Sodium and Water
    Lecture for Fellows
     Joel M. Topf, M.D.
• 77 yo female
• increased intraocular pres-
  sure following cataract surgery

• admitted for mannitol infusion
  to reduce intraocular pressure

• PMHx: CHF, Htn, CKD
  (bl Cr 1.5 mg/dL)

• Meds: captopril, furosemide
• over 3 days she received
 • 2.5 liters of 20% mannitol
   •   how much mannitol is that?




 • ibuprofen for musculoskeletal pain
• day 4
 • confuision, dyspnea, anuria
• over 3 days she received
 • 2.5 liters of 20% mannitol
   •   how much mannitol is that?
       20% means 20 g per 100 mL
       2.5 L is 25 x 100 mL
       25 x 20 = 500 g of mannitol

 • ibuprofen for musculoskeletal pain
• day 4
 • confuision, dyspnea, anuria
112        38
                            180
                        3.2



• multiple seizures
• no measured osmolality
  calculate the serum osmolality:

• given 3% saline and lasix
112        38
                            180
                        3.2



• multiple seizures
• no measured osmolality
  calculate the serum osmolality: 247

• given 3% saline and lasix
119         38
                               180



• continues to have seizures
• developed anuria
• measured osmolality 326
  Calculate the osmolality
119         38
                               180



• continues to have seizures
• developed anuria
• measured osmolality 326
  Calculate the osmolality
                  262
119         38
                               180



• continues to have seizures
• developed anuria
• measured osmolality 326
  Calculate the osmolality and the gap
                  262
119         38
                               180



• continues to have seizures
• developed anuria
• measured osmolality 326
  Calculate the osmolality and the gap
                  262              64
MW 182    MW 180
C6H14O6   C6H12O6
• Gap is 64 mmol. How much mannitol is
  that?

• molecular weight of mannitol is 182
• 64 x 18.2 = 1,164 mg/dL
• use Katz’s and Hillier’s conversion to
  quantify the pseudohyponatremia
• Gap is 64 mmol. How much mannitol is
  that?

• molecular weight of mannitol is 182
• 64 x 18.2 = 1,164 mg/dL
• use Katz’s and Hillier’s conversion to
  quantify the pseudohyponatremia
   Katz: (1.6 x 11) + 119 = 136
• Gap is 64 mmol. How much mannitol is
  that?

• molecular weight of mannitol is 182
• 64 x 18.2 = 1,164 mg/dL
• use Katz’s and Hillier’s conversion to
  quantify the pseudohyponatremia
   Katz: (1.6 x 11) + 119 = 136
  Hillier: (2.4 x 11) + 119 = 145
Acute oliguric renal failure in mannitol
poisoning may be due to a combination of
mannitol-induced renal
vasoconstriction and direct
tubular toxicity. As mannitol is
excreted exclusively by the kidney, its
accumulation in renal failure will further
worsen renal function, thus making
prompt hemodialysis the most
appropriate treatment in such a
circumstance.
summary

     Na 112 and seizing patient

  3% was worst possible therapy

If you are treating altered osmolality,
     check the serum osmolality
Serum sodium falls from
133 to 99 in 2 hours
This patient:

 a. is doomed
 b. is lucky this is a lab
    error
 c. is asymptomatic
 d. requires 3% saline
    +/– loop diuretics
TURP
TURP   • Before the development of
         bipolar electrocautery
         allowed use of isotonic
         electrolyte based irrigants...

         ...used non-conducting:
        • distilled water
        • glycine
        • sucrose
        • manitol
• increased absorption with longer
  procedures

• higher infusion pressure
 • essentially no absorption at 15 cm
 • > 40 cm greatly increases absorption
• all the solutions (except distilled water) are
  isotonic or nearly isotonic

• lowers the serum sodium but the serum
  osmolality remains normal

• no cellular water shift
• Desmond et al., in a study of 72 TURPS
• sodium fell 10-54 mmol/L in 19
• Osmolality fell in only 2
• Those 2 developed pulmonary edema and
  encephalopathy

