Case description of crowned dens syndrome in a patient with Hashimoto’s thyroiditis—possible association mediated by systemic autoimmunity?

Introduction

First described in 1985, crowned dens syndrome (CDS) is a rare condition characterized by crystal deposition (1). It is a clinic-radiologic disease caused by the accumulation of phosphate or hydroxyapatite crystals in the area surrounding the dentate process (1). Its main clinical manifestations are acute head and neck pain, muscle stiffness, and fever; however, less than one in five patients exhibit these symptoms (2). Thus, the clinical presentation of CDS is uncommon, and it is often diagnosed incidentally. Studies suggest that many autoimmune diseases are risk factors for the development of CDS (3). We present this case report to explore the potential association between CDS and Hashimoto’s thyroiditis (HT).

Case presentation

A 68-year-old female presented with persistent pain in her bilateral shoulder and neck following a bus-related injury some 10 hours ago. The patient attended the Emergency Department of The Second People’s Hospital of Chengdu for further treatment. To assess for the presence of cervical fractures and dislocations, the patient underwent a computed tomography (CT) examination, which showed symmetrical striated hyperdense shadows around the dentate process in the transverse and sagittal views, forming a distinct “crown” shape. The patient was diagnosed with CDS (Figure 1).

Figure 1 Computed tomography images of the 68-year-old female patient. The transverse and sagittal views showed symmetrical strips of hyperdense shadow around the dentate process, forming a distinct “crown” shape. The arrow indicates calcium salt deposition.

The patient was further evaluated by the Orthopedic Department. The neck examination revealed an enlarged thyroid gland. The orthopedist suspected that the CDS was related to HT, and prescribed thyroid ultrasound and related laboratory tests. The laboratory analysis revealed an increase in hypersensitive C-reactive protein (CRP; 11.8 mg/L, reference range <3 mg/L), the erythrocyte sedimentation rate (ESR; 35 mm/h, reference range 0–15 mm/h for males and 0–20 mm/h for females), anti-thyroid peroxidase antibody (TPOAh; 336.05 IU/mL, reference range 0–34 IU/mL), and anti-thyroglobulin antibody (389.97 IU/mL, reference range 0–40 IU/mL). The ultrasound results are shown in Figure 2. The ultrasound and laboratory findings suggested HT.

Figure 2 The patient’s thyroid gland was enlarged in size with marked thickening of the isthmus. Internal echoes were diffusely hyperechoic and unevenly distributed, with strong echoes in the form of fine lines or coarse networks. Parenchymal blood flow signals were abundant, with a “sea of fire” sign, and the PSV values were elevated, suggesting hyperthyroidism or normal thyroid function. PSV, peak systolic velocity.

A biopsy was then performed. Hematoxylin and eosin staining microscopically showed massive lymphocyte and plasma cell infiltration, thyroid follicular epithelial cell atrophy, structural destruction, and mesenchymal hyperplasia. Based on the patient’s medical history and various examinations, a diagnosis of HT and CDS was made.

The patient was prescribed 10 mg of dexamethasone once daily for anti-inflammatory treatment (course of treatment: 3 days), 0.2 g of celecoxib capsules twice daily for analgesia, 1 flurbiprofen gel paste tablet, twice daily for external application, and 50 µg of levothyroxine sodium tablets once daily for thyroid hormone supplementation. After 1 week, the patient’s ultrasensitive CRP and ESR decreased to 8 mg/L and 30 mm/h, respectively. Her thyroid function also improved, and her anti-thyroglobulin antibody decreased to 200.89 IU/mL.

All procedures in this study were performed in accordance with the ethical standards of the institutional and/or national research committee(s). This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this article and the accompanying images. A copy of the written consent form is available for review by the editorial office of this journal.

Discussion

CDS is defined as acute head and neck pain due to calcification of the ligaments and structures surrounding the odontoid process of the cervical vertebra, accompanied by elevated CRP or ESR (4). The patient’s cervical spine CT showed calcification of the ligament around the dentate process. The patient suffered from shoulder and neck pain after a car accident. The patient’s CRP and blood sedimentation were elevated. Based on these symptoms, the patient was diagnosed with CDS. The current causes of CDS include calcium pyrophosphate crystal deposition, age and gender factors, and other diseases (e.g., autoimmune diseases).

HT, also known as chronic lymphocytic thyroiditis, is an autoimmune disease that develops specifically in the thyroid gland (5). Uh et al. suggested that autoimmune diseases can cause periapical calcification, which may occur in association with disease-induced inflammation (3). In the present case, the patient’s thyroid-stimulating hormone was elevated, and her anti-thyroglobulin antibody and TPOAh tests were positive. Thyroid ultrasound suggested diffuse echogenic changes in the thyroid gland and the presence of abnormal immune reactions. In combination with her thyroid pathology, a diagnosis of HT secondary to CDS was considered. A review of the literature revealed a paucity of clinical reports.

Hashimoto’s hyperthyroidism often occurs in the early stage of HT, resulting in changes in blood calcium concentration, which in turn leads to calcium salt deposition. The development of Hashimoto’s hyperthyroidism is associated with thyroid follicular cell destruction due to the inflammatory reaction of antibodies against thyroid antigens, as well as thyroid tissue stimulation by the autoimmune inflammatory reaction due to thyroid-stimulating antibody, which together promote the release of thyroid hormones into the bloodstream. Thyroid follicular cell damage and the thyroid antigen-antibody-induced inflammatory response activate other remaining thyroid follicular cells, causing them to function in a compensatory manner, which in turn activates other remaining thyroid follicular cells, leading to compensatory hyperfunction and thus to hyperthyroidism (6,7).

