Eye Infection in Humans Acute Conjunctivitis (Pink Eye)

Eye Infection in Humans Acute Conjunctivitis (Pink Eye) Allergic, Bacterial  Symptoms, Diagnosis, Treatment

Eye Infection in Humans if we were to actually break down the word conjunctivitis the prefix conjunctive refers to the conjunctiva of the eyes and the suffix itis refers to inflammation so acute conjunctivitis is an inflammation of the conjunctiva of the eye and acute conjunctivitis is also known as pink eye and it’s known as pink eye because this condition is characterized by a red or a pink eye but not all red or pink eyes are conjunctivitis so that’s also important.

Eye Infection in Humans Acute Conjunctivitis (Pink Eye)

To make note of as well now (Eye Infection in Humans)

There are many different causes of acute conjunctivitis we can break down causes of conjunctivitis into two main categories infectious and non-infectious so infectious are going to be viral and bacterial conjunctivitis and non-infections are going to include allergic and other causes including such things as chemicals that get into contact with the conjunctiva and also mechanical irritation or injury to the conjunctiva these are also causes of non-infectious conjunctivitis but the

Main causes or the three most (Eye Infection in Humans)

common causes of acute conjunctivitis are allergic conjunctivitis bacterial conjunctivitis and viral conductivitis so we’re going to talk about these three types in this lesson now the most common type of acute conjunctivitis is a viral conjunctivitis and viruses account for approximately 80 of all cases of acute conjunctivitis and although this is considered the most common type there are differences depending on the population that we look at for instance in children bacterial

Conjunctivitis is more common (Eye Infection in Humans)

whereas in adults viral conductivities is going to be more common and acute conjunctivitis is going to be a very common condition and is going to account for up to one percent of all primary care visits so before we get into the causes and the signs and symptoms of conjunctivitis let’s talk about the anatomy of the conjunctiva of the eye so the conjunctiva is connective tissue that lines the outside of the eye and into the inner eyelids so it overlays the outside of the eye and then folds in

And covers the inside of the eyelids (Eye Infection in Humans)

so the conjunctive is actually a transparent and lubricating layer now there are actually two types or two layers of the conjunctiva one is known as the bulbar conjunctiva this is what layers the outside of the eyeball itself and then there is the palpebral conjunctiva that lines the inside of the eyelid and then there are accessory lacrimal glands or accessory tear glands that are located in the conjunctiva and help to lubricate the conjunctiva and then the conjunctiva and other parts of

The surface of the eye are colonized (Eye Infection in Humans)

 by normal flora including species of streptococci staphylococci and criney bacteria so this layer of normal flora can help reduce some infection by other pathogenic types of organisms so what are some of those infective organisms some of them are going to include bacteria like staphylococcus aureus streptococcus pneumoniae hemophilus influenza or h flu more accelecatoralis so these three are going to be important causes of other upper respiratory tract infections and middle ear infections for

Instance chlamydia trachomatis (Eye Infection in Humans)

 is also going to be another important bacteria that causes bacterial conjunctivitis and chlamydia trachmatis is actually one of the most common cause in neonates and then the other important bacteria that can cause bacterial conjunctivitis is niceria gonorrhea so chlamydia trachmatis and niceri gonorrhea are going to be sexually transmitted infections the viruses that cause conjunctivitis include adenovirus now adenovice is going to be the most common cause of a viral conjunctivitis herpes

Simplex virus is also another important (Eye Infection in Humans)

 cause of conjunctivitis we can also see varicella or virus causing conjunctivitis as well some other viruses that are less common include enterovirus 70 and some pox viruses like molluscum contagiosum virus and then there are other organisms that can infect the conjunctiva we’re not going to talk about those in this lesson and these include fungi and protozoa as well so we’ll now briefly talk about the pathophysiology so again we split it into the different categories of causes

We talked about before again allergic (Eye Infection in Humans)

 is one of those types of conjunctivitis we talked about so in allergic conjunctivitis it’s not going to be an infective organism that we had listed in the previous slide it’s going to be an allergic response so it’s going to be an allergic response to some allergen like dust or pollen those types of allergens and there’s going to be an allergic response and there’s going to be histamine release and vasodilation in response to the allergen itself so that’s going to cause those symptoms of

