This document discusses water and sodium disorders and their physiology and hormonal regulation. It covers: - The role of ADH (anti-diuretic hormone) in water reabsorption and its production in the hypothalamus and storage in the pituitary gland. - Hormones like renin, angiotensin II, and aldosterone that increase sodium reabsorption. - Conditions like hyponatremia and its definition as a low plasma sodium level less than 135 mEq/L. - Treatment approaches for hyponatremia and risks of rapid sodium correction. - Mechanisms, causes, and treatment of hypernatremia. - Example multiple choice questions on

1. PRESENTED BY DR MOHAMMED AL SHAER
WATER AND SODIUM DISORDERS

2. PHYSIOLOGY OF WATER AND SODIUM BALANCE

3. ADH IS THE CORNER STONE OF OUR TOPIC TODAY

4. Arginine vasopressin (AVP), AKA anti-
diuretic hormone (ADH):
-ADH is produced in neuron cell bodies in
supraoptic and paraventricular nuclei of the
Hypothalamus, and stored in posterior pituitary.
- passive absorption of water from the
collecting ducts, concentrating the urine
- Causes a small degree of Na+
reabsorption, but the retention of water is
proportionately much greater

7. Hormones increasing sodium reabsorption:
Renin:
- Released from the juxtaglomerular apparatus of the kidney
- Release is stimulated by: raised sympathetic tone, falling plasma volume, and
certain prostaglandins, such as PGE2
- No direct effects promoting Na+
retention, it controls the renin-angiotensinaldosterone axis
Angiotensin II:
- Levels rise as result of renin release
- In turn, it stimulates the release of aldosterone
- Also increases tone in the efferent glomerular arteriole. The net effect is to
enhance Na+
reabsorption from the proximal tubule.
Aldosterone:
- Steroid hormone released from the adrenal cortex
- End product of the renin-angiotensin-aldosterone system
- Acts on the distal tubule and collecting duct to increase Na+ and water
reabsorption (proportionately more Na+
than water)
HORMONAL REGULATION OF SODIUM

9. WHAT HAPPENS IN CASE OF HYPOVOLEMIA?

12. URINE SODIUM AND OSMOLALITY IN DIFERRENT CONDITIONS

13. SIADH AND DIABETIS INSEPIDUS

17. URINE OSMOLALITY > 100 !!!
EUVOLEMIA ( INCREASED BODY WATER BUT NOT CLINICALLY APPARENT)
HIGH URINE SODIUM (IN CASE OF NORMAL WATER AND ALT INTAKE )
ABSENCE OF ADRENAL, THYROID, PITUITARY, OR
INSUFfiCIENCY OR DIURETIC USE..
ABSENCE OF THYROID,ADRENAL,PITUITARY,RENAL
INSUFFICIENCY OR DIURETIC USE..
OTHER SUPPLEMENTALS:HIGH UA,HIGH ADH DESPITE
LOW SERUM OSM.,SODIUM NOT CORRECTED WITH
WATER RESTRICTION NOT EXPANSION,CAN NOT
URINE OSM. TO < 100 WITH 20 ML PER KG OVER 4
SIADH CRITERIA:

18. HYPONATREMIA

19.  Definition: Hyponatremia is defined as a plasma Na+
concentration <135 mEq/L
 It is due to a relative excess of water in relation to sodium.
 It can result from excessive loss of sodium from excessive
sweating, vomiting, diarrhoea, burns, and diuretics.
 It is a very common disorder, occurring in up to 22% of
hospitalized patients.
 Result of an increase in circulating AVP and/or increased
renal sensitivity to AVP, combined with any intake of free
a notable exception is hyponatremia due to low solute

20. IS IT LOW SODIUM OR HYPONATREMIA
?..

21. SERUM OSMOLALITY
OSMOLALITY=2 Na +GLUCOSE +UREA IN MMOL
IF IN Mg DIVIDE GLUcoSE BY 18 AND UREA BY 2.8
CALCULATE CORRECTED OSMOLALITY FOR HIGH GLUCOSE
ADD 1.6 FOR EACH 100 MG INCREASE IN BLOOD SUGAR ABOVE
1OO MG AND 2.6 ABOVE 400…..

23. INITIAL APPROACH TO HYPONATREMIA

37. TREATMENT OF HYPONATREMIA

41. RISK OF RAPID CORRECTION OF HYPONATREMIA

61. HYPERNATREMIA

67. HOW TO APPROACH POLYURIA ?

73. CALCULATION OF WATER EXCESS AND DEFICIT

74. HYPERNATREMIA

75. MECHANISM OF HYPERNATREMIA

78. MCQ
23 years old schizophrenic lady on
sertraline,clozapine,valproate,who is euovolemic admitted with
these labs;
Na 116,normal other electrolytes and KFT with urine sodium 10
and urine osmolality 55 mOsm/kg.what is appropriate?
A-D/C SERTRALINE
B-D/C CLOZAPINE
C-WATER RESTRICTION
D-DEMECLOCYCLINE
E- START THYROXINE.

79. ANSWER IS C-WATER RESTRICTION

80. MCQ
64 Y MALE WITH SMALL CELL CA. ADMITTED WITH CHANGE IN
MENTAL STATUS,OBTUNDED,RESPONSE TO PAIN ONLY.HE IS
EUVOLEMIC.SERUM;Na 116 ,osm.260. URINE; OSM.670,Na 35,K
40..WHAT IS THE APPROPRIATE TREATMENT?
A-0.9% NaCl TO INCREASE SERUM Na BY 2 MeQ/L.
B-3% NaCl TO INCREASE SODIUM BY 2MEQ/L PER HR.
C-3%NaCl TO INCREASE SERUM SODIUM BY 0.5 meq/l
D-0.9 NaCl AND LASIX TO INCREASE SODIUM TO 140 OVER 12
HOURS.
E-WATER RESTRICTION ALONE.

81. THE ANSWER IS B
B-3% NaCl TO INCREASE SODIUM BY
2MEQ/L PER HR.

82. MCQ
32 Y MALE WITH ON LITHUM8 YEARS WITH POLYURIAAND
POLYDEPSIA.Na 144 BUN 12 MMOL/L CREATININE 170
MG,SERUM OSM 295 24 HOUR URINE VOLUME 4 L .URINE;
Na 30 meq/L OSM 204 .ALL OF THE FOLLOWING ARE TRUE
EXCEPT;
A-FLUID RESTRICTION
B-SALT RESTRICTION
C-D/C LITHIUM
D-AMILORIDE
E-THIAZIDE

83. THE ANSWER IS A
FLUID RESTRECTION

84. THANK
YOU