post midterm things Flashcards
what is the gray line/muscle of Riolan?
- superficial part of orbicularis muscle
- line roughly divides the eyelid in half, serves as an important surgical landmark
what are some secretory cicatricial causes of secondary obstructive MGD?
trachoma, ocular pemphigoid, erythema multiforme, atopy
what are some secretory non-cicatricial causes of secondary obstructive MGD?
seborrheic dermatisis, acne rosacea, atopy, psoriasis
describe the role bacterial lipases and esterases play in MGD:
- bacterial lipases and esterases hydrolyzes sterol and wax esters in the MG secretions
- free fatty acids as a byproduct – these are irritating and promote the inflammatory cycle
- saponification: foamy tears, increased tear evaporation rate
describe the Marx line grading system:
0 = Marx line (ML) totally posterior to meibomian orifices (MO)
1 = part of ML touches some MOs – most common, volcano presentation just starting to impinge into orifice
• this is when intervention is most useful
2 = all of ML runs through MO, level with orifices
3 = ML beyond MO to the anterior lid margin
what is the tx for level 2 MGD?
maintain level 1 for everyone (hot compresses), add:
-fish oil, flax seed oil @ 1000mg BID-QID each
–fish oil decreases inflammation
–flax seed oil thins out the Meibomian secretions
treat non-specific inflammation if present
what is the tx for level 3 MGD?
maintain levels 1 and 2:
- re-assess and treat concurrent disease
- add minocycline/doxycycline/azithromycin oral antibiotic for anti-inflammatory
Describe some of the benefits of mino/doxy for MGD:
- inhibition of MMP, macrophages (reduce ability to produce cytokines such as IL-1 and TNF), and bacterial lipases (convert secretions into irritating free fatty acids which drive an inflammatory process)
- effect on circulating neutrophils
- reduce bacterial flora at lid margin
describe some considerations for Rx’ing minocyc:
- bacteriostatic – don’t combine with bactericidal
- long half life – extended effectiveness; also low renal clearance
- long term effect (up to weeks) after Tx withdrawal – allows for use of pulsed therapy
Tx for level 4 MGD:
maintain level 3; add Restasis, Tacrolimus, or other stronger anti-inflammatory med
dosing levels for minocycline:
- begin 50mg BID x 2w, then 100mg BID x 10w
- use pulsed therapy, with 3mo on and 3mo off
dosing levels for doxycycline:
what are periostat and oracea?
- 100mg BID x2w then 50mg BID x 6w, then 25mg BID x 4mo
- Periostat: 20mg formula for gingivitis can be used for maintenance therapy 1-2x/day – very expensive
*Oracea: 40mg made up of 30mg immediate release and 10mg delayed release, usually given once daily
• usually for rosacea
**both oracea and periostat take on empty stomach, 1h before or 2h after eating
besides tetracyclines, what are some other antibiotic therapies for MGD? (also include dosing)
macrolide ABs: -erythromycin: preg B o 200mg BID x 30d -azithromycin o 250mg QD x14-21d o or 500mg/day x 3d in 3 cycles with 7d intervals
describe the pop typically affected by seberrhea:
- ages 20-50y, slightly more males (sebaceous secretion influenced by androgens)
- 3-5% prevalence overall
- risk groups: immunocompromised/HIV infection, Parkinson’s disease (low skin mobility so offending organism is not eradicated), gender change (hormonal changes alter the glands)
Describe the pathogenesis of seborrhea:
Malassezia yeast is an opportunistic pathogen, feeds on lipids
- enzymes break down lipids -> convert to free fatty aids which cause inflammation and irritation
- dandruff-like dermatitis that tends to be greasy (not always – depends on pts hygiene as well)
- increased neutrophils at sebaceous gland orificies -> glands plug, exfoliate a bit, turn over, etc.
- focal parakeratosis (superficial cells have nuclei signaling high cellular turnover), acanthosis, and spongiosis (cells break down and drift apart)
what is Meibomian seborrhea?
increased meibomian secretion/lipids -> easy for bacteria to chew on, forming free fatty acids and stimulating an inflammatory process
describe some of the changes you will see with the lids in seborrhea
-hyperemia and oily skin along the seborrheic zones
-scurf (flaky, dandruff) forms in later states
• pityriasis sicca: fine, brittle, dry scale
• pityriasis steatoides: oily, greasy looking scale
-scurfs on cilia – oily sleeves (or partial sleeves) that are pretty sticky and can glue the lashes together
-tylosis, lid corrugation
-MGD/posterior blepharitis: hyposectory or hypersecetory
Describe the pt profile for rosacea:
10% of adults, females 2-3x more than males but males usually more severe,
- onset 20-50y
- 50% of facial rosacea has ocular involvement, presenting sign in 20%
describe pathogen of
- intermittent vasodilation of skin capillaries – become permanent telangiectasias
- facial flushing when eat vasoactive amines (chocolate, cheese, red wine, nuts), with hormonal changes, environmental changes (sunlight), certain meds, emotional stress -> because the vessels are damaged and have weak walls they dilate easily
- sebaceous glands hypertrophy with papule and pustule formation
- unknown underlying cause, technically, but strong indication not infection
*damage vessels via wind, UV, toxins – become permanently dilated – leak immune complexes that lodge in skin to drive non-specific inflammatory response -> more dilation and leakage with vasoactive amines
Describe the stages and symptoms of rosacea:
stage 1 (early onset) – cheeks, nose, forehead flushing
2 – persistent erythema and beginning telangiectasias
3 – skin papules and pustules – firm changes in skin, sebaceous gland involvement – skin is not flat, but rather has a ruddy texture
4 – rhinophyma, most often in males
•nose looks bulbous, lumpy with sebacoues hyperplasia and telangiectasia
•medical Tx: debulking (dig out the glands) with surgical scalpel, dermabrasion, or resurfacing with CO2 laser
what are some signs/symptoms of facial rosacea?
- burning, irritation, itching
- signs/symptoms correlate weakly with ocular disease -> pts may have mild facial findings but severe ocular disease
- facial flush may be exacerbated by drinking alcohol, hot fluids, or eating foods with high vasoactive amines
Describe the signs and symptoms you find with ocular rosacea:
Sx: burning, irritation, dryness, photophobia, blurred vision
lids: tylosis, telangiectasias, hyperemia, obstructive MGD, cicatrical MGD (more with rosacea than with seborrhea), hordeola, chalazia (rosacea»_space; seborrhea), secondary blepharitis with greasy scurfs at lash bases
- conj – tarsal papillae (non-specific inflammation), hyperemia, variscosity, chemosis
- nodular and diffuse episcleritis – in females, episcleritis is usually idiopathic but there is a real association with rosacea if pt has rosacea
- limbus: inflammatory pannus / phlyctenules – chronic and long term so epi breakdown, ulceration, secondary superinfection may occur, scarring
- cornea: PEE, SPK, erosion
o fungal or sterile ulcers can occur – chronic steroid use may predispose fungal infection
how can you tx some of the facial telangiectasias in rosacea?
CO2 laser for telangiectasias – send earlier rather than later for Tx
what is Metronizadole gel and what is it used for?
imidazole derivative - antibacterial, antiparasitic, anti-inflammatory
• mode of action: oral/IV reduces DNA synthesis in anaerobic bacteria, topical acts as anti-inflammatory
