MICROBIAL DISEASES OF THE EYES AND SKIN Flashcards
The Etiological agents that may affect the eyes will
vary depending on the ______ of tissue
affected
area and type
Disease spread may be divided into:
➔ Eyelids and tissue surrounding the eyes
➔ Conjunctiva
➔ Cornea
➔ Intraocular area
BLEPHARITIS
● Etiological agent are
Demodex folliculorum (a mite)
Followed by bacterial infection Staphylococcus aureus
or Staphylococcus epidermidis
Diagnosis : Due to an allergic reaction to the mite
which resides in the eyelash or the eyebrow
BLEPHARITIS
Abscesses
may form in and around the follicles, destroying the
follicles, with the loss of lashes and the formation of
ulcers.
BLEPHARITIS
BLEPHARITIS
Treatment:
Glucocorticoid
Doxycycline or Minocycline
Azithromycin
Glucocorticoid-______
for the allergic reaction
There may be a history of itching and scaling
of the lid since early childhood. The patient
describes an incessant urge to pull on the
lashes in an attempt to remove the scales
BLEPHARITIS
HORDEOLUM AND CHALAZION
● Etiological agents are generally
Staphylococcus
aureus, but may also be caused by Pseudomonas
aeruginosa and Proteus spp.
Diagnosis: Obstruction of the orifice of a gland
(_____,_____,____) seems to be the primary
pathological event in the formation of hordeolum (______)
HORDEOLUM AND CHALAZION
Meibomian, Zeis, or Moll
Stye
A red nodule that is quite painful develops and is
surmounted with a yellowish top as the lesion matures.
HORDEOLUM AND CHALAZION
HORDEOLUM AND CHALAZION
The histopathology is typical of
acute suppurative
inflammation
(untreated stye) evolved from
hordeolum that do not drain spontaneously or
are not incised.
Chalazion
HORDEOLUM AND CHALAZION
There is usually persistent chronic
inflammation, and ______ may
occur as sebaceous secretions are impounded.
granuloma formation
HORDEOLUM AND CHALAZION
Treatment:
Erythromycin
Cefalexin
Doxycycline
Treatment
for susceptible strains and for
prevention of corneal and conjunctival
infections
Erythromycin:
may be added if there recurrent
lesions or significant meibomitis
Doxycycline:
PERIORBITAL CELLULITIS
● Etiological agent are
Staphylococcus aureus (most
common), S. pneumoniae, H. influenzae
PERIORBITAL CELLULITIS
Also known as
periseptal cellulitis
PERIORBITAL CELLULITIS
Diagnosis: Characterized by
acute eyelid erythema
and edema
PERIORBITAL CELLULITIS
Treatment
Clindamycin as empirical therapy
Doxycycline, cotrimoxazole
ACUTE DACROCYSTITIS
● Etiological agent are
Staphylococcus aureus,
Staphylococcus epidermidis and Streptococcus
Pneumoniae
Diagnosis:
➔ This is an infection of the lacrimal sac,
almost always secondary to obstruction of the
lacrimal duct.
ACUTE DACROCYSTITIS
Occurs when both the upper and lower ends of
the drainage system become partially or totally
obstructed. The major symptom is pain in the
tear sac area. There are also erythema,
edema, a purulent discharge and epiphora
ACUTE DACROCYSTITIS
ACUTE DACROCYSTITIS
Treatment
➔ Coamoxiclav, Sultamicillin (sulbactam +
ampicillin) , Levofloxacin (fluoroquinolone)
➔ Tobramycin ophthalmic
➔ Tobramycin plus dexamethasone
ophthalmic (too much inflammation)
are immunosuppressants which suppresses the
immune action like inflammation, redness and swelling.
Glucocorticoids
CHRONIC DACROCYSITITIS
● Etiological agents are
Streptococcus pneumoniae,
Haemophilus influenzae, Candida albicans ,Aspergillus sp., Actinomyces sp.
is usually caused by a single
site of partial or complete obstruction within the
lacrimal sac or within the nasolacrimal duct. The
infection is usually the result, and not the cause, of
obstruction
CHRONIC DACROCYSITITIS
CHRONIC DACROCYSITITIS
Obstruction may be due to:
➔ Trauma
➔ Tumors
➔ Foreign bodies
➔ Delayed canalization in neonates
➔ Closure of canal in postmenopausal women
(Sore eyes)
PINK EYE CONJUNCTIVITIS
PINK EYE CONJUNCTIVITIS (Sore eyes)
● Etiological agent are
Haemophilus aegypticus and/or
Moraxella lacunata
Diagnosis: The only symptoms are conjunctivitis,
either chronic or acute, and severe inflammation of the
cornea. Diagnosis is via isolation of the organism (
Gam-negative slender rod).
