Muscle weakness and stiffness

Organ system	Disease	Symptoms												History	Physical Examination	Diagnosis
		Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	Laboratory Findings			Creatine Kinase	Muscle Biopsy	Electromyogram
Endocrine	Adrenal insufficiency	30−50 years	Proximal	−	+	−	−	−	−	+	−	Signs of glucocorticoid, mineralocorticoid, and, androgen deficiency	Signs of postural hypotension History of tuberculosis History of malignancy History of other autoimmune disease	Hypotension  Hyperpigmentation  Auricular−cartilage calcification  Vitiligo	Electrolyte abnormalities Hypoglycemia	Normal	Normal	Normal
	Hyperthyroidism	40	Proximal	−	−	−	−	−	+	+	+	Signs of hyperthyroidism	H/o of weight loss	Sweating Tremor Neck swelling	Decreased TSH	↑↑	Non specific	Myotonic
	Hypothyroidism	55	Proximal	−	+	+	−	−	+	+	+ Rhabdomyolysis	Signs of hypothyroidism	H/o weight gain	Myxoedema  Muscle pseudohypertrophy	Increased TSH	↑↑	Nonspecific	Normal
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Inflammatory/ Rheumatologic	Dermatomyositis	40s−50s Can affect children	Proximal	+	+	−	−	−	−	+	−	Rash Dyspnea Weight loss Cough	Viral infections Cancer	Heliotrope rash on face and hands Telangiectasia Erythema Mechanic's hands Gottron's sign ( violaceous scaly eruption )	↑↑ ESR ↑↑ CRP	↑↑	Perimysial mononuclear infiltrate	Myopathic
	Polymyositis	> 18 years	Proximal	+	+	−	−	−	−	+	−	Similar to dermatomyositis without mucous and skin involvement	N/A	N/A	↑↑ ESR ↑↑ CRP	↑↑	Endomysial mononuclear infiltrate Patchy necrosis
	Polymyalgia Rheumatica	50s	Diffuse	+	+	−	−	−	−	+	−	Weight loss	History of joints stiffness, worse in the morning	Restricted shoulder motion	↑↑ ESR ↑↑ CRP	Normal	Normal	Normal
Genetic	Myotonic dystrophy	<18 years	Proximal & distal	−	−	+	+	−	−	+	−	Myotonia Cataracts Diabetes mellitus Frontal balding Cardiac arrhythmias Cholecystitis Pregnancy Eyelid ptosis	Positive family history	Muscles often contract and are unable to relax	Mutations in the DMPK gene	N/A	N/A	Myopathic
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Infectious	Pyomyositis	Variable	Proximal & Distal	+	+	−	−	−	−	+	−	Fever Malaise Psoas abscess	Immunocompromised	Muscles are painful, swollen, tender, and indurated. Depending on the site of involvement, it may mimic appendicitis (psoas muscle), septic arthritis of the hip (iliacus muscle), or epidural abscess (piriformis muscle).	Leukocytosis Elevated ESR	N/A	N/A	N/A
Neurologic	ALS	>35	Proximal & Distal Distal	−	−	−	−	+	+	+	−	Dysphagia Spasticity Hyperreflexia Babinski's +	N/A	Both upper and lower motor neuron signs	Clinical diagnosis	Normal	Nonspecific findings of chronic denervation with reinnervation	Neuropathic
	GBS	18 −350	Proximal	−	−	−	+	−	−	+	−	Ascending paralysis	Precedes a gastrointestinal disease	Weakness of lower extremities followed by upper extremities	Cytologic albumin ratio	Normal	Normal	Neuropathic
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Neuromuscular	Botulinum	Variable	Distal	−	−	−	+	−	−	+	−	Double vision Blurred vision Drooping eyelids Slurred speech Difficulty swallowing	H/O food exposure	Hyporeflexia Decreased strength	+Toxin	Normal	N/A	Myopathic
	Lambert−Eaton syndrome	Variable	Distal	−	−	+	+	−	−	+	−	Weakness of the bulbar muscles Ocular Limb weakness	Weaknessa is often relieved temporarily after exertion or physical exercise.		Antibodies against voltage−gated calcium channels
	Myasthenia gravis	Variable	Proximal	−	−	+	+	−	−	+	−	Ocular Bulbar  Limb weakness Isolated neck, limbs and respiratory weakness	Weakness often worsens with activity		Antibodies that block or destroy nicotinic acetylcholine receptors