Although diagnosis of<unk>  is simple, investigating the underlying cause of onset can be rather challenging. As such, after gaining stabilization of the patient's airways, breathing and circulation (the basic ABCs) various diagnostic tests, such as physical examinations and imaging tools (CT scan, MRI, etc.) are employed to access the underlying cause of the<unk> . When an unconscious person enters a hospital, the hospital utilizes a series of diagnostic steps to identify the cause of unconsciousness. According to Young, the following steps should be taken when dealing with a patient possibly in a<unk> : # Perform a general examination and medical history check # Make sure the patient is in an actual<unk> tose state and is not in a locked-in state or experiencing psychogenic unresponsiveness. Patients with locked-in syndrome present with voluntary movement their eyes, whereas patients suffering from psychogenic<unk> s, demonstrate active resistance to passive opening of the eyelids, with the eyelids closing abruptly and completely when the lifted upper eyelid is released (rather than slowly, asymmetrically and incompletely as seen in<unk> s due to organic causes). # Find the site of the brain that may be causing<unk>  (i.e., brainstem, back of brain...) and assess the severity of the<unk>  with the Glasgow<unk>  Scale # Take blood work to see if drugs were involved or if it was a result of hypoventilation/hyperventilation # Check for levels of “serum glucose, calcium, sodium, potassium, magnesium, phosphate, urea, and creatinine” # Perform brain scans to observe any abnormal brain functioning using either CT or MRI scans # Continue to monitor brain waves and identify seizures of patient using EEGs Initial evaluation In the initial assessment of<unk> , it is common to gauge the level of consciousness on the AVPU (alert, vocal stimuli, painful stimuli, unresponsive) scale by spontaneously exhibiting actions and, assessing the patient's response to vocal and painful stimuli. More elaborate scales, such as the Glasgow<unk>  Scale, quantify an individual's reactions such as eye opening, movement and verbal response in order to indicate their extent of brain injury. The patient's score can vary from a score of 3 (indicating severe brain injury and death) to 15 (indicating mild or no brain injury). In those with deep unconsciousness, there is a risk of asphyxiation as the control over the muscles in the face and throat is diminished. As a result, those presenting to a hospital with<unk>  are typically assessed for this risk ("airway management"). If the risk of asphyxiation is deemed high, doctors may use various devices (such as an oropharyngeal airway, nasopharyngeal airway or endotracheal tube) to safeguard the airway. Imaging and testing Imaging basically encompasses computed tomography (CAT or CT) scan of the brain, or MRI for example, and is performed to identify specific causes of the<unk> , such as hemorrhage in the brain or herniation of the brain structures. Special tests such as an EEG can also show a lot about the activity level of the cortex such as semantic processing, presence of seizures, and are important available tools not only for the assessment of the cortical activity but also for predicting the likelihood of the patient's awakening. The autonomous responses such as the skin conductance response may also provide further insight on the patient's emotional processing. In the treatment of traumatic brain injury (TBI), there are 4 examination methods that have proved useful: skull x-ray, angiography, computed tomography (CT), and magnetic resonance imaging (MRI). The skull x-ray can detect linear fractures, impression fractures (expression fractures) and burst fractures. Angiography is used on rare occasions for TBIs i.e. when there is suspicion of an aneurysm, carotid sinus fistula, traumatic vascular occlusion, and vascular dissection. A CT can detect changes in density between the brain tissue and hemorrhages like subdural and intracerebral hemorrhages. MRIs are not the first choice in emergencies because of the long scanning times and because fractures cannot be detected as well as CT. MRIs are used for the imaging of soft tissues and lesions in the posterior fossa which cannot be found with the use of CT. Body movements Assessment of the brainstem and cortical function through special reflex tests such as the oculocephalic reflex test (doll's eyes test), oculovestibular reflex test (cold caloric test), corneal reflex, and the gag reflex. Reflexes are a good indicator of what cranial nerves are still intact and functioning and is an important part of the physical exam. Due to the