Acute Pharyngitis

Acute Pharyngitis

·        Almost 100% given broad-spectrum antibiotics.  Inappropriate in 90% of cases

·        Pathogens:

·        Viruses: Adenovirus, also rhinovirus, coronaviruses, RSV, Parainfluenza virus, influenza, enteroviruses, EBV

·        Bacteria: S Pyogenes (GABHS = Group A Beta-Haemolytic Strep) in about 20 – 30% of cases, predominantly in those over 4 years

·        Differentiating (at best 70% predictive accuracy):

·        Exudative tonsillitis: Adenovirus, GABHS, EBV

·        > 4 years, enlarged tender anterior cervical lymph nodes and diffusely inflamed pharyngeal structures (+ exudates) suggests S Pyogenes

·        Diffuse, sandpaper-like red rash, accentuated in skin creases (Pastia lines) suggest Scarlet Fever.

·        Nasal discharge, cough, hoarseness, conjunctivitis or diarrhoea +/- fever +/- tonsillar exudates suggests virus

·        Throat swabs: usually identify organism, but 10 – 50% are carriers

Treatment:

·        Aim: Prevent acute rheumatic fever, suppurative complications (peri- or para tonsillar abscess) and hasten recovery

·        But

o   Only benzathine penicillin has been shown to reduce RF – and this was in military personnel

o   No convincing data which shows antibiotics reduce the risk of rare suppurative complications

o   Antibiotics reduce symptoms by 8 hours only 

o   Reinforces the notion that antibiotics are effective and increases the likelihood of their future use for trivial illnesses

·        If high risk for RF (eg Maori, PI, > 4 years of age) take swabs or treat empirically. However, prescribing penicillin for sore throat hasn‟t altered the rates of RF, and many children with RF haven‟t consulted their doctor

·        S Pyogenes: penicillin, 500 – 1000 mg BID for 10 days (Allergy: erythromycin)

·        Clinical signs: fever, respiratory distress, cervical lymphadenopathy, pharyngeal erythema, pharyngeal exudates

Causal Organisms

Bacterial Causes:

Fungal causes:

Diagnosis

·        Throat swabs:

o  For routine bacterial culture: especially to confirm/exclude Strep Pyogenes

o  Low sensitivity (?30%) and specificity (?75%)

o  40 – 50% of people with sore throats have bacteria isolated

o  Lots of variability: swab-taking technique, delays in transport, etc

o  Worth it for $18?

·        Nasopharyngeal washings (kids): Antigen detection by immunoflouresence for RSV, Influenza A & B, Parainfluenza 1 – 3 and adenovirus