Endocrine Disorders Parathyroid PDF

Endocrine disorders Parathyroid gland disorders Parathyroid glands are small endocrine glands in the neck of humans that produce parathyroid hormone. Humans usually have four parathyroid glands, variably located on the back of the thyroid gland. P...

Endocrine disorders Parathyroid gland disorders Parathyroid glands are small endocrine glands in the neck of humans that produce parathyroid hormone. Humans usually have four parathyroid glands, variably located on the back of the thyroid gland. Parathyroid hormone and calcitonin (one of the hormones secreated by the thyroid gland) have key roles in regulating the amount of serum calcium level in the blood(9-11 mg/100 ml blood) and within the bones. Mode of action of parathyroid hormone 1.  calcium absorption from GIT. 2. calcium reabsorption from kidney. 3. Stimulate osteoclastic activity thus bone minerals (Ca) are mobilized to blood. 4. phosphate excretion from kidney. 5. synthesis of 1.25 dihydroxy cholecalciferol (vit D) which aid in calcium absorption from GIT. Ca function in the body: Enter in the structure of bone and teeth. Necessary for coagulation, muscle contraction and nerve function. 1 Disorders of the parathyroid gland 1- Hypoparathyroidism Etiology Surgical excision accidentally during thyroidectomy. Di george syndrome (Congenital absence of parathyroid, thyroid gland, aortic arch anomalies, congenital heart defect, hypoplastic or absent thymus gland) Cell mediated autoimmune glandular destruction Radiation to the neck, metastatic cancer, infections….. Clinical features General manifestations When calcium level is below 7 mg/100 ml blood, signs of Tetany appear as: Nausea, vomiting. Parasthesia, Numbness of perioral tissue, lip, tongue, fingers and toes. Muscle cramps, irritability or excitability. Trousseau’s sign: carpopedal spasm occur when the blood supply to the hand is reduced by application of blood pressure cuff above the systolic pressure. Chvostek’s signs: twitching of facial muscles when tapping of facial nerve in the preauricular region. Oral manifestations Enamel hypoplasia. Abnormal dentin formation Delayed eruption of teeth. Wide pulp chambers. Apical foramen may remain open Short roots. 2 Diagnosis: serum calcium decreased below 7mg\100ml serum phosphorous elevated Dental implication Dental management: low Ca level may cause may result in arrhythmia and heart block. Frequent oral care is needed for patients with hypoplastic teeth. increased risk of caries Emergency treatment of tetany is IV injection of 10-30 ml of 10% calcium lactate. 2- Hyperparathyroidism Etiology Primary: Due to parathyroid gland enlargement (parathyroid adenoma). Secondary: To low serum calcium: due to renal failure, malabsorption or prolonged dialysis.(compensatory ) Tertiary: Due to long standing secondary hyperparathyroidism.(parathyroid tissue may become unresponsive to the blood calcium levels therefore absence of the negative feedback inhibition ) Clinical features General manifestations 1- Bone Generalized osteoporosis. Osteitis fibrosa cystica( replacement of bone by fibrous tissue). Giant cell lesion (brown tumor). Bone pain. Pathologic fracture, (clinician must be careful to avoid iatrogenic jaw fracture). 3 2- Kidney Renal stones. Hematuria. Urinary tract infection. Renal hypertension. 3- Gastrointestinal tract Anorexia. Nausea. Vomiting. Peptic ulcer. Crampy pain. Oral manifestations Bone: As in general manifestations. Loss of lamina dura. Looseness and drifting of teeth. Giant cell granuloma (brown tumor) Radiographically: cortical resorption and rarefaction, loss of trabeculation results in ground glass appearance Thining or even loss of cortical bone of the maxilla or mandible Dental implication Peptic ulcer Renal failure Bone fragility could complicate dental management. GOOD LUCK A. Prof. Dr. Souzy Kamal Anwar 4