Thyroid abscess.OS Rohondia, RS Koti, PP Majumdar, T Vijaykumar, RD Bapat
Department of General Surgery & Gastroenterology Surgical Services, Seth G S Medical College, Parel, Mumbai.
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 0010707713
Source of Support: None, Conflict of Interest: None
Thyroid abscess arising from Acute Suppurative Thyroiditis (AST) is a rare clinical disorder. The ability of the thyroid gland to resist infection is well known and infection in the thyroid gland is rare, particularly so with the advent of widespread usage of antibiotics. An internal pharyngeal fistula (Pyriform sinus fistula) is the most common underlying abnormality in patients with AST. We report a case of an adult male who presented with a thyroid abscess. The causal organism was found to be Staphylococcus aureus. Intravenous antibiotics and, incision and drainage of the abscess led to an uncomplicated recovery.
Keywords: Abscess, diagnosis,therapy,Adult, Antibiotics, administration &dosage,Case Report, Drainage, Follow-Up Studies, Human, Male, Staphylococcal Infections, diagnosis,therapy,Staphylococcus aureus, isolation &purification,Thyroid Diseases, diagnosis,therapy,Tomography, X-Ray Computed, Treatment Outcome,
Acute suppurative thyroiditis (AST) leading to thyroid abscess is a rare clinical entity. Thyroid abscess and AST represent only 0.1 to 0.7% of surgically treated thyroid pathologies. AST affects specially patients with pre-existing thyroid gland pathology and in childhood is associated with local anatomic defects. It has been reported that the pyriform sinus fistula (internal fistula) is the route of infection and is the most common underlying abnormality in the patient with AST. Because of its rarity arid unusual clinical features, the diagnosis of suppuration in thyroid gland is often delayed. Progress to abscess formation may then occur with all the inherent dangers of advanced suppuration in the neck.
The authors present a case of thyroid abscess in an adult male. This case is reported because of the rarity of the condition.
A 38 years old farmer presented with an enlarging, painful neck swelling of 15 days duration. There was history of high grade fever, odynophagia and dysphagia since the onset of the neck swelling. Prior to the onset of present complaints, he was completely asymptomatic and there was no history of thyroid abnormality. contact with tuberculosis, neck irradiation, foreign body impaction or respiratory tract infection. Past history was unremarkable.
On admission the patient was febrile, had tachycardia but no evidence of respiratory distress. Examination of the neck revealed a large swelling occupying the region of the thyroid gland, extending from posterior border of one sternomastoid to the other and more prominent on the left than the right side. The mass was tender, warm and fluctuant and the overlying skin were oedematous and erythematous. The upper limit was the thyroid cartilage above which skin and deeper tissues did not show any changes of inflammation. The swelling did not extend onto the anterior chest wall. The floor of the mouth and fauces showed no abnormality. Swallowing exacerbated the pain. The trachea showed a significant shift to the right. The limitation of the swelling to the thyroid region and presence of significant dysphagia prompted us to investigate further.
Laboratory investigations revealed leucocyte count of 17,600 with 84% polymorphs, haemoglobin of 9.5 gms % with hematocrit of 45%. Plain radiographs of the neck and chest in frontal and lateral views, showed a homogenous soft tissue density anterior to the trachea and displacing it to the right. The retro-pharyngeal space had normal dimensions on radiographs. Computed tomography revealed cystic areas in both the lobes of the thyroid gland which did not enhance with contrast, the left side having a larger cystic area extending into the superior mediastinum but without any distortion of the mediastinal structures [Figure - 1]. Needle aspiration of the fluctuant mass from the left side obtained thick yellow pus and culture yielded staphylococcus aureus. Thyroid hormone assay showed a moderate increase in levels of T3 and T4 with TSH suppression. 99m Technetium scan showed cold areas corresponding to the cystic areas in both the lobes of the thyroid gland.
In the operating room a small incision was made on the fluctuant mass on the left side and a thin tube drain was inserted which drained pus for 72 hours after which the drainage was scanty. The patient was given intravenous antibiotics and after 3 days the pain and dysphagia resolved and he could swallow solids without any discomfort.
The patient did well and had a uncomplicated recovery. Ultrasonography done 15 days following drainage revealed a near total resolution of the abscess on the left side and only a small sonoluscent area in the right lobe. The drain tract healed completely and the patient was discharged.
Primary thyroid abscess resulting from Acute Suppurative Thyroiditis (AST) is an unusual type of head and neck infection. The ability of the thyroid gland to resist infection is well known and inflammatory pathologies of the thyroid such as AST are uncommon. The frequency with which this proceeds to abscess formation is rare particularly with the advent of widespread usage of antibiotics- In a review of literature by Schweitzer and Olson in their publication in 1981, have noted that only 39 cases of thyroid abscess had been reported in the medical literature since 1950, of which 16 were in children.
The remarkable resistance of the thyroid gland to infection is attributed to many factors. A prosperous lymphatic and vascular supply, well developed capsule, high iodine content of the gland are various mechanisms suggested to account for this relative resistance to infection,. Since the gland has no external connections the route of infection was a mystery. In 1978, Takai et al reported 15 patients with AST where a piriform sinus fistula was the apparent route of infection' I. The pyriform sinus fistula is an internal pharyngeal fistula and has been shown to be the most common underlying abnormality in patients with AST. The fistula ends in or adjacent to the thyroid and allows bacterial infection to develop in or around the gland. The left side is more commonly involved than the right. Treatment includes incision and drainage of the abscess or partial thyroidectomy depending upon the presence or not of underlying thyroid pathologies. It is absolutely necessary to eliminate the source of infection often a piriform sinus fistula whose total resection effectively prevents a relapse.
The most important causal organisms are staphylococcus aureus and streptococci with frequent isolation of mixed flora. There have been reports in literature where klebsiella, Salmonella More Details typhi Salmonella bradenburg and Eikinella corrodens have been isolated in individual cases as the causal organisms. AST responds well to antibiotics (intravenous) with or without incision and drainage of the abscess and rarely causes an external fistula. In this case a decision to drain the abscess was taken in view of a large abscess in the left lobe extending into the superior mediastinum, which must have burst through the perithyroidal space.
The patient is doing well and asymptomatic at 1 month of follow-up. A repeat CT scan, thyroid scan and thyroid hormonal work up is intended.
[Figure - 1]