Final answer:
Coma in purulent meningitis is initially caused by toxic effects of inflammation and can progress to secondary complications such as increased intracranial pressure, shock, and multiple organ failure, often leading to severe outcomes or death.
Step-by-step explanation:
Coma in purulent meningitis can initially result from the toxic effects of inflammatory mediations. Following the onset of infection, a host of secondary complications can arise, including increased intracranial pressure, seizures, and shock. This pressure is consequential since the brain and meninges have limited space to expand within the skull.
Systemic inflammatory responses can lead to further complications such as hemorrhages, purpuric lesions, disseminated intravascular coagulation, and in severe cases, multiple organ failure and death. A lumbar puncture is often performed to diagnose the condition, indicated by elevated white blood cell count and abnormal glucose and protein levels in the cerebrospinal fluid (CSF).
This analysis helps in differentiating whether the inflammation is due to a bacterial or viral cause, with bacterial meningitis tending to have more severe outcomes including rapid progression to shock and coma. The presence of petechial rash, hemorrhagic lesions, and the progression to shock and multiple organ failure are particularly indicative of the severity of meningococcal meningitis.