Approach to Muscle Pain and Weakness Flashcards
Myalgia
Myopathy
Myositis
Muscle pain
Muscle fiber disorder with weakness
Muscle inflammation with pain and wekaness
Pathogenesis of muscle pain
True muscle pain is from visceral innervation so is a diffuse, dull ,aching or bruning pain
Sensitization can be result of changes to nervous system
Hyperalgesia or allodynia
Muscle pain may be from adjhacent structures
Muscular biochem changes
Pain from alt of muscle structure or function due to release of protons or ATP
Damage results in release of these which are detected by nociceptors
Prolonged exercise has production of lactate…does not directly cause pain but does potentiate H ions
Myalgia without weakness
Viral infection (flu, cox, EBV, HIV)
Systemic bac/spriochetal infection
Neuroleptic malg syn drome
Malig hyperthermia
Myalgia with weakness
Alcohol
Rhabdomyolosis
Weakness without myalgia
Transvese myelitis Guillan Barre Botulism Hypo/hypercalcium hpo/hpyerkalemia Hypophos Hypomag
Rhabdomyolysis patho
Muscle necrosis…due to increase in IC Ca which ativates proteases and leads to ROS
Increase in Ca form deletion of ATP leading to Ca ATPase pump dysfunction
OR
Direct injury to plasma membrane
Inflamm, toxic causes of rhabdo
POlymyositis, dermatomyosis, IBM
Alcohol, coacine, statins
Infection and injury causes of rhabdo
Viral myositis, pyomyositis
Exercise, electrical, crush, hyperthermia, msucle hypoxia
Rhabdo classic sx
Diffuse myaglia, muscle weakness, and dark urine
Myoglobin released from muscle damage gives the color of urine
Myoglobin can cause kidney damage by direct tubular toxicity or from obstructed flow
Elevation of CK to over 10,000
Urine positive for blood but negative for RBCs on microscopy
Hyperkalameia
Hyperphosphatemia
Hypocalcemia
Discontinue any contributing drugs
Monnitor acute kindey inijry y
Neuroleptic malginant syndrome
Life threating from dopamine antagonists
evolves over 1-3 days
Fever, mental status changes, lead pipe rgiditiy, tachy and labile BP
Evelation of CK to more than 1000
Hypocalcemia, hypomag, hyperkalemia, and metabolic acidosis
Serious complications are rhabdo and acute resp failure
Stop the anti-dopaminergic
Malignant hyperthermia
Inherited abnormality of ryanodine receptors
Unregulated passage of calcium causes sustained muscle contraction and rhabdo
Hypercarbia (acute resp failure) and muscle rigidity
Will develop hyperthermia, tachy, tachypnea, myoglobinuria, and hyoperkalemia
Hyperkalemia can lead to arrythmias in ventricular tachy and fibrillation
Discontinue agents
Dantrolene binds ryanodine and blocks Ca passaeg
Inhertied causes of myalgia without weakess
Myalgia with weakness
Weakness without myalgia
Mcardle dz (GSD 5)
Mitochondrial myopathy, myotonic dystropy, pompe disease(GSD 3)
DMD and BMD
DMD and BMD
Dystrophin mutation leading to myofibril instability and degen of muscle fibers
Located on X chromosome
Gower’s sign when young
Pseudohypertrophy and dilated cardiomyoapthy
Becker presents later but still cardio probs
Mitochondrial myopathy
Genetic defect in protein responsible for oxidative phosph
Kearns- Sayre syndrome
Adolescne
progressive extenral opthalmoplegia (diplopia and ptsosi)
Cerebellar ataxia, deaf, intellectaul
MELAS
Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes
Childhood
Progressive muscle weakness and myaglia
Focal or generalized seizures
Episodes of hemipareis, hemianopia, cortical blindenss
MERRF
Myoclonic epilepsy with ragged red fibers
Childhood and adolescence
Progressive muscle weakkess, myalgia, and spacticity
Myoclonus
Seizures, ataxia, peripheral neuropathy, dementtia
Pompe dz
Defect in glyocgen synthesis or breakdown
Def of acid maltase
Accumulation of glycogen in lysosomes and cytoplasm
Infantile with hypotonia, muscle weaknes and cardiomyopathy…usually resp distress and feeding difficulties
If onset older or adults…proximal and resp muscle weakness, muscle pain, and cramps
Early involvement of diaphram common so sleep disorder breathing is common
Late onset should be expected if progressive proximal muscle weaknessa nd reduced fixed vital capicty on pulm function testing
McArdle dz
Def of myophosphorylase which liberate glc-1phos from outer braches of glycogen
Usualy during adolescne or adulthood
Exercise intolerance, fatigue, myalgia and muscle cramps
Exercise leads to CK evleation and myoglobinuria
COntinued exercise may get rhabdo
Second wind phenomeme - due to increased blood flow and activation of FFA metab ofr energy
Acquired causes
Myalgia without weakness
Myalgia with weakness
Weakness without myalgia
Fibromyalgia, SEID, statin
DM, PM, adrneal insufficiency, hypothyroid, hyperthyroid, statin
Poly rhem, IBM, cushing, MG, alcohol, GCs
Fibromylagia
Exercise intolernace
unrefreshing sleep
Cong distubance
Psyc disorders
Based on clinical findings
Exercise is key compoennt of tx
Give TCAs (ami and cyclobenzarine), SNRIs (duloxetine), anticonvulstants (pregab and gabapentin)
Systemic exertion intolerance dz
More likely to have antibodies to virus than control
Early to middle adults andm ore in woemn
Abrupt onset of fatigue after URI
Exercise intolerance
Myalgia
Cog disturbance
Orthostatic infolterance
CBT and exercise…be careful not to overexert
Polymyalgia rheymatica
Symmetric pain, aching, morning stiffness of shoulders, neck, hips, and thights
Over 50
Modest elevation of ESR
Resolves with low-dose GCs
Alcohol myopathy
Directly toxic to both skeletal and cardiac muscle
Acute occurs with long stading alcohol abuse who bindge drink…generalized cramps, worse in calves, muscle tenderness and weakness…eelvated CK and rahdbo…discontinue the alcohol
Chronic - gradual onset of proximal weaknes and atrophy
Statin myopathy
Myalgia is much more common
Decrease cholesterol and inhibit CoQ10 and ubiquinone
Mostly affects proximal muslces and symmetric
Might want ot supplemtn CoQ10
GC myopathy
Myalgia typically absent and CK normal
Discontnue or reuce
Proximal muscle