PINK EYE CONJUNCTIVITIS (Sore eyes)
PINK EYE CONJUNCTIVITIS (Sore eyes)
Treatment
➔Topical sulfacetamide, erythromycin,
ciprofloxacin or ofloxacin.
➔ NEW agent: besifloxacin: Opthalmic
suspension
Ocular Lymphogranuloma Venereum
● Etiological agent:
Chlamydia trachomatis
Diagnosis:
➔ This is a chlamydial disease transmitted to
the fetus during passage down the birth
canal (vertical transmission)
Ocular Lymphogranuloma Venereum
Inflammation begins about five days after
birth and never results in follicle formation
(thus, it differs from trachoma and inclusion
conjunctivitis).
Ocular Lymphogranuloma Venereum
Corneal scars, conjunctival scars, and
micropannus formation occur.
Ocular Lymphogranuloma Venereum
It is rarely a cause of blindness.
Ocular Lymphogranuloma Venereum
Ocular Lymphogranuloma Venereum
Treatment
Azithromycin, Erythromycin, Doxycycline
(DOC) but caution in children
Trachoma
● Caused by
Chlamydia trachomatis
This disease is limited to man, infecting only epithelial
cells of the eye and possibly the nasopharynx; no
systemic involvement has been described. It is found
worldwide, and is the greatest single cause of blindness.
Trachoma
Scarring of the conjunctiva may cause the eyelids to
turn inward so that the lashes scratch the cornea
Trachoma
Pink, smooth, thin and transparent. Over the whole
area of the tarsal conjunctiva, there are large deeplying
blood vessels that run vertically
Normal Tarsal Conjunctiva
Presence of five or more follicles in the upper tarsal
conjunctiva
➔ Follicles are round swellings that are paler
than the surrounding conjunctiva, appearing
white, grey or yellow
➔ 0.5 mm in diameter
(TF)Trachomatous Inammation- follicular
Pronounced inflammatory thickening of the tarsal
conjunctiva that obscures more than half of the normal
deep tarsal vessels in
➔ The tarsal conjunctiva appears red, rough and
thickened, with numerous follicles which
may be covered by the thickened conjunctiva
(TI)Trachomatous Inammation-Intense
● Scars are visible as white lines or sheets in the tarsal
conjunctiva. They are glistening and fibrous in
appearance.
Trachomatous scarring (TS)
_____especially diffuse fibrosis, may obscure the
tarsal blood vessels
Scarring,
● At least one eyelash rubs on the eyeball
● Evidence of recent removal of inturned eyelash
Trachomatous Trichiasis (TT)
The pupil margin is blurred viewed through the
opacity. Such corneal opacities cause significant visual
impairment ( less than 6/18 or 0.3 vision) and visual
acuity should also be measured
corneal opacity
Trachoma Treatment
● DOC for trachoma: Azithromycin
● Alternative: 1% tetracycline ointment
VIRAL CONJUNCTIVITIS
● Etiological agents are
-Adenovirus types 3,7 and 8,
-Human Herpesvirus 1 (Herpes simplex 1 virus) ,
-Human Herpesvirus 2 (Herpes simplex 2 virus),
-Varicella-Zoster virus and
-Cytomegalovirus
Diagnosis: Bilateral conjunctivitis which is usually self
limited. No
constitutional symptoms are present
VIRAL CONJUNCTIVITIS
VIRAL CONJUNCTIVITIS
Treatment:
➔ Artificial tears
➔ Azalastine ophthalmic
Ketotifen
Relatively selective H1 receptor antagonist that
inhibits the release of mast cell
Ketotifen
caused by a virus, like the
common cold. This type of pink eye is very
contagious, but usually will clear up on its own
within several days without medical treatment .
Viral conjunctivitis
Caused by eye irritants
such as pollen, dust and animal dander among
susceptible individuals. Allergic conjunctivitis may be
seasonal (pollen) or flare up year-round (dust; pet
dander)
Allergic Conjunctivitis -
caused by bacteria, this
type of conjunctivitis can cause serious damage to
the eye it left untreated
Bacterial conjunctivitis
VIRAL CONJUNCTIVITIS
● Etiological agents are
Candida albicans, Sporothrix
schenkii, Allescheria sp., Aspergillus sp., Mucor sp
Diagnosis: An uncommon disease which can be acute
or chronic. Often secondary to fungal infections of
other parts of the body. Often aggravated by
glucosteroids and initiated after antibiotic therapy.
