Keratoconus Overview Quiz

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Questions and Answers

What is typically the initial immune response to inhaled spores of the fungus in individuals with an intact immune system?

Phagocytosis by macrophages (correct)

Production of antibodies

Blood transfusions

Inflammatory response in the lungs

Which patient population is NOT highlighted as being at risk for fungal infections?

Healthy individuals with no predisposing conditions (correct)

Patients taking chronic steroids

Immunocompromised patients

Patients with diabetes mellitus

What symptom is commonly associated with the early presentation of fungal sinus infection?

Nasal congestion (correct)

Black eschar formation

Severe abdominal pain

Joint inflammation

In the management of a severe fungal infection, what is the purpose of monitoring blood urea nitrogen (BUN) and creatinine levels daily?

To assess kidney function and renal compromise Signup and view all the answers

Which of the following is a common complication associated with untreated fungal sinus infection?

Proptosis and visual loss Signup and view all the answers

What is a common symptom of keratoconus?

Painless diplopia Signup and view all the answers

What characterizes the progression of keratoconus?

Progressive irregular astigmatism due to paracentral thinning Signup and view all the answers

Which of the following signs indicates the presence of keratoconus?

Vogt’s striae Signup and view all the answers

What is the primary treatment approach for managing keratoconus?

Correcting refractive errors with glasses or rigid gas permeable lenses Signup and view all the answers

What separates preseptal cellulitis from orbital cellulitis?

Location of infection Signup and view all the answers

Which group in the Chandler Classification describes Orbital cellulitis?

Group II Signup and view all the answers

What condition can result from ruptured Descemet membrane in keratoconus?

Corneal hydrops Signup and view all the answers

Which of the following factors is NOT commonly associated with keratoconus?

Age above 40 years Signup and view all the answers

What is a common consequence of Mucormycosis in diabetic patients?

Orbital cellulitis Signup and view all the answers

Which symptom is specifically associated with orbital involvement due to Mucormycosis?

Prominent lid edema Signup and view all the answers

Which of the following findings is likely present on a CT scan for a patient with Mucormycosis?

Preseptal and orbital opacification Signup and view all the answers

Which cranial nerves are primarily involved in the diplopia seen with orbital issues?

CN 3, 4, and 6 Signup and view all the answers

What is a distinguishing symptom between Mucormycosis and pre-septal infections?

Fever and malaise Signup and view all the answers

What should be suspected in a patient with a history of diabetes presenting with significant pain and vision loss?

Mucormycosis Signup and view all the answers

Which of the following tests would you perform to check for meningitis?

Brudzinski test Signup and view all the answers

Which finding might indicate an afferent pupillary defect?

Pupil reacts poorly to direct light Signup and view all the answers

What aspect of patient history is crucial when suspecting Mucormycosis?

History of immunosuppressive illness Signup and view all the answers

What is the typical characteristic of pain associated with cranial nerve involvement in orbital conditions?

Dull ache that increases with movement Signup and view all the answers

Which of the following is NOT a contraindication for MRI?

Blood cultures Signup and view all the answers

What is the expected duration of intravenous antibiotics treatment for a suspected infection?

2-3 weeks Signup and view all the answers

What should be done after administering Vancomycin for the fourth dose?

Check Vancomycin levels Signup and view all the answers

Which combination of antibiotics is indicated for MRSA coverage?

Vancomycin and Ceftriaxone Signup and view all the answers

Which treatment option is indicated for rhino-orbital mucormycosis?

Orbital decompression Signup and view all the answers

For adults allergic to penicillin or cephalosporins, which antibiotic can be used with Vancomycin?

Ciprofloxacin Signup and view all the answers

What is a key indicator for considering invasive treatment?

Compromised vision Signup and view all the answers

Which of the following antibiotics is suggested for an anaerobic infection suspected in a patient?

Metronidazole Signup and view all the answers

When can a patient be switched from intravenous to oral antibiotics?

If they have been afebrile and show resolution of symptoms Signup and view all the answers

Which antibiotic is specifically noted as truly effective for MRSA?

Trimethoprim Signup and view all the answers

What condition arises if the optic nerve is not decompressed during treatment?

Severe damage to the optic nerve Signup and view all the answers

What is a common maximum daily dose limit for Vancomycin in adults to avoid nephrotoxicity?

4 g Signup and view all the answers

If a patient presents with chronic orbital cellulitis, what additional treatment should be considered?

Metronidazole Signup and view all the answers

Which treatment is recommended for exposure keratopathy due to proptosis?

Erythromycin ung QID Signup and view all the answers

Which intravenous antibiotic is indicated every 6 hours for an adult patient?

Unasyn (Ampicillin-sulbactam) Signup and view all the answers

What type of infection is rhino-orbital mucormycosis characterized as?

Opportunistic fungal infection Signup and view all the answers

In cases of a suspected orbital or subperiosteal abscess, what is the recommended action?

Obtain culture material Signup and view all the answers

Which medication is NOT effective against MRSA according to treatment guidelines?

Cefpodoxime Signup and view all the answers

What is a common source for the fungus causing rhino-orbital mucormycosis?

Decaying vegetation Signup and view all the answers

Which of the following is considered a condition for needing invasive treatments?

