A 65-year-old Female with Spontaneously Resolving Hyperparathyroidism?

Sarah Jane B. Samalca, M.D. and Ma. Karen Celine I. Vega, M.D.

This is a case of a 65-year-old female who was admitted at our institution for sudden onset of palpitations, non-rotatory dizziness, and generalized body malaise. Two weeks prior to admission, she missed a step while walking down a staircase and fell on her right arm. She then sustained a comminuted fracture and dislocation of her right humerus, which was treated with immobilization using a sling. Her medical history includes hypertension and dyslipidemia, and she takes the following oral maintenance medications: Telmisartan 40 mg daily, Bisoprolol 5 mg daily, Rosuvastatin 5 mg thrice weekly, and Clopidogrel 75 mg every other day. She has no history of arrhythmias and cardiac diseases. Her family history is significant for hypertension, diabetes, and breast cancer. She is a housewife with no vices. Upon admission, her vital signs were normal except for a heart rate of 120 to 170 beats per minute with irregularly irregular rhythm. Her body mass index was 26.4 kg/m². She was seen wearing a right arm sling with a swollen right shoulder. The rest of her physical examination was unremarkable.

Diagnostic work-up revealed new-onset atrial fibrillation on a 12-lead electrocardiograph and hypercalcemia (ionized calcium 6.6 and 6.36 mg/dL, reference range 4.48 – 5.28 mg/dL), with normal renal and thyroid function. Her vitamin D level was mildly decreased at 29.10 ng/mL (reference range 30 – 40 ng/mL), indicating Vitamin D insufficiency. Elevated parathyroid hormone (PTH) level (234.80 pg/mL, reference range 15 – 65 pg/mL) and 24-hour urinary calcium level (427 mg/24hr, reference range 100-300 mg/24hr) indicated primary hyperparathyroidism. Neck ultrasound demonstrated a parathyroid focus on the left lower pole with concurrent multiple nodules on both thyroid lobes with no cervical lymphadenopathy (Fig. 1). During hospitalization, the patient was managed for paroxysmal atrial fibrillation, hypertensive atherosclerotic cardiovascular disease, vitamin D insufficiency, and primary hyperparathyroidism likely due to a parathyroid adenoma. After stabilization, the patient was discharged with a regimen of antihypertensives, antiarrhythmics, antiplatelet, and Vitamin D supplement. She was not given medications for hypercalcemia, but she was given instructions for further outpatient examinations.

Fig. 1. Neck ultrasound. A, B, C. Normal-sized thyroid gland with bilateral lobe nodules, as described. D. A parathyroid focus is seen in the left lower lobe.

Subsequent parathyroid scintigraphy revealed a Sestamibi-avid focus in the mid-pole of the right thyroid lobe, suggesting a hyperfunctioning thyroid nodule or adenoma or a hyperfunctioning intrathyroid parathyroid gland (Fig 2). Bone densitometry was also done which showed osteoporosis. The patient, although generally well, experienced occasional palpitations and abdominal discomfort, prompting a referral to a head and neck surgeon for potential parathyroidectomy. Ultrasound-guided fine-needle aspiration biopsy (FNAB) of the Sestamibi-avid nodule was performed since it had a thyroid imaging reporting and data systems (TIRADS) score of 4 and a sonographic measurement of 1.15 x 0.99 x 0.82 cm. This resulted in post-biopsy neck swelling and pain lasting for one week. FNAB results indicated cytological features consistent with a colloid nodule (Bethesda II) and non-diagnostic smears (Bethesda I) from the right lower pole of the thyroid gland.

Fig. 2. Dual-Phase Parathyroid Scintigraphy using 99mTc-Sestamibi. A. Parathyroid scintigraphy shows an intrathyroidal Sestamibi-avid focus in the mid-pole of the right lobe which is non-specific. Considerations include a hyperfunctioning thyroid nodule or adenoma, malignancy, and a hyperfunctioning intrathyroid parathyroid. B. Planar and SPECT-CT images of the neck and thorax were acquired 10 minutes and 2 hours after tracer administration. Delayed images reveal tracer uptake in the mid-pole of the right lobe. This affected area exhibits a high-density HU (approximately 75 HU).

Three weeks after her FNAB was done, she presented at the clinic with no symptoms, normal calcium levels, and a significant decrease in intact PTH level (from 234.8 pg/mL to 140.60 pg/mL), hence parathyroidectomy was deferred. A repeat x-ray of her right arm and shoulder showed a less delineated fracture and cortical irregularities of the humerus with callus formation. No medications were prescribed, and the patient was advised close monitoring and to return for follow-up after three months.

At the three-month follow-up, the patient remained asymptomatic with unremarkable physical examination findings. Her calcium levels were still within normal ranges. The patient’s intact PTH further decreased to 84.30 pg/mL, hence no medications such as cinacalcet and bisphosphonates were given. She was advised follow-up with repeat laboratory tests and a repeat bone densitometry.

The table below shows a summary of her laboratory trends:

In summary, this patient with primary hyperparathyroidism secondary to a parathyroid adenoma exhibited apparent recovery following ultrasound-guided FNAB. The question arises: Is this resolution indicative of a response to the procedure, or could this be a case of spontaneous resolution of primary hyperparathyroidism? The apparent resolution of hyperparathyroidism following ultrasound-guided FNAB prompts contemplation on the factors contributing to this unexpected outcome. It beckons us to question whether the procedural intervention played a decisive role in mitigating the hyperparathyroid state or if this case represents an instance of spontaneous resolution.

In light of the intriguing clinical course observed in this patient, further inquiry into the long-term prognosis becomes paramount. Does this observed resolution denote permanence or is there a potential for recurrence? Considering the implications for clinical management and prognostication, a comprehensive understanding of the underlying mechanisms and the potential for recurrence is imperative. As we navigate the complexities of parathyroid pathology, an exploration into the anticipated prognosis and the likelihood of sustained resolution would undoubtedly contribute valuable insights to the broader discourse on the management of primary hyperparathyroidism.