Internal Medicine: Pain, Chest Discomfort, and Abdominal Pain

A comprehensive set of vocabulary flashcards covering the definition, pathophysiology, treatment, and clinical assessment of pain, chest discomfort, and abdominal pain based on lecture notes and Harrison's Principles of Internal Medicine.

Pain

An unpleasant sensory and emotional experience associated with actual or potential tissue damage, often localized to a part of the body.

Acute Pain

Pain described as sudden, sharp, intense, and localized, usually lasting less than 6 months and associated with physiologic changes.

Chronic Pain

Pain not associated with cancer that persists for more than 3 to 6 months, or pain lasting more than 1 month beyond the course of an acute illness or injury.

Dual Property of Pain (Sensation)

The aspect of pain described in terms of penetrating or tissue-destructive processes, such as stabbing, burning, twisting, or squeezing.

Dual Property of Pain (Emotion)

The bodily reaction to pain described as terrifying, nauseating, or sickening.

Primary Sensory Afferent (Primary SA)

Neurons with cell bodies in the dorsal root ganglia that project centrally to the spinal cord and peripherally to innervate tissues.

Type A-Beta ($A\beta$) Fibers

Large-diameter myelinated afferent fibers that respond maximally to light touch or moving stimuli in the nerves innervating the skin.

Type A-Delta ($A\delta$) Fibers

Small-diameter myelinated afferent fibers that, along with C fibers, respond maximally to intense (painful) stimuli.

Type C Fibers

Small-diameter unmyelinated axons that respond to intense stimuli; all sympathetic postganglionic fibers belong to this category.

Placebo Effect

A significant analgesic effect resulting from the suggestion that a treatment will relieve pain.

Nocebo Effect

Increased perceived intensity of pain following the suggestion that pain will worsen after the administration of an inert substance.

Pain Modulation Circuit

Brain circuits linked to the hypothalamus, midbrain, and medulla that selectively control spinal pain transmission through a descending pathway.

Endogenous Opioid Peptides

Substances produced by the body, such as enkephalins and $\beta$-endorphin, found within the pain-modulating circuit.

Peripheral Sensitization

A lowering of the activation threshold for primary afferent nociceptors at the level of the peripheral nerve terminal due to inflammation or injury.

Central Sensitization

Increased excitability of spinal and supraspinal pathways leading to an amplification of pain signals in the CNS.

Hyperalgesia

An exaggerated response to a noxious stimulus, such as the pain felt from a sunburn.

Allodynia

The perception of pain from normally innocuous stimuli, such as light touch on the skin.

Silent Nociception

Nociceptors that cannot be activated by normal mechanical or thermal stimuli but become sensitive in the presence of inflammatory mediators.

Substance P

An 11-amino-acid peptide and potent vasodilator that degranulates mast cells and increases the production of inflammatory mediators.

Glutamate

The major neurotransmitter released by primary afferents that rapidly excites dorsal horn neurons.

Referred Pain Phenomenon

Spatial displacement of pain sensation from the site of injury due to the convergence of sensory inputs to a single spinal pain-transmission neuron.

Spinothalamic Tract

The major ascending pathway for pain, formed by axons that cross to the contralateral side and ascend to the thalamus.

Somatosensory Cortex

The part of the cerebral cortex that mediates purely sensory aspects of pain, such as location, intensity, and quality.

Cingulate Gyrus

A cortical region linked to the affective or unpleasant emotional dimension of pain and suffering.

Complex Regional Pain Syndrome (CRPS)

A constellation of spontaneous pain and signs of sympathetic dysfunction following injury.

CRPS Type I

Also known as reflex sympathetic dystrophy, this occurs without obvious nerve injury.

CRPS Type II

Also known as posttraumatic neuralgia or causalgia, this is associated with an identifiable nerve injury.

PQRST Mnemonic

A diagnostic tool for assessing pain: Provocative/Palliative, Quality, Region/Radiation, Severity, and Timing.

Wong-Baker FACES Scale

A visual rating scale utilized for pediatric patients and those who cannot verbally describe their pain severity.

Neuropathic Pain

Pain caused by a lesion or disease of the somatosensory nervous system, often described as burning, shooting, or electric shock.