• the 5 largest changes in sodium (34-54
  mmol/L) had no signs of TURP syndrome
• massive extracellular fluid gain
 • 200 mL/min
 • pulmonary edema
 • reflex bradycardia
 • hypertension
• use of distilled water can cause
 • hemolysis
 • hyponatremia
 • hemoglobinuria and acute renal failure
glycine
• metabolized to ammonia
• major inhibitory neurotransmitter (GABA
  activity).
 • likely cause of blindness
• potentiates NMDA activity
 • anti-PCP, anti-ketamine
• don’t be fooled, neurologic symptoms may
  not be symptomatic hyponatremia
...   glycine      after TURP has been
reported at a level greater than   14,300
pmol/L. This concentration is         17
times greater than that in
children dying from glycine
encephalopathy and over 65

times that in adults. Normal
adult level, 219 pmol/L.
• do not treat isolated hyponatremia
• caution in use of diuretics to treat volume
  overload, patients are in sodium balance,
  and loop diuretics may cause salt wasting
  and worsen the hyponatremia.

• experts recommend saline and loop
  diuretics to correct the volume overload
  while preserving sodium balance
esrd and hyponatremia
• does urea protect patients from CPM?
 • is the rapid rise in Na balanced by a
    simultaneous decline in urea?
  • are other factors protective?
• how do you dialyze as patient with severe
  hyponaremia?
• scientific data supports the theory that
  uremia is protective against CPM

  • uremia is associated with rapid uptake of
    the osmolyte myoinositol
Soupart et al. Rapid reaccumulation of brain organic osmolytes in azotemic rats after
         correction of chronic hyponatremia. J Am Soc Nephrol (2002) 13: 1433-41.
• one study found reversibility of MRI
  diagnosed CPM.

• in 6 of 9 patients with follow-up MRI
  showed improvement or resolution. Found
  within one month of onset.

• Frequent findings in their cases of CPM
 • Sodium < 136 in 10/17
 • BUN:Cr <13.5:1 in 11/17
       Tarhan et al. Osmotic demyelination syndrome in end-stage renal disease after
       recent hemodialysis: MRI of the brain. Am j roentgenology (2004) 182; 809-16.
• 52 y.o. admitted with nausea and vomitting
• CKD for 1 year, HTN 2 years
 100        102
             17

• Dialysis was initiated
 • 2.5 hours               Sanguida. Central pontine and extrapontine

 • qB 150 mL/min
                                 myelinolysis after rapid correction of
                             hyponatremia by hemodialysis in a uremic
                                      patient. Ren Fail 2007: 29 635-8.
• 52 y.o. admitted with nausea and vomitting
• CKD for 1 year, HTN 2 years
 100        102                121
             17

• Dialysis was initiated
 • 2.5 hours               Sanguida. Central pontine and extrapontine

 • qB 150 mL/min
                                 myelinolysis after rapid correction of
                             hyponatremia by hemodialysis in a uremic
                                      patient. Ren Fail 2007: 29 635-8.
day after hemodialysis
•   bilateral limb tremors        •    action tremor

•   progressive facial diplegia   •    mask facies

•   dysarthria                    •    cogwheel rigidity

•   dysphagia                     •    bradykinesia

•   four limbs weakness


                                      Sanguida. Central pontine and extrapontine
                                            myelinolysis after rapid correction of
                                        hyponatremia by hemodialysis in a uremic
                                                 patient. Ren Fail 2007: 29 635-8.
Sanguida. Central pontine and extrapontine myelinolysis after rapid correction
 of hyponatremia by hemodialysis in a uremic patient. Ren Fail 2007: 29 635-8.
Sanguida. Central pontine and extrapontine myelinolysis after rapid correction
 of hyponatremia by hemodialysis in a uremic patient. Ren Fail 2007: 29 635-8.
• Strategies to consider when dialyzing a
  patient with hyponatremia
  • lower the dialysate sodium
  • lower the blood and dialysate flow
  • shorten the treatment
• Strategies to consider when dialyzing a
  patient with hyponatremia
  • lower the dialysate sodium
  • lower the blood and dialysate flow
  • shorten the treatment
exercise induced
      hyponatremia

• 87% of marathon runners drop their
  sodium
• 12-20% become hyponatremic
• almost none are symptomatic
risk factors
•   female

•   slow

•   more water intake

•   small body size

•   NSAIDs

•   decreased urination
weight loss   weight gain
• weight gain argues against volume
  deficiency as the cause

• near uniform finding in the literature for
  measurable ADH in patients with exercise
  induced hyponatremia

  • ADH secretion normally stops at
    osmolality < 275 mOsm/Kg
Rx: 3% saline
dose: 1 mL/kg/hr or

