Test 169  (MRCS Questions, 2003)

1. The following statements about tuberculosis are true: 

a. caseous necrosis is only seen in primary lesions

b. Langhans cell presence is a must for histological 
    diagnosis. 

c. viable bacteria may be found in calcified lesions. 

d. BCG may be given to neonates

e. the bacteria appear blue with acid fast staining

 
Answera.F   b.F  c.T   d.T  e.F
Caseation occurs in both primary and secondary infection.
Langhans cell is seen in TB granuloma but is not necessary for diagnosis. 
The bacteria is contained within the granuloma but remain viable and can reactivate when the immunity is low.
BCG is given to neonates at risk of TB especially if the mother is affected.
The bacteria appear red with acid fast staining.

2. The following are not seen in sarcoidosis:

a. epitheloid cells

b. caseation

c. asteroid bodies

d. Schaumann bodies

e. Touton's cells
 

Answera.F  b.T  c.F  d.F  e.T
Although small necrosis may be seen in sarcoidosis, caseation is not a feature its presence should suggest tuberculosis.
Asteroid bodies are star-shaped acidophilic bodies.
Schaumann bodies are spherical basophilic bodies containing calcium oxalate.
Touton's cells are not a feature of sarcoidosis it is seen in juvenile xanthogranuloma.
 
 

3. The following are first line treatment for postoperative endophtalmitis:

a. subconjunctival gentamicin

b. intravitreal amikacin

c. intravenous ciprofloxacin

d. intravitreal vancomycin

e. oral steroid
 

Answer
a.F   b.T  c.F  d.T  e.F
The first line treatment for postoperative endophthalmitis is intravitreal administration of antibiotics covering Gram positive and negative bacteria such as vancomycin and amikacin.

 

. 4. The following are true about the needles used in ophthalmic 
      surgery: 

a. round body needle: corneal transplant

b. reverse cutting: strabismus surgery

c. half-circle needle: suturing of posterior flap in DCR

d. spatulated needle: skin laceration

e. round body needle: iris repair 
 

Answer
a.F  b.F  c.T  d.F  e.T
Round body needle is used for soft tissue such
as iris repair. Reverse cutting may perforate 
the sclera and spatulated needle is recommended. Reverse cutting is used for skin.
.

5. Echothiophate:

a. is a muscarinic blocker

b. increases accommodation

c. causes iris cysts

d. lower intraocular pressure by surpassing aqueous
    production

e. prolongs the action of succinylcholine
 

Answer
a.F   b.T  c.T  d.F  e.T
Echotiophate is an indirect muscarinic agonist and 
works by inhibiting acetylcholinesterase. It can be 
used to treat accommodative esotropia by increasing accommodation. Like pilocarpine it lowers intraocular pressure by increasing the aqueous outflow.
Succinylcholine is broken down by acetylcholinesterase and echotiophate can prolongs its action.

 

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