COMA

Definition of consciousness : refers to a state of cerebral arousal which allows the brain to executes it’s functions of sensory perception of data input to him from the 5 common senses. The principal causes of coma are: (1) lesions that damage the reticular activating system in the upper pons or its projections (2) destruction of large portions of both cerebral hemispheres. (3) suppression of reticulocerebral function by drugs, toxins, or metabolic derangements such as hypoglycemia, anoxia, uremia, and hepatic failure

Levels of loss of consciousness: -Coma : defined as a deep sleeplike state from which the patient cannot be aroused. -Stupor : refers to a higher degree of arousability in which the patient can be transiently awakened only by vigorous stimuli. -Drowsiness : which is familiar to all persons, simulates light sleep and is characterized by easy arousal and the persistence of alertness for brief periods

Levels of loss of consciousness: -Vegetative state : signifies an awake but nonresponsive state in a patient who has emerged from coma. In the vegetative state, the eyelids may open, giving the appearance of wakefulness. Respiratory and autonomic functions are retained. Yawning, coughing, swallowing, as well as limb and head movements persist and the patient may follow visually presented objects , it indicate bilateral cerebral hemispheric lesion , if this state persist for more than 1 year then described as persistent vegetative state which carries a very poor prognosis.

Levels of loss of consciousness: -Confusion , a mental and behavioral state of reduced comprehension, coherence, and capacity to reason. -Delirium , a term used to describe an acute confusional state, with agitation and autonomic disturbances with visual hallucination .

Causes of confusion and coma A-diseases that not cause focal or lateralizing sign 1-intoxication like alcohol, sedative drugs ,opiates 2-metabolic causes like : uremia , liver failure , hyponatremia , hypernatrmia, hypoglycemia , brain anoxia ,diabetic ketoacidosis , non ketotic hyperosmolar coma , hypo and hyperthyroid , Addison disease 3- sever systemic infection like : pneumonia , typhoid fever , septicemia 4- postictal state , status epilepticus , non convulsive status 5- shock from any cause 6- hypertensive encephalopathy , eclampsia 7- sever hypothermia and hyperthermia 8- concussion 9- acute hydrocephalus

B- diseases with meningial irritation with or without fever 1-acute bacterial meningitis 2-viral encephalitis 3-TB meningitis 4-subarachnoid hemorrhage 5-carcinomatuos meningitis

C-diseases that cause focal or lateralizing sign 1-intracerebral hemorrhage 2-cerebral infarction 3-brian abscess 5-epidural and subdural hemorrhage 6-brain tumor 7-wide spread brain injury 8-acute disseminated encephalomyelitis 9-cerebral venous thrombosis 10- pituitary apoplexy

Aproach Of Patient With Coma Or Confusion HISTORY In many cases, the cause of coma is immediately evident (e.g., trauma, cardiac arrest, or reported drug ingestion). In the remainder, certain points are especially useful: (1) the antecedent symptoms (confusion, weakness, headache, fever, seizures, dizziness, double vision, or vomiting). (2) the use of medications, illicit drugs, or alcohol. (3) chronic liver, kidney, lung, heart, or other medical disease

General and systemic examination look for : -Jaundice , anemia , cyanosis, purpura -Check vital signs for pulse , temp. , resp. rate , B.P , -Check lung , abdomen , abdomen for any systemic abnormality -Look for signs of head trauma (racoon eye indicate anterior cranial fossa fracture ,battle sign indicate middle or posterior fossa fracture ).

Neurological assessment for the followings: 1-conciousness level : confused , drowsy , stuporus ,comatos. 2-pupile for size, shape ,reaction to light, if there is miosis , midriasis , anisochoria (unequal size pupil). Pupillary Sings 1-unilat. Dilated pupil mean 3rd. nerve lesion from uncal herniation. 2-bilat. Small size pupil reacting to light means bilat. Deep cerebral lesion or thalamic lesion or metabolic cause. 3- bilat.pinpoint pupil indicate pontine lesion or opiate toxicity 4-bilat. Dilated pupil indicate midbrain lesion.

3-ocular motility by dolls eye maneuver to detect midbrain or pontine lesion. 4-brainstem reflexes : corneal reflex , gag reflex. 5- meningial signs. 6- examine for any focality or lateralization by applying painful stimulus if there is paralysis of one side. 7-check for planter response if there is unilat. Extensor planter or bilat.

8-check for respiratory pattern if there is apneustic breathing ,ataxic breathing , chennystok breathing. 9-examine for abnormal posture decerbrate or decorticate. 10- fundoscopic examination for papilloedema. 11-looking for any abnormal movement like focal or generalized seizure or myoclouns. 12- look for any eye deviation to one side (gaze preference or palsy) .

LABORATORY STUDIES AND IMAGING 1-Random blood sugar 2-Renal function test 3-liver function test 4-serum electrolyte 5-thyroid function test 6 -complet blood count 7-serum cortisol level 8- arterial blood gas analysis

9- urgent ct scan of brain looking for hemorrhage , srtoke,mass lesion 10- chest x ray 11-MRI if CT brain does not reveal specific insult also looking for demyelination, MRV to detect cerebral venous thrombosis. 12- lumbar puncture if there is meningeal signs or if CNS infection suspected this is done after exclusion of mass lesion by brain ct. 13-EEG if there is focal or generalized fit or there is loss of consciousness without obvious cause to exclude non convulsive status epilepticus 13- toxicology screen for drugs and alcohol

Treatment 1-ABC patent airway if airway occluded put tube even mechanical ventilator if needed, oxygen , canula for drawing blood for full biochemical, toxicological and hematological assay and for circulatory support. 2-thiamin 100mg i.v then glucose hyprtonic i.v if alcoholic intoxication suspected or if there is hidden cause of coma . 3-naloxone i.v if opiate toxicity suspected or if there is hidden cause for coma. 4- NG tube for feeding and for oral drugs. 5-If there is seizure start antiepleptics or if there is status epilpticus manage it accordingly.

6- treat underlying cause like correct metabolic , toxicological causes if identified or treat the structural cause if present accordingly like stroke, hemorrhage , meningitis….etc. 7- if intracranial pressure high start to decrease it by manitol ,hypertonic saline , hyperventilation using mechanicalventilator and by hypothermia.