Hyponatremia mannitol

Improves CO Increased CSF absorption between mannitol doses hyponatremia ... 

The major adverse reactions associated with mannitol administration are headache, nausea, vomiting, chest pain, and hyponatremia. Too rapid an administration of large amounts may cause an excessive shift of fluid from the intracellular to the extracellular compartment and result in congestive heart failure. 

Mannitol is rapidly distributed in the extracellular compartment and extracts water from cells. Prior to the diuresis, this leads to expansion of the extracellular volume and hyponatremia. This effect can complicate heart failure and may produce florid pulmonary edema. Headache, nausea, and vomiting are commonly observed in patients treated with osmotic diuretics. 

When used in patients with diminished renal function, parenterally administered mannitol is retained intravenously and causes osmotic extraction of water from cells, leading to hyponatremia. 

Mannitol Physical osmotic effect on tissue water distribution because it is retained in the vascular compartment Marked increase in urine flow, reduced brain volume, decreased intraocular pressure, initial hyponatremia, then hypernatremia Renal failure due to increased solute load (rhabdomyolysis, chemotherapy), increased intracranial pressure, glaucoma IV administration Toxicity Nausea, vomiting, headache... 

Four cases of acute renal insufficiency have been described in men aged 20-42 years who received mannitol 1172 (sd 439) g over 58 (sd 28) hours (7). The onset of acute renal insufficiency was detected 48 (sd 22) hours after the start of infusion. All the patients had dilutional hyponatremia (average 120 mmol/1) and serum hyper-osmolarity (osmolar gap 70 mosm/kg water). In the three anuric cases, in which hemodialysis was performed, there was immediate recovery of diuresis. This emphasizes the risk of renal insufficiency with mannitol and stresses the importance of early hemodialysis. Mannitol is dialysable and once its suppressive effect on renal perfusion is eliminated functional recovery is prompt. 

Hyponatremia occurs with an increased amount of other solutes in the ECF, causing an extracellular shift of water or intracellular shift of Na. to maintain osmotic balance between the ECF and ICF compartments. The most common cause of this type of hyponatremia is severe hyperglycemia. As a general rule, the Na" decreases —1.6 mmol/L for every 100 mg/dL increase of glucose above 100 mg/dL. The clinical use of mannitol for osmotic diuresis can have a similar effect. 

B. Mannitol causes movement of Intracellular water to the extracellular space and can produce both transient hyperosmolality and hyponatremia. 

Others have proposed that the symptoms result from cellular water intoxication, itself a result of hyponatremia. The salutary but transient effect of mannitol administration is invoked in support of that concept. Hypertonic mannitol withdraws water from the intracellular space into the extracellular space, thereby at least temporarily restoring the sodium balance in the... 

Fluid balance In two patients undergoing transurethral resection, the bladder was irrigated with large volumes of mannitol 5%, which was absorbed and caused pulmonary edema and severe hyponatremia (serum sodium 99 and 97 mmol/1) [63 ]. Hypertonic saline increased the serum sodium concentration and plasma volume expansion corrected hypotension one patient also required positive-pressure ventilation and intravenous noradrenaline. Both recovered completely. 

In a 51-year-old woman, absorption of a solution containing mannitol and sorbitol after irrigation during hysteroscopy led to hypocalcemia and hyponatremia hyperglycemia and lactic acidosis also occurred, because of metabolism of sorbitol [64 ]. 

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