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Malaria is often associated with abnormalities of fluid,
electrolytes and acid-base balance. These can occur in anybody, but are more common in
severe falciparum malaria, extremes of age, and in patients with high degree of fever and
vomiting/diarrhoea.
Patients with
severe falciparum malaria often have signs of dehydration (thirst, dry tongue, reduced
ocular tension and reduced skin turgor) and hypovolumia (low central venous pressure,
postural hypotension, oliguria with high urinary specific gravity). Mild hyponatremia (S.
Sodium 125-135 mmol/L) is common. Severe, symptomatic hyponatremia, however, is rare.
Metabolic acidosis may develop in
severely ill patients with shock, hypoglycemia, hyperparasitemia or renal failure. Lactic
acidosis is common in such patients and carries a high mortality.
Management of fluid balance is of utmost
importance in severe falciparum malaria. While untreated dehydration and hypovolumia can
result in hypoperfusion of kidneys, brain and other vital organs, thereby aggravating the
complications, enthusiastic over-hydration can precipitate pulmonary oedema. Therefore,
fluid balance should be managed carefully and meticulously.
Assess the status of hydration- moisture
on the tongue, ocular tension, skin turgor, temperature of extremities, blood pressure and
postural changes in blood pressure, peripheral venous filling and jugular venous pressure,
urine output, urine specific gravity (>1.015 indicates dehydration), urinary sodium
(<20 mmol/L indicates low renal perfusion).
Serum electrolytes, blood urea and serum
creatinine should be done in all these cases. If acidosis is suspected, arterial blood
gases and blood pH should also be done.
Treatment:
Re-hydration- Isotonic saline should be
used for correcting dehydration and hyponatremia. Generally 3000 ml of saline may be
required in the first 24 hours. Hypokalemia in malaria rarely requires treatment .
Metabolic acidosis can be due to renal
dysfunction and/or lactic acidosis (which should be suspected if the anion gap exceeds
10-12 meq/L). Attempt should be made to correct acidemia only if the arterial pH is less
than 7.20. Sodium bicarbonate can be added to isotonic saline infusion for this purpose.
However, sodium bicarbonate itself may contribute to pulmonary oedema by increasing the
sodium load. THAM and dichloroacetate are other alternatives.
It is also important to improve
oxygenation of blood. A clear airway should be ensured. Concentration of oxygen in the
inspired air should be increased by administering oxygen through facemasks or nasal
prongs. If necessary, mechanical ventilation should be done.
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