Plasma osmolality, osmoregulation and prognosis after head injury

Emergency anesthesia for evacuating a traumatic acute subdural hemorrhage in a child overdosed with hypertonic saline

A previously healthy 1-year-old child with a traumatic acute subdural hemorrhage received 10 times higher dose of hypertonic saline inadvertently immediately before surgery. This case report describes deviations in fluid management needed to alleviate salt toxicity and its adverse effects during surgery under anesthesia perioperatively. The child made an uneventful recovery with no evident residual damage at follow-up.

[Hypernatremia in head-injured patients: friend or foe?]

Hypernatremia is defined by a serum sodium concentration of more than 145 mmol/L and reflects a disturbance of the regulation between water and sodium. The high incidence of hypernatremia in patients with severe brain injury is due various causes including poor thirst, diabetes insipidus, iatrogenic sodium administration, and primary hyperaldosteronism. Hypernatremia in the intensive care unit is independently associated with increased mortality and complications rates. Because of the rapid brain adaptation to extracellular hypertonicity, sustained hypernatremia exposes the patient to an exacerbation of brain edema during attempt to normalize natremia. Like serum glucose, serum sodium concentration must be tightly monitored in the intensive care unit.

La Crosse encephalitis in children

BACKGROUND

La Crosse encephalitis is a mosquito-borne disease that can be mistaken for herpes simplex encephalitis. It has been reported in 28 states but may be underrecognized.

METHODS

We investigated the manifestations and clinical course of La Crosse encephalitis in 127 patients hospitalized from 1987 through 1996. The diagnosis was established by serologic testing for IgM and IgG antibodies to La Crosse virus. Data were collected by chart review.

RESULTS

Most of the patients were school-aged children (mean [+/-SD] age, 7.8+/-3.5 years; range, 0.5 to 15.0). Symptoms included headache, fever, and vomiting (each in 70 percent or more of the patients), seizures (in 46 percent), and disorientation (in 42 percent). Thirteen percent had aseptic meningitis. Hyponatremia developed in 21 percent, and there were signs of increased intracranial pressure in 13 percent. Six patients, including three with cerebral herniation, underwent intracranial-pressure monitoring. The 13 patients (11 percent) whose condition deteriorated in the hospital had decreases in serum sodium levels (P=0.007), and increases in body temperature (P=0.003) at the time of deterioration. At admission, these patients more often had a history of vomiting (P=0.047) and a score of 12 or lower on the Glasgow Coma Scale (P=0.02) than the others; a trend toward a greater prevalence of seizures at admission was also evident in this group (P=0.07). All the patients survived, but 15 of them (12 percent) had neurologic deficits at discharge. Follow-up assessments, performed in 28 children, suggested an increase in cognitive and behavioral deficits 10 to 18 months after the episode of encephalitis.

CONCLUSIONS

La Crosse virus infection should be considered in children who present with aseptic meningitis or encephalitis. Hyponatremia and increasing body temperature may be related to clinical deterioration.

Outcome analysis of patients with severe head injuries and prolonged intracranial hypertension

OBJECTIVE

To describe the functional outcome of a select group of patients with severe head injuries who would a priori be assumed to have a dismal outcome and to determine prognostic factors that can be used for effective family counseling and rational utilization of scarce resources.

METHODS

Thirty-seven patients with severe head injuries (admission Glasgow Coma Scale (GCS) score < 8) with prolonged (> 96 hours) intracranial hypertension were studied. Parameters recorded included admission age, GCS, evidence of prehospital hypotension, initial computed tomography findings, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and therapeutic intensity level.

RESULTS

Thirty-eight percent of patients in this study achieved a Glasgow Outcome Scale score (GOS) of 4 (moderate disability) or better when assessed 1 year after injury. Patients who achieved these good outcomes were significantly younger (mean 23.6 +/- 8.8 years) than patients who were severely disabled or worse (GOS 1-3) (34.3 +/- 15.0 years) (p = 0.0098). The mean admission GCS in the good-outcome group tended to be higher than that of the poor-outcome group (5.8 +/- 1.5 vs 4.8 +/- 1.6, p = 0.065). When patients with good outcomes (GOS 4 or 5) were compared with those with poor outcomes (GOS 1-3), no significant differences in mean or peak ICP, percentage of time intervals with elevated ICP, lowest recorded CPP, or length of ICP monitoring were detected.

CONCLUSION

Younger patients, particularly those with GCS > 5, have the potential for excellent recovery despite prolonged (> 96 hours) intracranial hypertension. These patients will benefit from continued aggressive ICP and CPP management.