Causes of coma

1. Diseases that cause no focal or lateralizing neuro signs, usually with normal brain stem function.
Ct scan and CSF are normal.
A] intoxication: alchohol,sedative,drugs,opiates
B]metabolic disturbances: hyponatremia,hypernatremia,hypercalcemia,diabetic acidosis, hypoglycaemia, nonketotic hyperosmolar hyperglycaemia,uraemia, hepatic coma,hypercarbia,addisonian crisis,hypo and hyperthyroid states,profound nutritional deficiency.
C]severe systemic infection:pneumonia,septicemia,typhoid fever,malaria,Waterhouse Friderichsen syndrome.
D]shock from any causes
E] post seizure,status epilepticus
F]hypothermia,hyperthermia
G]Hypertensive encephalopathy,eclampsia
H]concussion
I]acute hydrocephalus

2. Diseases causes meningeal irritation with or without fever, snd with excess WBC or RBc in CSF. CT no mass lesion
a]subarachnoid hemorrhage
b]bacterial meningitis
c]encephalits
d]fat embolism,cholesterol embolism

3.Diseases that cause focal neuro signs. CT abnormal
a]hemispheral hemorrhages
b]brainstem infarction due to basal artery thrombosis or embolism
c]brain abscess
d]subdural haemorrhages
e]cerebellar and pontine hemorrhages
f]brain tumour
g]traumatic brain injury
i]miscellanous:cortical vein thrombosis,herpes simplex encephalitis,acute disseminated encephalomyelitis,TTP,pit apoplexy.