title: Idiopathic orbital hemorrhage related to the inferior rectus muscle: a rare cause for acute-onset diplopia and unilateral proptosis.
abstract: OBJECTIVE
  To report 6 patients with spontaneous orbital hemorrhage in relation to the inferior rectus muscle.
  
  
  METHODS
  Retrospective observational case series.
  
  
  METHODS
  Six patients with acute onset orbital pain, diplopia, and proptosis referred to the orbital clinic at the Royal Victorian Eye and Ear Hospital, January 1995 through December 2004.
  
  
  METHODS
  Review of clinical history, imaging studies, and follow-up.
  
  
  METHODS
  Resolution of proptosis and diplopia and imaging studies of the orbit, including computed tomography (CT), magnetic resonance imaging (MRI), or both.
  
  
  RESULTS
  Six patients (4 men, 2 women; mean age, 68 years) were referred with acute onset of unilateral proptosis and diplopia. None of the patients had a history of bleeding disorder. Visual acuity and intraocular pressure were normal; 3 patients showed marked limitation in upgaze on the affected side. Imaging studies of the orbit by CT, MRI, or both showed inferior orbital hemorrhage either within (4 patients) or adjacent to (2 patients) the inferior rectus muscle, possibly within the muscular sheath. Symptoms resolved completely in all but 1 patient, who had persistent diplopia in extreme upgaze. Follow-up CT, MRI, or both showed complete resolution in 3 patients and mild persistent inferior rectus muscle thickening in 2 patients.
  
  
  CONCLUSIONS
  Acute onset proptosis and diplopia may be secondary to spontaneous orbital hemorrhage within the inferior rectus muscle or its sheath with no other orbital or systemic pathologic features. Symptoms resolved spontaneously over the course of days to weeks, and orbital imaging showed complete resolution or mild persistent enlargement of the muscle without significant symptoms.
authors.affiliation: Orbital, Plastic and Lacrimal Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia. guybensimon@gmail.com
authors.forename: Guy J
authors.initials: GJ
authors.lastname: Ben Simon
authors.forename: Alan A
authors.initials: AA
authors.lastname: McNab
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D004172:Diplopia / Q000175:diagnosis / Q000209:etiology*; D005094:Exophthalmos / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000473:pathology*; D010146:Pain / Q000209:etiology; D019315:Retrobulbar Hemorrhage / Q000150:complications* / Q000175:diagnosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014792:Visual Acuity