Diagnosed by isolation of the etiological agent
VIRAL CONJUNCTIVITIS
VIRAL CONJUNCTIVITIS
Treatment
➔ Natamycin: Initial drug for fusarium disease
➔ Amphotericin B: First agent of choice for
corneal infections due to yeast such as
candida
➔ Azoles: For Fusarium, Aspergillus,
Curvilaria and Candida
➔ Flucytosine: Active against Candida and
Cryptococcus
➔ Voriconazole: DOC for aspergillus, Fusarium
Blastomyces, Coccidiodes, Curvularia and
other fungal infection - azole that inhibits the
conversion of lanosterol to ergosterol
PARASITIC CONJUNCTIVITIS:
Onchocerciasis
African eye worm
River blindness
(Onchocerca vulvulus)
Onchocerciasis: transmitted by
simulium
blackflies
Second leading cause of blindness in the world
Onchocerciasis
Onchocerciasis
Treatment
Ivermectin
Moxidectin
Doxycycline
a macrolytic lactone for 12 yrs and
older, does not kill adult O. vulvulus
Moxidectin
may be used to eliminate the
endosybiotic bacteria Woblachia;
this disrupts production of
microfilariae by the adult female worm
Doxycycline
African eye worm
LOA LOA
LOA LOA
Transmitted by
Chrysops deer fly
LOA LOA
● Treatment:
Diethylcarbamazine
Albendazole
Serves as inhibitor of arachidonic
acid metabolism in microfilaria
Available only through CDC
Diethylcarbamazine
For treatment of symptomatic
loiasis with parasitemia of 8000
microfilariae/mL
Albendazole
OPHTHALMIA NEONATORUM
● Etiological agent is
Neisseria gonorrhoeae
Diagnosis: The disease is contracted from a mother
with gonorrhea as the fetus passes down the birth
canal. Infection does not occur in utero. At one time
about 10% of all cases of blindness in the United States
was due to this disease.
OPHTHALMIA NEONATORUM
OPHTHALMIA NEONATORUM
major clinical sign
Corneal inflammation
OPHTHALMIA NEONATORUM
Treatment
➔ Erythromycin oral or ointment
★ Systemic treatment is necessary
➔ Silver nitrate drops ( rarely used now)
★ May be used to prevent disease
Inflammation of the cornea
BACTERIA KERATITIS
➔ Rapid progression
➔ Corneal destruction may occur in 24-48 hours
(blindness)
BACTERIA KERATITIS
BACTERIA KERATITIS
Features:
Corneal ulceration, stromal abscess
formation, surrounding corneal edema and
anterior segment inflammation
BACTERIA KERATITIS
Etiological agents:
Streptococcus, Pseudomonas,
Enterobacteriaceae ( Klebsiella, Enterobacter,
Serratia and Proteus), Staphylococcus
BACTERIA KERATITIS
Treatment
➔ Tobramycin (14 mg/mL)
★ 1 drop every hour, alternating with
fortified cefazolin or vancomycin.
➔ Fourth-Generation Fluoroquinolones
★ Moxifloxacin and Gatifloxacin :
Penetrates better than Gati
➔ New Fluoroquinolone : Besifloxacin
★ Approved in 2009 for bacterial
conjunctivitis.
_____ species is the most common isolate in
fungal keratitis world wide, followed by _____ and
_____
Aspergillus
Fusarium
penicillium
● More common in men than in women
● May be acquired through unhygienic contact lens use
● This may extend from the cornea to the sclera and
intraocular structures
FUNGAL KERATITIS
FUNGAL KERATITIS
May cause
scleritis, endopthlamitis, panopthalmitis
Very difficult to treat and may result to visual loss and
loss of eye
FUNGAL KERATITIS
FUNGAL KERATITIS
Treatment
Ampothericin B
Natamycin
Common causes of Anterior uveitis
➔ Mumps virus, Human Herpesvirus 3
(Varicella-Zoster virus), Rubella virus,
Rubeola virus, Human Herpesvirus 1
(Herpes simplex 1 virus)
Common causes of Posterior uveitis:
➔ Toxoplasma gondii (25% of all cases)
Toxocara sp., Cryptococcus neoformans,
Histoplasma capsulatum, Mycobacterium
tuberculosis, Cytomegalovirus, Herpessimplex 1 virus, Human immunodeficiency
virus