Excessive suppuration suspected Signup and view all the answers

Study Notes

Keratoconus

Ectatic corneal dystrophy: thinning and bulging of the cornea, most commonly diagnosed between ages 10-30.
Progresses for 7-8 years, then stabilizes.
Bilateral and asymmetric (one eye is usually worse than the other).
Symptoms: slow, progressive vision changes, frequent history of allergies, chronic eye rubbing, glare, photophobia, diplopia, and polyopia.
Signs:
- Progressive irregular astigmatism: secondary to paracentral thinning.
- Maximal thinning near the apex of the protrusion.
- Vogt’s striae: vertical lines of tension in the posterior cornea.
- Irregular retinoscopy reflex: irregular motion.
- Egg-shaped K's: if the mires are round on the keratometer, the patient does not have KC.
- Fleischer’s ring: epithelial iron deposits at the base of the cone.
- Munson’s sign:
- Superficial corneal scarring: due to excessive thinning.
- Corneal hydrops: stromal edema in the cone area due to Descemet rupture.
- Prominent corneal nerves: nerves may become more prominent due to corneal thinning.
Corneal topography: helpful tool to diagnose keratoconus. Blue areas represent flatter regions, while red areas represent steeper regions.
Treatment:
- Correct refractive error with glasses or rigid gas permeable (RGP) contact lenses.
- Intacs: intrastromal corneal rings, PMMA rings inserted in the peripheral stroma to flatten the cornea.
- Corneal transplant: for severe thinning or recurrent hydrops.
- Corneal hydrops protocol: cycloplegia, hypertonic ointment, remove contact lens in 24 hours, NaCl 5% solution/ointment BID-QID until resolved.

Infectious Orbital Inflammations

Orbital septum: thin, fibrous membrane that serves as a barrier between the superficial lids and the orbit.
Chandler Classification:
- Group I: Preseptal cellulitis (eyelid disease).
- Group II: Orbital cellulitis (inflammation of orbital contents without abscess formation).
- Group III: Subperiosteal abscess (between bone and periosteum).
- Group IV: Orbital abscess (collection of purulent material within the orbital contents).
- Group V: Cavernous sinus thrombosis (septic emboli at the cavernous sinus, extending posterior to the orbit).

Preseptal Cellulitis

Group I of Chandler Classification.
Not an orbital disease but can progress into one.
Infection of the soft tissue of the eyelids anterior to the orbital septum.
Orbit and globe are NOT involved.
Most common causes: eyelid lesions (internal hordeolum, dacryocystitis), spread from sinusitis, trauma, bites.
Etiology: contiguous infectious spread from injuries, insect/animal bites, conjunctivitis, internal hordeolum, dacryocystitis, or sinusitis.
Most common causative organism: Staphylococcus aureus and Streptococcus pneumoniae. Important to ask if the patient has received the Haemophilus influenzae type B (Hib) vaccine.
Signs and symptoms: prominent lid edema and redness, distention, proptosis, significant pain upon palpation, diplopia, loss of visual acuity, and afferent pupillary defect.
Work-up: history (trauma, ENT, systemic infection, mental status, diabetes), complete ophthalmic evaluation, vital signs, mental status, neck flexibility, CT scan of orbits and sinuses, CBC with differential, blood cultures, gram stain and culture if wound is present, lumbar puncture if meningitis suspected.
Management: IV antibiotics for 2-3 weeks or until improvement. This is a true Emergency and requires immediate hospitalization with intravenous antibiotics!

Rhino-orbital Mucormycosis

Aggressive opportunistic fungal infection.
Can affect other parts of the body, including lungs and GI tract.
Found in soil and decaying vegetation.
Spores are inhaled through the mouth and nose but rarely cause infection in individuals with healthy immune systems.
Immunocompromised individuals are at risk for infection.
May spread to paranasal sinuses, particularly the ethmoid sinus, and then to the orbital apex.
Difficult to diagnose early due to nonspecific symptoms. By the time orbital apex involvement is evident, vision loss is likely, and patient’s eye or life is at risk.
Associated with a high mortality rate.
Predisposing factors: diabetes mellitus, multiple blood transfusions, immunosuppression (transplant recipients, hematopoietic malignancies), chronic steroids, or immunosuppressants.
Fungal hyphae directly invade blood vessels, leading to tissue infarction and necrosis with bone destruction.
Signs: proptosis, necrotic mucosa, facial and periorbital swelling, diplopia, visual loss, ischemic infarction, black eschar (dead tissue shed from healthy skin).
Symptoms: pain, proptosis, nasal congestion, postnasal drip, dark blood-tinged or purulent rhinorrhea, sinus tenderness, headache, fever, and malaise.
Treatment: hospitalization, infected disease specialist, IV Amphotericin B, blood urea nitrogen (BUN) and creatinine levels checked daily, daily irrigation of affected areas with Amphotericin B, excision of devitalized and necrotic tissues, adjunctive hyperbaric oxygen, exenteration in severe unresponsive cases.

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Description

Test your knowledge on keratoconus, an ectatic corneal dystrophy characterized by thinning and bulging of the cornea that primarily affects individuals aged 10-30. This quiz covers symptoms, signs, and the progression of the disease, helping you understand its impact on vision and eye health.