Coma

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton and Kim Jackson  

Introduction

Deep coma state: no motor response to intense painful stimulation.

Coma reflects brain failure that may occur from a process originating in the central nervous system or may reflect a systemic metabolic process. Causes of coma range from easily correctable metabolic abnormalities to catastrophic life-threatening mass lesions.

• Coma is defined as a state of deep unconsciousness, an eyes-closed unresponsive state.
• The person is alive and looks like they are sleeping, but unlike in a deep sleep, the person cannot be awakened by any stimulation, including pain.
• Coma is usually a transitory state though it may last for an indefinite or even prolonged period.

Pathophysiology

The accepted pathophysiology of a coma involves neuronal dysfunction from a decrease in the supply of glucose or oxygen to the brain. A myriad of etiologies may lead to essential substrate disruption with diffuse central nervous system (CNS) dysfunction and coma as the extreme clinical condition.

Causes

More than 50% of comas are related to head trauma or disturbances in the brain's circulatory system.

Causes are many and include:

• Brain injuries caused by an accident or violence. Additionally people can be put into a medically induced coma with medicines. This helps their brain to keep functioning after an injury and saves the patient from feeling extreme pain.
• Structural brain diseases such as subdural or epidural traumatic hematomas, spontaneous intracranial hemorrhages, venous thrombosis, tumors, acute hydrocephalus, raised intracranial pressure, anoxic brain injury, or brainstem strokes may all cause altered mental status or coma.
• Common toxic or metabolic causes include hypoglycemia, hyperglycemia, excessive alcohol intake, medication overdose, illicit drug use. Of all the nonstructural causes of coma, hypoglycemia and systemic infections likely account for the majority of patients presenting with coma
• Less common metabolic causes include hepatic encephalopathy, hyponatremia, hypernatremia, hypercalcemia, endocrine abnormalities.
• Primary central nervous system infections such as meningitis or encephalitis (relatively uncommon)
• Seizure

Evauluation and Treatment

Initial evaluation of the comatose patient should always include assessment with intervention as necessary of the airway, breathing, and circulatory conditions (A,B,C's). Recording of the neurologic examination and can be roughly quantified by the Glasgow Coma Scale.

Simplistically, the treatment of a coma is treatment of conditions that lead to coma. These patients may require care of many organ systems and an interprofessional team approach is essential.

Someone in a coma needs intensive care in hospital. They may need help with breathing, they will be fed through a tube and they will receive blood and fluids through a drip inserted into the vein. The cause of the coma will also need to be treated to prevent further brain damage.

They need

• Medical support to stop their condition worsening and to prevent complications eg pressure sores, infections, DVTs.
• Joints and muscles need to be exercised gently to prevent contractures.
• May need medicine to calm them down if they get agitated.

Prognosis

• Patients with reversible causes of coma, eg hypoglycemia, may be discharged after the appropriate intervention.
• Patients with persistent coma need hospital admission with ongoing monitoring, supportive care, and targeted care to the underlying cause of coma.
• Prognosis is difficult and may become clear only after a period of observation.

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