Allergic conjunctivitis (Eye Infection in Humans)

and then with regards to infective organisms there’s going to be alteration or disruption of the normal floor in some way and then there can be adherence of pathogenic organisms to the conjunctiva so again remember that we’ve got this normal flora of organisms that reside or colonize the conjunctiva in other parts of the eye and these can help to compete against those pathogenic organisms but in some cases there can be some alteration or disruption of those normal flora and then there can be infection or

Adherence of those other pathogenic organisms (Eye Infection in Humans)

 like we talked about in the last slide to the conjunctiva those organisms can then multiply and overwhelm the host immunity leading to signs and symptoms now looking at those infective conjunctivitis conditions more specifically in bacterial conjunctivitis it’s going to be caused by an infection with one of those bacteria we talked about in the last slide and typically if it is an infection with a gram-negative bacteria it’s going to be more virulent or the

Condition is going to be more severe (Eye Infection in Humans)

 so gram-negative bacteria are going to include chlamydia trachomatis nicer gonorrhea and marxalicatoralis some risk factors for getting bacterial conjunctivitis are going to include direct and indirect contact with an infected individual so direct meaning that you have a direct contact with that individual or if it’s indirect it could be where the infected individual has touched their eyes and touched other objects in the environment and then that person comes along and

Touches those same objects (Eye Infection in Humans)

then touches their eyes that could be a way to get this indirectly contact lens use is going to be another risk factor for getting a bacterial conjunctivitis and then we can also see it with prior trauma trauma to the eye or a prior eye condition and with viral conjunctivitis this is going to be highly contagious it’s going to be even more contagious than bacterial conjunctivitis and it’s actually going to be contagious as long as the eyes are red so this condition can be contagious for weeks and again

The risk factors are going to (Eye Infection in Humans)

include direct and indirect contact with an infected individual so this is going to be even more key with viral conjunctivitis and if a patient has an upper respiratory tract infection like a common cold or they’re in contact with someone with an upper respiratory tract infection this also is a risk factor as well as upper respiratory tract infections are associated with viral conjunctivitis and then once a patient has that allergic response or gets infected with a pathogenic organism the

Bulber and or palpebral conjunctive (Eye Infection in Humans)

 are going to become inflamed so this is going to be an acute conjunctivitis condition so let’s talk about the symptoms we’re going to break down the symptoms depending on the type of conjunctivitis the first type we’re going to talk about is allergic conjunctivitis so allergic conjunctivitis is going to occur bilaterally this is going to be a systemic condition the patient’s going to have more systemic signs and symptoms like sneezing runny nose because it’s

Going to be an allergic response (Eye Infection in Humans)

 and because of that they’re going to have both of their eyes being affected so they’re going to have it bilaterally so they’re going to have eye redness and they may have some conjunctival injection this is where we see blood vessels in the whites of the eye and what’s going to be key with allergic conjunctivitis is itching so itching is going to be the hallmark finding because this is an allergic response with histamine release it’s going to be very itchy for the patient so they’re going

To be scratching their eyes (Eye Infection in Humans)

 they could also be rubbing their nose or sneezing as well and this allergic conjunctivitis is going to have tearing and runny eyes and the discharge is going to be clear or watery they may also have chemosis chemosis is where the conjunctiva itself becomes edematous so there’s swelling or edema so you can see in this image here the conjunctivity becomes swollen and they may have a little bit of eye burning perhaps from the rubbing or from the itching but there’s no pain

And then there’s again associated symptoms (Eye Infection in Humans)

 because this is due to allergic responses to some allergen so they’re going to have mucus production and sneezing and the associated conditions with allergic conjunctivitis include allergic rhinitis so hay fever asthma and atopic dermatitis so these are going to be the atopic triad now moving on to bacterial conjunctivitis symptoms bacterial conjunctivitis is more likely to be unilateral although it could be bilateral in some cases so again we’re going to see eye redness

