2. Learning Objectives Dietary sources Daily Requirements Metabolism
Important functions and
Deficiency diseases

3. POTASSIUM Kalium K At. No. 19 Atomic mass 39.0

4. Potassium Alkali metal Highly reactive,
Found in combined state, mostly as Salt.

5. Requirement (mg) Infants 0 – 0.5 yr = 350 – 925
Children 1 – 3 yr = 550 – 1650
4 – 6 yr = 775 – 2325
7 – 10 yr = 1000 – 3000
11+ = 1525 – 4575
Adult = 1875 – 5600

6. Human milk contains about 500mg/liter, cow’s milk contains 1365 mg/liter.
In infants lean body mass and fecal losses are main determinants of potassium need.
Adults can maintain potassium balance with intake as low as infants.
Conc. of K+ is low in sweat. Less than 390 mg or 10 mEq/L as compared to sodium 25 – 30 mEq/L.

7. Dietary sources Chicken , Beef, Beef liver Milk
Dried apricots, Peaches
Oranges, Banana,
All vegetables
Broccoli, Tomato

8. Absorption and Metabolism
K is readily absorbed from gut.
Very little K is lost in feces
Kidneys regulate its secretion under the influence of change in acid-base balance and activity of adrenal cortex.
Hyper kalemia not likely to develop even after ingestion or injection of large amount of K, if kidney function is intact.

9. DIETARY INTAKE AND EXCRETION
Daily intake recommended … 4.5 grams
Average Diet contains … grams
EXCRETION
Excreted mostly in Urine
K ions filtered freely in the glomerular filterate
93 % is reabsorbed mostly in the proximal convoluted tubules

10. Postassium
Major cation in ICF, maintains intracellular osmotic pressure.
ECF K+ is also an important factor in the skeletal and cardiac muscle activity
Contraction and depolarization of heart require potassium

11. Functions Proper plasma potassium level is essential for :
Normal heart function
Normal function of skeletal muscle fibers
Many enzyme reactions
Neuron and muscle activity

12. Functions Resting membrane potential
An important role in the renal tubule, where K+ compete with H+ for exchange with Na+
K + are required for the activity of Na / K- ATPase
98% body potassium is found within cells

13. Hypokalemia Hypokalemia occurs with: Excessive loss through diarrhea
Diabetic Acidosis
Certain laxatives and
Diuretics

14. Causes of Hypokalemia
When Glucose is converted to glycogen for storage,some K is also stored.
Treatment with insulin results in glucose metabolism and storage along with K with-drawl from blood and results in Hypokalemia
K replacement should be considered.

15. Causes of Hypokalemia
Chronic wasting disease  K lowering / deficit associated with malnutrition prolonged –ive Nitrogen balance and GE losses.
K is stored with nitrogen as muscle protein. Therefore, when breakdown occurs, K also transferred from ICF to ECF and removed by kidney.

16. Management
When rehabilitating from these diseases, diet should contain K+ along with amino acid to ensure adequate retention.

17. Very high sudden intake 12 gms
(250 – 300 mEqt / per sq. m. of body surface area/day or 18 gms for an adult may be fatal because leads to Cardiac arrest.

18. Signs and symptoms of Hypokalemia
Muscle weakness
Irritability
Paralysis
Tachycardia

19. Hyperkalemia In health, generally not seen
K+ ion excretion is efficient
However certain clinical conditions lead to hyperkalemia

20. 1. Release from tissues Crushed or infected tissues
Intra vascular hemolysis
Hematomas
Burnt tissues
Extensive surgical operations
Sudden lysis of tumors

21. 2. Renal Insufficiency
Excretion by the distil convoluted Tubules if lower, leads to retention of K+
It is normally the case ,when oligouria is associated

22. 3. Chronic Dehydration & Shock
Decreased formation of urine
K+ retention

23. Less K+ secreted by distal tubules into urine
4. Acidosis :H+ ion displaces K+ ion 5. Fever :  temp excessive break down of tissues body proteins
6. Addisons Disease
Less K+ secreted by distal tubules into urine
7. I.V. administration

24. Symptoms Heart ECG changes when plasma K+ reaches 7 mmoles/L
T-waves becomes high peaked
P-waves disappears
QRS-complex broad
Wide spread cardiac blocks appear
Bradycardia and arrhythmias appear
Sudden death may take place

25. Symptoms 2. Nervous Symptoms Mental confusion Weakness of muscles
Tingling of the extremities
Treatment:
Removal of the primary cause

26. Hypokalemia Decrease K+ intake Malnutrition Old age K free fluid I.V
Starvation
Malnutrition
Old age
K free fluid I.V

27. Hypokalemia Excessive renal loss
a. Diuresis with Frusemide and Thiazide
b. Metabolic Alkalosis
_ Deficiency of H+ ion
Tubular cells
More K+ ions undergo change with Na+
Accelerate hypokalemia

28. Hypokalemia Renal Diseases
Excessive loss of K+ ion due to any cause/diuretic
Recovery phase of Acute Renal Failure
Chronic Pyelonephritis
Renal tubular Disorders

29. Hypokalemia Post operatively e. Hormones Aldosterone  loss of K+
Excess cortisol or overdose of ACTH same effect

30. Loss from GIT Vomiting Diarrhea GI. Fistulas
Excessive use of purgatives

31. Hypokalemia
Excessive Transfer to Cells
Glycogenesis
Paralysis

32. Symptoms Anorexia Nausea Muscle weakness Mental depression
Respiratory weakness

33. Symptoms Dyspnea Rapid and irregular pulse Low BP
ECG Changes: T-wave inversion
Reduce insulin secretion