unconscious status of the patient, only a limited number of the nerves can be assessed. These include the cranial nerves number 2 (CN II), number 3 (CN III), number 5 (CN V), number 7 (CN VII), and cranial nerves 9 and 10 (CN IX, CN X). Type of reflex Description oculocephalic reflex Oculocephalic reflex also known as the doll's eye is performed to assess the integrity of the brainstem. * Patient's eyelids are gently elevated and the cornea is visualized. * The patient's head is then moved to the patient's left, to observe if the eyes stay or deviate toward the patient's right; same maneuver is attempted on the opposite side. * If the patient's eyes move in a direction opposite to the direction of the rotation of the head, then the patient is said to have an intact brainstem. * However, failure of both eyes to move to one side, can indicate damage or destruction of the affected side. In special cases, where only one eye deviates and the other does not, this often indicates a lesion (or damage) of the medial longitudinal fasciculus (MLF), which is a brainstem nerve tract. Pupillary light reflex Pupil reaction to light is important because it shows an intact retina, and cranial nerve number 2 (CN II) * If pupils are reactive to light, then that also indicates that the cranial nerve number 3 (CN III) (or at least its parasympathetic fibers) are intact. Oculovestibular Reflex (Cold Caloric Test) Caloric reflex test also evaluates both cortical and brainstem function * Cold water is injected into one ear and the patient is observed for eye movement * If the patient's eyes slowly deviate toward the ear where the water was injected, then the brainstem is intact, however failure to deviate toward the injected ear indicates damage of the brainstem on that side. * The cortex is responsible for a rapid nystagmus away from this deviated position and is often seen in patients who are conscious or merely lethargic. Corneal Reflex The corneal reflex assess the proper function of the trigeminal nerve (CN 5) and facial nerve (CN 7) and is present at infancy. * Lightly touching the cornea with a tissue or cotton swab induces a rapid blink reflex of both eyes. * Touching the sclera or eyelashes, presenting a light flash, or stimulating the supraorbital nerve will induce a less rapid but still reliable response. * Those in a<unk> tose state will have altered corneal reflex depending on the severity of their unconscious and the location of their lesion. Gag Reflex The gag, or pharyngeal, reflex is centered in the medulla and consists of the reflexive motor response of pharyngeal elevation and constriction with tongue retraction in response to sensory stimulation of the pharyngeal wall, posterior tongue, tonsils, or faucial pillars. * This reflex is examined by touching the posterior pharynx with the soft tip of a cotton applicator and visually inspecting for elevation of the pharynx. * Those in<unk> tose states will often demonstrate poor gag reflexes if there has been damage to their glossopharyngeal (CN 9) or vagus nerve (CN 10). Decorticate posturing, indicating a lesion at the red nucleus or above. This positioning is stereotypical for upper brain stem, or cortical damage. The other variant is decerebrate posturing, not seen in this picture. Assessment of posture and physique is the next step. It involves general observation about the patient's positioning. There are often two stereotypical postures seen in<unk> tose patients. Decorticate posturing is a stereotypical posturing in which the patient has arms flexed at the elbow, and arms adducted toward the body, with both legs extended. Decerebrate posturing is a stereotypical posturing in which the legs are similarly extended (stretched), but the arms are also stretched (extended at the elbow). The posturing is critical since it indicates where the damage is in the central nervous system. A decorticate posturing indicates a lesion (a point of damage) at or above the red nucleus, whereas a decerebrate posturing indicates a lesion at or below the red nucleus. In other words, a decorticate lesion is closer to the cortex, as opposed to a decerebrate posturing which indicates that the lesion is closer to the brainstem. Pupil size Pupil assessment is often a critical portion of a<unk> tose examination, as it can give information as to the cause of the<unk> ; the following table is a technical, medical guideline for common pupil findings and their possible interpretations: Pupil sizes (left eye vs. right eye) Possible interpretation 250px Normal eye with two pupils equal in size and reactive to light.
Coma
Glioma
Brain abscess
Brain metastasis
Hematoma
Gliosis
Brain tumor
Seroma