Key findings	Suggested diagnoses
History
Diplopia, blurry vision	Myasthenia gravis (intermittent), diabetic neuropathy (permanent)
Dysphagia	Inflammatory myopathy, motor neuron disease, myasthenia gravis, muscular dystrophy, botulism
Facial nerve paralysis (Bell palsy)	Lyme disease, herpes zoster (Ramsay Hunt syndrome), herpes simplex virus 1 infection
Fevers, arthralgias, rash	Inflammatory or infectious myopathy
Monocular vision loss, bladder dysfunction	Multiple sclerosis
Pain	Nerve compression, rhabdomyolysis, inflammatory myopathy, inflammatory neuropathy (e.g., Parsonage-Turner syndrome), muscle damage due to toxins or medications (e.g., statins, fluoroquinolones)
Paresthesia	Hereditary sensorimotor disorders (e.g., Charcot-Marie-Tooth disease), nerve compression, nerve damage due to toxins, multiple sclerosis
Raynaud phenomenon	Inflammatory myopathy
Tendon rupture	Fluoroquinolone use
Physical examination
Cardiac arrhythmias	Inflammatory myopathy, genetic disorders, electrolyte imbalances
Cholinergic toxidrome	Organophosphate poisoning
Chvostek sign,* Trousseau sign,† tetany	Hypocalcemia
Cushingoid appearance (buffalo hump, purple striae)	Glucocorticoid excess (endogenous [Cushing syndrome] vs. exogenous [long-term glucocorticoid use])
Fatigable weakness, ptosis	Myasthenia gravis
Hyperreflexia	Upper motor neuron lesion, hyperthyroidism, hypercalcemia
Hyporeflexia	Hypothyroidism, lower motor neuron lesion
Muscle atrophy	Lower motor neuron pathology, frailty/sarcopenia
Skin bronzing	Hypoaldosteronism (Addison disease)
Third cranial nerve (oculomotor nerve) palsy	Diabetic neuropathy
Violaceous rash on the knuckles and extensor surfaces of upper extremities (Gottron papules [Figure 2]), violaceous rash on the eyelids and periorbital edema (heliotrope rash), violaceous rash on the upper chest and neck (V-sign) or back (shawl sign)	Dermatomyositis