Trachoma

Question 1

How was chlamydia classified earlier ?

Answer 1

It was classified in between bacteria and viruses , as a separate organism

Question 2

How is chlamydia classified now ?

Answer 2

Now classified as bacterium belonging to the family chlamydiaceae

Question 3

What are the two genera coming under the family chlamydiaceae ?

Answer 3

Chlamydia
Chlamydophilia

Question 4

What is chlamydia ?

Answer 4

Small , obligate INTRACELLULAR , GRAM NEGATIVE BACTERIA

Has both DNA & RNA , ribosomes and cell wall similar to gram negative bacteria

Question 5

How does it differ form true bacteria ?

Answer 5

It lacks the peptidoglycan layer

Question 6

Why chlamydia is called as a energy parasite ?

Answer 6

This is because it lacks the ability to produce its own ATP , therefore it uses the host ATP

Question 7

What are the two morphologically distinct forms of chlamydia ?

Answer 7

Elementary bodies
Reticulate bodies

Question 8

What are EB ?

Answer 8

EB / elementary bodies - extracellular infectious particles that attaches to susceptible host cells , enters the cytoplasm of the host cells forms a vesicle and differentiates into RB

Question 9

What is RB ?

Answer 9

RB - Reticulate body
Metabolically active form divides by binary fission inside the vesicle and develops into inclusion body ( vesicle having many EB ) which is peri nuclear in nature and releases EB by burst of inclusion body infecting new cells

Question 10

Other name of trachoma

Answer 10

Egyptian ophthalmia

Question 11

Define trachoma

Answer 11

Trachoma is a CHRONIC KERATOCONJUNCTIVITIS , primarily affecting the superficial epithelium of cornea and conjunctiva simultaneously ; characterised by mixed follicular and papillary response of conjunctival Tissue , pannus formation and cicatrization in late stages giving rough appearance

Question 12

Causative Agent of trachoma ?

Answer 12

Chlamydia trachomatis biovar TRIC

Question 13

What are HP bodies ?

Answer 13

Halberstaedter prowazek bodies - cytoplasmic inclusion bodies produced by chlamydia trachomatis biovar tric

Question 14

How many serovars are present under chlamydia trachomatis biovar tric ?

Answer 14

12 serovars

A,B,Ba,C - hyperendemic trachoma
D to K - inclusion conjunctivitis

Question 15

What is the source of infection of trachoma in endemic zones?

Answer 15

Discharge of the affected person

Question 16

Clinical features of trachoma is described in how many stages ?

Answer 16

Two stages

Phase of active inflammatory trachoma - occurs in childhood due to active chlamydial infection

Phase of chronic cicatricial trachoma - occurs in middle age due to chronic mild grade inflammation

Question 17

What determines the symptoms of active inflammatory / active trachoma ?

Answer 17

Presence (most common ) / absence of secondary bacterial infection

Question 18

Features of pure trachoma ( no secondary bacterial infection )

Answer 18

M - mild foreign body sensation
O - occasional lacrimation
S - stickiness of the lids
S - scanty mucoid discharge

These symptoms are so mild that the disease is usually neglected and hence called TRACHOMA DUBIUM

Question 19

Symptoms of trachoma in the presence of secondary bacterial infection ?

Answer 19

Similar to acute bacterial conjunctivitis / acute mucopurulent conjunctivitis

Discomfort , foreign body sensation , redness of sudden onset ( due to engorgement of vessels )

Blurring of vision due to presence of mucus flakes in front of cornea

Mild photophobia

Mucopurulent discharge

Stickiness of the lid early in the morning

Coloured halos that disappears on washing the discharge

Question 20

What are the conjunctival signs of active inflammatory trachoma with secondary bacterial infection ?

Answer 20

Congestion
Follicles
Papillae

Question 21

Structure of conjunctival follicles

Answer 21

Boiled sago grain appearance found in palpebral and bulbar conjunctiva (pathognomonic of trachoma)

Central part - mononuclear histiocytes , multinucleated cells called LEBER CELLS , few lymphocytes

Cortical part - zone of lymphocytes showing active proliferation

Peripheral part - blood vessels + signs of necrosis

Question 22

Describe papillary hyperplasia

Answer 22

Gives red velvety appearance to the Tarsal conjunctiva

Has dilated blood vessels , lymphocytes covered with hypertrophied epithelium

Question 23

What are the corneal signs in active inflammatory trachoma having secondary bacterial infection ?

Answer 23

Superficial keratitis
Corneal ulcer
Progressive pannus
Herbert follicles