Bone Dysmorphia-Induced Blindness Following a Secondary Hyperparathyroidism: A Case Report

Abstract

Introduction: Conjunctival-corneal or choroidal calcifications are frequent in SHPT, blindness is however exceptional. We report a case of blindness secondary to compressive ischemic optic neuropathy. Case Report: Mr. B.E.K., 49 years old, has a chronic renal failure secondary to unlabeled glomerular nephropathy for 17 years. He has been on chronic hemodialysis for 12 years and has had SHPT for nine years. He secondarily developed disabling segmental osteoarticular deformities associated with kyphoscoliosis, “drumstick” fingers and facial dysmorphism. Five months before admission he developed eye pain and reduced visual acuity progressing within one month to blindness. Biology noted: serum creatinine at 726 umol/l (60 - 120 umol/L), azotemia at 14.3 mmol/l (2.5 - 7.5 mmol/L), serum calcium at 2.25 (2.25 - 2.55 mmol/L), phosphatemia at 1.13 (0.8 - 1.35 mmol/L), alkaline phosphatases at 2196 (5 - 270 IU/L) and parathyroid hormone level at 2257 (10 - 60 pg/mL). Retinal angiography revealed lesions suggestive of ischemic neuropathy. The orbit CT scan with 3D coronal reconstruction revealed narrowing of the caliber of the optical channels with dystrophic thickening of the skull base and cranial vault. Cranioencephalic and orbital MRI revealed diffuse brown tumors and pre-chiasmatic optic atrophy. Discussion: The most frequent ocular complications of SHPT are conjunctival-corneal or sclero-choroidal calcifications, asymptomatic, associated with hypercalcemia. Compressive manifestations are rarer, represented mainly by an amputation of the visual field, diplopia, ptosis or blindness, as described in our patient. The main cause is osteodystrophy and brown tumors of the skull base (1% - 2%). Conclusion: This case report underlines the importance of early detection of SHPT, in order to avoid its major complications, such as blindness, especially since current preventive and curative measures have proven their effectiveness.