100 mL bolus which can be repeated twice
at 10 minute intervals based on clinical
improvement
is it siadh or volume
       deficiency?
• this should be easy but in a study of 35
  non-edematous patients, clinical prediction
  of hypovolemia:

  • correctly found only 41% of cases
    (sensitivity)

  • Specificity was 80%
                    Musch W, Thimpont J,Vandervelde D et. al. Am J Med. 1995;
                                                                   99:348-55.
• A second study by Shrier et al. of 58
  hyponatremic patients without edema.
• A second study by Shrier et al. of 58
  hyponatremic patients without edema.
• A second study by Shrier et al. of 58
  hyponatremic patients without edema.
• clinical distinguishing siadh from volume
  depletion difficult and is missed in roughly
  half of cases

• gold standard for diagnosis is sodium
  response to fluid challenge

• prospective use of the lab can help make
  the diagnosis
• urine Na < 30 mmol/L
• urine Na runs higher in elderly patients
  (50-60 mmol/L)
• SIADH
                                               ° Salt depletion




Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
• SIADH
                                               ° Salt depletion
                                UNa < 30 is pretty good
                                misses salt depletion in
                                the elderly




Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
• SIADH
                                               ° Salt depletion
                                UNa < 30 is pretty good
                                misses salt depletion in
                                the elderly




Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
• SIADH
                                                ° Salt depletion




Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                      diuresis. Nephron Physiol96 :11 –18,2004
• seless
                                   a < 1% is u
                                               SIADH
                           • FEN
                           • FEN a < 0.5% identifies all of the
                                          ° Salt depletion
                             SD patients but misclassifies
                             nearly half the SIADH




Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                      diuresis. Nephron Physiol96 :11 –18,2004
• seless
                                   a < 1% is u
                                               SIADH
                           • FEN
                           • FEN a < 0.5% identifies all of the
                                          ° Salt depletion
                             SD patients but misclassifies
                             nearly half the SIADH




Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                      diuresis. Nephron Physiol96 :11 –18,2004
• seless
                                   a < 1% is u
                                               SIADH
                           • FEN
                           • FEN a < 0.5% identifies all of the
                                          ° Salt depletion
                             SD patients but misclassifies
                             nearly half the SIADH




Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                      diuresis. Nephron Physiol96 :11 –18,2004
• seless
                                        a < 1% is u
                                                    SIADH
                                • FEN
                                • FEN a < 0.5% identifies all of the
                                               ° Salt depletion
                                  SD patients but misclassifies
                                  nearly half the SIADH




U/P is a measure of daily
urine production


     Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                           diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                      diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5% and FEurea <55%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5% and FEurea <55%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5% and FEurea <55%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5% and FEurea <55%                    FENa <0.15%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5% and FEurea <55%                    FENa <0.15% and FEurea <45%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5% and FEurea <55%                    FENa <0.15% and FEurea <45%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
• SIADH ° Salt depletion




FENa <0.5% and FEurea <55%                    FENa <0.15% and FEurea <45%


       Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low
                                             diuresis. Nephron Physiol96 :11 –18,2004
criteria for salt
          depletion
• Urine Cr / Plasma Cr < 140
 • FENa < 0.5% and
 • FE Urea < 55%
• Urine Cr / Plasma Cr > 140
 • FENa < 0.15% and
 • FE Urea < 45%
Saline infusions
• Gold standard for diagnosis
• necessary in patients with combined salt
  depletion and SIADH
• Caution in the interpretation of the saline
  infusion challenge
  • increase of 5 mmol/L has been proposed
  • Sensitivity 71% and Specificity 70%
    Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
Saline responsive SIADH?
• 2 liter isotonic saline infusion in 17 SIADH
  patients
  • Na 126
  • Urine Na + Urine K = 128
  • Urine Osm = 502
  • All patients had fixed urine osmolality
    despite fluid restriction
538
uric acid and SIADH
• uric acid falls 50% in SIADH
 • drop due to dilution should only be 10%
 • due to increase in uric acid clearance or
    FE Uric Acid
    • less uric reabsorption
    • stable uric acid secretion
  • FE Uric Acid >12% (16% in the elderly)
Fenske et al. Value of fractional uric acid excretion in differential diagnosis of
hyponatremic patients on diuretics. J Clin Endocrinol Metab (2008) 93: 2991-7
done...
now go fix some numbers

