Myopathy: A Myopathy: A Closer LookCloser Look

Sofiya Prilik, MDSofiya Prilik, MD

Physical Physical Medicine and Medicine and RehabilitationRehabilitation

MyopathyMyopathy

DefinitionDefinition

neuromuscular disorders in which the neuromuscular disorders in which the primary symptom is muscle weakness due primary symptom is muscle weakness due to dysfunction of muscle fiber.*to dysfunction of muscle fiber.*

* Definition by the National Institute of Neurological Disorders and Stroke* Definition by the National Institute of Neurological Disorders and Stroke

Let’ Start With Basics!Let’ Start With Basics!

Muscle Anatomy: gross and Muscle Anatomy: gross and microscopicmicroscopic

MUSCLE FIBER

Function of MuscleFunction of Muscle

Motor UnitMotor UnitA motor unit is made up of a motor neuron and all the muscle cells it stimulates. Motor units vary in size. Small motor units are used for precise, small movements; large motor units are are used for gross movements.

The number of cells within a motor unit determines the degree of movement when the motor unit is stimulated. Muscle tone is maintained by asynchronous stimulation of random motor units.

Normal MuscleNormal Muscle

Characteristics of the Three Muscle Fiber TypesCharacteristics of the Three Muscle Fiber Types

Fiber TypeFiber Type Slow Twitch Slow Twitch Type IType I

Fast Twitch A Fast Twitch A Type IIAType IIA

Fast Twitch B Fast Twitch B Type IIBType IIB

Contraction timeContraction time SlowSlow FastFast Very fastVery fast

Size of motor Size of motor neuronneuron SmallSmall LargeLarge Very largeVery large

Resistance to Resistance to fatiguefatigue HighHigh IntermediateIntermediate LowLow

Activity used forActivity used for AerobicAerobic Long term Long term anaerobicanaerobic

Short term Short term anaerobicanaerobic

Force Force productionproduction LowLow HighHigh Very highVery high

Mitochondrial Mitochondrial densitydensity HighHigh HighHigh LowLow

Capillary densityCapillary density HighHigh IntermediateIntermediate LowLow

Oxidative Oxidative capacitycapacity HighHigh HighHigh LowLow

Glycolytic Glycolytic capacitycapacity LowLow HighHigh HighHigh

Abnormal MuscleAbnormal Muscle

Myopathy: symptomsMyopathy: symptoms

Muscle WeaknessMuscle Weakness Proximal Muscles>distal musclesProximal Muscles>distal muscles FatigueFatigue Difficulty rising from a chair, floor, Difficulty rising from a chair, floor,

tubtub Difficulty with stairsDifficulty with stairs Difficulty with overhead tasksDifficulty with overhead tasks Respiratory musclesRespiratory muscles Bulbar weakness- speech, Bulbar weakness- speech,

swallowing, oculomotor, facialswallowing, oculomotor, facial

Myopathy: symptomsMyopathy: symptoms

PainPain Mostly with inflammatory and Mostly with inflammatory and

metabolicmetabolic High serum CK levelHigh serum CK level Aching, dull, crampingAching, dull, cramping Patients will say: “sore”, “ache”, Patients will say: “sore”, “ache”,

“spasm”“spasm” No numbness or paresthesiasNo numbness or paresthesias

Physical Exam:Physical Exam:

Full exam is importantFull exam is important!!ObservationObservation – look for muscle – look for muscle atrophy, deformitiesatrophy, deformitiesStrength testingStrength testing – manual – manual muscle testmuscle testROM testingROM testingFunctional testingFunctional testing

Stand up from a chairStand up from a chair WalkWalk Step up on a low stoolStep up on a low stool

Don’t forget Don’t forget REFLEXESREFLEXES and and SENSATIONSENSATION

Myopathic DisordersMyopathic DisordersInflammatory MyopathiesInflammatory Myopathies

PolymyositisPolymyositis DermatomyositisDermatomyositis Inclusion body myositisInclusion body myositis ViralViral

