Multi-organ involvement and intratubular calcium phosphate deposition in the kidney biopsy: what should we investigate?

Background Anorexia nervosa is frequently associated with alcohol use disorder. Both of them may adversely affect almost every body system, leading to worse clinical outcomes and high mortality risk. Nonetheless, there is little evidence interrelating anorexia nervosa, alcohol use disorder, and kidney failure. Case We report a case of a 30-year-old male with multi-organ involvement at admission, including pancytopenia, electrolyte alterations, impaired liver function, and renal failure. The kidney biopsy revealed calcium phosphate crystalline nephropathy and IgA nephropathy. The bone marrow biopsy and aspiration showed a hypocellular bone marrow and a focal spindle cell infiltrate with atypical vascular proliferation. Nonspecific liver disease was revealed by ultrasound. Further investigation was performed, uncovering a possible masked diagnosis of anorexia nervosa and alcohol use disorder. With the restoration of adequate nutrition and the withdrawal of possible external triggers, a partial recovery was achieved. Conclusions Anorexia nervosa and alcohol use disorder may promote tissue injury, including kidney failure, specifically calcium phosphate crystalline nephropathy and IgA nephropathy. This multi-organ involvement may lose its reversibility if anorexia nervosa and alcohol use disorder remain persistent. An early diagnosis and a successful multidisciplinary approach may prevent life-threatening complications. Level of evidence Level V, case report.