Hyponatremia

  • 1.
    Sodium and Water Lecture for Fellows Joel M. Topf, M.D.
  • 2.
    • 77 yofemale • increased intraocular pres- sure following cataract surgery • admitted for mannitol infusion to reduce intraocular pressure • PMHx: CHF, Htn, CKD (bl Cr 1.5 mg/dL) • Meds: captopril, furosemide
  • 3.
    • over 3days she received • 2.5 liters of 20% mannitol • how much mannitol is that? • ibuprofen for musculoskeletal pain • day 4 • confuision, dyspnea, anuria
  • 4.
    • over 3days she received • 2.5 liters of 20% mannitol • how much mannitol is that? 20% means 20 g per 100 mL 2.5 L is 25 x 100 mL 25 x 20 = 500 g of mannitol • ibuprofen for musculoskeletal pain • day 4 • confuision, dyspnea, anuria
  • 5.
    112 38 180 3.2 • multiple seizures • no measured osmolality calculate the serum osmolality: • given 3% saline and lasix
  • 6.
    112 38 180 3.2 • multiple seizures • no measured osmolality calculate the serum osmolality: 247 • given 3% saline and lasix
  • 7.
    119 38 180 • continues to have seizures • developed anuria • measured osmolality 326 Calculate the osmolality
  • 8.
    119 38 180 • continues to have seizures • developed anuria • measured osmolality 326 Calculate the osmolality 262
  • 9.
    119 38 180 • continues to have seizures • developed anuria • measured osmolality 326 Calculate the osmolality and the gap 262
  • 10.
    119 38 180 • continues to have seizures • developed anuria • measured osmolality 326 Calculate the osmolality and the gap 262 64
  • 11.
    MW 182 MW 180 C6H14O6 C6H12O6
  • 12.
    • Gap is64 mmol. How much mannitol is that? • molecular weight of mannitol is 182 • 64 x 18.2 = 1,164 mg/dL • use Katz’s and Hillier’s conversion to quantify the pseudohyponatremia
  • 13.
    • Gap is64 mmol. How much mannitol is that? • molecular weight of mannitol is 182 • 64 x 18.2 = 1,164 mg/dL • use Katz’s and Hillier’s conversion to quantify the pseudohyponatremia Katz: (1.6 x 11) + 119 = 136
  • 14.
    • Gap is64 mmol. How much mannitol is that? • molecular weight of mannitol is 182 • 64 x 18.2 = 1,164 mg/dL • use Katz’s and Hillier’s conversion to quantify the pseudohyponatremia Katz: (1.6 x 11) + 119 = 136 Hillier: (2.4 x 11) + 119 = 145
  • 15.
    Acute oliguric renalfailure in mannitol poisoning may be due to a combination of mannitol-induced renal vasoconstriction and direct tubular toxicity. As mannitol is excreted exclusively by the kidney, its accumulation in renal failure will further worsen renal function, thus making prompt hemodialysis the most appropriate treatment in such a circumstance.
  • 16.
    summary Na 112 and seizing patient 3% was worst possible therapy If you are treating altered osmolality, check the serum osmolality
  • 17.
    Serum sodium fallsfrom 133 to 99 in 2 hours This patient: a. is doomed b. is lucky this is a lab error c. is asymptomatic d. requires 3% saline +/– loop diuretics
  • 19.
  • 20.
    TURP • Before the development of bipolar electrocautery allowed use of isotonic electrolyte based irrigants... ...used non-conducting: • distilled water • glycine • sucrose • manitol
  • 21.
    • increased absorptionwith longer procedures • higher infusion pressure • essentially no absorption at 15 cm • > 40 cm greatly increases absorption
  • 22.
    • all thesolutions (except distilled water) are isotonic or nearly isotonic • lowers the serum sodium but the serum osmolality remains normal • no cellular water shift
  • 23.
    • Desmond etal., in a study of 72 TURPS • sodium fell 10-54 mmol/L in 19 • Osmolality fell in only 2 • Those 2 developed pulmonary edema and encephalopathy • the 5 largest changes in sodium (34-54 mmol/L) had no signs of TURP syndrome
  • 24.
    • massive extracellularfluid gain • 200 mL/min • pulmonary edema • reflex bradycardia • hypertension
  • 25.
    • use ofdistilled water can cause • hemolysis • hyponatremia • hemoglobinuria and acute renal failure
  • 26.
    glycine • metabolized toammonia • major inhibitory neurotransmitter (GABA activity). • likely cause of blindness • potentiates NMDA activity • anti-PCP, anti-ketamine • don’t be fooled, neurologic symptoms may not be symptomatic hyponatremia
  • 27.
