Pain and Pain Syndromes

1. Pain and Pain Syndromes Dayna Ryan, PT, DPT Winter 2012

2. Neuropathic Pain (excluding headache) • What will the patients tell you? • numbness / tingling / pins / shooting / needles / uncomfortable / burning • Definition of pain • “...unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage…” • Neuropathic pain caused by direct lesions or disease affecting somatosensory pathways • e.g. sensory nerves, nerve roots, thalamus, cortex

3. Central Post-Stroke Pain Syndrome • Overview • First described by Déjerine & Roussy in 1906 as “Thalamic Pain Syndrome” • Characterized by gradual onset of neuropathic pain & sensory disturbances after stroke (~50% within 1 month of stroke) • Vascular lesions in somatosensory pathways in the brain, especially spinothalamic cortical tract • Etiology is central sensitization

4. Signs & Symptoms • Distribution of symptoms • Sensory disturbances • Abnormal sensation • Allodynia: pain evoked by stimuli that is usually not painful (e.g. touch or brush) • Neuropathic pain • A variety of qualities: burning, pricking, aching, lacerating, shooting, squeezing • Spontaneous • Evoked, elicited by mechanical or thermal stimuli • Intense, 3-6 on 10 point scale • Usually a daily pain with varying pain-free intervals lasting a few hours at the most

5. Diagnosis • History of pain • Imaging confirming a CNS lesion (CT, MRI) • Comprehensive somatosensory test • Rule out other causes • Treatment • Antidepressants (amitriptyline) • Anticonvulsants (gabapentin) • TENS is occasionally helpful

6. Migraine • Overview • Varies in intensity, frequency, duration • Commonly unilateral • Associated with anorexia, nausea & vomiting • Some are preceded by neurologic & mood disturbances • Incidence • 6% of men / 18% of women = 1/3 • 1st attack before age 40 in 90% of patients Lesion involves vasculatures of the brain (blood vessels dilation cause headache) Etiology: unknown • Genetic factors • Environmental factors, e.g. stress, pain

7. Phases of Migraine • Prodrome: last hours or days • Aura: last < 1 hour prior to pain • Headache: last 4 to 72 hours • Postdrome: hours or days after pain • Classification of Migraine • Migraine with aura • Migraine without aura Visual aura

8. Signs & Symptoms • Prodrome • Mood disturbances, loss or changes in appetite • Aura • Focal neurological symptoms • #1 visual disturbances; #2 paresthesias • Headache • Episodic, commonly unilateral, build up gradually • Dull, throbbing pain • Nausea, vomiting, fatigue, pallor • Photophobia, sonophobia, blurred vision • Aggravated by physical activities • Postdrome • Fatigue, aching, tender head • Increased urination (i.e. diuresis)

9. Diagnosis • History • Occasionally EEG (focal slowing) • Treatment • Acute • NSAID, narcotics • analgesics (+caffeine) • rest in dark & quiet place • Prophylactic medication • PT • Biofeedback • C-spine manipulation & modalities • Sleep

10. Cluster Headache • Overview • Rare but most painful • Episodic (80% of patients) • Chronic (pain >= 12 months without remission) • Primarily in men age 20 to 50 • Black males • Lesion Site: vasodilation of one external carotid artery • Etiology • Vasodilatation ipsilateral to the pain • ANS dysfunction (activation of trigeminal vascular & parasympathetic systems) • Genetic link

11. Signs & Symptoms • Pain • Sudden, excruciating, mostly unilateral • Orbital & frontotemporal • Boring & non-throbbing • Short duration (15-180 min) • Wake patient up from sleep • Autonomic symptoms • Ipsilateralto the headache • Photophobia • Tearing, nasal congestion • Horner’s syndrome • constricted pupils • droopy eyelid

12. Diagnosis • History • Treatment • Avoid precipitating factors • alcohol • abrupt changes of sleeping patterns • anger, anxiety • altitude > 5000 feet • laying down • Ergotamine (vasoconstrictor) • Biofeedback & exercise

13. Muscle Tension Headache • Overview • Most common type of headache • “bandlike”, “tightness” head pain • Intermittent, recurrent, or chronic • Etiology • Lesion site: Musculoskeletal disorders at C-spines, TMJ, and atlanto-occipital joint • Previous trauma to neck • Abnormal neck & trunk posture • Stress increases muscle tension • More common in women

