syndrome of inappropriate ADH secretion

1. DR.MUMTAZ ALI
JPMC KARACHI

2. Aim
 Normal values
 Definition
 Pathophysiology
 Causes
 Symptoms
 Diagnostic criteria
 SIADH VS CSW VS DI
 Treatment protocol
 Complication

3.  Serum osmolarity = 2*((Na+) + (K+)) + (BUN)/2.8 + (glucose)/18
 Effective serum osmolarity = measured osmolarity – (BUN)/2.8
 Normal value = 275-290 m0s/l
 SIADH/CSW < 275 mos/l , DI > 290 mos/l
 SIADH/CSW =Urine osmolarity > 100 mos/l , DI < 100 mos/l
 (Na+) = 135-148 meq/l
 SIADH/CSW =[Na+] <135 mEq/L=mild, <130 =moderate, <125 =severe
 DI= (Na+) > 150 meq/l
 Solute ratio = urinary (Na+) + urinary (K+) / plasma (Na+)
 0.9% N/S has 0.9 gm of NaCl/100 ml , 3% NaCl has 3 gm NaCl/100 ml
 1 mg NaCl has 17 mEq Na+. 1 mg Na+ has 43 mEq Na+
 1 teaspoon of table salt (NaCl) has 2.3 gm of Na+
 Daily requiremnt = 2 gm of Na+ per day

4. Definition
 Schwartz-Bartter syndrome

9. Symptoms
 Na+ <135 or < 130 mEq/L) :
 Anorexia
 Headache
 difficulty concentrating
 Irritability
 Dysgeusia
 muscle weakness
 Na+ <125 mEq/L) :
 neuromuscular excitability
 cerebral edema
 muscle twitching and cramps
 nausea/vomiting
 confusion, seizures
 Respiratory arrest
 coma or death

13. Routine treatment protocol and maintenance therapy
 Indications :
 asymptomatic nonsevere hyponatremia (serum [Na+] =125–135 mEq/L)
 severe hyponatremia (serum [Na+] <125 mEq/L) AND
 a) duration >48 hours or unknown AND
 b) asymptomatic
 Treatment :
 a)fluid restriction
 b)refractory cases:
 Demeclocycline =>antagonise ADH on renal tubule=>300–600 mg BID
 Conivaptan =>vasopressin receptors antagonist=>loading dose 20mg
IV for 30 min
=> maintenance dose 2omg/24 hr for 3days
• Lithium : not recommended

14. Intermediate treatment protocol
 Indications :
 symptomatic nonsevere hyponatremia (serum [Na+] =125–135 mEq/L)
 severe hyponatremia (serum [Na+] <125 mEq/L)
 a) duration >48 hours or unknown
 b) only moderate symptoms or nonspecific symptoms
 Treatment:
 0.9% saline infusion 120ml/hr
 furosemide 20 mg IV q d
 conivaptan for refractory cases
 check serum [Na+] every 4 hours
 [Na+] increase of 0.5–2 mEq/L/hr
 do not exceed 8–10 mEq/L in 24 hrs and 18–25 mEq/L in 48 hrs

15. Aggressive treatment protocol
 Indications :
 severe hyponatremia (serum [Na+] <125 mEq/L)
 duration <48 hours
 severe symptoms (coma, seizure)
 Treatment :
 transfer patient to ICU
 3% saline: start 1–2 ml/kg / hour or 2–4 ml/kg/hr
 furosemide 20 mg IV q d
 serum [Na+] every 2–3 hours
 1–2 mEq/L/hr
 do not exceed 8–10 mEq/L in 24 hrs and 18–25 mEq/L in 48 hr
 K+ lost in urine and replace accordingly

17. Osmotic demyelination syndrome
 Rapid correction
 CPM =>pontine white matter
 flaccid quadriplegia
 mental status changes
 cranial nerve palsies
 pseudobulbar palsy