Case 1: Case history #1 A 7-year-old girl fever, nausea, vomiting, and sore throat. NO cough, rhinorrhoea, or nasal congestion. oral temperature is 38.5°C exudative pharyngitis with enlarged, tender anterior cervical lymph nodes. Whats the diagnosis?
Acute pharyngitis
Significance of Absence of cough, nasal congestion, and nasal discharge
distinguishes bacterial from viral aetiologies.
Present: viral
Absent: bacterial
Define acute pharyngitis
rapid onset of sore throat and pharyngeal inflammation (with or without exudate).
What is the most common organism that causes this condition?
viral organisms or
group A Streptococcus (GAS).
List the common viruses
- Epstein-Barr virus (mononucleosis),
- adenoviruses
- enteroviruses
- influenza A and B, and
- parainfluenza
- corona virus
differentiate between viral and bacterial pharyngitis
Viral: Conjunctivitis cough, nasal congestion, and nasal discharge Mouth ulcer Hoarse voice
Bacterial: FOUR CRITERIA (3/4 indicates GAS) fever >38 Tonsilar/pharyngeal exudate Cervical lymphadenopathy No cough
List common bacterial causes:
• Streptococcus Group A ( S. pyogenes); is most common
bacterial causes of pharyngitis (5-15 years)
• Group C and G Streptococci
• Corynebacterium diphtheriae ( rare cause) why?
• Neisseria gonorrhoea (in patients with STD)
• Mycoplasma species and Arcanobacterium haemolyticum
(found rarely in adolescents with pharyngitis) .
What investigations would you perform?
It is microbiologically confirmed by a rapid antigen test, and if negative, a throat culture for GAS
The “gold standard” for diagnosis of S. pyogenes pharyngitis
Culture of throat swab
Culture of throat swab for group A Streptococcus
- Culture of a throat swab on a sheep-blood agar plate • β-hemolytic colonies
- Bacitracin susceptibility
- Gram-positive cocci in chains
- catalase-negative
- Groupidentification:LancefieldantigenAtest
GAS histology
Gram + cocci in chains
Beta hemolytic colonies
GAS is Bacitracin sensitive or not?
Yes
GAS: catalase + or -
-
Group identification
LancefieldantigenAtest
Treatment
- Antibiotic treatment:
• Penicillin or amoxicillin for 10 days
• For penicillin –allergic patients:
❖ Erythromycin
❖ first-generation cephalosporin 2. Adjunctive therapy:
• an analgesic/antipyretic agent (acetaminophen, ibuprofen)
Throat swab medium
Sheep blood agar
Complications of GAS
Glomerulonephritis
Acute rheumatic fever
Goal of treatment
Short symptoms
Prevent transmission
Prevent complications
