An unusual cause of recurrent tonsillitis

Abstract

Primary tuberculosis of the oral cavity and oropharynx is quite uncommon, and primary isolated tuberculosis of the tonsils is extremely rare. We report a case of primary tonsillar tuberculosis, in an otherwise healthy man, mimicking chronic non-specific tonsillitis.

Background

Tuberculosis (TB) is regarded as the most common communicable disease worldwide. After the introduction of antitubercular therapy and immunisation, the incidence of tubercular infection declined dramatically.¹ Approximately 2% of patients with active pulmonary TB show evidence of upper respiratory tract involvement.² Before the introduction of chemotherapy, 6.5% of all tonsils removed from asymptomatic patients were infected with tubercles. With the advent of effective antitubercular therapy and pasteurisation of cow’s milk, a considerable reduction in the worldwide prevalence of TB was achieved and tonsillar TB became rare. The epidemiology of TB has changed recently with an increasing incidence of unusual presentations.¹ Oral and oropharyngeal TB lesions are uncommon. It is estimated that only 0.05–5% of total TB cases may present with oral manifestations. The most common site for oral and oropharyngeal TB is the tongue; however, other sites may also be affected. Involvement of the oral cavity and oropharynx by TB can be primary or, more often, secondary to pulmonary TB. The lesions of primary oral TB generally occur in younger patients. On the other hand, secondary lesions are most commonly seen in older individuals.³ Primary TB of the tonsils, mimicking chronic non-specific tonsillitis in the absence of pulmonary TB, in an otherwise healthy young male without any predisposing factor is rare, which has prompted us to report this case.

This paper serves to highlight the need to be constantly vigilant as tubercular tonsillitis may spring surprises on the clinician.

Case presentation

A 25-year-old man, an x-ray technician in a dental department, presented to the otolaryngology clinic with complaints of sore throat and difficulty in swallowing, with occasional fever. He had no prior history of any serious illness, cough, weight loss or exposure to TB or HIV. He had taken many courses of antibiotics and analgesics for sore throat without any relief.

While the general physical examination revealed normal findings, the oropharyngeal examination revealed bilateral enlarged tonsils with cheesy material filling the crypts and multiple ulcers over the surface. The posterior pharyngeal wall was slightly congested. There was no clinically palpable cervical lymphadenopathy.

Investigations

Chest and paranasal skiagram showed no abnormality. Routine haematological investigations were within normal limits, including the erythrocyte sedimentation rate (ESR) which was 06 mm at the end of first hour. Throat swab and sputum for acid fast bacilli was negative. The patient was seronegative for HIV and HBsAg.

Differential diagnosis

Differential diagnosis of oral and pharyngeal TB includes traumatic ulcers, aphthous ulcers, haematological disorders, actinomycosis, syphilis, midline granuloma, Wegner’s granulomatosis and malignancy, and chronic non-specific tonsillitis.²

Treatment

Bilateral tonsillectomy was done under general anaesthesia. Strangely, the tonsils were abnormally friable during the dissection; this raised suspicions and the specimen was sent for histopathology and tissue polymerase chain reaction (PCR). The PCR report was negative for TB but the histopathology showed stratified squamous lining of epithelium underneath lymphoid tissue, showing many granulomas scattered with many epithelioid cells, Langhan’s type giant cells with caseous necrosis. The impression was granular (tubercular) tonsillitis.

Outcome and follow-up

On the basis of the histopathology report, antitubercular treatment was started for 6 months. The patient, who was followed up regularly, completely recovered from his symptoms and the follow-up was uneventful.

Discussion

TB of the oral cavity is uncommon and tonsillar lesions are extremely rare. Oral cavity TB may be either primary or secondary. Tongue and palate are the common sites whereas tonsillar TB is rare.⁴ The upper respiratory tract is generally resistant to TB. Saliva by virtue of its cleansing action is thought to have an inhibitory effect on tubercular bacilli. The presence of saprophytes, the antagonism of striated musculature to bacterial invasion, and thickness of the protective epithelial covering of the oropharyngeal mucosa have an inhibitory affect.⁵

Isolated pharyngeal lesions are acquired by inhalation with harbouring of disease in Waldayer’s ring. Extrapulmonary localisation of TB is rare, and is usually encountered in patients with poor host reaction due to chronic alcoholism, HIV infection, etc.⁶ In our case, the patient was seronegative for HIV infection and had no predisposing factors. Our patient had recurrent episodes of chronic tonsillitis which makes the epithelium vulnerable for other infections. Since he was an x-ray technician in a dental department, occupational exposure of the already inflamed tonsil to TB is the only possible explanation for the localisation of tubercular bacilli in Waldayer’s ring.

During our investigation we encountered normal ESR, negative sputum and throat swab culture, and normal chest x-ray. For confirmation, histological examination, acid fast staining and culture should be done. Culture of microorganisms has shown good results, although it has technical difficulties, lacks sensitivity, and may take 4–6 weeks. Sophisticated techniques such as PCR can be used alternatively, especially when the conventional methods of diagnosis renders equivocal results.³ In our patient the tissue PCR was also negative. If PCR shows negative results when TB is strongly suspected, PCR results should be correlated with histopathology before starting treatment.⁷

The most common local symptom of tonsillar TB is difficulty in swallowing, which was also seen in our case. The histological findings of the resected tonsils confirmed the diagnosis of tonsillar TB.⁵ Though the PCR was negative, on the basis of histopathology the antitubercular therapy was started for 6 months and the patient’s symptoms completely resolved. Nevertheless, a history of exposure must be elicited in order to establish a proper diagnosis. Chronic non-specific tonsillitis not responding to antibiotic treatment is a very important differential diagnosis which mimics tubercular tonsillitis and is commonly overlooked.

Learning points

• Although TB of the tonsils is a relatively rare entity, a case with recurrent throat infection not responding to antibiotics, with evidence of inflamed tonsils, should alert the clinician to the possibility of TB as a causative factor, especially in regions where the incidence of TB is high.