Primary hyperparathyroidism (PHPT) is the third most common endocrine disease, often accompanied by severe multiple organ damage: nephrocalcinosis / nephrolithiasis, decreased filtration function of the kidneys, erosive and ulcerative lesions of the gastrointestinal tract, osteoporosis and fibrocystic progenitor low-energy osteitis and recurrent cystic fibrosis with high-energy osteitis and low-energy pereferitis. Unfortunately, despite the rather vivid clinical picture, the manifest forms of PHPT remain unrecognized for a long time, which causes the deterioration of the patients’ condition. In the description of this clinical case, a long way to establishing a diagnosis in a patient with a severe course of primary hyperparathyroidism is presented. The given example is intended to increase the alertness of specialists in relation to this pathology.