Introduction

Tonsillitis

Tonsillitis is defined as inflammation of the tonsils, usually caused by infection with common viruses or bacteria. Tonsillitis is one of the most frequent reasons for attending the general practitioner. The tonsils are collections of lymphoid tissue - tissue involved in the production and regulation of lymphocytes, a type of white cell that forms an important part of the body’s defence against pathogens. Further, the term tonsil refers to the palatine tonsils, the pair of tonsils located at either side of the throat. There are, in fact, several tonsils which form a circumferential ring at the opening of the throat known as Waldeyer’s ring. This also includes the nasopharyngeal tonsil (adenoids), the lingual tonsil in the substance of the rear third of the tongue and two small tonsils at the opening of the tube that connects the middle ear to the throat (the eustachian tube). For the purpose of this article, the term tonsil will refer to the palatine tonsils.

Overview of quinsy (peritonsillar abscess) as a complication

The palatine tonsils lie between two pillars formed by muscles that connect the palate to the mouth and throat; the palatopharyngeus muscle to the front and the palatoglossus muscle to the rear. Between them these muscles form a recess in which the tonsil sits, surrounded by the tonsillar capsule. Spread of infection and formation of pus outside of the tonsillar capsule into the peritonsillar space is known as a quinsy or peritonsillar abscess and is the most common type of deep neck space infection. Usually these lie above the tonsil and extend toward the midline.

Causes of Tonsillitis

Tonsillitis results from common acute infections of the pharynx (throat). The majority of these are viral in nature and caused by the viruses that commonly cause coughs, colds, and sore throat - rhinovirus, influenza, adenovirus, and respiratory syncytial virus (RSV). Enteroviruses such as coxsackie virus, which causes hand-foot-mouth disease, are also a common cause in children. The Epstien-Barr virus (EBV), which causes glandular fever, is often found in adolescents. Other viral causes include cytomegalovirus (CMV) and herpes simplex virus (HSV).¹

Bacterial infections of the tonsils are also common. In children, around 30% of these will be due to group A beta-haemolytic streptococcus (GABHS) (commonly known as “strep throat”). However many other bacteria have been cultured, both aerobic and anaerobic.¹ 

In sexually active patients, neisseria gonorrhoeae (the cause of gonorrhoea), chlamydia, and even treponema pallidum (the cause of syphilis) have been implicated in tonsillitis.¹

Symptoms and signs of Tonsillitis

Tonsillitis typically presents with a fever, sore throat, painful swallowing (odynophagia), drooling (particularly in younger children), and restricted opening of the mouth (trismus). Generalised symptoms are dependent on the cause of tonsillitis and are features of infection with the causative organism. Conjunctivitis, cough and runny nose, and diarrhoea are strongly suggestive of a viral infection. Generalised swelling of the lymph nodes is typical of EBV and CMV and inflammation of the mouth and lips (stomatitis) is found in HSV infections.

Diagnosis

Physical examination may reveal the presence of fever and cause specific signs mentioned above. Examination of the oropharynx (mouth and throat) will show enlargement of the tonsils with redness of the pharyngeal tissues and pus in the tonsillar crypts. Examination of the neck may reveal enlargement of the cervical lymph nodes (“glands”).

Approaches to testing in tonsillitis differ greatly between the US and the UK. In the US, rapid antigen testing for GABHS is widely performed by primary care physicians (GPs) and antibiotics are prescribed frequently. The Infectious Disease Society of America (IDSA) recommends routine testing with rapid antigen testing unless the symptoms strongly suggest a viral cause or in children under the age of 3 years old.² In the UK, the National Institute for Health and Care Excellence (NICE) does not recommend routine rapid antigen testing as it does not see it as a prudent use of NHS resources.³ Rapid antigen testing provides a quick result with reasonable levels of sensitivity to detect GABHS infections. A throat swab sent to the lab for culture is more accurate but takes at least 1-2 days for the results to become available. Specific blood tests for viruses such as EBV may be indicated including a monospot test (more rapid result) and EBV serology (more accurate). General blood tests may show a raised white cell count on Full Blood Count and raised markers of inflammation such as ESR and CRP. Generally speaking however, in the UK, the diagnosis of tonsillitis is made on clinical grounds and does not routinely require any laboratory testing to confirm diagnosis.³