Muscular dystrophiesMuscular dystrophies X-linkedX-linked Limb-girdle(ar/d)Limb-girdle(ar/d) CongenitalCongenital Fasioscapulohumeral (ad)Fasioscapulohumeral (ad) Scapuloperoneal (ad)Scapuloperoneal (ad) Distal (Welander) (ad/r)Distal (Welander) (ad/r)

Myotonic SyndromesMyotonic Syndromes Myotonic dystrophy (ad)Myotonic dystrophy (ad) InheritedInherited Schwarz-JampelSchwarz-Jampel Drug-inducedDrug-induced

Congenital myopathiesCongenital myopathies Central core diseaseCentral core disease Nemaline myopathyNemaline myopathy MyotubularMyotubular Fiber-type disproportionFiber-type disproportion

Metabolic myopathiesMetabolic myopathies GlycogenosesGlycogenoses MitochondrialMitochondrial Periodic paralysisPeriodic paralysis

Endocrine myopathiesEndocrine myopathies ThyroidThyroid ParathyroidParathyroid Adrenal/steroidAdrenal/steroid PituitaryPituitary

Drug-induced/toxicDrug-induced/toxic

Myopathy: typesMyopathy: types

Muscular dystrophiesMuscular dystrophies InheritedInherited Abnormal muscle proteinsAbnormal muscle proteins Progressive course and early onsetProgressive course and early onset

CongenitalCongenital Slowly progressive or non-progressiveSlowly progressive or non-progressive Distinct finding on muscle biopsyDistinct finding on muscle biopsy

MetabolicMetabolic Defect in intracellular energy productionDefect in intracellular energy production

Inflammatory Inflammatory AcquiredAcquired Caused by immune or infectious processCaused by immune or infectious process Almost always are associated with elevated Almost always are associated with elevated

Creatinine Kinase level in serum.Creatinine Kinase level in serum.

AtrophicAtrophic Drug-induced (Colchicine, AZT, ETOH, Statins Drug-induced (Colchicine, AZT, ETOH, Statins

(1/10,000 per year)(1/10,000 per year) Endocrine (steroid)Endocrine (steroid) CK is most often normalCK is most often normal

MyotonicMyotonic Congenital or adultCongenital or adult Cardiopulmonary compromiseCardiopulmonary compromise

EpidemiologyEpidemiology

Worldwide incidence of all inheritable Worldwide incidence of all inheritable myopathies is about 14% myopathies is about 14% Overall incidence of muscular dystrophy is about Overall incidence of muscular dystrophy is about 63 per 1 million. 63 per 1 million. Worldwide incidence of inflammatory Worldwide incidence of inflammatory myopathies is about 5–10 per 100,000 people. myopathies is about 5–10 per 100,000 people. More common in women More common in women Corticosteroid myopathy is the most common Corticosteroid myopathy is the most common endocrine myopathy and endocrine disorders endocrine myopathy and endocrine disorders are more common in women are more common in women Overall incidence of metabolic myopathies is Overall incidence of metabolic myopathies is unknown.unknown.

DiagnosisDiagnosisCase: Case:

59 year-old male with history of smoking, who was diagnosed with severe 59 year-old male with history of smoking, who was diagnosed with severe COPD/emphysema 2.5 years ago. Since then, he had several hospitalizations COPD/emphysema 2.5 years ago. Since then, he had several hospitalizations due to worsening SOB and productive cough. He was treated with high doses of due to worsening SOB and productive cough. He was treated with high doses of IV corticosteroids followed by very slow oral steroid tapers. After the last IV corticosteroids followed by very slow oral steroid tapers. After the last hospitalzation 4 months ago, he has been maintained on a Prednisone 5 mg hospitalzation 4 months ago, he has been maintained on a Prednisone 5 mg daily. daily.

Normally, the patient is independent with transfers, ambulation and ADL’s. His Normally, the patient is independent with transfers, ambulation and ADL’s. His walking tolerance is about 1-2 blocks, limited by SOB. walking tolerance is about 1-2 blocks, limited by SOB.

2 weeks ago, patient presented to his PMD c/o progressive functional decline in 2 weeks ago, patient presented to his PMD c/o progressive functional decline in walking tolerance, and especial difficulty with transfers and stairs.walking tolerance, and especial difficulty with transfers and stairs.

