0071643192.pdf

PATHOPHYSIOLOGY

■ Tick toxin →decreased release of acetylcholine at neuromuscular junc-

tion→symptoms.

SYMPTOMS/EXAM

■ Symmetric ascending paralysis

DIFFERENTIAL

■ Other disorders at neuromuscular junction (botulism, myasthenia)

DIAGNOSIS

■ Based on finding an attached feeding tick

TREATMENT

■ Supportive

■ Remove tick: Resolution of symptoms ranges from hours to days.

Polymyositis/Dermatomyositis

Polymyositis and dermatomyositis are both inflammatory myopathiesof auto-

immune etiology that produce muscle weakness. Dermatomyositis can occur in

children.

SYMPTOMS/EXAM

■ Chronic symmetric proximal muscle weakness

■ Muscle pain and tenderness

■ Dermatomyositis has additional skin findings including photosensitivity

and extensor rashes.

DIAGNOSIS

■ Electromyography and muscle biopsy confirm diagnosis.

■ CK may (or may not) be elevated.

■ Significant rhabdomyolysis is unlikely.

TREATMENT

■ Oral prednisone or cytotoxic drugs

Periodic Paralysis

Periodic paralysis is a disorder characterized by generalized muscle weakness

due to muscle ion channel abnormalities.

■ Hyperkalemic and hypokalemic periodic paralysis:

■ Most common

■ Familial

■ Hyperthyroid periodic paralysis:

■ Secondary to related hypokalemia

SYMPTOMS/EXAM

■ Episodic muscle weakness of rapid onset

■ Flaccid paralysis of extremities

NEUROLOGY