Life-threatening acute water intoxication in a woman undergoing hysteroscopic myomectomy: a case report and review of the literature – BMC Blogs…

Hysteroscopic procedures are performed using an endoscope, with intrauterine distention using either gas (CO2) or fluid distending media. The procedure can lead to life-threatening events if systemic absorption of distending media such as AWI occurs (0.060.2% of women) [2].

Excessive absorption of non-electrolyte distending media such as 1.5% glycine (200mOsm/L), 3% sorbitol (165mOsm/L), and 5% dextrose can cause AWI [3]. In patients undergoing hysteroscopic procedures, symptoms develop when serum sodium concentration drops below 125mmol/L [3].

Premenopause, hypoxia, and young age are common risk factors associated with worsened prognosis of hyponatremia encephalopathy in postoperative AWI. The relative risk of death or permanent neurological damage from hyponatremic encephalopathy is 30 times higher for women than men and 25 times greater for menstruating compared to postmenopausal females [4]. The proposed mechanism is associated with the inhibitory effects of estrogen on the ATPase pump that regulates electrolyte flow through the bloodbrain barrier [5]. Additionally, the effects of vasopressin on cerebral vasoconstriction and hypoperfusion of brain tissue also precipitate the risk of hyponatremic encephalopathy in premenopausal women [6]. The differential diagnosis of cardiopulmonary failure and acute consciousness disturbance after hysteroscopy in the present case included AWI, acute gas embolism, and thromboembolism. Irrigation media included hypotonic, normal tonic, and gas-like CO2. Gas media contribute to a higher risk of developing acute air embolism during hysteroscopy. Although gas media was not administered in the present case, the incidence of acute air embolism is higher in patients undergoing bipolar electrosurgery, especially when more than 1000mL of fluid is absorbed [3, 6]. In the present case, we believed that the patient suffered from postoperative AWI (lower than 125mmol/L) before admission to the emergency department because of the large amount of sodium bicarbonate (266mmol) resuscitation during CPR.

Common risk factors of AWI in patients undergoing hysteroscopic procedures include prolonged operative time, large irrigation fluid amount, higher pressure created by the intrauterine media with higher systemic absorption, visceral perforation, and general anesthesia [3, 6]. The actual volume of distension fluid often exceeds the declared volume by 2.810% owing to incomplete collection of spilled fluids or false lower fluid deficit as a result of significant bleeding during hysteroscopic surgery as in the present case [7]. The AAGL Guidelines consensus view is that once a fluid deficit of 1000ml of hypotonic solution or 2500ml with an isotonic solution is reached immediate suspension of the procedure is imperative. When high-viscosity distending media are used, the maximum infused volume should not exceed 500mL, and in the elderly and those with cardiopulmonary compromise should not exceed 300mL [6]. Patients with decreased serum sodium of 10meq/L, which is representative of 1000mL of hypo-osmotic irrigation fluid absorption in women undergoing hysteroscopy, are more are likely to develop neurological symptoms [4, 6]. Thus, we believe that irrigation of 8000mL of dextrose water with absorption of more than 1000mL occurred in our patient. Sudden-onset neurogenic stunned myocardium has been reported after AWI especially in a younger woman [1]. Neither irrigation fluid absorption related non-cardiogenic pulmonary edema nor postcardiopulmonary resuscitation pulmonary edema can lead to severe hypoxemia, which is a strong predictor of high mortality in AWI [4].The danger of combined hypoxemia and hyponatremia should be stress out because hypoxemia impairs the ability of the.

brain to adapt to hyponatraemia, leading to a vicious cycle of worsening hyponatraemic encephalopathy. Hyponatraemia cause derangement in both cerebral.

blood flow and arterial oxygen content. Symptomatic hyponatremia can lead to hypoxemia through both non-cardiogenic pulmonary edema and hypercapnic respiratory failure. Besides, the cerebral edema from hyponatremia also lead to non-cardiogenic pulmonary edema [4]. Thus, early recognition of AWI with the aid of ECMO support in cardiopulmonary decompensation is vital. With the presentation of anuric acute kidney injury with severe metabolic acidosis [8], hemodialysis can rapidly correct hyponatremia, acidosis, osmotic derangements, and volume expansion as well as remove non-electrolyte irrigation fluid. In hemodynamically unstable conditions, CVVH is the better choice [9].

Plasma sodium level slowly and continuously shifts toward normal with CVVH treatment, rendering it a safe and effective option for the treatment of acute hyponatremia. Moreover, the rate of sodium correction may be controlled by changing the dialysate or the delivery and composition of the replacement fluid [8]. In the present case, the sodium correction ratewas rapid (16mmol/L within 7h), relative to acute symptomatic hyponatremia without developing osmotic demyelination. Currently, no data from controlled trials exist to enable the examination of maximal correction rate in AWI after hysteroscopy. A correction rate of 25mEq/L is generally recommended within 48h. The correction rates reported by most publications were higher than that in the present case despite developing osmotic demyelination [10].

The utmost caution is necessary when looking for hidden risk factors prior to hysteroscopic procedures. During surgery, constant vigilance regarding change in vital signs, input, output, irrigation fluid amount, and duration are critical in preventing AWI. Once AWI manifests, rapid elimination of free water deficits and normalization of sodium levels by adopting measures such as hypertonic saline and CRRT in anuric cases, and ECMO therapy in cases of severe cardiopulmonary decompensation is essential.

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