Pain Flashcards

Question

What are the 5 desirable effects of analgesia?

Answer 1

Analgesia Euphoria Constipation Sedation Cough suppression

Answer 2

Respiratory depression Constipation (methylnaltrexone) Sedation Nausea & vomiting Tolerance Itching Dependence

Answer 3

Most widely used therapeutic agents Over 50 types available eg. aspirin, ibuprofen, diclofenac, (paracetamol) Anti-inflammatory, anti-pyretic, analgesic All effects related to decreased, prostaglandin synthesis

Answer 4

multiple side effects severe gastric irritation kidney disorders paracetamol overdose

Answer 5

Pain unrelated to peripheral nociception Sometimes called pathological pain – serves no purpose Peripheral nerve damage (eg. Diabetic neuropathy) Peripheral nerve terminal damage or infection (eg. Post-herpetic neuralgia) Spinal damage Thalamic stroke Generally don’t respond to opioids / NSAIDs

Answer 6

Tricyclic antidepressants (eg. imipramine), antiepileptic drugs (eg. gabapentin, pregabalin), tramadol For neuropathic pain – mechanism of action largely unknown Capsaicin cream For neuropathic pain and others (eg. Arthritis) Cannabinoid receptor agonists Multiple sclerosis – under development for non-neuropathic pain Glutamate receptor blockers (MK801) Block afferent transmission and ‘wind-up’-- severe side effects Neurokinin receptor blockers / CGRP receptor blockers Block afferent transmission and ‘wind-up’ - under development Vanilloid receptor blockers / ATP receptor blockers Sodium channel blockers Block detection of noxious signals Under development

Answer 7

No detectable underlying cause Tension-type headache Migraine Cluster headache

Answer 8

Caused by underlying condition Extracranial: e.g. sinusitis, otitis Intracranial: e.g. vasculitis, meningitis, abscess, tumour

Answer 9

Pain comes and goes Feeling of pressure or tightness Not associated with other symptoms Bilateral localization Variable duration, episodic Patient remains active or prefers to rest

Answer 10

Typically patient rests in quiet dark room Episodic severe headaches for 4-72h, Pulsating, throbbing quality 60-70% unliateral location common Moderate or severe intensity Worsened by routine physical activity > 1 episode per month in 75% of ‘migraineurs’ Plus one of the following: Nausea and/or vomiting Photophobia and/or phonophobia (sensitivity to light/sound) May occur with aura (‘classic migraine’) or without aura (‘common migraine’) Migraine is the second leading cause of disability

Answer 11

Abrupt onset Continuous excruciating pain Associated with tearing, congestion, rhinorrhea, pallor, sweating Unilateral localization Duration 0.5-3h, many per day Patient remains active

Answer 12

Lifetime risk of experiencing tension type headache is 70-80% About 50% of adults aged 40 years experience episodic tension-type headache Prevalence is higher in women than men Most patients treated with OTC medicines and do not seek medical attention Episodic – infrequent episodic, frequent episodic, chronic Pathophysiology unclear Theory of increased muscle tension unproven – often posterior neck muscles Episodes of headache are not associated with nausea or vomiting. Photophobia or phonophobia may be present (but not both)

Answer 13

1st - paracetamol, NSAIDs 2nd - Aspirin + paracetamol + caffeine

Answer 14

Continued use of painkillers causes headache – mechanism unknown Worldwide prevalence 1-2% of population affected Headache present > 15 days/month Drugs causing overuse headaches Paracetamol, aspirin and non-steroidal anti-inflammatory drugs on 15 or more days per month Triptans, opioids, ergots or combination analgesic medications on at least 10 days per month

Answer 15

Approximately 10-15% of adult population * Pre-puberty 6% in both males and females * Post-puberty, rises to 18% in menstruating women * Menstrual migraine attacks triggered by falling oestrogen levels * Post-menopause, migraine frequency falls in many women

Answer 16

Focal neurological disturbance preceding or accompanying headache may include Motor features Sensory disturbance, typically visual Occurs regularly in 15% of migraine patients Linked to CSD: Slowly propagating wave of depolarisation – triggered by K+ disturbance? => Decrease in regional cerebral blood flow

Answer 17

Genetic Factors: 50% of migraine sufferers have 1st degree relative Cortical Spreading Depression (CSD) Wave of depolarization followed by a period of suppression across the cerebral cortex. Can spread and lead to altered blood flow Neurotransmitters Serotonin: Involved in blood vessel tone and pain perception. Low levels during. Dopamine: Involved in the initiation of migraines Glutamate: Elevated levels of glutamate found and contribute to neuronal hyperexcitability. Hormonal changes eg estrogen is thought to influence the activity of neurotransmitters and may trigger migraines. Stress: Can increase the release of stress hormones, which in turn can trigger changes in brain activity and vascular tone. Dietary Factors: Certain foods (e.g., chocolate, cheese, caffeine, red wine, and cured meats) contain substances that can either directly influence neurotransmitter activity or trigger changes in blood flow. Irregular sleep patterns flashing lights, weather changes

Answer 18

Vascular theory Implicated intracerebral vasoconstriction, followed by extracerebral vasodilatation, as cause of headache Neuronal theory Cortical spreading depression (CSD) – an advancing wave of neural inhibition progresses slowly over the cortical surface at 2mm/min - leads to ionic balance disturbance and local blood flow reduction Inflammation theory Activation of trigeminal nerve terminals in the meninges and extracranial vessels is primary event in a migraine attack- triggers pain directly Induces inflammatory changes through the release of neuropeptides and other inflammatory mediators from sensory nerve terminals

Answer 19

The triptans are selective serotonin receptor agonists, with high affinity for the 1B and 1D 1B receptors are on smooth muscle cells of blood vessels and cause vasoconstriction 5HT1D receptors lie on trigeminal nerve terminals and their stimulation blocks activity Triptans taken in many different ways

Answer 20

b-blockers antiepileptic drugs antidepressants ca channel block

Answer 21

CGRP antagonists e.g. Gepants are effective, no vasoconstriction BUT risk of liver toxicity Three anti-CGRP mAbs have been approved recently for use in NHS: fremanezumab for prevention of migraine erenumab galcanezumab Glutamate receptor antagonists

Answer 22

Acute subcutaneous sumatriptan - rapid and effective nasal triptan as optional alternative Prophylaxis Verapamil, calcium channel blocker can be considered, off-label use Verapamil reduces cardiac output, slows heart rate…..