Treatment

As with diagnostic tests, there is wide variation in the use of antibiotics to treat tonsillitis between the US and the UK with 76% of adults and 71% of children being treated with antibiotics in the US, despite the majority of cases being viral in origin and unresponsive to antibiotic therapy.⁴ In the UK, the National Institute for Health and Care Excellence (NICE), recommends the use of clinical scoring systems to define populations of patients most likely to benefit from an antibiotic. These two scoring systems are known as fever PAIN (scored based on presence of fever, Purulence on the tonsils, Attending rapidly, severely Inflamed tonsils, and No cough) and CENTOR (based on tonsillar exudates, tender anterior cervical nodes, fever greater than 38 degrees, and an absence of cough). A fever PAIN score of 4-5 equates to a 62-65% chance of finding streptococcus and a CENTOR score of 3-4 a 32-56% chance of streptococcal infection. Patients with scores in these ranges are deemed most likely to benefit from an antibiotic.³

Oral penicillin V for 10 days is the antibiotic treatment of choice, so far there are no penicillin resistant strains of GABHS. Alternatives in patients allergic to penicillin include first generation cephalosporins or in the case of previous anaphylactic reactions to penicillin, macrolide antibiotics such as clindamycin, erythromycin, and clarithromycin.¹

Supportive treatment with analgesics and antipyretics is useful in all patients - paracetamol or NSAIDs such as ibuprofen or diclofenac help relieve pain and fever. Aspirin should be avoided in children because of the risk of Reye’s syndrome.¹

In recurrent episodes of tonsillitis, a tonsillectomy operation may be recommended. Currently in the UK, NICE recommends consideration of tonsillectomy in instances of 5 or more episodes in each of the two previous years.⁵

Complications of Tonsillitis

The complications of tonsillitis can be divided into those resulting from the spread of infection from the tonsils into the deep spaces of the neck forming abscesses (suppurative complications) and generalised complications.

Suppurative complications of tonsillitis are peritonsillar abscess (quinsy) - the most common with an incidence of 1 in 10,000, pharyngeal abscess, retropharyngeal abscess, and suppurative cervical lymphadenitis.⁶ Generalised complications are due to complications of GABHS infection and include acute glomerulonephritis (inflammation of the kidneys), scarlet fever, rheumatic fever, and streptococcal toxic shock syndrome.

Peritonsillar abscess (quinsy)

Infection spreads from the tonsil leading to a collection of pus forming in the peritonsillar space. It is generally accepted that this forms from an infection developing in the intratonsillar cleft and then spreading beyond the capsule surrounding the tonsil leading to peritonsillar cellulitis and subsequent abscess formation. Cases of abscesses forming in patients who have had a previous tonsillectomy are recorded however, leading to the alternative theory that peritonsillar abscesses develop from infection causing obstruction of minor salivary glands in the peri-tonsillar space.¹ 

Symptoms and signs

Peritonsillar abscess presents with fever, marked trismus (limited ability to open the mouth), enlargement of the cervical lymph nodes (“glands”), in severe cases drooling or inability to swallow own saliva, and significant pain on swallowing. Examination reveals unilateral (one-sided) enlargement around the tonsil with deviation of the affected tonsil and uvula to the opposite side. Bulging deformity of the area around the pharynx at the apex of the anterior tonsillar pillar is seen as the abscess develops usually above and lateral to the tonsil. Patients may develop so-called “hot-potato speech”, a thick, muffled voice caused by restriction of the muscles involved in speech. The neck may be held in a fixed position, a sign called torticollis. If there is significant obstruction of the upper airway, particularly if there has been extension into the pharyngeal or prevertebral spaces, a stridor (noisy, raspy breathing) may develop, indicating an airway threatening emergency.

