basic science, investigations and lasers Flashcards
ocular structures are derived from which layer
germ
which conditions are autosomal dominant
Congenital cataracts Best disease
Fuchs’ corneal dystrophy (also sporadic) Granular and lattice corneal dystrophies Marfan syndrome
Neurofibromatosis
Retinitis pigmentosa (also AR or XLR) Retinoblastoma (most commonly sporadic) Stickler syndrome
Tuberous sclerosis
Von Hippel-Lindau (VHL)
which conditions are autosomal recessive
Congenital glaucoma (most commonly sporadic)
Oculocutaneous albinism
Stargardt disease
Retinitis pigmentosa-like conditions
X linked recessive conditions
Fabry disease Lowe syndrome Ocular albinism
Retinoschisis
X linked dominant
alport
mitochondrial
Kearns-Sayre syndrome
Leber hereditary optic neuropathy
most common cause of endogenous endophthalmitis
Candida albicans
in immunocompromised patients
w white fluffy retinal lesions
types of filamentous fungi
Aspergillus spp. and Fusarium spp.
filamentous fungi are common when
common in warm climates and can cause fungal keratitis, usually following ocular trauma.
what is toxoplasma gondi
Cats are the definitive host. Transmission to humans is via fecal-oral spread, inhalation or undercooked meats. It can also be transmitted in pregnancy via vertical transmission. T. gondii can cause congenital or adult toxoplasmosis.
what is acanthamoeba
Protozoa that can be found in soil, water or swimming pools. It can cause severe keratitis.
what is toxocara
Their hosts are cats and dogs. It can be transmitted to humans through fecal-contaminated material. It causes toxocariasis which presents with endophthalmitis in children.
what is river blindness and what causes it
onchocerciasis
Onchocerca volvulus: The most common helminth-related ocular infection. The vectors are Simulium blackflies.
which ABx inhibit cell wall synthesis
Penicillin
Cephalosporin
Vancomycin
which ABx inhibits cell membrane function
Antifungals: Imidazoles, amphotericin and
nystatin
which ABx inhibit protein synthesis
Aminoglycosides
Tetracyclines
Erythromycin
Chloramphenicol
which ABx inhibit nucleic acid synthesis
Fluoroquinolones (DNA gyrase)
Metronidazole
what is the innate immune system
rapid nonspecific response of the immune system towards a foreign antigen. Neutrophils, macrophages, dendritic cells and the complement system
what is the adaptive immune system
refers to an immune response towards a specific antigen, mediated by lymphocytes (T and B cells).
where is MHC and HLA found
short arm of chromosome 6
where is MHC 1 are
are expressed on all cells and stimulate CD8+ cytotoxic T cells.
display peptide fragments of proteins from within the cell to cytotoxic T cells;
where is mHC2 and role
stimulate CD4+ T-helper cells and are expressed on specialized antigen-presenting cells such as macrophages.
what are cytokines
molecules responsible for recruitment and proliferation of the innate and adaptive immune systems.
what is TNF
proinflammatory cells produced by macrophages. They help in the activation and differentiation of immune cells and increase vascular permeability. They are therefore mediators of inflammation and septic shock.
what are interleukins
communication between different cells and are important in regulating immune responses.
IL 1 2 5 6 8 10 12
● IL-1: Induces immune responses and causes fever
● IL-2: Proliferation of T and B cells
● IL-5: Regulates growth and activation of eosinophils
HLA subtypes
Conditions
8 Basic science, investigations and lasers
● IL-6: Involved in differentiation of B cells and production of c-reactive protein (CRP); causes fever
● IL-8: Attracts neutrophils, T cells, basophils and eosinophils
● IL-10: Suppresses immune cells
● IL-12: Differentiates T cells into TH1 and enhances cytotoxicity
What are chemokines
involved in chemotaxis
what are interferons
proinflammatory or immunomodulatory cells. They can be also thought of as antiviral agents. Interferon beta can be used in managing multiple sclerosis (MS).
what is normal IOP
10 and 21 mmHg
Drugs that can raise IOP
● Steroids
● Tropicamide (close-angle glaucoma)
● Ketamine
IOP lowering agents
● Cannabinoids: Short-lasting effect and tachyphylaxis (reduced response to the drug over time)
● Alcohol: Transient effect on IOP
drugs that cause cataracts
● Steroids ● Tobacco smoke ● Amiodarone ● Allopurinol ● Chlorpromazine
mechanism of beta-blockers
decreases aqueous production
SEs of beta blockers
Decreased corneal sensation dry eye tachyphylaxis bradycardia bronchospasm and nocturnal hypotension
role of prostaglandin analogues ie lantaoprost
Increase aqueous drainage via the uveoscleral outflow
SEs of prostaglandin analogue
Conjunctival hyperaemia, iris hyperpigmentation, increased eyelash length and cystoid macular oedema (CMO)
role of alpha2 agonists
Decrease aqueous production and increase uveoscleral outflow
SEs of alpha 2 agonists
Follicular conjunctivitis, contact dermatitis, tachyphylaxis, dry mouth and sedation. Used with caution in infants as they can cross the blood-brain barrier
role of topical anhydrase inhibitors - dorzolamide
Decrease aqueous production
SEs of topical anhydrase inhibitors
Ocular stinging, bitter taste and punctate keratitis. Contraindicated in patients with sulphonamide allergies
role of systemic anhydrase inhibitors
decrease aqueous production
SEs of systemic CAI
Paraesthesia, urine frequency (diuretic effect), hypokalaemia, Steven-Johnson syndrome and metabolic acidosis
Role of miotics - pilocarpine
Parasympathomimetics that increase aqueous drainage via trabecular meshwork by causing contraction of ciliary muscles
SEs of miotics
Myopia, brow ache, miosis and retinal detachment
role of osmotic agents - mannitol
Lowers IOP by decreasing vitreous volume
SEs of osmotic agents
CVS overload
what is cystoid macular oedema
painless disorder which affects the central retina or macula. When this condition is present, multiple cyst-like (cystoid) areas of fluid appear in the macula and cause retinal swelling or edema.
drugs that cause cystoid macular oedema
Latanoprost, epinephrine, rosiglitazone and nicotinic acid
what is bull’s eye maculopathy
causes a dartboard, or ring-shaped, pattern of damage around the macula.
drugs that cause bull’s eye maculopathy
Hydroxychloroquine and chloroquine
what is crystalline maculopathy
physical accumulation of refractile crystalline deposits in the superficial retina
what drug causes crystalline maculopathy
tamoxifen
what drugs cause optic neuropathy
● Chloramphenicol ● Amiodarone ● Vigabatrin: Causes binasal visual field defects ● Isoniazid ● Ethambutol
what is vortex keratopathy
describes a whorl-like pattern of golden brown or gray opacities in the cornea.
byproducts in the basal epithelial layer of the cornea.
drugs that cause vortex keratopathy (corneal verticillata)
phenothiazines.
Amiodarone, chloroquines, indomethacin
which disease cause vortex keratopathy (corneal verticillata)
fabry
what is fabry disease
An XLR condition characterised by a deficiency of alpha-
galactosidase A. Other features of the disease include burning pain in the extremities, angiokeratomas, renal failure and posterior subcapsular cataracts.
ocular features of river blindness
system features
Mx
decreased VA sclerosing keratitis anterior uveitis BL chorioretinitis optic neuritis can visualise microfilariae with slit lamp examination
maculopapular rash
ivermectin
