Acute Neck Pain from Crowned Dens Syndrome: A Case Report and Clinical Insights

Introduction

Crowned dens syndrome, also known as calcium pyrophosphate deposition disease, has a reported prevalence of 15% among individuals aged 65–74 years, with no sex differences [1]. If calcification of the cartilage occurs in the ligaments around the odontoid process, it can result in either years of asymptomatic behavior or acute episodes of headaches and neck pain, mimicking the symptoms of meningitis (eg, fever, severe pain, acute onset) [2]. CDS can cause acute cervical pain, more commonly in females (60%) [3,4]. First described in 1985 [2], the syndrome is most prevalent in individuals over the age of 60. The pathological basis is a metabolic disorder characterized by the deposition of calcium pyrophosphate crystals around the odontoid process of the C1 and C2 cervical vertebrae and the surrounding transverse ligaments [5]. Blood tests usually reveal elevated markers of inflammation [6]. Conventionally, NSAIDs have been regarded as the first-line drugs for CDS [7]. It was found that nonsteroidal anti-inflammatory drugs and prednisolone in combination were most effective and thus are the recommended treatment [4,7,8].

If misdiagnosed as an infection, invasive cervical procedures may be performed by physicians, whereas conservative treatment is actually the best approach [9]. This article presents a case of a 62-year-old man with CDS with acute headache and neck pain, to increase clinicians’ awareness and reduce mis-diagnosis rates.

Case Report

A 62-year-old man with a medical history of hypertension and hyperlipidemia presented to the Emergency Department with “cutting-like” headaches and neck pain for 2 days. The preliminary examination revealed that his blood pressure was 155/85 mmHg, body temperature was 37.2°C, and heart rate was 74 beats/min. Physical examination also revealed a soft cervical spine with limited range of motion and no neurological signs. A cervical computed tomography (CT) scan and hematological tests were recommended. Test results indicated leukocyte count of 12 000/µl and C-reactive protein levels of 53.1 mg/dl. CT findings showed linear calcification around the odontoid process, suggesting CDS (Figure 1). The patient was advised to take oral nonsteroidal anti-inflammatory drugs and to rest, and his symptoms improved after 3 days. A 2-month follow-up in the outpatient clinic revealed that his neck pain had almost completely resolved.

Discussion

CDS was first reported by Bouvet in 1985 and is most common in individuals over the age of 60 [10]. It presents as mild to severe pain in the neck and shoulders, accompanied by occipital headaches [11]. Patients often experience short-term fever, exacerbated neck pain, and headaches [12]. The condition is more common in females and is associated with pseudogout, hyperparathyroidism, hemochromatosis, and hypophosphatasia [13]. However, Koyfman et al reported on a 53-year-old woman with CDS who did not have inflammatory indicators [14], suggesting that our consideration for CDS needs to be more extensive.

The pathological basis involves deposition of calcium pyrophosphate or hydroxyapatite crystals in and around the odontoid process, synovial membranes, joint capsules, transverse ligaments, cruciate ligaments, and alar ligaments [15]. While usually asymptomatic, it can trigger further non-specific inflammatory responses, leading to attachment of various protein molecules to its surface. Neutrophils phagocytose these protein complexes, causing an inflammatory response and the release of proteolytic enzymes that erode the ligamentous tissue, further exacerbating the inflammation [16]. The pathophysiological mechanisms behind the deposition of calcium pyrophosphate or hydroxyapatite are not yet fully understood.

Imaging diagnosis can be confirmed through a cervical CT scan, making it crucial to suspect this diagnosis and perform a cervical CT scan accordingly [12]. The syndrome is frequently misdiagnosed as several other conditions, including cervical trauma, meningitis, osteomyelitis, intervertebral disc infection, and fever of unknown origin. Importantly, it is necessary to perform a cervical CT scan during the acute phase; otherwise, the calcification may be absorbed, making it difficult to diagnose CDS on subsequent scans [17]. Therefore, multiple follow-up examinations are recommended.

Complications of CDS include persistent degeneration of the atlantoaxial joint, ligamentous erosion leading to atlantoaxial instability, and atlantoaxial dislocation resulting in spinal cord compression [18]. Overall, the prognosis in these reported cases is generally good. During acute episodes, treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) is recommended for 2–3 weeks. If symptoms do not significantly improve, a short course of corticosteroids can usually alleviate the condition. To date, no medications have been developed to eliminate existing crystal deposits in the ligaments or to prevent their formation, so the focus of treatment is on reducing the associated inflammation. Low-dose colchicine has been suggested as a long-term treatment option to prevent recurrence of CDS [9]. For long-term cases leading to atlantoaxial dislocation and spinal cord compression with resultant neurological decline, surgical decompression and internal fixation fusion are the primary treatment options [18].

Koyfman et al reported a case of CDS in which a patient had occipital pain and calcified deposits in the alar ligament, while our patient had head and neck pain and linear calcification around the odontoid process. There are subtle differences in the location of calcification between the 2 cases, and their patient did not have inflammatory symptoms, but our patient had obvious inflammatory symptoms – elevated body temperature, C-reactive protein, and white blood cells [14]. Comparison of these 2 cases shows that the location of calcification and the presence or absence of inflammatory response adds great difficulty to the diagnosis of CDS. When dealing with cases of pericervical pain, the possibility of CDS should be considered.

Conclusions

For older patients presenting with new-onset headaches and neck pain accompanied by elevated inflammatory markers, especially those with a history of pseudogout, the possibility of CDS should be considered. A cervical CT scan is the preferred initial investigation to avoid unnecessary lumbar punctures as well as antibiotic or antiviral treatments. To date, there have been no large-scale clinical studies for follow-up treatment of this disease. However, data from case reports suggest that oral NSAIDs and short courses of corticosteroids can generally alleviate symptoms.