Exam revealed a thin male, with O2 saturation of 93% on RA. No apparent Exam revealed a thin male, with O2 saturation of 93% on RA. No apparent respiratory distress was noted. No cushinoid features were seen. Pertinent respiratory distress was noted. No cushinoid features were seen. Pertinent positives included visibly apparent atrophy in the proximal muscles groups of positives included visibly apparent atrophy in the proximal muscles groups of both UE and LE. Strength testing was within normal limits. Patient had difficulty both UE and LE. Strength testing was within normal limits. Patient had difficulty standing up from a sitting position. He was unable to perform squats.standing up from a sitting position. He was unable to perform squats.

Labs – WBC 11.8, Glu 120, otherwise normal. CK - normalLabs – WBC 11.8, Glu 120, otherwise normal. CK - normal NCS/EMG - normalNCS/EMG - normal

DIAGNOSISDIAGNOSIS

Steroid induced myopathy.Steroid induced myopathy.

STEROID INDUCED MYOPATHYSTEROID INDUCED MYOPATHY

Insidious disease process Insidious disease process

weakness of proximal muscles of the upper and lower limbs weakness of proximal muscles of the upper and lower limbs and neck flexors. and neck flexors.

First described by Cushing in 1932First described by Cushing in 1932

An excess of either endogenous or exogenous corticosteroids is An excess of either endogenous or exogenous corticosteroids is believed to cause the condition. believed to cause the condition.

Chronic or acute (less common)Chronic or acute (less common)

Catabolic effect on muscle – gluconeogenesis from aminoacidsCatabolic effect on muscle – gluconeogenesis from aminoacids

STEROID INDUCED MYOPATHYSTEROID INDUCED MYOPATHY

Fluorinated steroids are implicatedFluorinated steroids are implicated DexamethasoneDexamethasone TriamcinoloneTriamcinolone

Also seen with non-fluorinated onesAlso seen with non-fluorinated ones PrednisonePrednisone

Inhaled steroidsInhaled steroids

PathophysiologyPathophysiology

decreased protein synthesisdecreased protein synthesis

increased protein degradationincreased protein degradation

alterations in carbohydrate metabolismalterations in carbohydrate metabolism

mitochondrial alterationsmitochondrial alterations

electrolyte disturbanceselectrolyte disturbances

decreased sarcolemmal excitability decreased sarcolemmal excitability

EpidimiologyEpidimiology

For a given dose of steroid, women appear to be twice For a given dose of steroid, women appear to be twice as likely as men to develop muscle weaknessas likely as men to develop muscle weakness

Worldwide incidence or prevalance is unknownWorldwide incidence or prevalance is unknown

Diagnostic studiesDiagnostic studies

LabsLabs Routine LabsRoutine Labs Special labsSpecial labs

Creatinine Kinase – normalCreatinine Kinase – normal

Urine Creatinine – increasedUrine Creatinine – increased

No myoglobinuria or rhabdomyalysisNo myoglobinuria or rhabdomyalysis Muscle biopsy Muscle biopsy

type IIB fibers are mostly affectedtype IIB fibers are mostly affected

No inflammation, necrosis or regenerationNo inflammation, necrosis or regeneration

DIAGNOSTIC STUDIESDIAGNOSTIC STUDIES

Electrodiagnostic studiesElectrodiagnostic studies Normal nerve conduction studies (NCS)Normal nerve conduction studies (NCS) Electromyography can be normalElectromyography can be normal

(EMG tests type I fibers, while SM mostly affects (EMG tests type I fibers, while SM mostly affects IIB)IIB)

DON’T FORGET:DON’T FORGET:A chronically or critically ill patient, can have other A chronically or critically ill patient, can have other co-morbid conditions, that may impact NCS or co-morbid conditions, that may impact NCS or EMGEMG

TREATMENTTREATMENT

Steroid treatment modificationSteroid treatment modification

Pain controlPain control

Prevention of contracturesPrevention of contractures

Avoid exercise to the point of exhaustionAvoid exercise to the point of exhaustion Aerobic exerciseAerobic exercise ROMROM Moderate resistance exerciseModerate resistance exercise

Assistive devicesAssistive devices

Other: ventilation, percutaneous enteric feedOther: ventilation, percutaneous enteric feed

MYOPATHY RELATED TO MYOPATHY RELATED TO CRITICAL ILLNESSCRITICAL ILLNESS

Common in patients even after a brief period in the Common in patients even after a brief period in the intensive care unit. Estimated to be about 25%.intensive care unit. Estimated to be about 25%.