    ... glycine after TURP has been reported at a level greater than 14,300 pmol/L. This concentration is 17 times greater than that in children dying from glycine encephalopathy and over 65 times that in adults. Normal adult level, 219 pmol/L.
  • 28.
    • do nottreat isolated hyponatremia • caution in use of diuretics to treat volume overload, patients are in sodium balance, and loop diuretics may cause salt wasting and worsen the hyponatremia. • experts recommend saline and loop diuretics to correct the volume overload while preserving sodium balance
  • 29.
    esrd and hyponatremia •does urea protect patients from CPM? • is the rapid rise in Na balanced by a simultaneous decline in urea? • are other factors protective? • how do you dialyze as patient with severe hyponaremia?
  • 30.
    • scientific datasupports the theory that uremia is protective against CPM • uremia is associated with rapid uptake of the osmolyte myoinositol
  • 31.
    Soupart et al.Rapid reaccumulation of brain organic osmolytes in azotemic rats after correction of chronic hyponatremia. J Am Soc Nephrol (2002) 13: 1433-41.
  • 32.
    • one studyfound reversibility of MRI diagnosed CPM. • in 6 of 9 patients with follow-up MRI showed improvement or resolution. Found within one month of onset. • Frequent findings in their cases of CPM • Sodium < 136 in 10/17 • BUN:Cr <13.5:1 in 11/17 Tarhan et al. Osmotic demyelination syndrome in end-stage renal disease after recent hemodialysis: MRI of the brain. Am j roentgenology (2004) 182; 809-16.
  • 33.
    • 52 y.o.admitted with nausea and vomitting • CKD for 1 year, HTN 2 years 100 102 17 • Dialysis was initiated • 2.5 hours Sanguida. Central pontine and extrapontine • qB 150 mL/min myelinolysis after rapid correction of hyponatremia by hemodialysis in a uremic patient. Ren Fail 2007: 29 635-8.
  • 34.
    • 52 y.o.admitted with nausea and vomitting • CKD for 1 year, HTN 2 years 100 102 121 17 • Dialysis was initiated • 2.5 hours Sanguida. Central pontine and extrapontine • qB 150 mL/min myelinolysis after rapid correction of hyponatremia by hemodialysis in a uremic patient. Ren Fail 2007: 29 635-8.
  • 35.
    day after hemodialysis • bilateral limb tremors • action tremor • progressive facial diplegia • mask facies • dysarthria • cogwheel rigidity • dysphagia • bradykinesia • four limbs weakness Sanguida. Central pontine and extrapontine myelinolysis after rapid correction of hyponatremia by hemodialysis in a uremic patient. Ren Fail 2007: 29 635-8.
  • 36.
    Sanguida. Central pontineand extrapontine myelinolysis after rapid correction of hyponatremia by hemodialysis in a uremic patient. Ren Fail 2007: 29 635-8.
  • 37.
    Sanguida. Central pontineand extrapontine myelinolysis after rapid correction of hyponatremia by hemodialysis in a uremic patient. Ren Fail 2007: 29 635-8.
  • 38.
    • Strategies toconsider when dialyzing a patient with hyponatremia • lower the dialysate sodium • lower the blood and dialysate flow • shorten the treatment
  • 39.
    • Strategies toconsider when dialyzing a patient with hyponatremia • lower the dialysate sodium • lower the blood and dialysate flow • shorten the treatment
  • 43.
    exercise induced hyponatremia • 87% of marathon runners drop their sodium • 12-20% become hyponatremic • almost none are symptomatic
  • 44.
    risk factors • female • slow • more water intake • small body size • NSAIDs • decreased urination
  • 45.
    weight loss weight gain
  • 46.
    • weight gainargues against volume deficiency as the cause • near uniform finding in the literature for measurable ADH in patients with exercise induced hyponatremia • ADH secretion normally stops at osmolality < 275 mOsm/Kg
  • 47.
    Rx: 3% saline dose:1 mL/kg/hr or 100 mL bolus which can be repeated twice at 10 minute intervals based on clinical improvement
  • 48.
    is it siadhor volume deficiency?
  • 49.
    • this shouldbe easy but in a study of 35 non-edematous patients, clinical prediction of hypovolemia: • correctly found only 41% of cases (sensitivity) • Specificity was 80% Musch W, Thimpont J,Vandervelde D et. al. Am J Med. 1995; 99:348-55.
  • 50.
    • A secondstudy by Shrier et al. of 58 hyponatremic patients without edema.