Nociceptive Pain

Pain resulting from the activation of nociceptors by noxious stimuli, such as mechanical, thermal, or chemical injury.

Somatic Pain

A type of nociceptive pain that is well-localized and described as sharp or aching, such as from a fracture or arthritis.

Visceral Pain

A type of nociceptive pain that is poorly localized, cramping, and often referred, such as from myocardial infarction.

Nociplastic Pain

Pain arising from altered nociception without clear evidence of tissue or nerve damage, such as in fibromyalgia.

Idiopathic Pain

Pain that exists without an elicited etiology.

WHO Analgesic Ladder: Step 1

Mild pain treatment consisting of non-opioids like acetaminophen or NSAIDs, with or without adjuvants.

WHO Analgesic Ladder: Step 2

Moderate pain treatment consisting of weak opioids like tramadol or codeine, plus non-opioids and adjuvants.

WHO Analgesic Ladder: Step 3

Severe pain treatment using strong opioids like morphine, oxycodone, or fentanyl.

Acetaminophen (Paracetamol)

A first-line medication for mild pain with a ceiling effect and a hepatotoxicity risk at doses exceeding $4\,g/day$.

Non-selective COX Inhibitors

Drugs like Aspirin (ASA) and Ibuprofen that block both COX-1 and COX-2 enzymes.

COX-2 Inhibitors

Selective drugs like Celecoxib that aim to spare COX-1 to reduce gastric irritation but may increase cardiovascular risk.

Naloxone

A narcotic antagonist used to reverse the side effects of opioids, such as respiratory depression.

Gabapentinoids

Adjuvant analgesics like gabapentin and pregabalin which are first-line for neuropathic pain.

Tricyclic Antidepressants (TCAs)

Medications like Nortriptyline used in low doses for chronic pain, particularly effective for diabetic neuropathy.

Stable Angina

Chest discomfort characterized by retrosternal pressure triggered by exertion and relieved by rest or nitroglycerin.

Unstable Angina

Chest pain occurring at rest or with minimal exertion, signifying a high risk of progression to myocardial infarction.

Acute Myocardial Infarction (AMI)

Cardiac pain lasting more than $30\,minutes$, often unrelieved by nitroglycerin and associated with diaphoresis.

STEMI

ST-Segment Elevation Myocardial Infarction, characterized by a completely or partially occlusive coronary thrombus.

Pericarditis

Inflammation of the pericardium causing sharp, positional pain relieved by sitting forward.

Aortic Dissection

A life-threatening condition involving tearing pain radiating to the back, often associated with hypertension.

Pulmonary Embolism (PE)

A cause of pleuritic chest pain associated with dyspnea, tachycardia, and hypoxia.

Primary Spontaneous Pneumothorax

A lung collapse seen in young, lanky people involving sudden unilateral chest pain and absent breath sounds.

Costochondritis

Musculoskeletal chest pain characterized by reproducible tenderness on palpation of the chest wall.

Levine's Sign

A sign of myocardial ischemia where the patient clutches their chest with a clenched fist against the sternum.

Troponin I/T

The preferred cardiac biomarkers for the diagnosis of myocardial infarction.

D-dimer

A laboratory test measured when pulmonary embolism is suspected.

Echocardiography

An imaging tool used to assess wall motion, valvular disease, and the presence of pericardial effusion.

Visceral Abdominal Pain

Pain due to stretching of fibers in hollow or solid organs, typically intermittent, colicky, and poorly localized.

Somatic Abdominal Pain

Pain caused by irritation of the parietal peritoneum, described as steady, aching, and located directly over the inflamed area.

Peritonitis

Inflammation of the peritoneum characterized by a patient lying quietly in bed to avoid pain-inducing motion.

Colic

Abdominal pain resulting from hollow viscera obstruction, causing the patient to thrash about for comfort.

Leukocytosis

An elevated white blood cell count, sometimes exceeding $20,000/\mu L$ in cases of perforated viscus.

Warm-up Angina

A phenomenon where cardiac patients experience relief from angina as they continue or increase their level of exertion.

Biliary Tree Distention

A condition causing steady rather than colicky pain, often radiating to the back or the tip of the right scapula.