Gained recognition in the last decadeGained recognition in the last decade

Often misdiagnosed or missedOften misdiagnosed or missed

Can occur in conjunction with polyneuropathyCan occur in conjunction with polyneuropathy

Associated with prolonged ventilation and difficult Associated with prolonged ventilation and difficult weaningweaning

Differential DiagnosisDifferential Diagnosis

Motor neuron diseaseMotor neuron disease ALSALS Late onset spinal muscular atrophyLate onset spinal muscular atrophy Post-polio syndromePost-polio syndrome

Neuromuscular junction disordersNeuromuscular junction disorders Myasthenia GravisMyasthenia Gravis Lambert-Eaton myasthenic syndromeLambert-Eaton myasthenic syndrome

Motor neuropathyMotor neuropathyMyelopathy/ spinal stenosisMyelopathy/ spinal stenosisParkinson’sParkinson’s

QUESTIONS?QUESTIONS?

What is PPS?What is PPS?

Initiated January 1, 2002Initiated January 1, 2002

Inpatient Rehab Facility Prospective Payment System Inpatient Rehab Facility Prospective Payment System (IRF-PPS) is the reimbursement program for Medicare Part-A (IRF-PPS) is the reimbursement program for Medicare Part-A patients based on their specific impairment + level of patients based on their specific impairment + level of functioning upon admissionfunctioning upon admission

21 general Rehab Impairment Categories (RIC), 85 specific 21 general Rehab Impairment Categories (RIC), 85 specific Impairment Group Codes (IGC), Admission FIM scores and Impairment Group Codes (IGC), Admission FIM scores and sometimes Age, determine the Case Mix Group (CMG) sometimes Age, determine the Case Mix Group (CMG)

The CMG determines the one-time fixed reimbursement The CMG determines the one-time fixed reimbursement amount per patient per stay at an IRF and generates an amount per patient per stay at an IRF and generates an Average Length of Stay (ALOS) based on national normsAverage Length of Stay (ALOS) based on national norms

~ 70% Rusk population are MCR Part-A recipients~ 70% Rusk population are MCR Part-A recipients

What is the 60% Rule?What is the 60% Rule?

To qualify as an IRF, a provider must To qualify as an IRF, a provider must deliver intensive rehabilitation services to deliver intensive rehabilitation services to a population of inpatients, currently 60% a population of inpatients, currently 60% of whom, fall into one or more of 13 of whom, fall into one or more of 13 specific impairment categories, (the specific impairment categories, (the “CMS 13”), from the total 21 Rehab “CMS 13”), from the total 21 Rehab Impairment Categories (RICs)Impairment Categories (RICs)

PPS vs. CMS 60% RulePPS vs. CMS 60% Rule

PPSPPS::21 IGCs21 IGCsSpecific ICD-9-CM Specific ICD-9-CM codes for codes for comorbscomorbs that that provide provide additional additional reimbursementreimbursement 3 Tiers (B,C,D) – High 3 Tiers (B,C,D) – High to low to low levels of levels of additional additional reimbursementreimbursement

60% Rule60% Rule::13 Qualifying IGCs13 Qualifying IGCsSpecific ICD-9-CM Specific ICD-9-CM codes for codes for etiologies and etiologies and comorbscomorbs that qualifythat qualify cases in the rulingcases in the rulingNo impact on No impact on reimbursementreimbursementCompliance maintains Compliance maintains facility’sfacility’s status as an status as an IRFIRF

Active ComorbiditiesActive Comorbidities

““Conditions resulting in Conditions resulting in functional deficitsfunctional deficits that will be that will be addressed or monitored during the inpatient rehab addressed or monitored during the inpatient rehab stay”:stay”:

Medical conditions requiring consults, testing Medical conditions requiring consults, testing and/or medications and/or medications

Conditions affecting ADLsConditions affecting ADLs

Conditions or complications that affect rehab Conditions or complications that affect rehab treatment course or plan of caretreatment course or plan of care

How Can Health Care How Can Health Care Providers Contribute?Providers Contribute?