And we can see conjunctival injections (Eye Infection in Humans)

 so we can see these blood vessels here’s another image of bacterial conjunctivitis with chlamydia trachomatis infection there can also be itching in some cases so it’s not going to be a hallmark finding like we see in allergic conductivities they may have some tearing as well and they’re going to have eye discharge that is going to be more purulent so purulent meaning that it’s going to be pus-like so it’s going to be white green and yellow in appearance and there can

Be so much eye discharge (Eye Infection in Humans)

that a patient when they fall asleep and they wake up in the morning their eyelids can be stuck together or what we would call glued shut in the morning so all of that discharge can get hardened when they’re sleeping and their eyelids get stuck together and they can’t open their eyes their eyes get glued shut so this is going to be a key finding with bacterial conjunctivitis and then if you’re to actually zoom in on some of this discharge it can be more globular as well there’s another form of

Bacterial conjunctivitis (Eye Infection in Humans)

that’s more severe and this is going to be bacterial keratitis this is where the cornea becomes involved this is going to be more common in people who wear contact lenses and in this bacterial keratitis they may have eye pain blurred vision in photophobia or light sensitivity so these are going to be more characteristic findings of a bacterial keratitis and then there  be even other complications of bacterial conjunctivitis as well including vision loss and blindness that may occur in

 Very severe cases (Eye Infection in Humans)

then in some cases ocular perforations some of these more severe complications can occur in chlamydia and gonorrheal conjunctivitis cases now let’s talk about viral conjunctivitis the signs and symptoms of viral conjunctivitis can occur unilaterally or bilaterally so they can occur on one side of the other one eye or both eyes so again we’re going to see eye redness and with viral conjunctivitis we’re going to more commonly see follicles so follicles are going to be these little

Elevated areas that we see (Eye Infection in Humans)

so these little bums so we can see this in viral conjunctivitis but we could also see it in allergic inductivity as well there may be some itching although again this is going to be a less common finding there can also be tearing and what’s going to be important here is that there’s going to be a foreign body sensation so oftentimes patient is going to feel burning or a gritty sensation like sand in the eyes so this can be something that can be noted as well and then the discharge in viral

Conjunctivitis is going (Eye Infection in Humans)

 to be watery or serous and in some patients this eye discharge can lead to some eyelid stickiness as well so like bacterial conjunctivitis the eyelids can start to stick together especially in the morning when they first wake up but the eyelids are not going to be as stuck as they are in bacterial conjunctivitis so there can be a little bit of stickiness but not as bad as bacterial conjunctivitis and we can also see pre-auricular lymphadenopathy this is going to be a common finding in viral conjunctivitis

So pre-auricular lymphadenopathy (Eye Infection in Humans)

is a swollen tender lymph node in the front of the ear this is the pre-auricular lymph node in this location here so that could also be swollen and tender as well in viral conjunctivitis and there may be eye pain or irritation especially if the viral conjunctivitis is caused by herpes simplex fires but most of the time is not going to have eye pain or irritation except for that burning sensation or gritty sensation we can see with the foreign body sensation and as we mentioned before viral conjunctivitis

May be associated with an upper (Eye Infection in Humans)

respiratory tract infection so it could be that a patient has a viral conjunctivitis first and then they go on to having a upper respiratory tract infection like a common cold or they may have already had an uprespiratory tract infection and then once that has resolved then they have this viral conjunctivitis after so this is again associated with an upper respiratory tract infection and another important point to note is that there is a more severe form of viral conjunctivitis and

That is known as viral keratoconjunctivitis (Eye Infection in Humans)

so viral keratoconjunctivitis is where the conjunctive and the cornea are involved so once the cornea becomes involved there can be some other signs and symptoms as well these include eye pain vision loss or vision distortion photophobia like light sensitivity so these are going to be similar to the bacterial keratitis we saw before increased eye redness so it’s going to be more inflammatory there’s going to be more inflammation and the discharge here may become purulent so the discharge can

Be more purulent in a viral (Eye Infection in Humans)

 keratoconjunctivitis and viral keratoconjunctivitis is going to be very important because there is potential for vision loss from it and it’s going to be caused by infection with adenovirus serotypes 8 11 19 and 37 and herpes simplex fires so a quick way to remember the different types of conjunctivitis can be by the discharge that we can see from the conjunctivitis so with allergic conjunctivitis this is going to be an easy one to spot because it is due to some allergen and there’s

