title: A case of chronic hypomagnesemia in a cancer survivor.
abstract: OBJECTIVE
  Hypomagnesemia is common among hospitalized patients, particularly those who are critically ill. It can be associated with a number of potentially life-threatening cardiovascular, neurological and behavioral manifestations. As opposed to acute, chronic hypomagnesemia is often underdiagnosed and underreported and as such may pose a diagnostic and therapeutic problem.
  
  
  METHODS
  We describe a case of magnesium wasting in a middle-aged woman with head and neck cancer who presented with recurrent syncopal episodes complicated by a femur fracture 4 months after completing a course of carboplatin-containing chemotherapy. Fractional excretion of magnesium of 16% was consistent with renal wasting of magnesium. After ruling out all common causes of hypomagnesemia, it was concluded that she sustained carboplatin-induced renal tubular damage making her relatively resistant to magnesium supplementation.
  
  
  CONCLUSIONS
  Several antineoplastic agents have been linked to chronic hypomagnesemia including anti-epidermal growth factor receptor agents such as cetuximab and panitumumab, cyclosporine, and the platinum-based agents cisplatin and carboplatin. The example case presented here illustrates the importance of chronic hypomagnesemia and its possible debilitating effects following carboplatin-containing chemotherapy. A growing numbers of cancer survivors are treated with these antineoplastic agents, and are hospitalized for non-cancer-related problems. These patients may have prolonged hypomagnesemia, and hence pose a diagnostic dilemma. We review the pathophysiology, etiology, diagnosis, clinical manifestations, monitoring and treatment of hypomagnesemia, with special attention to mechanisms of renal damage caused by platinum-containing chemotherapeutic agents.
authors.affiliation: a Hospital Medicine Unit, Massachusetts General Hospital , Boston , MA , USA.|b Harvard Medical School , Boston , MA , USA.
authors.forename: Marko
authors.initials: M
authors.lastname: Velimirovic
authors.affiliation: a Hospital Medicine Unit, Massachusetts General Hospital , Boston , MA , USA.|b Harvard Medical School , Boston , MA , USA.
authors.forename: Joshua Charles
authors.initials: JC
authors.lastname: Ziperstein
authors.affiliation: a Hospital Medicine Unit, Massachusetts General Hospital , Boston , MA , USA.|b Harvard Medical School , Boston , MA , USA.
authors.forename: Andrew Zoltan
authors.initials: AZ
authors.lastname: Fenves
mesh_terms: D016190:Carboplatin / Q000009:adverse effects* / Q000627:therapeutic use; D002908:Chronic Disease; D005260:Female; D005264:Femoral Fractures / Q000473:pathology; D006258:Head and Neck Neoplasms / Q000188:drug therapy; D006801:Humans; D007674:Kidney Diseases / Q000139:chemically induced* / Q000150:complications*; D008274:Magnesium / Q000097:blood*; D008875:Middle Aged; D017741:Survivors; D013575:Syncope / Q000473:pathology
chemical_list: D016190:Carboplatin; D008274:Magnesium
keywords: Chronic hypomagnesemia; carboplatin; chemotherapy; head and neck cancer; magnesium wasting