Acquired: Inflammatory, Endocrine/Metabolic, Toxic, Infectious

Hereditary: LGMD, Dystrophinopathy, Metabolic, Myotonic Dystrophy and Channelopathies, Congenital Myopathy, Congenital Muscular Dystrophy, Other: FSHD, OPMD, Distal Myopathies

Disorder	Features	Lab Investigations
HEREDITARY
Mitochondrial myopathy		Lactate, urine organic acids, plasma amino acids
Carnitine deficiency		Serum carnitine
Periodic Paralysis		K+ in an episode
Acid Maltase		Alpha-glucosidase
Arginine:glycine amidinotransferase (AGAT) deficiency (creatine deficiency syndrome) Developmental delay, epilepsy, myopathy Dx: Low guanidinoacetate (GAA) in body fluids (urine, plasma) Tx: Oral creatine
ACQUIRED
Sarcoid		ACE,CXR, Eos on CBC, ESR, hypogammaglobulins, anergy on ppd, high urine Ca(more often than serum calcium)
Inclusion Body Myositis		*NT5C1A autoantibodies (70% sens, 90% specific?-more resp weak, facial, dysphagia) *Cd4:cd8 ratio reduced. Much cheaper than flow cytometry almost perfect surrogate T cell large granular lymphocytosis Cd57,cd8 positive T cells Tclgl autoimmune causes pancytopenia Bottom line. If low blood counts check cd4:cd8
PM/DM		ANA, RF, ENA, CRP/ESR
SLONM (sporadic Late Onset Nemaline Myopathy)	proximal/axial weakness (spine pain), respiratory weakness, dysphagia/diplopia possible; asymmetric	IgG Monoclonal myopathy (treat IVIg, autologous SCT) HIV association(treat prednisone)
Myositis confirmed		HIV (usually presenting as a polymyositis) HTLV1 (rare myositis) HepB&C (rare myositis) Lyme (rare myoSITIS)-serum, CSF antibody
Necrotizing myopathy	PMID: 27086869	*anti-HMGCR autoantibodies *anti-SRP antibody -if these are positive it is much less likely underlying malignancy (though still possible)
*anti-HMGCR autoantibodies	Mohassel 2018. insidious onset responsive to IVIg	CK>1000, LGMD(+/- scapular), disease onset over years (3+), degen/regen on biopsy; neg genetics
Eosinophilic		CBC – incr Eo, anemia
Amyloid		UPEP/SPEP, Congo Red Bx
Thyroid Dysfunction		TSH, T3, T4
Parathyroid/Vitamin D		Vit D, Ca, PO4, Mg, Albumin
Uremic		Beta2microglobulin, hyper PTH malnutrition, VitD def, high metals(Al), low PO4
Statin Myositis	PMID: 27038110 *No patient with severe self-limited cerivastatin-related myopathy had anti-HMGCR autoantibodies *Statin intolerance improved when vitamin D deficiency treated Riche2016 *Alirocumab praluent proprotein convertase subtilisin/kexin type9 PCSK9 inhibitor subcutaneous q2-4weeks. Statin intolerant or muscle diseases.	*anti-HMGCR autoantibodies

Myotonic Discharges (on EMG) Myopathy

• DM1 (DMPK)
• DM2(Zinc Finger 9)
• Paramyotonia congenita (CLCN1, SCN4A)
• Myotonia congenita(CLCN1)
• Dynamin 2 associated myopathy (pubmed 29105112)
  • DNM2 (centronuclear myopathy)

Mitochondrial disease notes

• Retinitis pigmentosa – night blindness
• SN hearing loss
• DM2
• PEO ptosis
• Brain – IQ, epilepsy, migraines, movement disorders
• GI – constipation, emesis
• cardiac – CD, CMO
• nephron-RTA, nephrotic, glomerulosclerosis
• PN Dem, axonal
• PYR decarboxylase common in ojicree
• Adult 80%mito
• Child 80% nuclear DNa
• MELAS; <40 yo acute onset, IV arginine/citrilline
• VPA affects mito – causes liver failure in ??POLG??
• statin affects mitto??
• labs:
• CSF lactate/PYR ratio>20
• PAAcids: high alanine
• UOAcids: dicarboxylic acid?, methylglutajkjhkjhkjh acid
• MRI basal ganglia calcifications
• MRI GRE
• electron transport train in TO