The ascending reticular activating system is a postulated group of neural connections that receives sensory input and projects to the cerebral cortex through the midbrain and thalamus from the reticular formation. Since this system is thought to modulate wakefulness and sleep, interference with it, such as injury, illness, or metabolic disturbances, could alter the level of consciousness.Normally, stupor and coma are produced by interference with the brain stem, such as can be caused by a lesion or indirect effects, such as brain herniation. Mass lesions in the brain stem normally cause coma due to their effects on the reticular formation. Mass lesions that occur above the tentorium cerebelli normally do not significantly alter the level of consciousness unless they are very large or affect both cerebral hemispheres. Diagnosis
Assessing LOC involves determining an individuals response to external stimuli. Speed and accuracy of responses to questions and reactions to stimuli such as touch and pain are noted. Reflexes, such as the cough and gag reflexes, are also means of judging LOC. Once the level of consciousness is determined, clinicians seek clues for the cause of any alteration. Usually the first tests in the ER are pulse oximetry to determine if there is hypoxia, serum glucose levels to rule out hypoglycemia. A urine drug screen may be sent. A CT head is very important to obtain to rule out bleed. In cases where meningitis is suspected, a lumbar puncture must be performed. A serum TSH is an important test to order. In select groups consider vitamin B12 levels.
Pruritus scroti is itchiness of the scrotum that may be secondary to an infectious cause. : 55

See also
Pruritus vulvae
Pruritus ani
Pruritus

References


== External links ==