Orbital Inflammatory and Infectious Disorders

Question 1

Most common cause(s) of preseptal cellulitis in adults and in kids?

Answer 1

Adults: penetrating cutaneous trauma or dacrocystitis
Kids: sinusitis (formerly from H. flu, but since Hib vaccine GPC most common)

Question 2

Geographic delineation of preseptal and orbital cellulitis?

Answer 2

orbital septum

Question 3

Empiric tx preseptal cellulitis in kids?

Answer 3

• anterior etiology: cephalexin (Keflex)
• spread from sinusitis: amoxicillin-clavulanate (Augmentin)
• warm compresses and nasal decongestants (oxymetazoline nasal spray) in both cases

Question 4

Most common organism causing preseptal cellulitis from trauma?

Answer 4

S. aureus

Question 5

Signs that differentiate orbital cellulitis from preseptal cellulitis?

Answer 5

pain with eye movement, motility restrictions, chemosis, visual impairment

Question 6

Empiric tx of preseptal cellulitis in teens and adults?

Answer 6

TMP-SMX (bactrim), clinda, doxy, ampicillin-sulbactam (Unasyn)

Question 7

Clinical presentation of MRSA preseptal cellulitis?

Tx for community-acquired MRSA? For nosocomial MRSA?

Answer 7

• fluctuant abscess with surrounding cellulitis, pain out of proportion to findings
• oral TMP-SMX, clinda, or rifampin
• iv vanc or linezolid

Question 8

Treatment of orbital cellulitis in adults and in kids?

Answer 8

Adults: broad spectrum abx, tx for multiple organisms (GPC and anaerobes common). Surgical drainage of sinuses if associated sinusitis

Kids: abx (usually caused by single GP organisms), less likely require sinus drainage, may benefit from concomitant steroids

Question 9

Indications for drainage of subperiosteal abscess (SPA)?

Answer 9

• 9 years or older
• presence of frontal sinusitis
• nonmedial location of SPA
• large SPA
• suspicion of anaerobic infection (gas in abscess on CT)
• recurrence after prior drainage
• evidence of chronic sinusitis (eg, nasal polyps)
• acute optic nerve or retinal compromise
• infection of dental origin (anaerobic more likely)

Question 10

Signs of cavernous sinus thrombosis in setting of orbital cellulitis?

Answer 10

rapidly progressing proptosis, ipsilateral ophthalmoplegia, anesthesia to V1 and V2

Question 11

Most common cause of necrotizing fasciitis?

Answer 11

Group A beta-hemolytic streptococcus

Question 12

Which antibiotic is particularly effective against the toxins of group A strep?

Answer 12

clindamycin

Question 13

Tx of necrotizing fasciitis?

Answer 13

Early surgical debridement and broad spectrum iv abx. Adjunctive steroids after abx have been started has been advocated

Question 14

Dx and tx for unilateral proptosis, motility dysfunction, bone destruction, and chronic draining fistulas misdiagnosed as orbital malignancy on imaging?

Answer 14

orbital tuberculosis; antituberculosis therapy alone is usually curative

Question 15

Clinical presentation of zygomycosis?

Answer 15

proptosis and orbital apex syndrome (internal and external ophthalmoplegia, ptosis, decreased cornel sensation, decreased vision)

Question 16

Pathogenesis of orbital zygomycosis?

Answer 16

direct extension from nasal cavity or sinuses. fungus invades blood vessel walls causing thrombosing vasculitis and tissue necrosis

Question 17

Histology of zygomycosis?

Answer 17

nonseptate fungus with large, branching hyphae that stain with H&E

Question 18

Predisposing risk factors to mucor infections?

Answer 18

anything causing systemic acidosis (esp DM), malignancies, immunosuppressed

Question 19

Treatment of orbital zygomycosis?

Answer 19

control of underlying predisposing factors, local surgical debridement, and iv ampho-B or iv liposomal ampho-B

Question 20

Dx and tx of orbital infection with associated fulminant sinusitis, tissue biopsy stained with Gomori methenamine silver revealing septate branching hyphae of uniform width?

Answer 20

Acute aspergillosis; aggressive surgical excision and ampho-B, flucytosine, rifampin, voriconazole, caspofungin, or combination thereof

Question 21

Findings in allergic Aspergillus sinusitis?

Answer 21

chronic sinusitis in immunocompetent patients with nasal polyposis, peripheral eosinophilia, elevated IgE

Question 22

Tx of allergic Aspergillus sinusitis?

Answer 22

endoscopic debridement with oral and topical steroids