Tonsillitis
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Direct answer
Count the episodes before you count anything else. Most sore throats are viral, but group A beta-haemolytic Streptococcus pyogenes tonsillitis — suggested by the modified Centor features of fever, tonsillar exudate, tender anterior cervical nodes and absence of cough — is treated with penicillin, orally for ten days or as a single intramuscular injection of benzathine penicillin G 1.2 million units (6 lakh units below 27 kg). Recurrent attacks meeting the Paradise criteria (seven in a year, five per year for two years, or three per year for three years) justify tonsillectomy, as do obstructive sleep apnoea and quinsy, while the feared complications follow their own timeline: peritonsillar abscess within days, rheumatic fever at two to three weeks and post-streptococcal glomerulonephritis at one to three weeks.
What you must remember
- Centor or modified Centor/McIsaac scoring: fever, tonsillar exudate, tender anterior cervical lymphadenopathy and absence of cough raise streptococcal probability; each added point in the modified score also adjusts for age.
- Bacterial causes: Streptococcus pyogenes above all; diphtheria (grey adherent membrane, bull neck) and infectious mononucleosis (posterior cervical lymphadenopathy, splenomegaly) are the classical mimics.
- Penicillin is drug of choice: oral phenoxymethylpenicillin for 10 days, or a single deep intramuscular injection of benzathine penicillin — 1.2 mega units in adults and children over about 27 kg, 0.6 mega units below that, the convention taught across Indian practice.
- Avoid ampicillin or amoxicillin in suspected infectious mononucleosis: a florid maculopapular rash follows, and its appearance in a question stem is practically a diagnosis.
- Paradise criteria for recurrent tonsillitis: at least 7 episodes in the preceding year, 5 in each of 2 years, or 3 in each of 3 years — with each episode truly documented.
- Other tonsillectomy indications: obstructive symptoms and sleep-disordered breathing in a child (the commonest modern indication), peritonsillar abscess (quinsy), suspicion of malignancy (asymmetric tonsil), and diphtheria carriers.
- Post-tonsillectomy haemorrhage: primary within the first 24 hours and secondary at 5–10 days from slough separation — the timing pair examiners test every year.
Numbers worth knowing
Take a 6-year-old with six documented attacks in the past year, each with fever above 38 degrees, exudate and cervical nodes. She is one attack short of the Paradise bar, so the examinable answer is continued medical management with attention to hygiene and carrier states in the family, not surgery. Her individual attacks are managed by the Centor logic: four features present means treat empirically with penicillin and review; zero or one feature means symptomatic care. Add the antibiotic conventions: ten full days of oral penicillin to eradicate the organism and prevent rheumatic fever, or single-dose benzathine penicillin where adherence is doubtful — the standard Indian field option, also the regimen used in rheumatic fever secondary prevention at intervals of three to four weeks.
Now extend the timeline. An untreated attack can become quinsy within days (trismus and a bulging soft palate — a different topic, but it earns a tonsillectomy discussion after drainage). Two to three weeks later, a migratory polyarthritis with carditis answers rheumatic fever, and one to three weeks after pharyngitis, periorbital oedema with hypertension and cola-coloured urine answers post-streptococcal glomerulonephritis — which, unlike rheumatic fever, does not recur after subsequent infections and is not prevented by treating every sore throat of the household. Finally, if the same child returns a week after tonsillectomy with fresh bleeding from the mouth, that is secondary haemorrhage from slough separation: return to theatre, and check for a bleeding disorder. Scarlet fever completes the set — "strawberry tongue" and a sandpaper rash with circumoral pallor answering group A streptococcus with erythrogenic toxin.
How the exam frames it
The three question families are the criteria family (Centor features, Paradise numbers), the antibiotic family (drug of choice, duration, benzathine dose split by weight), and the complication family (quinsy, rheumatic fever, glomerulonephritis with their intervals, scarlet fever rash). The planted traps are simple once seen: the amoxicillin-rash stem points to mononucleosis; the membrane-that-bleeds points to diphtheria, not routine exudate; and a child snoring with apnoeic pauses answers adenotonsillar hypertrophy as the indication for surgery, not infection counts at all.
Frequently asked questions
What are the Centor criteria?
Fever, tonsillar exudate, tender anterior cervical lymphadenopathy and absence of cough; more features present means higher probability of streptococcal pharyngitis.
What is the dose of benzathine penicillin for streptococcal throat infection?
1.2 million units intramuscularly as a single dose in adults and children over about 27 kg, and 0.6 million units below that weight.
What are the Paradise criteria for tonsillectomy?
Seven or more episodes in one year, five per year for two consecutive years, or three per year for three consecutive years, with each episode clinically documented.
When does post-tonsillectomy bleeding occur?
Primary haemorrhage within the first 24 hours, and secondary haemorrhage classically 5–10 days post-operatively from slough separation of the tonsillar fossa.
Which complication follows streptococcal pharyngitis at one to three weeks?
Post-streptococcal glomerulonephritis; rheumatic fever follows at two to three weeks — a timing pair that decides many one-liners.