ملخص

COMA

Is a sleeplike state in which the patient makes no purposeful response to the environment and from which he or she cannot be aroused.
Coma results from lesions that affect either the reticular activating system or both hemispheres since these are the brain regions that maintain consciousness

APPROACH TO MANAGEMENT

Ensure patency of the airway and adequacy of ventilation and circulation
Insert an intravenous catheter and withdraw blood for laboratory studies
Begin an intravenous infusion and administer dextrose, thiamine, and naloxone

1-Every comatose patient should be given 25 g of dextrose intravenously, typically as 50 mL of a 50% dextrose solution, to treat possible hypoglycemic coma.
2-administration of dextrose alone may precipitate or worsen Wernicke's encephalopathy in thiamine-deficient patients, all comatose patients should also receive 100 mg of thiamine by the intravenous route.
3-To treat possible opiate overdose, the opiate antagonist naloxone, intravenously, should also be administered .

Institute treatment for seizures, if present

Persistent or recurrent seizures in a comatose patient should be considered to represent status epilepticus and treated accordingly

History

1- A sudden onset of coma suggests a vascular origin
2- Rapid progression from hemispheric signs, is characteristic of
intracerebral hemorrhage
3- A more protracted course leading to coma (days to a week or more) is seen with tumor, abscess, or chronic subdural hematoma
4- Coma preceded by a confusional state or agitated delirium, without lateralizing signs or symptoms, is probably due to a metabolic derangement


Lateralizing (Focal ) Signs
1- Assymmetry of pupils.
2- Squint
3- Assymmetry of the face
4- Gaze palsy
5- Assymmetry of motor response, reflexes & plantar response

Diseases that cause no focal or lateralizing neurologic signs

A. Intoxications:
B. Metabolic disturbances: anoxia, diabetic acidosis, uremia, hepatic failure,
C. Severe systemic infections
D. Circulatory collapse (shock)
E. Postseizure states and convulsive
F. Hypertensive encephalopathy
G. Hyperthermia and hypothermia. state,
H. Concussion
I. Acute hydrocephalus
Diseases that cause focal brainstem or lateralizing cerebral signs
A. Hemispheral hemorrhage or massive infarction
B. Brainstem infarction
C. Brain abscess
D. Epidural and subdural hemorrhage
E. Brain tumor
F. Cerebellar and pontine hemorrhage.
G. Miscellaneous: cortical vein thrombosis, viral encephalitis


In these cases no focal sing present as at involve all of brain
A. Subarachnoid hemorrhage from ruptured aneurysm. B. Acute bacterial meningitis
C. Some forms of viral encephalitis

General Physical Examination

A. SIGNS OF TRAUMA
B. BLOOD PRESSURE
Elevation of blood pressure may also be a consequence of the process causing the coma, as in intracerebral or subarachnoid hemorrhage
C. TEMPERATURE
Hypothermia can occur in coma caused by ethanol or sedative drug intoxication, and hypoglycemia.
Coma with hyperthermia is seen in heat stroke, status epilepticus, malignant hyperthermia .
E- Breathing
1- Pattern : Air hunger indicate metabolic cause as aspirin over dose or renal failure or metabolic ketoacidosis
Cheyne- stokes indicate intracranial or cardiac cause
2- Smell : Drugs
Alcohol
Acetone smell metabolic ketoacidosis
Fetor hepaticus hepatitis

Abnormal gait

skeletal abnormalities, usually characterised by pain producing
Gaits that do not fit either pattern may be due to psychiatric disorders and are usually incompatible with any anatomical or physiological deficit .


Pyramidal gait Upper motor neuron (pyramidal) lesions
Foot drop lower motor neuron lesion
Myopathic gait proximal muscle weakness, usually caused by muscle disease
Ataxic gait lesions in the cerebellum , vestibular apparatus or peripheral nerves
Sensory ataxia Impairment of joint position sense
Apraxic gait higher cerebral dysfunction
Extrapyramidal gait in Parkinson disease and other extrapyramidal diseases

INVOLUNTARY MOVEMENTS

Rest tremor pathognomonic of Parkinson disease . It is characteristically pill rolling

Physiological tremor most common type of action tremor It is common in normal subjects and exaggeration occurs in anxiety and in Fatigue, Toxins , Alcohol withdrawal
Essential tremor The condition is often inherited , Alcohol often suppresses it, distinct from a physiological tremor, although resembling it superficially
Intention tremor occurs in cerebellar disease , characterised by oscillation at the end of a movement
Asterixis (flapping tremor) seen in metabolic disturbances, result of intermittent failure of the parietal mechanisms required to maintain a posture. Causes of asterixis : Renal failure
Liver failure, Hypercapnia, Acute focal parietal or thalamic lesion

Chorea, athetosis, ballism

These are due to disturbance of balance of activity in the basal ganglia
Chorea : Jerky, small-amplitude, purposeless involuntary movements causes : Hereditary , Cerebral birth injury , Cerebral trauma
, Drugs
, Endocrine disease, Infective inflammatory


Hemiballismus: More dramatic ballistic flying violent movements of the limbs usually occur unilaterally in vascular lesions of the subthalamic structures.
Athetosis : Slower writhing movements of the limbs . These are often combined with chorea (and have a similar list of causes) and are then termed 'choreo-athetoid' movements

Dystonia sustained involuntary contraction that causes abnormal posture or movement. It may be generalised in various diseases of the basal ganglia or may be focal or segmental, segmental dystonias can be treated by the administration of botulinum toxin to a few of the responsible muscles
Tics Tics are repetitive semi-purposeful movements such as blinking , distinguished from other involuntary movements by the ability of the patient to suppress their occurrence, at least for a short time.