14. Signs & Symptoms Pain Bilateral forehead, temples, or back of head & neck Radiates to neck & shoulders Non-Pulsating, vasoconstricting, moderate intensity Last <= 7 days Minimum aggravation by physical activity Tender scalp, rigidity/spasm of neck Diagnosis History, rule out other causes, referred pain Treatment NSAID or anagelsics (+ caffeine), TCAs Biofeedback, massage, heat

15. Trigeminal Neuralgia (CN V) • Etiology • Unknown • Herpes zoster, multiple sclerosis, tumors • Demyelination • pain fibers become hyper-excitable in response to mechanical stimulation (e.g. pressure, touch) • Incidence • More common in women • More common in older adults age 50-70 • Spontaneous remission in some cases

16. Signs & Symptoms • Sudden onset • “like a lightning bolt inside my head that lasts for seconds to minutes” • Sharp, shooting pain • Most common in 5th CN V2 (maxillary) & V3 (mandibular) branches • Diagnosis • History • No sensory or motor impairment • Imaging studies to rule out other causes • Treatment • Anticonvulsant (Tegretol) • Neurosurgical procedure (rhizotomy)

17. Post-Herpetic Neuralgia: “shingles” • Etiology • Reactivation of varicella zoster virus (chicken pox) causes inflammation in cranial or dorsal roots ganglia • Demyelination & degeneration of affected nerves secondary to inflammation • Onset & Course • Mostly in older adults age 50 to 70 • Immuno-compromised individuals at risk • 1%-2% (rarely) develops motor paralysis • Prognosis is good unless motor neurons or vision is affected

18. Early Signs & Symptoms • Fever, malaise, GI disturbances • Tingling and pain, followed by rash and blisters along affected dermatomes • Thoracic & trigeminal most commonly affected • Skin lesions last ~ 1 month • Later Signs & Symptoms • Pain • chronic • severe • constant • aching, burning, cutting, stabbing

19. Diagnosis • Clinical presentation • Treatment • Treat symptoms. No cure. • Corticosteroids (for itching), antiviral (Acyclovir) • Analgesics, Lidocaine patches • Controlled-release oxycodone • Implications for PT • Relaxation • Avoid heat & ultrasound • Get vaccinated yourself! • Don’t touch the skin lesions! (Contagious!)

20. Complex Regional Pain Syndrome • Overview • usually affect arm or leg • uncommon, chronic condition • Classification • CRPS1: Type 1 (“Reflex Sympathetic Dystrophy”) • 90% of cases • Occurs after an illness or injury that did not directly damage the nerves • CRPS2: Type 2 • Occurs after a distinct nerve injury • Etiology: secondary to some type of trauma usually • Lesion site: Overactive sympathetic efferent fibers

21. General Signs & Symptoms • Intense burning or aching pain • Swelling (cycles with pain) • Trophic skin changes • Thinning • Shininess • Loss of wrinkling • Stages • Stage 1 • Pain increases with stress • Changes in skin & nails • Stage II • Tremor, dystonia, inability to initiate movements • Joint stiffness, swelling • Stage III • Muscle atrophy • Joint contracture

22. Diagnosis • X-ray, bone scan identifies the bone affected • Thermographic to study skin temperature • Sympathetic ganglion block will abolish pain • Medications • Sympathetic nerve block • Corticosteroids (prednisone) • NSAIDs for pain and inflammation • Antidepressants (amitriptyline) & anticonvulsants (neurotin) • Intrathecal Baclofen to control dystonia • Implanted dorsal column stimulation to reduce pain • PT to increase mobility, TENS, modalities

23. Phantom Limb Pain • Overview • Pain is felt distal to residual limb • Pain varies from mild electrical shock, tingling, to intense shooting, throbbing or burning • Present in 75% of amputee, persistent & chronic in ~ 5% of amputees • Prognosis is poor with pain > 6 months • Etiology • Overactive central pain pathways due to loss of peripheral sensory inputs • Maladapted cerebral cortex remapping

24. Treatment • Anesthesia to brachial plexus fibers • Pain medications • Surgery to remove scar entangling a nerve • Mirror Therapy • Virtual Reality • Biofeedback, relaxation • Heat & massage (PT) • TENS (PT)