Abdominal Aortic Aneurysm Rupture

A vascular disturbance causing sudden, diffuse, and severe abdominal pain.

Diabetic Neuropathy

A common condition in diabetic patients causing damaged primary afferents and chronic neuropathic pain.

Postherpetic Neuralgia

Pain persisting for months after the resolution of a herpes zoster (shingles) infection.

Trigeminal Neuralgia

A neuropathic condition involving the trigeminal nerve that responds well to carbamazepine and gabapentin.

Ketorolac

A non-opioid analgesic available for parenteral (IM/IV) use, with a usual dose of $15-60\,mg$.

Ibuprofen Usual Dose

The standard oral dose is $400\,mg$ every $4-6\,hours$.

Naproxen Characteristics

An NSAID posing the least cardiovascular risk but with a higher incidence of gastrointestinal bleeding.

Fentanyl Patch

A narcotic analgesic administered via a $72\text{-}h$ transdermal patch at doses of $25-100\,\mu g/h$.

Tramadol

A mixed-action opioid/adrenergic agent that does not require an S2 license for prescription in the PH.

Codeine

A narcotic analgesic given at $30-60\,mg$ every $4\,hours$, where nausea is a common side effect.

Meperidine Warning

An agent whose routine use is not recommended due to its toxic metabolite, normeperidine.

Amitriptyline Sedative Potency

A TCA characterized by high sedative potency and the highest anticholinergic potency.

SNRIs

Serotonin-Norepinephrine Reuptake Inhibitors like Duloxetine approved for diabetic neuropathy and fibromyalgia.

Gabapentin Target

Binds to the $\alpha_2\delta$ subunit of voltage-gated calcium channels to reduce neurotransmitter release.

HEART Score

A validated decision-aid tool used for risk stratification of patients with acute chest pain.

Widening of the Mediastinum

A key finding on chest radiography that warns of a possible aortic dissection.

Hampton’s Hump

A radiographic sign on a chest X-ray indicative of pulmonary embolism.

S3 and S4 Heart Sounds

Sounds heard during cardiac auscultation reflecting myocardial systolic or diastolic dysfunction.

Mitral Regurgitation Murmur

A potential complication of STEMI detectable during physical examination.

Pericardial Friction Rub

A scratchy sound heard during auscultation that is diagnostic of pericardial inflammation.

Small Bowel Obstruction Pain

Poorly localized, intermittent periumbilical or supraumbilical pain.

Colonic Obstruction Pain

Pain commonly located in the infraumbilical area that may radiate to the lumbar region.

Right Upper Quadrant (RUQ) Pain Causes

Includes cholecystitis, cholangitis, hepatitis, and Bud-Chiari syndrome.

Epigastric Pain Causes

Includes peptic ulcer disease, gastritis, GERD, pancreatitis, and myocardial infarction.

Left Lower Quadrant (LLQ) Pain Causes

Includes diverticulitis, salpingitis, inguinal hernia, and ectopic pregnancy.

Diffuse Nonlocalized Pain Causes

Includes gastroenteritis, peritonitis, mesenteric ischemia, and metabolic diseases.

Splinting

A protective reaction where the hemithorax movements are limited to reduce referred pain from the thorax.

Metabolic Abdominal Crises

Conditions like diabetic acidosis or porphyria that can simulate various abdominal diseases.

Indomethacin

An NSAID where gastrointestinal side effects are particularly common.

Buprenorphine Transdermal Patch

A narcotic analgesic administered via a 7-day patch at $5-20\,\mu g/h$.

Venlafaxine

An antidepressant with an average dose of $150\,mg/d$ used as an adjuvant for pain.

Oxcarbamazepine

An anticonvulsant with properties similar to carbamazepine, usually dosed at $300\,mg$ bid.

Carbamazepine Side Effects

Potential side effects include rare aplastic anemia, GI irritation, and hepatotoxicity.

Aortic Stenosis

A chronic condition causing angina-like discomfort due to a heart oxygen demand-supply mismatch.

Hepatotoxicity Threshold

The risk of liver damage significantly increases when Acetaminophen intake exceeds $4\,g/day$.

Levorphanol

A narcotic analgesic that is longer acting than morphine sulfate and well absorbed per orem (PO).