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A summary of the diagnostic strategy model is presented in TABLE 73.2.
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Probability diagnosis
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The majority of sore throats, mainly pharyngitis, will be caused by a virus. A viral infection is supported by the presence of coryza prodromata, hoarseness, cough, conjuctivitis and nasal stuffiness.
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Serious disorders not to be missed
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It is vital to be aware of Haemophilus influenzae infection in children, especially between 2 and 4 years, when the deadly problem of epiglottitis can develop suddenly. These patients present with a short febrile illness, respiratory difficulty (cough is not a feature) and are unable to swallow.
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Apart from acute epiglottitis it is important not to overlook cancer of the oropharynx or tongue, or the blood dyscrasias, including acute leukaemia (see CHAPTER 26). The severe infections not to be missed include streptococcal pharyngitis with its complications, including quinsy, diphtheria and HIV infection (including AIDS).
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A foreign body may stick in the supraglottic area and may not be seen on oral examination.
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There are many pitfalls, the classic being to diagnose the exudative tonsillitis of EBM as streptococcal tonsillitis and prescribe one of the penicillins, which may precipitate a severe rash. Primary HIV infection can present with a sore throat along with other symptoms. Adenovirus pharyngitis can also mimic streptococcal pharyngitis, especially in young adults.
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Traumatic episodes are important but are often not considered, especially in children. They include:
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a foreign body—may cause a sudden onset of throat pain, then drooling and dysphagia
vocal abuse—excessive singing or shouting can cause a sore throat and hoarseness
burns—hot food and drink, acids or alkalis
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Red flag pointers for sore throat
Persistent high fever
Failed antibiotic treatment
Medication-induced agranulocytosis
Mouth drooling: consider epiglottitis (don’t examine the throat)
Sharp pain on swallowing (? foreign body)
Marked swelling of quinsy
Candidiasis: consider diabetes or immunosuppression
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Various irritants, especially cigarette smoke in the household and smoke inhalation from fires, can cause pharyngeal irritation with sore throat, especially in children.
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The mouth and pharynx may become dry and sore from mouth breathing, which is often associated with nasal obstruction (e.g. adenoid hypertrophy, allergic rhinitis).
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Tonsilloliths are concretions of debris entrapped within deep tonsillar crypts. They are a common cause of halitosis, vague sore throat and possibly recurrent bouts of tonsillitis.
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Seven masquerades checklist
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Depression may be associated with a sore throat. Diabetes and aplastic anaemia and drugs are indirectly associated through candidiasis, neutropenia and agranulocytosis respectively. NSAIDs can cause a sore throat. The possibility of thyroiditis presenting as a sore throat should be kept in mind.
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The issues of making a reliable diagnosis and prescribing antibiotics are rather contentious and at times difficult. It is difficult to distinguish clinically between bacterial and viral causes. The main issue is to determine whether the sore throat has a treatable cause by interpretation of the clinical and epidemiological data.
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The appearance of the pharynx and tonsils is not always discriminating. A generalised red throat may be caused by a streptococcal or a viral infection, as may tonsils that are swollen with follicular exudates. On probability, most sore throats are caused by a virus and generally do not show marked inflammatory changes or purulent-looking exudates (see FIG. 73.1). Such throats should be treated symptomatically.
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