Despite variations in sodium and water concentrations, our body relies on several mechanisms to maintain the plasmatic osmolality within the normal range of 275-290 mOsm/L 1 . Hyponatremia is defined as a reduction in plasma sodium concentration below 136 mmol/L 2 . It occurs in 12% of the hospitalized patients and in 30% of the patients in the intensive care unit (ICU) 3 . Hyponatremia installed progressively usually causes no symptoms. If installed acutely, severe symptoms such as vomiting, progressive somnolence and confusion, coma and seizures often occur 2,4 . Hyponatremia related to the ingestion of free water is uncommon in healthy subjects that are neither athlete nor have psychiatric disorders [2][3][4][5] . Thus, after approval of the Hospital Ethics Committee and signed informed consent obtained from a patient representative.We report a case of hyponatremia associated with fast ingestion of large amounts of potable water causing severe neurological impairment. CaSeA 34-year-old male, previously healthy, was admitted in ICU of the Hospital da Cidade (Salvador BA, Brazil). The patient was transferred from the emergency department with a history of ingestion of 40 glasses of potable water, equivalent to approximately 8 liters, during a period of a few hours. The patient was playing domino and the players bet that one who loses a game should drink a full glass of water. The unlucky patient lost one game after the other and started to become sleepy, culminating with a generalized tonic-clonic seizure. Taken to the hospital, he developed new episode of seizure, lingered, requiring intubation and mechanical ventilation. The admission tests revealed plasma sodium of 123 mmol/L and mild cerebral edema at CT scan. The diagnosis of hypovolemic hyposmolar hyponatremia with low urinary osmolality ("the marathon runner's hyponatremia") was made based on plasmatic osmolality (262 mmol/L), urinary osmolality, urinary sodium (undetectable) and the volemic status was estimated by pre-load pressures. Since the installation of hyponatremia was rapid with severe symptoms, 3% saline solution was started with infusion rate of 0.5 mL/kg/h. Plasma sodium was measured hourly, aiming for an elevation of sodium level by 0.5 mEq/L/hour. After discontinuing sedation he gradually recovered, being disconnected from mechanical ventilation in the third day of hospitalization. He was discharged from ICU after five days without any neurological deficit. diSCuSSionThe initial approach to hyponatremia requires determination of plasmatic osmolality , in order to classify the hyponatremia in hypertonic, isotonic or hypotonic. The determination of osmolar gap -difference between measured and calculated osmolality, normal <10 mOsm/kg -helps with the interpretation and suggests which solutions should be utilized in the treatment 6 . Hypertonic hyponatremia is typically observed during hyperglycemia or after mannitol use and is also known as translocational hyponatremia. Isotonic hyponatremia is diagnosed in settings of severe hypertriglyceri...

Snakebites are common and lead to potential complications like neuromyopathies and strokes, these last associated with disturbances of blood coagulation. We report on a 65 years old woman of cerebral intraparenchymal hemorrhage associated with snakebite by a Bothrops jararaca that occurred in the Reconcavo of Bahia, BA, Brazil. The patient was submitted to a surgical evacuation of the hematoma, with a good result. This report is accompanied by a revision about the association among snakebite and neurological complications, emphasizing strokes. Statistics reveal a high incidence of snakebite in the world, mainly in tropical countries and gets attention for his socioeconomic impact. The clinical and laboratory characteristics to identify the victims that present a high risk of presenting strokes are discussed in order to identify early those patients, so that they may be treated in a more precocious and effective way.

Isolated thrombosis of the vein of Galen is a rare and serious entity with few cases reported in the literature. We report the case of a previously healthy 18-year-old male who was admitted after developing headache and subsequently worsening mental status, requiring endotracheal intubation for airway protection. During his admission he developed symptoms of severe paroxysmal sympathetic hyperactivity and posturing. The computed tomography and magnetic resonance imaging of the brain showed bilateral thalamic lesions. The magnetic resonance angiography and digital arteriography revealed a thrombosis of the deep cerebral venous system (vein of Galen). We call attention to a case with rapid symptom progression and specific radiological findings, with atypical clinical course, characterized by paroxysmal sympathetic hyperactivity, but with good clinical functional outcome.