Haemophilus Influenzae

Question 1

Describe the shape of H.Influenzae

Answer 1

It is seen as short coccoid bacilli pairs or short chains

Question 2

How is H.Influenza diagnosed in a lab?

Answer 2

H.Influenzae can be cultured on chocolate agar as it contains both X factor (hematin) and V factor(NAD).
Alternatively, it can grow in the presence of staph aureus as it is hemolytic and produces V factor.

Question 3

Which virulence factors are associated with H.Influenzae?

Answer 3

IgA protease
Polyribosephosphate (PRP) capsule
Adherence factor pilli
Biofilm formation (common mostly in un-encapsulated variation)

Question 4

What diseases are associated with H.Influenzae?

Answer 4

Epiglottitis
Meningitis
Otitis media
Pneumonia

Question 5

Describe the symptoms of epiglottitis. (At least 4)

Answer 5

Fever
Drooling
Dysphagia
Muffled voice
Stridor
Respiratory retractions
Tripod position.

On a lateral X-ray, Thumbprint sign can be observed

Question 6

A child presents in the clinic sitting on their hands with their tongue out and head forward. What is this position called and why is the child sitting like this?

Answer 6

This is the Tripod position and the child assumes this stance to help them breath better presumably due to an inflamed epiglotis associated with H.Influenzae.

Question 7

What treatment options are available for H.Influenza?

Answer 7

H.Influeanzae is susceptible to Ampicilling

Mucosal infections can be treated with Amoxicillin

Meningitis can be treated with Ceftriaxone

Prophylaxis caused by H.Influenzae can be treated with Rifampin