title: Hyponatremia associated with unilateral hand weakness and numbness: a case report.
abstract: BACKGROUND
  The key clinical features in this case are to make the diagnosis apical lung cancer (Pancoast tumor) in a patient with brachial plexopathy and to recognize the association between syndrome of inappropriate secretion of antidiuretic hormone (SIADH) as a paraneoplastic syndrome and non-small cell lung cancer (NSCLC).
  
  
  METHODS
  We herein describe a rare case of NSCLC presented as pancoast tumor complicated by brachial plexopathy and associated with SIADH as a paraneoplastic phenomena. There were no renal insufficiency, congestive cardiac failure, liver insufficiency, volume depletion, diuretic use, hypoadrenalism, and hypothyroidism in our patient. Furthermore, the findings of serum hyponatraemia and hypo-osmolality associated with an inappropriate high urinary osmolality indicate that the SIADH was present in our patient due to the NSCLC.
  
  
  CONCLUSIONS
  Our case also emphasizes that early recognition and appropriate applied management may significantly improve symptoms and prevent complications of hyponatremia which may enhance quality of life in patients with paraneoplastic SIADH.
authors.affiliation: Department of Hospital Medicine, Institute of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Khaldoon
authors.initials: K
authors.lastname: Shaheen
authors.affiliation: Department of Pulmonary Diseases, Critical Care, and Environmental Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA.
authors.forename: Abdul Hamid
authors.initials: AH
authors.lastname: Alraiyes
authors.affiliation: Department of Hospital Medicine, Peninsula Regional Medical Center, Salisbury, Maryland, USA.
authors.forename: Motaz
authors.initials: M
authors.lastname: Baibars
authors.affiliation: Department of Hospital Medicine, Institute of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Naseem
authors.initials: N
authors.lastname: Eisa
authors.affiliation: Department of Hospital Medicine, Institute of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: M Chadi
authors.initials: MC
authors.lastname: Alraies
keywords: Hyponatremia; Inappropriate secretion of antidiuretic hormone; Non-small cell lung cancer; Paraneoplastic syndrome