Woman develops diplopia 2 weeks postpartum
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A 37-year-old white woman 2 weeks postpartum from an uncomplicated pregnancy and normal spontaneous vaginal delivery presented to the Tufts Medical Center emergency room.
She had a 1-week history of intermittent vertical binocular diplopia in downgaze, right eye pain with eye movement, right upper eyelid swelling with ptosis and right eye redness superiorly.
Ocular history was significant only for contact lens wear and glasses. Medical history included four pregnancies, transient hypothyroidism during a previous pregnancy, depression and generalized anxiety. She had a family history of lupus in her maternal aunt.
On arrival in the emergency room, she was hemodynamically stable and afebrile. Initial laboratory studies included a normal basic metabolic panel, normal complete blood count, and normal ESR and CRP.
Examination
On bedside exam, near visual acuity with glasses was 20/20 in both eyes with no dyschromatopsia. Pupils were equal and briskly reactive to light without any relative afferent pupillary defect. IOP was 11 mm Hg and 12 mm Hg in the right and left eyes, respectively. Extraocular motility was full in both eyes at the time of examination with orthophoria on alternate cover testing. However, sharp pain was experienced with extreme infraduction and supraduction in the right eye. Confrontation visual fields were full in both eyes.
Source: Daniel B. Azzam, MD, and Lianna Valdes, MD
External evaluation of the eyelids revealed right upper eyelid ptosis with a margin to reflex distance 1 of 2.5 mm on the right and 4.5 mm on the left (Figure 1a). There was mild right upper eyelid edema with preservation of the eyelid crease, no exophthalmos, no lid lag, no lid erythema and no mass on lid eversion. Facial sensation was intact in the V1 to V3 distribution bilaterally. Anterior segment exam was remarkable for 2+ conjunctival hyperemia superiorly in the right eye that only partially blanched with 2.5% phenylephrine, mild chemosis, no corkscrew episcleral vessels and no anterior chamber reaction (Figure 1b). Fundus examination was unremarkable.
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Postpartum diplopia, pain with eye movement
The patient’s symptoms of acute unilateral intermittent vertical diplopia, pain with eye movement, chemosis and injection raised concern for an orbital process. Differential diagnoses included thyroid-associated orbitopathy, orbital cellulitis, orbital myositis with an associated autoimmune systemic disease, granulomatosis with polyangiitis, sarcoidosis, IgG-4-related orbitopathy, orbital neoplasm, nonspecific orbital inflammation or a carotid-cavernous sinus fistula. The acute nature of the condition was concerning for orbital cellulitis; however, in this patient without a history of any trauma, surgery or sinusitis and who presented without significant periorbital swelling, proptosis, fever or leukocytosis, an infectious process was felt to be less likely. In the setting of sectoral conjunctival hyperemia with seemingly localized extraocular muscle involvement, an inflammatory process causing orbital myositis with possible scleritis was highest on the differential.
Workup and management
The patient underwent urgent CT of the orbits with contrast (Figure 2). The scan demonstrated asymmetric thickening of the right superior rectus muscle at the myotendinous junction (Figure 2a on page 28), while the remaining extraocular muscles were symmetric in size. There was no sinus disease, retro-orbital mass, enlargement of the lacrimal gland or dilated ophthalmic veins. The involvement of the tendon would be atypical for thyroid-associated orbitopathy, and the absence of fat stranding or adjacent sinusitis pointed away from orbital cellulitis. These imaging findings were most consistent with a unilateral inflammatory myositis of the superior rectus muscle.
Additional laboratory workup was performed, and the patient was started on IV vancomycin and ceftriaxone out of an abundance of caution to cover for the possibility of an infectious process. She simultaneously received IV methylprednisolone 80 mg, a dose confirmed with the pharmacy to be safe for breastfeeding. Due to hospital policies precluding her breastfeeding newborn from staying with her in an adult inpatient room, the patient declined admission and informed the team that she planned to leave against medical advice that night. Interdisciplinary discussion was held to create a safe discharge plan, which included prescription of oral doxycycline 100 mg twice per day, oral prednisone 75 mg daily and close follow-up in the ophthalmology clinic within 24 hours.
The following day in clinic, the patient endorsed immediate improvement of all ocular symptoms, including improvement in diplopia and pain with eye movement, resolution of lid heaviness and reduced conjunctival injection. The fellow eye remained stable with no symptoms. The oral antibiotic was discontinued, and the oral prednisone was decreased to 60 mg for 2 weeks with a plan to taper thereafter.