Imaging

Imaging can help identify peritonsillar abscesses in very young children, in whom adequate intra-oral examination may be difficult, or to identify spread of infection into the pharyngeal and retropharyngeal (prevertebral) spaces. The following imaging methods may be employed:

• Soft-tissue lateral x-rays of the neck: Predominantly to identify extension of the soft tissues of the neck in front of the cervical vertebrae found in retropharyngeal extension of infection (retro-pharyngeal abscess). Because of the availability of far more accurate CT scanning, these are now relied on less frequently
• Intra-oral Ultrasound scanning: provides a quick and non-invasive way of differentiating between peritonsillar cellulitis and a peritonsillar abscess
• CT scanning with Contrast: the investigation of choice in unco-operative young patients and in cases where there is suspected spread into pharyngeal and retropharyngeal spaces. The drawback of CT scanning is the dose of radiation it exposes the patient to⁷

However, imaging is not required in many cases as the diagnosis of peritonsillar abscess can be made on clinical findings alone.⁷

Treatment

Medical treatment with intravenous broad spectrum penicillin plus metronidazole or clindamycin should be started (or a suitable alternative used in penicillin allergic patients), along with intravenous fluids to help manage dehydration from poor oral intake. 

Aspiration of the abscess contents using a wide bore needle and topical lignocaine spray for local anaesthesia is both therapeutic and diagnostic, not only confirming the presence of an abscess but in relieving pain. Pus can be sent to microbiology for culture and antibiotic sensitivity to tailor antibiotic treatment.⁸ 

Incision and drainage can be performed through the mouth using local anaesthetic spray. A guarded scalpel blade is used to make an incision either at the point of maximum bulge into the oropharynx or alternatively at the intersection of two imaginary lines drawn from the base of the anterior tonsillar pillar and the junction of the base of the uvula and the soft palate, The abscess cavity is then opened with forceps.⁸

In young children incision and drainage may need to be performed under general anaesthesia. 

Rarely, a procedure called a quinsy tonsillectomy is performed. In this procedure, the tonsils are removed at the same time as performing incision and drainage under general anaesthesia. This is generally only performed if there is airway compromise or a history of deep pharyngeal abscess. Secondary bleeding rates due to infection are higher in quinsy tonsillectomy than ordinary tonsillectomy.⁸

Complications

The most frequent serious complication of a peritonsillar abscess is acute obstruction of the upper airway. In severe cases, this may require intubation (placing a breathing tube into the upper airway) and mechanical ventilation. Intubation procedures can be challenging due to the occurrence of trismus (limited ability to open the mouth) and may require specialist intubation techniques eg. fibre-optic assisted intubation. 

Other deep neck space infections - pharyngeal and retropharyngeal abscesses can occur either through spread of infection from a peritonsillar abscess or directly from infected lymph nodes in the neck. Pharyngeal and retropharyngeal abscesses are most common in children under the age of 5 and may spread into the chest cavity infecting the space surrounding the heart (mediastinitis). They are fortunately rare with an incidence of 0.22 cases per 10,000.⁹ Patients with conditions affecting immunity such as diabetes or IV drug use are also more at risk of developing deep neck space infections.

Prevention

The identification of cases of tonsillitis most likely to benefit from antibiotic treatment based on current NICE guidelines has already been discussed. Special consideration may be given to patients who are at increased risk due to immune compromise (diabetes, HIV, IV drug abuse). However, a 2013 study published in the British Medical Journal concluded that clinical scoring systems were unable to predict which patients would go on to develop suppurative complications of tonsillitis including peritonsillar abscess. It recommended that appropriate safety-netting by clinicians and the use of “delayed prescriptions” (when a prescription is generated for future use should the symptoms worsen) was employed.¹⁰

In cases of recurrent peritonsillar abscess (2 or more episodes), this is an indication for an elective tonsillectomy procedure, to prevent further episodes.⁵

Summary

Tonsillitis is one of the most common infections presenting to the primary care physician (GP).

Most tonsillitis is caused by viruses and requires only symptomatic treatment however antibiotics may be indicated in certain cases. The use of clinical scoring systems is recommended in the UK to identify patients who may benefit from antibiotics. Peritonsillar abscess is the most common suppurative complication of tonsillitis. Treatment of peritonsillar abscess is by incision and drainage of the abscess under local anaesthesia. In cases of recurrent peritonsillar abscess, a tonsillectomy may be performed. Studies have shown that it is not possible to predict which cases of tonsillitis will go on to develop peritonsillar abscesses using clinical scoring systems.