Isolated abscess in superior rectus muscle in a child.

Pyomyositis is a primary bacterial infection of striated muscles nearly always caused by Staphylococcus aureus. Development of the intramuscular abscess involving the extra-ocular muscles (EOMs) remains an extremely rare process. We herein present a case of isolated EOM pyomyositis involving superior rectus muscle in a 2-year male child who was referred with complaints of swelling in left eye (LE) and inability to open LE since last 1-month. Orbital computed tomography (CT) scan showed a well-defined, hypo-dense, peripheral rim-enhancing lesion in relation to left superior rectus muscle suggestive of left superior rectus abscess. The abscess was drained through skin approach. We concluded that pyomyositis of EOM should be considered in any patient presenting with acute onset of orbital inflammation and characteristic CT or magnetic resonance imaging features. Management consists of incision and drainage coupled with antibiotic therapy.

Orbital myositis: diagnosis and management.

Orbital myositis is an inflammatory process that primarily involves the extraocular muscles and most commonly affects young adults in the third decade of life, with a female predilection. Clinical characteristics of orbital myositis include orbital and periorbital pain, ocular movement impairment, diplopia, proptosis, swollen eyelids, and conjunctival hyperemia. The most common presentation is acute and unilateral, which initially responds to systemic corticosteroid therapy. However, chronic and recurrent cases may involve both orbits. Many inflammatory, vascular, neoplastic, and infectious conditions that affect the extraocular muscles and other orbital tissue can mimic orbital myositis. The most important differential diagnoses include thyroid-related eye disease, other orbital inflammatory processes (unspecific idiopathic inflammation, vasculitis, and sarcoidosis), orbital cellulitis, and orbital tumors. In refractory, chronic, or recurrent cases, steroid-sparing agents, inmmunosuppressants, or radiation therapy may be indicated.

Tick inoculation in an eyelid region: report on five cases with one complication of the orbital myositis associated with Lyme borreliosis.

PURPOSE: To determine the frequency and dependence of Lyme borreliosis after tick infestation in the eyelid region. MATERIAL AND METHODS: Five patients after tick inoculation were investigated by immunofluorescence assays for IgM and IgG system). Ophthalmologic evaluation of myositis was supported with MRI, laboratory, and internal clinical investigations. RESULTS: Four children showed negative Borrelia serology after a bite from a tick. In one case the left abducens nerve palsy was found, which was diagnosed in MRI as a thickened left lateral rectus muscle. The diagnosis of myositis with positive Borrelia burgdorferi serology was consistent with Lyme borreliosis. Other laboratory examinations were negative. The symptoms were reduced after treatment with ceftriaxon. CONCLUSIONS: Lyme borreliosis was found in one in five patients after tick infestation in the eyelid region. Antibiotic prophylaxis against Lyme borreliosis with ampicillin is recommended for children after a tick bite.

Clinical evidence of extraocular muscle fiber-type specificity of botulinum toxin.

OBJECTIVE: To compare the effects of botulinum toxin on static and dynamic aspects of eye movements, and thereby elucidate the mechanisms of its action on eye muscles. BACKGROUND: Laboratory evidence indicates that static alignment and saccades are subserved by different extraocular muscle fiber types, and botulinum toxin may cause specific dysfunction of the fibers controlling static alignment. Diplopia is a well-known side effect of periorbital botulinum toxin injections in humans, and may be a clinical correlate of the laboratory findings. METHODS: Search coil recording of eye movements was performed in one patient with systemic botulism, and in three patients with diplopia following periorbital injection of botulinum toxin A. RESULTS: In the patient with acute botulism, eye movement alignment, range, and saccadic velocity profiles were abnormal. In three patients with iatrogenic diplopia, static alignment was abnormal but movement range and saccadic velocities were within normal limits. Edrophonium improved the range of movements and saccadic velocities in the patient with systemic botulism but was ineffective in reversing ocular misalignment in the one iatrogenic patient to whom it was administered. CONCLUSIONS: Precise alignment is subserved by orbital singly innervated muscle fibers, and the effects of botulinum toxin are greatest on these fibers. This predilection is apparent when the toxin dose is very small, as must have been the case in our patients with iatrogenic diplopia. The lack of a response to edrophonium probably reflects structural damage to muscle fibers. In contrast, larger doses of toxin produce an acute dysfunction of all extraocular muscle fiber types, which is responsive to edrophonium and consequently reflects partial blockade at the neuromuscular junction.

Intracisternal A type particles of the extraocular muscle of hereditary muscular dystrophy mouse.

Intracisternal A type virus (IA) particles were observed in the extraocular muscle fiber of hereditary muscular dystroph mouse. The particles appeared approximately 65-75 mmu in diameter, with electron lucent cores.