Retina infections & trauma Flashcards
DUSN
Helminth infection by – Toxocara canis, Baylisascaris procyonis (Midwest/racoons/larger), or Ancylostoma caninum (SE USA and S. America) • White dots in fundus with vitritis • Wiped-out” fundus late
Decreased ERG late
Treatment?
laser worm
Toxoplasmosis: Acquired vs. Congenital? Ocular findings? Treatment?
most common cause of posterior uveitis in the world (~25% of all cases of posterior uveitis in USA).
Infection with T gondii (protozoan)
Acquired vs. Congenital?
Acquired: ingestion of bradyzoites from raw meat or cat litter)
Congenital: transmission of tachyzoites from mother’s blood
Ocular findings?
Vitritis/retinitis next to old scars (congenital lesions usually in macula; acquired lesions usually in periphery)
Headlight in fog appearance
Systemic signs in congenital toxo?
Seizures, cerebral calcifications
If AIDS patient, check neuroimaging (30% have brain lesions)
Treatment? Triple therapy (x 1 yr if congenital) Pyrimethamine, sulfadiazine, folinic acid +/-prednisone Bactrim DS BID Atovaquone (attacks cyst too!) 750mg TID Clindamycin (if pregnant) Intravitreal clindamycin + dexamethasone
Toxocariasis Rx
Toxocariasis
• Unilateral, children
• Ingestion of contaminated soil with dog feces
• Visceral larva migrans
• Signs?
– Unilateral leukocoria from chronic endophthalmitis
– Localized or peripheral eosinophilic granuloma
– Pseudo XT
Rx if significant inflammation
AC rxn: as usual uveitis
Panuveitis: Rx w/topical, periocular, and systemic corticosteroids (0.5–1 mg/kg body weight reduces the inflammatory response).
Antihelminthic drugs have been used in visceral larva migrans, but this treatment can exacerbate ocular inflammation and therefore is not recommended.
Surgery if TRD or RRD, intravitreal FVP, and endophthalmitis.
Neuroretinitis
DFE: swollen left optic nerve along with prominent macular exudates forming a “macular star.”
While neuroretinitis can be harbinger of serious systemic disease and these entities should be ruled out with blood work, the majority of cases are idiopathic. When a cause is identified, the most common causative pathogen is Bartonella henselae. This gram negative rod is often transmitted via cat bites or cat scratches and often leads to “cat scratch fever” which can have protean manifestations including fever, lymphadenopathy, hepatitis, endocarditis, and encephalopathy. Despite the potential for serious manifestations, the disease is self-limited unless the patient is immunocompromised.
Treatment of neuroretinitis has never been proven to be beneficial although some practitioners will treat with doxycycline or rifampin. Interestingly, many patients with laboratory proven Bartonella henselae infection do not recall a cat scratch / bite.
Some other known causes / associations with neuroretinitis include sarcoidosis, syphilis, Epstein-Barr virus, Lyme disease, histoplasmosis, toxocariasis, and toxoplasmosis. When a work-up fails to reveal an etiology, the term Leber’s idiopathic stellate neuroretinitis is sometimes used.
Abx causing macular infarction
Intravitreal injection of aminoglycoside antibiotics like gentamicin has been associated with macular infarction.
Aspergillus Si/Sx/Rx (vs. candida)
angio-invasive fungus that thrives in patients who are immunosuppressed status post liver transplantation.
rapidly destructive endophthalmitis or infiltrative sino-nasal process (a different neuro-ophthalmic problem caused by this fungus).
severe endogenous endophthalmitis with chorioretinal exudative lesions that are typically larger than Candida and more severe associated vitritis but need vitreous Cx/PCR to Dx
Rx: IV Amphotericin B for both Candida and Aspergillus endophthalmitis.
Cryptococcus Si/Sx
causes a meningitis in immunosuppressed patients and is a cause of severe, rapidly progressive vision loss from severe papilledema.
Pneumocystis jiroveci (formerly known as Pneumocystis carinii)
not a fungus but an extracellular parasite that is a common cause of lung infection in immunocompromised patients (particularly AIDS patients)
can cause a choroiditis with multiple small elevated creamy lesions and minimal vitritis. This almost always occurs concomitantly or following active Pneumocystis jiroveci lung disease.
chalcosis
copper toxicity - may lead to loss of the eye if the copper object is not removed promptly
Si/Sx: deposits in DM, “sunflower” cataract, greenish-color iris, brown vitreous opacities, and metallic flecks on retinal vessels.
Inert objects, like glass, can be left alone if discovered several days after the initial injury.
siderosis
Iron toxicity to the eye: characteristic changes in the ERG.
early phases: increased (more negative) a-wave and a normal b-wave
more advanced phases: b-wave amplitude becomes smaller.
Eventually, siderosis may lead to total extinguishing of the ERG. Removal of a small iron foreign body is justified if the b-wave amplitude decreases.
Cholesterolosis
aka “synchysis scintillans” occurs in eyes that have undergone previous accidental or surgical trauma with subsequent intraocular hemorrhage. The crystals in this condition are typically inferiorly-located in contrast to the even distribution in asteroid hyalosis.
Bacillus cereus
most common intravitreal antibiotics used for Bacillus cereus endophthalmitis are vancomycin and clindamycin.
Overall rarely causes endophthalmitis. The exception is in cases involving trauma especially when a foreign body is involved. In fact, this gram positive rod accounts for
~25% of posttraumatic endophthalmitis cases. It has a
rapid and severe course with very poor overall prognosis for visual recovery.
endogenous fungal endophthalmitis
“fluffy” yellow-white lesions that appear to be projecting into the vitreous
Risks: prolonged indwelling catheters chronic antibiotic use hyperalimentation recent abdominal surgery diabetes.
MC caused by Candida species
Clinical Dx if known systemic Candida infection
Otherwise: vitreous culture (or other test like PCR) - BEST FROM PPV (not tap)
Endogenous Candida endophthalmitis localized to the choroid or retina and without systemic involvement can be treated with oral fluconazole or voriconazole x 2 months.
If the infection extends into the vitreous (as in this case), then pars plana vitrectomy + intravitreal amphotericin or voriconazole is added to the aforementioned systemic anti-fungal treatment.
widespread white-centered retinal hemorrhages
known classically as Roth spots
hypersensitivity reaction: type III (immune complexes),
2/2 rupture of retinal capillaries with exudation of whole blood which eventually results in fibrin being deposited in the middle of the hemorrhage.
Classically associated with subacute bacterial endocarditis whose other systemic manifestations include: fever, chills, heart murmur, splenomegaly, “Janeway lesions” (non-painful erythematous palm lesions), “Osler’s nodes” (tender lesions on toes and fingertips), and splinter hemorrhages of the nailbeds.
Roth spots can also be found in a wide range of other conditions, including: leukemia severe anemia thrombocytopenia sepsis hypertensive or diabetic retinopathy anoxia carbon monoxide poisoning intracranial hemorrhage birth trauma shaken baby syndrome prolonged intubation multiple myeloma ocular decompression after glaucoma surgery
Bleb-associated endophthalmitis
Strep species G(+) cocci in chains H flu G(-) coccobacilli Staph epi / coag (-) G(+) cocci in clusters G(-) species