Going to be associations with sneezing (Eye Infection in Humans)

 mucus production and other atopic triad conditions so the discharge is going to be watery or cirrus or mucoceros so this can be something that can be noted in a larger connectivity in bacterial conjunctivitis the discharge is going to be purulent so we can see this purulent white yellow or green discharge and the eyelids are going to be glued together in the morning in chlamydia and gonorrheal conjunctivitis we didn’t talk about this in much detail but the discharge is going to be slightly

Different it’s going to be mucopurulent (Eye Infection in Humans)

so it’s going to be mucusy and purulent so there’s going to be a combination of the two and then in viral conjunctivitis it’s going to be serous and watery and in some cases if it is due to herpes zos or virus we didn’t talk about this before but if it is due to herpes osteovirus it can be mucopurulent and if it is a viral keratoconjunctivitis we may see a more purulent discharge as well let’s talk about how the different types of conjunctivitis are diagnosed most of

 Them are going to be by clinical diagnosis (Eye Infection in Humans)

so just looking at the history and physical examination the clinician can often make a diagnosis of the different types of conjunctivitis but more specifically if we’re to actually do some different tests and procedures with allergic conjunctivitis superficial conjunctival scrapings may be utilized and this may help in the diagnosis of allergic conjunctivitis in bacterial conjunctivitis it could be again by clinical diagnosis or could be by a bacterial culture conjunctival scrapings

A gram stain so the gram stain can help (Eye Infection in Humans)

determine if it is caused by a gram positive or a gram negative bacteria a gem sustain can be used to detect intracellular inclusion bodies from chlamydia so if there is some question of whether or not this is a chlamydial conjunctivitis a gem sustain is going to be important and with bacterial conjunctivitis we’re going to see high neutrophils when we look at some of those scrapings and i didn’t mention this before but in allergic conductivities we’re going to

 See high levels of eosinophils and then in viral conjunctivitis (Eye Infection in Humans)

 we can also do a culture in conjunctival cytology smear only usually in severe recurrent or refractory cases and then there is a kit that can be used called adenoplus amino acid to detect for adenoviral conjunctivitis again this is going to be the most common type of conjunctivitis and then we can also use a fluorescein stain if there is viral kerato-conjunctivitis so this can help determine the involvement of the cornea this fluorescein stain and we can see

High lymphocytes in the conjunctival smear in viral conjunctivitis (Eye Infection in Humans)

so how are these types of conjunctivitis treated so again the treatment depends on the underlying cause if it is an allergic conjunctivitis allergic conjunctivitis is going to be seasonal it’s going to occur at different seasons or different times of the year and it’s going to resolve on its own when the allergen has been removed in some cases though if a patient needs symptom relief or if they are continuously exposed to those allergens nasal sprays can help

 Especially with some of those associated symptoms antioxidants (Eye Infection in Humans)

 can help as well cold compress so cold compression of the eyes can help with some of those symptoms topical corticosteroids may be used in some cases in an artificial tears with regards to viral conductivitis viral conjunctivitis usually resolves spontaneously within two weeks and it could be up to four weeks and in the meantime cold compressed and artificial tears can be a supportive treatment in some cases though if it is going to be caused by herpes simplex virus or some

Other more severe virus or causes a more severe case of viral conjunctivitis (Eye Infection in Humans)

ganciclovir and acyclovir may be used in those cases and then glucocorticoids may be used in the case of keratoconjunctivitis especially if there is a lot of inflammation due to that viral keratoconus vitis and with regards to bacterial conjunctivitis again this is usually a self-limiting infection lasting one to two weeks but what’s going to be most helpful is if the patient gets broad spectrum antibiotic eye drops so these are going to be topical antibiotic eye drops that are used this can help resolve the bacterial conductivities quite quickly and then in some very severe cases if there are systemic signs and symptoms from this bacterial infection systemic antibiotics may be used and again it’s going to occur in severe cases or in cases involving neonates in children and especially for chlamydial and gonorrhoeal infections again these are going to be the causes of very severe complications in some individuals.