  • 51.
    • A secondstudy by Shrier et al. of 58 hyponatremic patients without edema.
  • 52.
    • A secondstudy by Shrier et al. of 58 hyponatremic patients without edema.
  • 54.
    • clinical distinguishingsiadh from volume depletion difficult and is missed in roughly half of cases • gold standard for diagnosis is sodium response to fluid challenge • prospective use of the lab can help make the diagnosis
  • 55.
    • urine Na< 30 mmol/L • urine Na runs higher in elderly patients (50-60 mmol/L)
  • 56.
    • SIADH ° Salt depletion Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
  • 57.
    • SIADH ° Salt depletion UNa < 30 is pretty good misses salt depletion in the elderly Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
  • 58.
    • SIADH ° Salt depletion UNa < 30 is pretty good misses salt depletion in the elderly Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
  • 59.
    • SIADH ° Salt depletion Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 60.
    • seless a < 1% is u SIADH • FEN • FEN a < 0.5% identifies all of the ° Salt depletion SD patients but misclassifies nearly half the SIADH Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 61.
    • seless a < 1% is u SIADH • FEN • FEN a < 0.5% identifies all of the ° Salt depletion SD patients but misclassifies nearly half the SIADH Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 62.
    • seless a < 1% is u SIADH • FEN • FEN a < 0.5% identifies all of the ° Salt depletion SD patients but misclassifies nearly half the SIADH Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 63.
    • seless a < 1% is u SIADH • FEN • FEN a < 0.5% identifies all of the ° Salt depletion SD patients but misclassifies nearly half the SIADH U/P is a measure of daily urine production Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 64.
    • SIADH °Salt depletion Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 65.
    • SIADH °Salt depletion FENa <0.5% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 66.
    • SIADH °Salt depletion FENa <0.5% and FEurea <55% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 67.
    • SIADH °Salt depletion FENa <0.5% and FEurea <55% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 68.
    • SIADH °Salt depletion FENa <0.5% and FEurea <55% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 69.
    • SIADH °Salt depletion FENa <0.5% and FEurea <55% FENa <0.15% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 70.
    • SIADH °Salt depletion FENa <0.5% and FEurea <55% FENa <0.15% and FEurea <45% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 71.
    • SIADH °Salt depletion FENa <0.5% and FEurea <55% FENa <0.15% and FEurea <45% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 72.
    • SIADH °Salt depletion FENa <0.5% and FEurea <55% FENa <0.15% and FEurea <45% Musch W, Hedeshi A, Decaux G: Low sodium excretion in SIADH patients with low diuresis. Nephron Physiol96 :11 –18,2004
  • 73.
    criteria for salt depletion • Urine Cr / Plasma Cr < 140 • FENa < 0.5% and • FE Urea < 55% • Urine Cr / Plasma Cr > 140 • FENa < 0.15% and • FE Urea < 45%
  • 74.
    Saline infusions • Goldstandard for diagnosis • necessary in patients with combined salt depletion and SIADH • Caution in the interpretation of the saline infusion challenge • increase of 5 mmol/L has been proposed • Sensitivity 71% and Specificity 70% Musch and Decaux.. International urology and nephrology (2001) vol. 32: 475-93
  • 75.
    Saline responsive SIADH? •2 liter isotonic saline infusion in 17 SIADH patients • Na 126 • Urine Na + Urine K = 128 • Urine Osm = 502 • All patients had fixed urine osmolality despite fluid restriction
  • 77.
  • 78.
    uric acid andSIADH • uric acid falls 50% in SIADH • drop due to dilution should only be 10% • due to increase in uric acid clearance or FE Uric Acid • less uric reabsorption • stable uric acid secretion • FE Uric Acid >12% (16% in the elderly)
  • 79.
    Fenske et al.Value of fractional uric acid excretion in differential diagnosis of hyponatremic patients on diuretics. J Clin Endocrinol Metab (2008) 93: 2991-7
  • 80.
    done... now go fixsome numbers