Questions and Answers
Which antibiotic is known to inhibit bacterial DNA gyrase?
What is a common consideration for prescribing antibiotics in children?
Which of the following antibiotics is approved for use in infants 2 months and older?
What is the mechanism of action of macrolides?
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Which antibiotic combination is known for its dual action of disrupting membrane integrity and inhibiting folic acid synthesis?
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Which antibiotic is most commonly prescribed for skin infections?
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Which antibiotic is approved use for all ages?
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Why is Neomycin primarily used in combination with other medications?
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What is the common cause of orbital cellulitis in children under 5 years of age?
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Which antibiotic should be avoided in children under 8 years of age due to potential side effects?
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Which bacteria are primarily responsible for preseptal or orbital cellulitis?
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What is the initial treatment of choice for preseptal cellulitis in children?
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When is hospitalization and IV antibiotics indicated for treatment of orbital cellulitis?
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Which of the following antibiotics can be prescribed if a patient has a penicillin allergy?
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What role do nasal decongestants play in the treatment of sinusitis-related conditions?
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What is the best empirical treatment approach for preseptal cellulitis when the pathogen is not identified?
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Which condition is commonly associated with in preseptal cellulitis?
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Which sinus is well developed at birth and is most commonly associated with orbital cellulitis in young children?
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Study Notes
Antibiotic Uses and Considerations
- Indicated for bacterial conjunctivitis, corneal ulcers, corneal abrasions, and conjunctivitis due to nasolacrimal duct obstruction.
- Culturing not routinely performed in children; broad-spectrum antibiotics are preferred.
- Long-acting formulations available, with consideration for cost-effectiveness.
Antibiotic Mechanisms of Action (MOA)
- DNA Gyrase Inhibition: Critical for bacterial DNA synthesis.
- Protein Synthesis Inhibition: Targeting 30S and 50S ribosomal subunits.
Antibiotic Types and Examples
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Fluoroquinolones:
- Ciloxan (Ciprofloxacin 0.3%): >2 years, cost-effective.
- Ocuflox (Ofloxacin 0.3%): >1 year.
- Quixin (Levofloxacin 0.5%): >6 years, rarely prescribed.
- Zymar (Gatifloxacin 0.3%): >1 year.
- Vigamox (Moxifloxacin 0.5%): Suitable for all ages.
- Moxeza (Moxifloxacin 0.5%): Approved for ≥4 months.
- Besivance (Besifloxacin 0.6%): >1 year.
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Aminoglycosides:
- Tobrex (Tobramycin 0.3%): Solution and ointment; for infants ≥2 months often combined with other agents.
- Neomycin: Used only in combination treatments.
- Gentamicin: Approved for children ≥6 years.
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Macrolides:
- Erythromycin: Available in ointment, oral, and IV forms; used for infants/newborns as a lubricating ointment.
- Azasite (Azithromycin 1%): ≥1 year, recommended for its twice-daily dosing but is expensive.
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Combination Agents:
- Polytrim (Polymyxin B + Trimethoprim): Targets bacterial cell wall synthesis; approved for ≥2 months.
- Mupirocin: Used for skin infections.
- Sulfacetamide: Rarely utilized at 10% and 15% concentrations.
Oral Antibiotic Use in Children
- Penicillins: Include Amoxicillin and Dicloxacillin; common allergy noted.
- Cephalosporins: Similar to penicillins; examples include Cefazolin, Cefaclor, Ceftriaxone; also common allergies.
- Macrolides: Example is Erythromycin.
- Tetracyclines: Not prescribed for children under 8 years due to potential dental staining and growth delays.
Preseptal and Orbital Cellulitis
- Preseptal cellulitis occurs when infection is superficial, while orbital cellulitis involves deeper tissues.
- Ethmoidal sinusitis is the most common cause of orbital cellulitis (84-100% cases).
- Traumatic skin breaches and infections like hordeolum or dacryocystitis lead to preseptal cellulitis.
- Common pathogens: Staphylococcus aureus and Streptococcus spp.
Sinus Development
- Ethmoid sinuses are present at birth; maxillary sinuses develop in the first two years.
- Explained why ethmoidal sinusitis is prevalent in younger children.
Treatment Approaches
- Antibiotics prescribed empirically, targeting common pathogens without prior identification.
- Amoxicillin + Clavulanate (Augmentin) often prescribed at 250-500 mg PO TID or 875 mg PO BID.
- Cephalexin (Keflex) is another treatment option at 250-500 mg PO TID.
- Allergies to penicillin and sulfa monitored; alternatives include Azithromycin (Z-Pak) or Levofloxacin (500 mg PO).
- Avoid tetracyclines in children under 8; hospitalization may be required for severe cases.
Additional Treatments
- Nasal decongestants used if sinusitis is present.
- Topical treatments like Polysporin or Erythromycin for conjunctivitis.
- Surgical drainage indicated for abscesses.
Specific Antibiotics for Conditions
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Internal Hordeolum: Amoxicillin/Clavulanate or Cephalexin.
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Preseptal Cellulitis: Amoxicillin/Clavulanate or Sulfamethoxazole/Trimethoprim.
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Dacryocystitis: Amoxicillin/Clavulanate or Sulfamethoxazole/Trimethoprim.
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Canaliculitis: Typically treated with Cephalexin.
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A cheat sheet for pediatric oral antibiotics is useful for quick reference.
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Description
This quiz covers antibiotic uses, mechanisms of action, and the types of antibiotics relevant for treating ocular infections. It highlights considerations for prescribing and offers examples of various antibiotic formulations. Test your knowledge on the essential aspects of antibiotic therapy in eye care.