Familiarize yourselves with commonly seen comorbid Familiarize yourselves with commonly seen comorbid conditions, including, but not limited to, qualifiers in the conditions, including, but not limited to, qualifiers in the 60% rule and PPS reimbursable comorbidities60% rule and PPS reimbursable comorbiditiesIdentify patients who have deficits indicative of Identify patients who have deficits indicative of myopathy and discuss deficits with the rehab physiciansmyopathy and discuss deficits with the rehab physiciansClearly document the current deficits, assign accurate Clearly document the current deficits, assign accurate motor and cognitive FIM scores to represent the motor and cognitive FIM scores to represent the patient’s true functional levels of assistance and burden patient’s true functional levels of assistance and burden of care while in rehabof care while in rehabClearly document any residual deficits from previous Clearly document any residual deficits from previous illnesses/events that are still being addressed in illnesses/events that are still being addressed in therapy sessions, including “resolving” conditionstherapy sessions, including “resolving” conditions

Specificity in Documentation – Specificity in Documentation – Importance of Communication Importance of Communication between Therapists and MDsbetween Therapists and MDs

Rehab-designated Medical Records Coders can only Rehab-designated Medical Records Coders can only assign ICD-9-CM Codes for conditions included in assign ICD-9-CM Codes for conditions included in physicianphysician documentation documentation

If therapies or nursing alone provide documentation - If therapies or nursing alone provide documentation - conditions will not be codedconditions will not be coded

Accurate coding contributes to both qualifying cases Accurate coding contributes to both qualifying cases in the 60% Rule and additional reimbursement for in the 60% Rule and additional reimbursement for PPSPPS

60% rule Qualifying ICD-9-CM Codes and 60% rule Qualifying ICD-9-CM Codes and Verbiage for MyopathyVerbiage for Myopathy

359.0 - Congenital Hereditary Muscular Dystrophy359.0 - Congenital Hereditary Muscular Dystrophy

359.1 - Hereditary Progressive Muscular Dystrophy359.1 - Hereditary Progressive Muscular Dystrophy

359.2 - Myotonic Disorders359.2 - Myotonic Disorders

359.3 - Familial Periodic Paralysis359.3 - Familial Periodic Paralysis

359.4 - Toxic Myopathy359.4 - Toxic Myopathy

359.5 - Myopathy in Endocrine Diseases Classified Elsewhere359.5 - Myopathy in Endocrine Diseases Classified Elsewhere

359.6 - Symptomatic Inflammatory Myopathy in Diseases Classified Elsewhere359.6 - Symptomatic Inflammatory Myopathy in Diseases Classified Elsewhere

359.81 - Critical Illness Myopathy359.81 - Critical Illness Myopathy

359.89 - Other Myopathies359.89 - Other Myopathies

710.3 - Dermatomyositis710.3 - Dermatomyositis

710.4 - Polymyositis710.4 - Polymyositis

Contact your PPS Coordinators Contact your PPS Coordinators anytime with Questions anytime with Questions

Meryl EisdorferMeryl Eisdorfer, R.N.,B.S.N. , R.N.,B.S.N. x 33754, In-house pager: 1910 x 33754, In-house pager: 1910 meryl.eisdorfer@nyumc.orgmeryl.eisdorfer@nyumc.org

Randi FarkasRandi Farkas, M.A.,CCC-SLP, M.A.,CCC-SLP x 33744, In-house pager: 2522, x 33744, In-house pager: 2522, Cell: 917-589-9386Cell: 917-589-9386 randi.farkas@nyumc.orgrandi.farkas@nyumc.org