In Rare Cases, Hypoparathyroidism Can Be Linked With SLE

Hypoparathyroidism associated with systemic lupus erythematosus (SLE) is uncommon, but a new case report serves as a reminder that clinicians ought to consider the possibility of the endocrine disorder when treating patients with SLE.

Corresponding author Alireza Khabbazi, MD, of Iran’s Tabriz University of Medical Sciences, and colleagues, noted that SLE can present in a wide variety of systemic manifestations, including the endocrine system. Yet, they said simultaneous SLE and hypoparathyroidism is believed to be uncommon.

“SLE associated with hypoparathyroidism is underestimated and usually has subclinical manifestation,” they said. “Hypoparathyroidism associated with SLE is extremely rare; to our knowledge, only 10 cases have been reported.”

Writing in Clinical Case Reports, Khabbazi and colleagues describe a patient who had symptoms of hypoparathyroidism concurrently with her initial diagnosis of SLE. The patient, a 19-year-old woman, sought medical attention in February 2021 due to a low-grade fever and myoclonus. She informed physicians that she had previously sought medical care for delayed menstruation. In that case, which occurred 40 days prior, she was treated with dydrogesterone. That led to a diffuse erythematous rash. She was then given an antihistamine, but did not improve. Instead, she began experiencing myoclonic movements and developed a fever, prompting her to return to the hospital.

“On admission, she had an erythematous rash across the nose and cheek and myoclonic movements in the tongue and lower limbs,” Khabbazi and colleagues said. “Her body temperature was 37.8°C (100.04°F).”

The rest of the patient’s vital signs were normal, the authors said. However, both Trousseau’s and Chvostek’s signs were positive.

After a series of laboratory tests and electrocardiography that revealed a prolonged QT interval, the patient was treated for hypocalcemia. Investigators suspected hypoparathyroidism secondary to autoimmune disease.

“Thyroid ultrasound showed a large heterogeneous thyroid consisting of many hypoechoic nodules (Hashimoto type),” they noted.

The patient’s malar rash, pancytopenia, and antibody tests were used to diagnose the patient with SLE, for which doctors prescribed prednisolone and hydroxychloroquine. Khabbazi and colleagues then determined that the patient’s hypocalcemia was likely due to hypoparathyroidism, given that the hypocalcemia was severe, phosphorus levels were average, and parathyroid hormone levels were low.

“In our opinion, autoimmune damage to parathyroid glands could be considered the best explanation for hypoparathyroidism in this patient, given no history of surgery or irradiation in the neck, negative family history, or absence of other genetic factors disorders, and underlying SLE disease,” they wrote.

The patient was also diagnosed with Hashimoto’s thyroiditis, they added.

Khabbazi and colleagues noted that postsurgical and idiopathic hypoparathyroidism are the most common types of hypoparathyroidism, but they said autoimmune causes are also possible. Though they said few cases of hypoparathyroidism have been reported in SLE specifically, the coincidence of the 2 conditions can be serious.

“Despite the low incidence, hypoparathyroidism has significant complications and symptoms, including prolonged QT interval, which may lead to sudden death; severe hypocalcemia may lead to heart failure; long-term hyperphosphatemia may cause calcification and ossification of several vital tissues,” they wrote.

In most cases, the authors said, hypoparathyroidism presents either before or simultaneously with SLE. They said it is important for physicians to remember the possibility of hypoparathyroidism when treating patients with SLE.

“This study reminds us to consider the possibility of autoimmune hypoparathyroidism and pay attention to the symptoms of this condition before and during the diagnosis of SLE,” the authors concluded.

Reference

Gadakchi L, Ebrahimi AA, Sadra V, Moslemi M, Khabbazi A. Hypoparathyroidism as one of the initial presentations of systemic lupus erythematosus. Clin Case Rep. Published online September 5, 2022. doi:10.1002/ccr3.6288