Viral and bacterial Infections of the tonsils and / or pharynx 2

Question 1

How do skin infections typically occur?

Answer 1

They occur through breaks in skin
Cuts, bites, wounds, burns
* Can be minor/hardly visible

Question 2

List 3 skin infections in their order of severity

Answer 2

Mild to severe and life-threatening
* Impetigo
* Cellulitis
* Necrotising fasciitis

Question 3

What is bacteremia?

Answer 3

Spread of bacteria into blood, causing serious infections in other parts of the body.

Question 4

Describe impetigo

Answer 4

It is superficial, with clear yellow crusts. It is very contagious

Question 5

What is cellulitis?

Answer 5

It is a common bacterial skin infection that causes redness, swelling, and pain in the infected area of the skin.

Question 6

What would happen if cellulitis would be left untreated?

Answer 6

If untreated, it can spread and cause serious health problems.

Question 7

How is cellulitis prevented?

Answer 7

Good wound care and hygiene are important for preventing cellulitis.

Question 8

What is necrotising fasciitis?

Answer 8

It is an infection of fascia causing necrosis.
It is a rare bacterial infection that spreads quickly in the body and can cause death.

‘flesh eating infection/bacteria’

Question 9

How does necrotising fasciitis present clinically?

Answer 9

Often skin looks normal on outside but underneath tissues are necrotic.
Person is usually in severe pain and very sick

Question 10

How is necrotising fasciitis treated?

Answer 10

Needs rapid antibiotics and prompt surgery to remove dead tissue

Question 11

What are the suppurative complications of S. pyogenes infections?

Answer 11

Suppurative = Pus forming
* Abscesses (collection of pus)
* Swelling of local draining lymph nodes (adenitis)

Can also get spread from throat
* Locally to respiratory tract – middle ear, sinuses, lungs
* Via bloodstream to other parts of the body

Question 12

In a case of tonsilitis, what would be an example of a suppurative complication

Answer 12

quinsy or peritonsillar abscess forms between tonsil and the throat wall

Question 13

To what other areas can an infection of the throat spread?

Answer 13

-Locally to respiratory tract – middle ear, sinuses, lungs
* Via bloodstream to other parts of the body

Question 14

Name 2 immune-mediated complications of S. pyogenes infection

Answer 14

Rheumatic fever
Acute glomerulonephritis

Question 15

What does rheumatic fever affect?

Answer 15

Affects heart and heart valves sometimes causing permanent damage

Question 16

How does rheumatic fever occur?

Answer 16

Somehow immune reaction to S.pyogenes cross reacts with heart tissue
* Follows pharyngeal infection with certain ‘rheumatogenic’ M type strains of S. pyogenes

Question 17

T/F: rheumatic fever happens after streptococcal skin infections

Answer 17

F
Doesn’t happen after streptococcal skin infections. It happens after pharyngeal infection

Question 18

How is recurrent episodes of rheumatic fever prevented?

Answer 18

use long term penicillin
prophylaxis to prevent recurrent strep throat infections.

Question 19

What is acute glomerulonephritis?

Answer 19

Acute inflammation of glomeruli in kidney causing (usually) temporary decrease in renal function

Question 20

What causes acute glomerulonephritis?

Answer 20

Due to different ‘nephritogenic’ M type strains
* After throat or skin infections

Question 21

T/F: immune-mediated complications occur after a few days following initial infection with streptococcus pyogenes

Answer 21

F.
immune mediated complications are delayed, usually weeks after original streptococcal
infection which has usually disappeared, even without antibiotic treatment

Question 22

Name two diseases caused by pyrogenic exotoxins that are released by S. pyogenes.

Answer 22

Scarlet fever
Streptococcal toxic shock syndrome

Question 23

Explain streptococcal toxic shock syndrome.

Answer 23

Streptococcus produces a toxin that acts as a ‘super-antigen’ stimulating a massive inflammatory reaction.
Leads to shock and multi-organ failure.

Question 24

Streptococcal toxic shock syndrome is sometimes associated with which infection?

Answer 24

Necrotising fasciitis

Question 25

Clinical presentation of streptococcal toxic shock syndrome

Answer 25

Low Bp
Multiple organ failure, and even death

Question 26

How is Streptococcal toxic shock syndrome prevented?

Answer 26

Good wound care
Hand hygiene
Cough etiquette

Question 27

Who are streptococcal infections diagnosed? Name three tests

Answer 27

-Culture of swab from tonsils or skin lesion
-Antigen test
-Serology

Question 28

What are the downsides of culture of swab from tonsils or skin lesion? (3)

Answer 28

• Microscopy less valuable for throat because lots of other types of streptococci are mouth commensals
• Susceptibility testing less important because almost always susceptible to penicillin
• Problem is time to test result: at least 24 hrs

Question 29

How does Antigen test work? Also state 1 pro and 1 con of this test?

Answer 29

• Detects Lancefield Group A antigen directly.
  *Pro: Rapid
• Con: Less sensitive – so may miss some cases

Question 30

How does serology work?

Answer 30

Look for antibodies in serum to streptococcal toxins= indirect evidence of streptococcal
infection
Look for antibodies in serum to streptococcal toxins= indirect evidence of streptococcal
infection
* Anti-streptolysin O titre (ASOT)
* Anti-DNAse B

Question 31

Name 2 antibodies detected by serology

Answer 31

Look for antibodies in serum to streptococcal toxins= indirect evidence of streptococcal
infection
* Anti-streptolysin O titre (ASOT)
* Anti-DNAse B

Question 32

When is serology most useful?

Answer 32

Most useful for supporting diagnosis of immune complications which only happen some weeks
after initial infection