HYPERNATREMIA =Na > 144mEq/L

Etiology: 

1. The easiest way to find the cause is to estimate the ECF status, i.e. Hypovolemic ( BP, tachycardia), Hypervolemic (edema, rales), Isovolemic (normal BP, no edema). Also the SMA 7 will help in establishing the etiology.

DX :  ________________________________________________________
                    ¯                                  ¯                                               ¯ 
          Hypovolemic                     Isovolemic                                 Hypervolemic
            hypernatremia                  hypernatremia                           hypernatremia
                        ¯                                           ¯                                                            ¯
cause: H2O > Na loss                     H2O=Na loss                                H2O < Na loss

                             ¯                                            ¯                                                             ¯      
                Renal ( diuretics )             Diabetes insipidus                        Steroid excess
                GI                                   Skin (hyperthermia)                      Iatrogenic
                Respiratory                                                                         Salt ingestion
                Adrenal deficiency   
                       ¯                                            ¯                                                             ¯ 
treatment: IVF with                          IVF with D5W                          IVF with D5W + diuretic
                 Isotonic fluid
         

Formula :

1. Water deficit = (0.6 x Body Weight) x (measured / normal Na - 1)
2. Give the ½ of estimated IVF over 24hrs. The IVF is NS or D5W depending
   on etiology as discussed in the algorithm

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