I.V FLUIDS IN DIARRHEA

INTRODUCTION

• In diarrhoea stool contains large amount of sodium chloride,potassium,bicarbonate along with water.

ELECTROLYTE CONTENT OF DIARRHOEA : [mEq/L]

	SODIUM	POTASSIUM	CHLORIDE	BICARBONATE
CHOLERA – ADULT	140	30	109	44
CHOLERA- CHILDREN	101	27	92	32
NON CHOLERA DIARRHEA CHILDREN < 5 YEARS	56	25	55	14

FLUID &ELECTROLYTE ABNORMALITY IN DIARRHOEA IS SUMMARIZED BELOW: 

1. HYPOVOLEMIA :
2. Abnormal increased secretion of fluid into the small bowel [secretory diarrhoea due to GI infection e.g-E.coli,Vibrio Cholerae,Rota virus]
3.  Decreased absorption of fluid by intestine [osmotic diarrhoea due to purgatives like magnessium sulphate/malabsorption of glucose/lactate in children.
4. Additional loss of water can also occur due to associated vomiting/fever.
5. SODIUM DEFICIT :
6. Diarrhoea cause loss of  sodium,resulting in sodium deficit in all patients,but proportion of sodium loss as compared to water loss will decide serum sodium concentration and type of dehydration
7. In some infants with diarrhoea net loss of water is in excess of sodium which leads to hypertonic dehydration
8. If net loss of sodium is greater than loss of water,diarrhoea will cause hypotonic dehydration
9. HYPOKALEMIA :
10. Hypokalemia occurs because fluid lost in diarrhoea is rich in potassium.
11. Normally 8-15mEq potassium ions are excreted in             faeces daily.much greater loss occurs with diarrhoea
12. HYPERCHLOREMIA :
13. The ileal and colonic mucosa possesses a luminal chloride/bicarbonate exchanger that is capable of reabsorbing chloride in exchange of bicarbonate
14. So during diarrhoea when more bicarbonte is secreted,more chloride is absorbed from intestine causing hyperchloremia.
15. METABOLIC ACIDOSIS :
16. fluid secreted distal to pylorus is rich in bicarbonate.
17. Diarrhoea leads to large amount of bicarbonate secretion [30-45mEq/L] in the gut which is excreted,and leads to metabolic acidosis.
18. If diarrhoea causes severe hypovolemia or renal failure,renal compensation to loss of bicarbonate is lost and severe metabolic acidosis may develop rapidly.
19. Acidosis may also result from excessive production of lactic acid when patient has hypovolemic shock.
20. So hyperchloremic,hypokalemic,metabolic acidosis occurs in patients with diarrhoea.

TREATMENT :

• Specific treatment for control of diarrhoea
• Fluid therapy

AIM OF FLUID THERAPY IS :

• Correction of dehydration
• Correction of sodium deficit
• Correction of hypokalemia & metabolic acidosis.treatment of both need to be done simultaneously. If only metabolic acidosis is treated,due to its correction potassium will be shifted intracellularly. If patient is hypokalemic,only correction of the acidosis can precipitated dangerous hypokalemia

                         On the contrary,with out correction of acidosis, potassium supplementation can cause dangerous hyperkalemia.this is due to failure of potassium shift into the intracellular compartment even in state of potassium deficit of the body. 

• Fluid and electrolytes losses can be replaced either orally/intravenously.intravenous route is usually needed only for initial rehydration of patients with severe diarrhoea.
• ORAL REHYDRATION THERAPY :
• Oral rehydration therapy is easily available,simple to use and safe.
• It is preferred method of fluid replacement.losses due to diarrhoea can be effectively corrected by oral rehydration solutions[ORS].
• Readily available ORS provides sodium,potassium,chloride and bicarbonate along with glucose,which effectively corrects fluid and electrolyte abnormalities,and also provide calories.
• Glucose enhances sodium and secondary water transport across the mucosa of the upper intestine,even in presence of infective diarrhoea.
• Avoid correction of losses due to diarrhoea,totally with electrolyte free solutions.as it provides only fluid,but lacks electrolytes,it can cause hyponatremia and is not effective in correction of hypovolemia.
• INTRAVENOUS FLUID THERAPY :
• I.V fluid therapy is indicated when rapid correction of blood volume is required for severe dehydration and shock,inability of patient to take ORS due to persistent vomiting or ORT fails to correct volume depletion due to greater losses.
• The preferred I.V fluids to correct losses due to diarrhoea are ringers lactate and isotonic saline.
• RINGERS LACTATE SOLUTION :
• It is the best commercially available solution
• It is the preffered solution because it not only provides an adequate concentration of sodium but also provides bicarbonates for the correction of metabolic acidosis
• Its potassium & solution provides no glucose to prevent hypoglycemia.so the patient with diarrhoea may require additional potassium,glucose,and at times bicarbonate supplementation.
• ISOTONIC SALINE:
• It effectively corrects hypovolemia and provides sodium along with water. Isotonic saline does not contain potassium to replace potassium deficity or base to correct metabolic acidosis.
• So patient may require additional supplementtion of potassium[10-20mEq/L]and sodium bicarbonate [20-30mEq/L] to correct existing hypokalemia and metabolic acidosis.
• 5% DEXTROSE ;
• It is not an acceptable I.V fluid because it does not correct acidosis,hypokalemia,and sodium deficity
• 5% dextrose is not effective in correction of hypovolemia .
• Rapid infusion large volume of 5% dextrose also carries the risk of hyponatremia and hyperglycemia leading to osmotic diuresis
• However,dextrose 5%with 45mEq bicarbonate [2 amp-50ml of 7.5% of sodium bicarbonate] and 20-30mEq of potassium chloride is effective