Dental manifestation of primary idiopathic hypoparathyroidism.

Idiopathic hypoparathyroidism (IHP) is a rare endocrinopathic disorder, of idiopathic nature, characterized by a deficiency of parathyroid hormone causing low serum calcium (Ca) and high serum phosphorus concentrations. We present a case report ofa 40-year-old woman with complaint of bleeding gums and tingling sensation in fingers and toes reported to our department in March 2005 with no tangible diagnosis from previous medical examinations. Oral findings included abnormally short roots, cemental hyperplasia, widening of the periodontal ligament space and root resorption. Laboratory investigations revealed a low serum Ca level and along with the clinical findings, a diagnosis of IHP was reached. Oral prophylaxis was performed and Ca supplements were prescribed. We believe that this case report is a first of its kind reporting cemental hyperplasia, altered alveolar bone patterns and periodontal ligament widening in a patient with IHP.

INTRODUCTION

Hypoparathyroidism is an uncommon metabolic disorder characterized by hypocalcemia and hyperphosphatemia due to a deficiency or absence of parathyroid hormone (PTH) the abbreviation is correct secretion.[1] It may occur in combination with other disorders, including autoimmune problems (e.g., autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome)[2] or developmental defects (DiGeorge syndrome and Velocardiofacial syndrome).[3] Hypoparathyroidism may also develop as an isolated entity of unknown etiology called idiopathic hypoparathyroidism (IHP).

Hypoparathyroidism can occur in two phases acute or chronic. In the acute form, it presents as consequent paresthesias, muscle spasms (i.e., tetany) and seizures. In contrast, in chronic hypoparathyroidism the onset is so gradual that the only symptom may be visual impairment from cataracts.[3] Permanent physical and mental deterioration can occur if initiation of treatment for either acute or chronic cases is delayed.[4] Disorders of ectodermal tissues are also common in patients with IHP. These disorders include alopecia, scaling of the skin, deformities of the nails and dental abnormalities.[5678] A less common aberration is delayed or cessation of dental growth and development.[7]

Hypoparathyroidism is diagnosed on the basis of measurements of serum calcium (Ca) and PTH levels. The treatments available for these patients are Ca salts, vitamin D or its analogs and drugs that increase renal tubular resorption of Ca, to obtain adequate, but low, normal serum Ca levels. Clinical evaluation of the patient and frequent determinations of serum Ca levels are indicated in the early stages of treatment. If PTH is absent or nonfunctional, its hypocalciuric action cannot occur and thereby the increase in serum Ca concentration may cause hypercalciuria, nephrolithiasis, or renal damage. In general, treatment is satisfactory; however, in longstanding cases, repair of cerebral and dental changes is not likely.

This case report describes atypical dental changes in a 40-year-old woman, which led to the diagnosis of primary IHP.

CASE REPORT

A 40-year-old female patient reported to the Department of Periodontics at SDM College Of Dental Sciences with the chief complaint of bleeding gums. She gave a medical history of hypothyroidism and complained of profuse bleeding from her gums andalso, general weakness, muscle cramps, tingling sensation over hands, feet and perioral region. A detailed dental examination revealed bleeding on probing, sub gingival calculus, generalized gingival inflammation, deep bite and periodontal pockets measuring 4-5 mm in depth with teeth 16, 26 and 12 [Figure 1]. Radiographic examination revealed abnormally short roots with respect to 16, 14, 15 and 26, 25 with intact lamina dura [Figure 2]. The orthopantamogram showed generalized cemental hyperplasia albeit mild in nature, widened periodontal ligament space and alteration in the bone trabecular pattern [Figure 3] warranting further investigation. Blood investigations showed decreased serum Ca level (7.1 mg/dl) and normal serum alkaline phosphatase level (126 U/L). Thyroid hormone (T3, T4 and thyroid-stimulating hormone) assay values were also normal, suggestive of Euthyroid state, whereas the PTH assay by Chemi-Luminescent Immuno Assay method showed subnormal parathormone values (7.3 pg/ml) [Table 1]. The lowered PTH in conjunction with lowered Ca levels led to a provisional diagnosis of hypoparathyroidism. Lateral skull radiographs were also taken to rule out any calcifications of the basal ganglia [Figure 4].

Figure 1

Clinical presentation

Figure 2

Full mouth intraoral periapical radiographs

Figure 3

Orthopantomogram

Table 1

Laboratory investigations

Figure 4

Lateral cephalogram

DISCUSSION

Two types of primary hypoparathyroidism have been described in medical literature-pseudohypoparathyroidism and IHP.[910] The basic difference between the two lies in their response to treatment with parathormone and dihydrotachysterol (vitamin D). In pseudohypoparathyroidism the Ca level returns to normal following vitamin D treatment but not following parathormone administration whereas IHP responds to both of these pharmacologic agents.

According to the consulted literature, only 6 studies investigating the oral findings in IHP patients have been published since 1966. Hypoplastic enamel is the most frequent finding, although short rounded roots, hypodontia and delay or lack of tooth eruption are also cited,[2711] some of which were observed in our patient as well. However, there were some atypical findings such as generalized cemental hyperplasia, altered trabecular pattern and widening of the periodontal ligament space, which have not been reported thus far in literature.

The dental findings in this patient are suggestive of reduced bone reparative capacity due to low serum Ca levels. The process of root resorption involves a complex interaction of inflammatory cells, resorbing cells, hard tissue, cytokines and enzymes such as collagenase, matrix metalloproteinase and cysteine proteinases.[12] The periodontal ligament is a specialized connective tissue, which acts as a barrier between the alveolar bone and cementum. Localized damage or loss of periodontal ligament renders the denuded cementum surface chemotactic to clastic cells such as osteoclasts, macrophages and monocytes, resulting in root resorption.[131415]

The presence of intact lamina dura in the intra oral periapical radiographs of the patient suggests that the short roots may be congenital in origin. Non-surgical periodontal therapy resulted in resolution of gingival inflammation and shallow periodontal pockets.

The patient was also prescribed vitamin D3 supplements, which alleviated her systemic symptoms. The serum Ca level were monitored periodically for 1 year post diagnosis and was found to be 9.7 mg/dl at the end of the first year; which was considered normal for age. She was also put on a periodontal maintenance phase.

CONCLUSION

A patient with a systemic disorder, such as IHP, a rare metabolic disorder, requires careful anamnesis and thorough clinical and radiographic examinations. The clinician must be alert to oral abnormalities such as cemental hyperplasia, enamel hypoplasia, widened pulp chambers, shortened roots, hypodontia which could be suggestive of a systemic disorder. A careful examination and diagnosis is fundamental to the treatment of such atypical systemic conditions.