Lab studies resulted with TSH slightly low at 0.04 uIU/mL, free T4 borderline at 0.86 ng/dL and ANA in a 1:80 titer with speckled pattern. Otherwise, lab results were normal for total T3, CBC, BMP, ESR, CRP, syphilis antibodies, CK, LDH, RF, ANCA, SPEP, ACE, lysozyme and IgG4. At this point, given a relatively unremarkable inflammatory workup, the presumed etiology was nonspecific orbital inflammation causing idiopathic orbital myositis with possible scleritis in the postpartum setting. The patient was instructed to address the borderline thyroid studies with her obstetrician, as she had mild hypothyroidism during a previous pregnancy. It was still felt that the condition was not consistent with thyroid-associated orbitopathy given isolated involvement of only the superior rectus muscle at the myotendinous junction with no lid retraction, lateral lid flare or proptosis and given immediate resolution with steroids. If she were to develop recurrence during the course of treatment or in the future, then further workup with an MRI of the orbits and thyroid antibodies would be warranted.
Discussion
Nonspecific orbital inflammation (NSOI) accounts for 4.7% to 6.3% of orbital disorders and can present with a variety of features depending on the anatomical target, with common subtypes being dacryoadenitis, myositis, scleritis and orbital fat involvement. Orbital myositis due to NSOI is a rare disorder characterized by benign noninfectious inflammation involving the extraocular muscles with no known local or systemic cause. It most often affects women in the third decade of life. Other than idiopathic causes from NSOI, orbital myositis can also be associated with infectious, autoimmune or paraneoplastic etiologies, systemic or local inflammatory diseases, or drug reactions. Orbital myositis is the second most common cause of extraocular muscle inflammation behind thyroid-associated orbitopathy.
In the postpartum setting, a rapid shift from pregnancy’s immunosuppressed state to a sudden rebound of exaggerated proinflammatory responses may result in the systemic manifestation of new or quiescent autoimmune or infectious processes. This concept is similar to the phenomenon whereby immunosuppressed HIV+ patients develop paradoxical rapid worsening of underlying infectious or inflammatory disorders within months of initiating antiretroviral therapy due to a renewed ability to mount an inflammatory response. Although exact mechanisms are unknown, these postpartum immune system changes are likely to have contributed to our patient’s orbital inflammation.
The classic presentation of idiopathic orbital myositis is pain in the eye or orbit, diplopia with decreased extraocular motility, swollen eyelids, proptosis and conjunctival hyperemia. The extraocular muscles most often involved are the medial rectus, followed by the lateral rectus, superior rectus, inferior rectus, superior oblique and inferior oblique. Visual acuity is not typically affected. The absence of pain should raise concern for other etiologies such as an infiltrative or neoplastic process that may require a biopsy.
The diagnosis of idiopathic orbital myositis involves prompt workup to rule out the conditions that it often mimics, including thyroid-associated orbitopathy and orbital cellulitis. Other etiologies to exclude are sarcoidosis, neoplasm or myositis related to a localized or systemic inflammatory syndrome. The workup should involve a complete ophthalmic exam, including optic nerve function, exophthalmometry, extraocular motility and eyelid position. Laboratory studies include CBC, ESR, CRP, thyroid function tests and thyroid stimulating antibody, as well as IgG4, ANCA, ACE and/or orbital biopsy if clinically indicated in atypical cases. Imaging often begins with a CT of the orbits if there is concern for an abscess or orbital cellulitis. However, an MRI with and without contrast and with fat suppression will best evaluate the soft tissues in myositis. Classic radiographic features are unilateral thickening of the affected extraocular muscles at the myotendinous insertion, unlike thyroid-associated orbitopathy, which spares the tendon.
Management in mild cases may include oral NSAIDs. However, the classic mainstay of treatment remains high-dose systemic corticosteroids of 1 mg/kg per day, which typically results in a rapid clinical response if the diagnosis of idiopathic orbital myositis is correct. Steroids should be tapered slowly to prevent relapse, which can occur in up to 80% of idiopathic orbital myositis cases. Alternative strategies may involve rheumatology consultation for steroid-sparing agents, radiation or pain clinic.
Clinical course continued
The patient continued to improve clinically, and at a 2-week follow-up, she had complete resolution of her condition with no recurrence (Figure 3). She completed a slow steroid taper by 10 mg weekly, and she has not had any recurrence of symptoms at 6 months out from initial presentation.
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- For more information:
- Edited by Jonathan T. Caranfa, MD, PharmD, and Angell Shi, MD, of New England Eye Center, Tufts University School of Medicine. They can be reached at jcaranfa@tuftsmedicalcenter.org and ashi@tuftsmedicalcenter.org.
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