4. Inflammation

Question 1

What are the causes of inflammation?

Answer 1

• Hypoxia
• Chemicals & drugs
• Physical agents
• Microbiologic agents
• Immunological agents
• Genetic defects
• Nutritional imbalances
• Age

Question 2

What are the 5 signs of inflammation?

Answer 2

• Redness
• Heat
• Swelling
• Pain
• Loss of function

Question 3

Cell injuries trigger ... inflammation via different mechanisms: ..., ..., and .... All of these events causes 5 different signs of inflammation: ` …, which causes redness and heat; Increase … , leading to swelling/ oedema; …, leading increase in …; …, leading to clots; and stimulation of …, causing …`.

Answer 3

Cell injuries trigger acute inflammation via different mechanisms: mast cell degranulation, activation of complement system, and release of cellular components. All of these events causes 5 different signs of inflammation: ` Vasodilation, which causes redness and heat; Increase vascular permeability , leading to swelling/ oedema; Cellular infiltration, leading increase in pus; Thrombosis, leading to clots; and stimulation of nerve endings, causing pain`.

Question 4

How does the following types of tissue injury influences the characteristics of acute inflammations?
* Bacterial infection
* Immunological/ Hypersensitivity injury
* Physical trauma
* Viral infection

Answer 4

• Bacterial infection - toxins causes high levels of neurophils and pus
• Immunological/ hypersensitivity injury can involve more of eosinophils and basophils in response to chemokines/ IgE
• Physical trauma can induce more oedema and haemorrhages
• Viral infections involve macrophages, NKT cells, T cells and can sometimes be haemorrhagic.

Question 5

Chronic inflammation tends to be very ..., overlaps with ... phases of acute response and depends on ... factors, but generallyare related to ` … ` or .... Typical characteristics of chronic inflammation involves the presence of ... and .... Chronic inflammation can involve the formation of ... and ....

Answer 5

Chronic inflammation tends to be very heterogenous, overlaps with later phases of acute response and depends on causative factors, but generallyare related to failure to remove injurious agents or failure to remove by-products of inflammatory response e.g. exudates. Typical characteristics of chronic inflammation involves the presence of lymphocytes/ plasma cells and macrophages. Chronic inflammation can involve the formation of granuloma and giant multinucleated cells.

Question 6

Image

Question 7

When the corneal epithelium is damaged, ... occur. If ... are intact, .... Without further injuries, corneal epithelium can .... However, if injury is caused by ..., ... will be killed, therefore corneal epithelium will not be able to regenerate. This caused .... The inability to regenerate causes the formation of .... If the conjunctival stroma is damaged, it can change the mechanics of the ... and cause ....

Answer 7

When the corneal epithelium is damaged, immediate death of epithelial cells occur. If limbal stem cells are intact, corneal epithelial cells will regrow. Without further injuries, corneal epithelium can regenerate. However, if injury is caused by chemical burns, limbal stem cells will be killed, therefore corneal epithelium will not be able to regenerate. This caused limbal stem cell deficiency. The inability to regenerate causes the formation of scars. If the conjunctival stroma is damaged, it can change the mechanics of the eyelids and cause dry eyes.

Question 8

Mast cells are .... They are particularly prevalent in .... They are histologically similar to ..., where they both stain ... and are ... in appearance. However, basophils have a .... Basophils are less common than ... in the eye, but they are characteristic in .... Neutrophils aka ... are major ... cells and are most prevalent in ... infections. Neutrophils has a ... staining cytoplasm, ... nuclei. Eosinophils are particularly prevalent in ... and ... infections. Eosinophils have a ... nucleus.

Answer 8

Mast cells are residents of the choroid and conjunctiva. They are particularly prevalent in allergy-driven hypersensitivity. They are histologically similar to basophils, where they both stain blue and are granular in appearance. However, basophils have a bi-lobed nucleus. Basophils are less common than eosinophils in the eye, but they are characteristic in acute allergy-driven conjunctivitis. Neutrophils aka PMNs are major inflammatory cells and are most prevalent in bacterial infections. Neutrophils has a pale staining cytoplasm, multi-lobed nuclei. Eosinophils are particularly prevalent in allergy-driven hypersensitivity and parasitic infections. Eosinophils have a bi-lobed nucleus.

Question 9

What are choroidal mast cells an early indicator of? Why?

Answer 9

Choroidal mast cells may be an early indicator of age-related macula degeneration. It is theorised that ARMD develops from subclinical inflammation involving mast cells.

Question 10

How does later phase or chronic ocular inflammation affect monocytes and lymphocytes respectively?

Answer 10

• Monocytes convert into macrophages and later into giant cells
• Lymphocytes such as B cells convert into plasma cell.

Question 11

What are keratic precipitates? What are they commonly found?

Answer 11

KP are macrophages that respond to chronic inflammation and have converted into giant cells and adhere to the corneal endothelium.

Question 12

What are the 5 signs of acute inflammation and 4 signs of chronic inflammation in the eye?

Answer 12

Acute
• Hypoxia
• Trauma
• Bacterial infection
• Chemical toxicity
• Abnormal membranes

Chronic
• Anterior uveitis
• Episcleritis
• Granuloma
• Immunogenicity responses

Question 13

Corneal hypoxia can present as ..., ... and .... Locally-induced corneal hypoxia can result from ..., ..., ..., ..., or .... Systemic corneal hypoxia can be caused by ....

Answer 13

Corneal hypoxia can present as epithelial blebbing, superficial punctate keratitis and stromal edema. Locally-induced corneal hypoxia can result from CL wear, infection, trauma, chemical burn, or hemifacial spasm. Systemic corneal hypoxia can be caused by obstructive sleep apnea.

