AAES GUIDELINES 4:
PARATHYROID LOCALIZATION MODALITIES/PREOPERATIVE PREPARATION.
RECOMMENDATION: Patients with pHPT who are candidates for parathyroidectomy should be referred to a surgeon to decide which imaging studies to perform based on their knowledge of regional imaging capabilities.
COMMENT: The message of this recommendation is that the diagnosis of pHPT is a biochemical one and imaging has no role whatsoever in confirming or excluding the diagnosis. The decision to operate is not based on imaging findings and results should not be used to select patients for surgical referral. Patients with negative imaging are still candidates for parathyroidectomy given the high rate of false negative imaging, especially in cases of MGD. In other words, a diagnosis of pHPT should lead to a referral to an experienced parathyroid surgeon who then undertakes the appropriate localisation studies.
RECOMMENDATION: Cervical US is recommended to localize parathyroid disease and assess for concomitant thyroid pathology.
RECOMMENDATION: Preoperative parathyroid FNAB is not recommended except in cases of difficult localization and should not be performed if parathyroid cancer is suspected.
RECOMMENDATION: An experienced parathyroid surgeon should help determine which type of sestamibi scan (if any) to use based on their knowledge of their region’s imaging capabilities.
RECOMMENDATION: US, sestamibi scanning, and 4D CT may be used independently or in combination, at the surgeon’s discretion.
RECOMMENDATION: MRI and venous sampling should be reserved for cases of difficult localization, contra-indications to ionizing radiation, or re-operative parathyroid surgery.
COMMENT: All the above recommendations simply note that three techniques are currently used, namely sestamibi scanning (Nuclear Medicine), ultrasound, and 4DCT scanning (a multiphase CT scan) and the parathyroid surgeon is best placed to advise. In Australia, 4DCT is becoming the most appropriate initial study other than for young patients, as it is rapid and provides both anatomical and functional information.
RECOMMENDATION: Most patients with pHPT should follow Institute of Medicine guidelines for calcium intake.
COMMENT: It is important not to restrict calcium intake prior to surgery
RECOMMENDATION: Prior to parathyroidectomy, patients who are vitamin D deficient should be started on supplementation.
COMMENT: Likewise it is important not to stop Vitamin D therapy prior to surgery
RECOMMENDATION: Preoperative voice evaluation should include specific inquiry about subjective voice changes with additional evaluation of vocal cord motion should be performed in patients with significant voice changes and/or a history of prior surgery (cervical or thoracic) in which the vagus and/or recurrent laryngeal nerve was at risk for injury.
COMMENT: Laryngoscopy is not a routine requirement prior to parathyroid surgery unless there are existing voice issues
RECOMMENDATION: Patients who present with hypercalcemic crisis should be medically managed and followed by expeditious parathyroidectomy.
COMMENT: A very high calcium level in a patient with pHPT is a an urgent surgical situation