Hypoparathyroidism and Fahr's syndrome: case series

Abstract

Hypoparathyroidism (HP) is a rare metabolic disorder and causes hypocalcemia because parathyroid hormone secretion is inadequate to mobilize calcium from bone and reabsorb calcium from kidney and gut. Anterior neck surgery is the most common cause of acquired HP and autoimmune HP is the next most common form in adults. The duration, severity, and rate of development of hypocalcemia determine the clinical presentation. A variety of organs can be affected by calcification, more frequently kidneys, but also joints, eyes, skin, vasculature, and other organ systems and, although rarely seen, intracerebral calcifications. We report four cases of bilateral basal ganglia calcifications (BGC) also known as Fahr's syndrome related to hypoparathyroidism. Fahr's syndrome is characterized by bilateral symmetrical calcification of areas of the brain that control movements including basal ganglia, thalamus, and others; it is a rare inherited or sporadic neurological disorder with a prevalence of less than 1/1.000.000. Main symptoms related to bilateral BGC include extra-pyramidal and cerebellar disorders, cognitive impairment, epileptic seizures, and psychiatric changes. BGC has been established as a possible outcome of HP. Its prevalence, demonstrated in the HP cohorts, varied significantly from 12 up to 74%. Currently, computed tomography (CT) is the most valuable method for diagnosis. The treatment include symptomatic support and identification of causes, but there is no specific treatment limiting the progression of calcification in the basal ganglia. Especially in HP, an early treatment can prevent calcification and neurophysiological disorders.

Figure 1. Cranial CT - Case 1 (A, B, and C): sparse white matter calcifications, base nucleus, thalamus, dentate nucleus, and cortical/subcortical regions in the occipital lobes. Case 2 (D and E): multiple symmetrical areas of calcifications in the supra/infratentorial deep gray matter and white matter in the perivascular and central pons territories. Case 3 (F): diffuse calcifications in the supratentorial white matter, base nucleus, thalamus, dentate nucleus, and some cortical/subcortical regions in the occipital lobes. Case 4 (G): calcifications in lentiform nucleus, heads of caudate nucleus, subcortical nucleus in frontal lobes, and cerebellar hemispheres.