Question 14

... can also lead to hypoxia of the eye and possibly lead to ... . A common inflammatory cause of this is ..., which is an ... condition. In histopathology of animals with this condition, there was significant loss of ..., ..., and increased presence of .... No ... are prevalent.

Answer 14

Ischaemia can also lead to hypoxia of the eye and possibly lead to Arteritic Anterior Ischaemic Optic Neuropathy. A common inflammatory cause of this is Giant cell arteritis, which is an autoimmune condition. In histopathology of animals with this condition, there was significant loss of RGCs, RNFL thinning, and increased presence of macrophages (microglia). No neutrophils are prevalent.

Question 15

..., such as lacerating injury of the conjunctiva results in .. and .... Under histopathology, ... and ... can be seen. No ... are prevalent.

Answer 15

Trauma, such as lacerating injury of the conjunctiva results in swelling and redness. Under histopathology, extended haemorrhage and plasma exudation can be seen. No neutrophils are prevalent.

Question 16

In bacterial infection, corneal ... can form alongside inflammation of the ... and .... Hypopyon may be formed from .... Redness and odema of the conjunctiva is caused by .. and .... Build up of ... is a characteristic sign of bacterial infection. In acute bacterial conjunctival inflammation, ... and ` …` occurs.

Answer 16

In bacterial infection, corneal ulcer can form alongside inflammation of the iris and conjunctiva. Hypopyon may be formed from neutrophil exudation from iris vessels. Redness and odema of the conjunctiva is caused by vasodilation and loosening of cell junctions. Build up of neutrophils is a characteristic sign of bacterial infection. In acute bacterial conjunctival inflammation, epithelial chemosis and neutrophil infiltration occurs.

Question 17

Chemical injury to the cornea can often induce .... In severe cases, ..., ... and ... may occur. Direct toxic damage can be exacerbated by ... due to the release of ..., thus causing corneal ....

Answer 17

Chemical injury to the cornea can often induce neutrophil infiltration. In severe cases, neovascularisation, chronic inflammation and scarring may occur. Direct toxic damage can be exacerbated by neutrophil infiltration due to the release of proteases, thus causing corneal perforation.

Question 18

Acute inflammation involves the release of ..., which contains .., ..., and .... There can also be formation of .... Membrane formation is ..., but can be caused by ..., ... or ....

Answer 18

Acute inflammation involves the release of fibrinous exudate, which contains fibrinogen, granulation tissue, and inflammatory cells. There can also be formation of pseudomembrane. Membrane formation is rare, but can be caused by bacterial/ viral infection, chemical or immunogenic injuries.

Question 19

Anterior uveitis can occur in the absence of .... This can be secondary to .... Initial stages involve ... from uveal vessels; whereas later stages mainly involves .... Acute and chronic uveitis can be differentiate by looking at the .... In chronic non-granulomatous anterior uveitis, there are ... which largely consist of ... and .... In acute anterior uveitis, they are mainly .... This condition can also lead to ....

Answer 19

Anterior uveitis can occur in the absence of bacterial infection. This can be secondary to systemic endotoxin. Initial stages involve neutrophil exudation from uveal vessels; whereas later stages mainly involves macrophages. Acute and chronic uveitis can be differentiate by looking at the size and colour of keratitic precipitates. In chronic non-granulomatous anterior uveitis, there are keratic precipitates which largely consist of macrophages and lymphocytes. In acute anterior uveitis, they are mainly neutrophils. This condition can also lead to iris stroma and dilator muscle atrophy.

Question 20

Episcleritis is associated with .... Episcleritis caused by chronic inflammation differs in which it involves infiltrate of ... on top of typical ... and ....

Answer 20

Episcleritis is associated with autoimmune diseases. Episcleritis caused by chronic inflammation differs in which it involves infiltrate of lymphocytes/ plasma cells on top of typical redness and oedema.

Question 21

Chronic granulomatous conjunctivitis involves ..., ..., ... and .... Chronic granulomatous inflammation can be secondary to .... Granuloma on a histological slide can appear with a ... of ... which initiated inflammation, surrounded by infiltrated cells.

Answer 21

Chronic granulomatous conjunctivitis involves epithelioid cells, giant cells, lymphocytes and plasma cells. Chronic granulomatous inflammation can be secondary to blocked meibomian glands (chalazion). Granuloma on a histological slide can appear with a clear centre area of dissolved lipid which initiated inflammation, surrounded by infiltrated cells.

Question 22

... is a form of immunogenic response of the eye, causing ..., ... inflammatory responses. A typical physical sign is the formation of .... These are ... of the palpebral conjunctiva. There is accumulation of ... and ..., which are indicative of an ... response.

Answer 22

Vernal kertoconjunctivitis is a form of immunogenic response of the eye, causing acute, IgE-mediated inflammatory responses. A typical physical sign is the formation of cobblestone papillae. These are hard, flat topped, central vessels of the palpebral conjunctiva. There is accumulation of eosinophils and basophils, which are indicative of an allergic response.

Question 23

Corneal ... is secondary to inflammation. This can be caused by ..., ... , ..., infection, ..., dry eye disease etc. Sterile epithelial injury can be resolved ..., therefore requires .... This process involves ... and ....

Answer 23

Corneal opacity is secondary to inflammation. This can be caused by Sx, injury, foreign body, infection, chemical, dry eye disease etc. Sterile epithelial injury can be resolved rapidly, therefore requires little intervention beyond pain control and topical antibiotics. This process involves neutrophil & macrophage infiltration and transient Keratocytes activation.