
2 types of pain fibers
Adelta (fast)
C (slow)
Sympathetic innervation
- Foregut
- Midgut
- Kidneys
- Hindgut
- Greater splanchnic nerve (T5-9/10)
- Lesser splanchnic nerve T10-11
- Least splanchnic nerve T12
- Splanchnic lumbar nerves, sacral splanchnic nerves L1/2
Do pain fibers travel along parasympathetic or sympathetic fibers to the spinal cord?
Sympathetic fibers
3 functions of sympathetic innervation of the abdomen
Controls arterial blood flow through vasoconstriction
Tonic inhibitory influence on mucosal secretion
Inhibitory on smooth muscle
Referred pain definition
Pain perceived in regions innervated by nerves other than those that innervate the site of noxious stimulation
Projected pain definition
Stimulation of a sensory nerve along its path may induce pain that is projected to the tissue innervated by the stimulated nerve
Somatic pain definition
The activation of peripheral nociceptors without actual damage to the nerves
Hurts where the damage is (bodily pain)
Visceral referred pain vs somatic referred pain
Visceral: from visceral nerve to somatic area (inflammation of gut causes pain of the dermatomes on abdomen)
Somatic: between a somatic nerve and somatic area (irritation of diaphragm causes shoulder pain)
Visceral pain
Stretching, distension, or ischemia of the viscera
Tends to be poorly localized and often ill defined
McBurney’s point
1/3 of the way from the anterior-posterior iliac spine to the umbilicus
On the right
Migration of pain in appendicitis
Initially the pain is felt in the mid-abdomen as visceral pain (from bowel distension, inflammation, ischemia, and transmitted by C fibers)
Migrates to the RLQ and is appreciated as somatic pain (direct irritation of the overlying somatic nociceptive nerves of the parietal peritoneum by inflammation/noxious agents)
Rovsing’s sign
Pain in the right lower quadrant during left sided pressure suggests appendicitis
(Press on left side, say it hurts at McBurney’s point)
Modified Rovsing’s sign
Right lower quadrant pain on quick withdrawal (referred rebound tenderness)
Because you slam the peritoneum onto the inflamed appendix
Push on the left side and then quickly remove hand and it hurts a lot at McBurney’s point
Psoas and obturator signs
Flexion and movement irritate the retroperitoneal parietal peritoneum overlying the psoas and/or obturator muscles and evoke somatic pain sensation
Cutaneous hyperesthesia
Picking up the abdominal skin is normally not painful, but in appendicitis may see localized pain
Guarding
Tensing of the abdominal wall musculature when palpated
Rigidity
Abdominal wall muscles so tense you can tap-dance on the abdomen
Constant guarding
Like when the appendix bursts
Appendix is part of which segment of the gut?
Midgut
Valentino’s syndrome
Perforated ulcer masquerading clinically as appendicitis
Big initial epigastric pain that migrated to the lower quadrant (because acid and food accumulated there)
Biliary colic
Gallstones preventing gallbladder emptying
Upper abdominal visceral pain from stretch receptors in gallbladder wall, that may radiate around or through to the back
Cholecystitis
More localized pain where the gallbladder is
Murphy’s sign
As gallbladder becomes inflamed somatic pain is perceived in the right upper quadrant, with tenderness on deep inspiration