In this clinical case cervical CT examination revealed calcified deposits around the dentate process of the C1–C2 segment, which is considered the “gold standard” for the clinical diagnosis of CDS (8). CDS needs to be differentiated from gout, cervical spondylosis, rheumatoid arthritis, ankylosing spondylitis, giant cell arteritis, and rheumatic polymyalgia, all of which are characterized by acute head and neck pain, and increased CRP and ESR, making the diagnosis of CDS difficult. Cervical spine CT is essential for the diagnosis of CDS and also aids in the prevention of unnecessary invasive procedures, such as temporal artery biopsy, lumbar puncture, or cervical spine surgery, and the use of medications (8).

As there is no direct pharmacologic therapy to eliminate the presence of crystal deposits in the joints or to prevent their deposition, treatment seeks to reduce the associated inflammation. The preferred treatment modality is non-steroidal anti-inflammatory drugs (NSAIDs). Corticosteroids have also been shown to be effective. Takahashi et al. found that the CRP levels and pain scores of patients with CDS improved following hormone therapy compared to NSAIDs. Patients with CDS are often elderly, and the use of high doses of corticosteroids can lead to further complications (9). Therefore, the primary treatment for CDS is a combination of NSAIDs and low-dose steroids (10). If CDS presents in a subacute or relapsing fashion, low-dose colchicine is recommended as a long-term treatment option (11).

Conclusions

The patient did not have any clinical symptoms of CDS before the car accident. Like most cases of CDS in clinical practice, the patient’s condition was discovered incidentally. In this case HT was also detected. While CDS is common, it is rare that HT and CDS are detected simultaneously. Autoimmune diseases are considered risk factors for the development of CDS. HT may be associated with CDS through mechanisms that promote calcium deposition and elevate blood calcium levels, leading to the development of CDS, assuming other risk factors are excluded. In clinical practice, following a diagnosis of CDS, clinicians should consider other comorbidities, perform early screening, administer timely treatment, and takes steps to minimize the risk of misdiagnosis.

Acknowledgments

None.

Footnote

Funding: None.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-382/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s). This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Bouvet JP, le Parc JM, Michalski B, Benlahrache C, Auquier L. Acute neck pain due to calcifications surrounding the odontoid process: the crowned dens syndrome. Arthritis Rheum 1985;28:1417-20. [Crossref] [PubMed]
2. Salaffi F, Carotti M, Guglielmi G, Passarini G, Grassi W. The crowned dens syndrome as a cause of neck pain: clinical and computed tomography study in patients with calcium pyrophosphate dihydrate deposition disease. Clin Exp Rheumatol 2008;26:1040-6.
3. Uh M, Dewar C, Spouge D, Blocka K. Crowned dens syndrome: a rare cause of acute neck pain. Clin Rheumatol 2013;32:711-4. [Crossref] [PubMed]
4. Constantin A, Bouteiller G. Acute neck pain and fever as the first manifestation of chondrocalcinosis with calcification of the transverse ligament of the atlas. Five case-reports with a literature review. Rev Rhum Engl Ed 1998;65:583-5.
5. Li Q, Wang B, Mu K, Zhang JA. The pathogenesis of thyroid autoimmune diseases: New T lymphocytes - Cytokines circuits beyond the Th1-Th2 paradigm. J Cell Physiol 2019;234:2204-16. [Crossref] [PubMed]
6. McLachlan SM, Rapoport B. Thyrotropin-blocking autoantibodies and thyroid-stimulating autoantibodies: potential mechanisms involved in the pendulum swinging from hypothyroidism to hyperthyroidism or vice versa. Thyroid 2013;23:14-24. [Crossref] [PubMed]
7. Cunha LL, Ferreira RC, Marcello MA, Vassallo J, Ward LS. Clinical and pathological implications of concurrent autoimmune thyroid disorders and papillary thyroid cancer. J Thyroid Res 2011;2011:387062. [Crossref] [PubMed]
8. Awisat A, Rosner I, Rimar D, Rozenbaum M, Boulman N, Kaly L, Silawy A, Jiries N, Ginsberg S, Hussein H, Slobodin G. Crowned dens syndrome, yet another rheumatic disease imposter. Clin Rheumatol 2020;39:571-4. [Crossref] [PubMed]
9. Takahashi T, Tamura M, Takasu T, Kamei S. Clinical and quantitative analysis of patients with crowned dens syndrome. J Neurol Sci 2017;376:52-9. [Crossref] [PubMed]
10. Tang J, Li J, Wu C, Li Y, Lu Q, Xie W, Zhang T, Li X. Report of four cases of crowned dens syndrome: Clinical presentation, CT findings and treatment. Exp Ther Med 2020;20:3853-9. [Crossref] [PubMed]
11. Zhang W, Doherty M, Pascual E, Barskova V, Guerne PA, Jansen TL, Leeb BF, Perez-Ruiz F, Pimentao J, Punzi L, Richette P, Sivera F, Uhlig T, Watt I, Bardin T. EULAR recommendations for calcium pyrophosphate deposition. Part II: management. Ann Rheum Dis 2011;70:571-5. [Crossref] [PubMed]