Ophthalmology · Infectious Disease
The facts most likely to be tested
Orbital cellulitis is a post-septal infection most commonly arising from contiguous spread of acute bacterial rhinosinusitis.
The hallmark clinical distinction from preseptal cellulitis is the presence of pain with extraocular movements, ophthalmoplegia, and proptosis.
Computed tomography (CT) of the orbits with contrast is the diagnostic modality of choice to confirm the diagnosis and evaluate for orbital abscess or cavernous sinus thrombosis.
The most common causative pathogens in children and adults are Streptococcus species, Staphylococcus aureus, and Haemophilus influenzae.
Immediate intravenous broad-spectrum antibiotics are required to prevent vision loss and life-threatening intracranial complications.
Surgical intervention via orbital decompression is indicated if there is a large abscess, vision loss, or failure to improve with medical therapy.
Cavernous sinus thrombosis is a feared complication characterized by cranial nerve palsies (III, IV, V1, V2, VI) and bilateral eye involvement.
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A 7-year-old boy is brought to the emergency department with a 2-day history of fever, eyelid swelling, and redness of the right eye. Physical examination reveals proptosis, restricted extraocular movements, and decreased visual acuity in the right eye. The patient has a history of recent purulent rhinosinusitis. The conjunctiva is injected, and there is significant periorbital edema.
What is the most appropriate next step in management?
Urgent CT scan of the orbits with contrast
The patient's presentation of proptosis and ophthalmoplegia indicates post-septal involvement; a CT scan is required to confirm orbital cellulitis and rule out a drainable abscess.
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Etiology / Epidemiology
Most common in children; usually secondary to bacterial rhinosinusitis (ethmoid).
Clinical Manifestations
Look for decreased extraocular motility, pain with eye movement, and proptosis.
Diagnosis
CT scan of orbits/sinuses with contrast is the gold standard for diagnosis.
Treatment
Requires IV Vancomycin + Ceftriaxone; surgical drainage if abscess present.
Prognosis
Risk of cavernous sinus thrombosis and blindness; requires urgent management.
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Epidemiology & Etiology
Primarily affects children, often following acute or chronic sinusitis. The most common pathogens are Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae. Direct extension from adjacent structures is the primary mechanism.
Pertinent Anatomy
The orbital septum acts as the critical anatomical barrier. Infections posterior to this septum define orbital cellulitis, distinguishing it from preseptal cellulitis.
Pathophysiology
Infection typically spreads from the ethmoid sinuses through the thin lamina papyracea. Inflammation leads to increased orbital pressure, venous congestion, and potential ischemia of the optic nerve. If untreated, the infection can breach the dural venous sinuses.
Clinical Manifestations
Patients present with fever, proptosis, and ophthalmoplegia. The hallmark is pain with extraocular movement and decreased visual acuity. Red flags include fixed, dilated pupils and papilledema, signaling impending cavernous sinus thrombosis.
Diagnosis
The CT scan of orbits/sinuses with contrast is the gold standard to confirm the diagnosis and identify abscess formation. Obtain blood cultures prior to initiating antibiotics. If intracranial involvement is suspected, MRI with gadolinium is the preferred imaging modality.
Treatment
Immediate admission for IV Vancomycin + Ceftriaxone is mandatory. Surgical drainage is indicated for large abscesses or if vision deteriorates despite medical therapy. Monitor for anaphylaxis and adjust based on culture sensitivities.
Prognosis
Complications include cavernous sinus thrombosis, meningitis, and permanent vision loss. Close monitoring of intraocular pressure and serial neuro-ophthalmologic exams are required.
Differential Diagnosis
Preseptal cellulitis: No pain with eye movement or ophthalmoplegia
Orbital pseudotumor: Usually painful but lacks signs of systemic infection
Cavernous sinus thrombosis: Bilateral eye involvement and rapid neurological decline
Graves ophthalmopathy: Bilateral proptosis without fever or leukocytosis
Mucormycosis: Black eschar on turbinates, common in immunocompromised/diabetic patients