Orbital Cellulitis Overview Quiz

Orbital Cellulitis

• Definition: Infection of soft tissues surrounding the eye, located posterior to the orbital septum.

• Pathophysiology: Infection spreads from sinuses (ethmoid sinus most common), dental, facial, globe, eyelid, and lacrimal infections.

  • Direct inoculation via trauma or surgery.
  • Spread from bacteremia.

• Etiology:

  • Bacterial: Streptococcus pneumoniae (lower incidence with pneumococcal vaccine), Staphylococcus aureus, Haemophilus influenzae, Gram-negative bacteria.
  • Fungal: Mucor and Aspergillus species.

• Common in children (M>F), adults (F>M with MRSA infections).

• Higher mortality in those with fungal infections and immunocompromised individuals.

Orbital Cellulitis Signs & Symptoms

• Fever, eyelid edema and redness.
• Ptosis (drooping eyelid), restricted extraocular movements (EOM).
• Orbital pain and tenderness.
• Exophthalmos (bulging eye), purulent discharge (pus), conjunctivitis.
• Visual decrease, sluggish pupillary response.
• Elevated intraocular pressure.

Diabetic Retinopathy

• Initially asymptomatic.
• Advanced stages: floaters, blurred vision, progressive vision loss.
• Fundoscopic Examination:
  • Microaneurysms (tiny bulges in retinal blood vessels).
  • Venous loops and beading.
  • Dot and blot hemorrhages.
  • Macular edema.
  • Flame-shaped hemorrhages.
  • Cotton-wool spots.
  • Retinal exudates (leaky fluid).

Diabetic Retinopathy

• Differential diagnosis: Retinal vein occlusion, ocular ischemic syndrome, macular edema (diabetics).

Diabetic Retinopathy treatment

• Triamcinolone (corticosteroid).
• VEGF inhibitors (Afibercept, Ranibizumab) for macular edema and neovascularization management.
• Glycemic control (A1C 6-7%) is the most critical modifiable factor.
• Optimize blood pressure, kidney function, and serum lipids.
• Laser photocoagulation and vitrectomy.

Diabetic Retinopathy Prevention

• Eye exam at diabetes diagnosis, every 5 years for Type 1 diabetes, annually for Type 2 diabetes.
• Report visual symptoms immediately.
• Smoking cessation and management of hypertension, kidney disease, and hyperlipidemia.

Hypertensive Retinopathy

• Retinal changes due to hypertension that may affect vision.
• Commonly associated with chronic hypertension.

Strabismus (Eye Misalignment)

• Misalignment of eyes.
• Can cause decreased vision, frequent blinking/squinting, head tilting, diplopia, faulty depth perception.

Strabismus Types

• Esotropia: inward deviation of one eye.
• Exotropia: outward deviation of an eye.
• Vertical strabismus: hypertropia (eye deviates upwards) or hypotropia (eye deviates downwards).
• Acquired esotropia: accommodative, occurs when children try to accommodate hyperopia (farsightedness).

Strabismus Risk Factors

• Family history, refractive error, Down syndrome, cerebral palsy, stroke/head injury.

Strabismus Treatment

• Eyeglasses, contact lenses, prism lenses.
• Vision therapy.
• Surgery.

Glaucoma

• Increased pressure within the globe, causing optic nerve damage.

Glaucoma Types

• Primary Acute Angle-Closure Glaucoma: Ophthalmologic emergency caused by closure of a narrow anterior chamber angle, obstructing outflow of aqueous fluid.
• Secondary acute angle closure glaucoma: Does not require pre-existing narrow angle, may occur due to uveitis, dislocated lens, or certain medications.
• Chronic Angle-Closure Glaucoma: Obstructed flow of aqueous fluid into the anterior chamber angle.
• Chronic Primary Open-Angle Glaucoma: Elevated intraocular pressure due to reduced drainage of aqueous fluid through the trabecular meshwork.

Glaucoma Signs & Symptoms

• Acute angle-closure glaucoma:
  • Rapid onset of red, painful eye with tearing, profound visual loss, halos around lights, fixed & mid-dilated pupil, diaphoresis (excessive sweating), nausea, abdominal pain.
  • Cloudy cornea, firm globe on palpation.
  • Intraocular pressure may exceed 50mm Hg (normal limits 10-20 mm Hg).
• Open-angle glaucoma (Chronic glaucoma):
  • No symptoms in early stages. Later stages can include blurred vision, headaches, halos around lights, decreased peripheral vision.

Hyperopia (Farsightedness)

• Ability to see distant objects clearer than close objects.
• Eye does not bend light properly due to a shorter eyeball or insufficiently curved cornea.
• Visual images focus behind the retina.
• Risk factors: Inherited.
• Signs & Symptoms: Difficulty focusing on close objects, eyestrain, squinting, headaches.

Astigmatism

• Blurred or distorted vision at ANY distance.
• Irregularly shaped cornea or lens, causing uneven focus.
• Risk factors: Hereditary, eye injury, surgery, or disease.
• Signs & Symptoms: Blurred vision, difficulty with night vision, headaches, squinting.

Presbyopia

• Gradual loss of the ability to focus on near objects.
• Shape of the lens changes with age, becoming harder and less flexible to adjust focus for close objects.
• Risk factors: Aging adult (early-mid 40's), diabetes, CVD, multiple sclerosis, certain medications.
• Signs & Symptoms: Blurred near vision, eyestrain (reading material needs to be held further away), headaches.

Test your knowledge on orbital cellulitis, its definition, pathophysiology, etiology, and symptoms. This quiz covers the causes of infection and the populations most at risk. Perfect for medical students and healthcare professionals looking to reinforce their understanding.