RAMB - Julho 2016

morim

RLO

382

ssoc

ras

2016; 62(4):377-384

stem is a real possibility in the presence of intracranial

hypertension. Structural causes of coma may be related

to subtle changes or even a normal CT scan (e.g. unilat-

eral chronic isodense subdural hematomas, subarach-

noid hemorrhage, deep vein thrombosis, herpes simplex

encephalitis, and meningitis).

Cerebrospinal fluid

Lumbar puncture is carried out upon suspicion of infec-

tion of the central nervous system or on suspicion of sub-

arachnoid hemorrhage with a normal head CT scan.

Magnetic resonance imaging

This is not an examination carried out routinely in the

emergency department. However, it may provide valuable

information on the number, characteristics and severity

of the lesions,

as well as allow the identification of in-

juries not visible to the head CT, as in cases of herpes sim-

plex encephalitis or diffuse axonal injury.

Functional

magnetic resonance imaging and positron emission to-

mography (PET-SCAN) have proved promising and can

help in the differential diagnosis of patients in a mini-

mally conscious or vegetative state.

The latest technologies include diffusion-weighted im-

aging (DWI) and diffusion-tensor imaging (DTI), which

are tests using methods similar to MRI, but with a more

advanced technology. They provide

in vivo

images of bio-

logical tissues, and allow the observation of molecular wa-

ter displacement as well as more accurate data about dam-

age occurring in specific structures of the nervous system.

Electroencephalogram (EEG)

This is most recommended upon suspicion of non-con-

vulsive seizures, especially in patients with worsening of

the level of consciousness that have a known underlying

neurological disease. Some studies have shown promis-

ing results in the integration of transcranial magnetic

stimulation (TMS) with simultaneous EEG for assess-

ment of brain connectivity and cortical interactions.

11,12

reatment

comatose

patients

The initial care of a comatose patient, the most serious

altered state of consciousness, should emphasize basic

precautions to maintain the airways and adequate venti-

lation, hemodynamic stability and other measures to min-

imize damage to the brain and other vital organs. We

should exclude causes requiring urgent surgical interven-

tion and medical causes that need immediate treatment.

In general, the patient has no ability to protect the

airways and the presence of hypoxia or hypoventilation

requires endotracheal intubation. At the same time, blood

is collected for determination of glucose, electrolytes and

renal and liver function tests. In patients with hypogly-

cemia, infusion of 25 to 50 mL of 50% glucose should al-

ways be supplemented with thiamine.

Gastric aspiration and lavage with saline solution can

be a diagnostic and therapeutic measure upon suspicion

of coma due to ingestion of drugs. Salicylates, opiates

and anticholinergic drugs induce gastric atony and can

be removed several hours after ingestion. Caustic mate-

rials should not be washed out because of the risk of gas-

trointestinal perforation. The administration of activat-

ed charcoal is indicated in certain cases of poisoning. This

is not effective in poisoning caused by heavy metals, cya-

nides and alcohol.

In patients with intracranial hypertension that are

getting worse neurologically (worsening of the GCS score,

anisocoria, decerebrate or decorticate posturing), proceed

with rapid infusion of 20% 1g/kg mannitol or hyperton-

ic saline solution (NaCl 20% 1 mL/kg), associated with

hyperventilation in order to maintain pCO

at around 30

mmHg. In lesions with expansive effects suggestive of

brain tumors, a bolus of 20 mg dexamethasone may be

given. In selected cases, intracranial pressure monitoring

may be appropriate. Lumbar puncture should be per-

formed upon suspicion of meningitis and preferably af-

ter a CT scan of the head.

Extreme hyperthermia or hypothermia must be avoid-

ed. To prevent bladder distension, a catheter should be

inserted. Aspiration pneumonia is prevented by proper

positioning, restriction of oral fluids, gastric tube and

orotracheal tube. As comatose patients have an increased

risk of deep vein thrombosis, elastic compression stock-

ings in the lower limbs and subcutaneous application of

unfractionated heparin 5000u every eight hours are to be

used (Figure 1).

onclusion

The care of patients presenting altered state of conscious-

ness is a medical emergency that requires a multidisci-

plinary team prepared to act quickly. Altered states of

consciousness may have structural or metabolic causes,

and clinical manifestations can include changes to pu-

pillary reactivity, motor and verbal functions, vital signs,

laboratory or imaging tests. Patient management begins

with the assessment of airways, breathing pattern, hemo-

dynamic support, monitoring of vital signs and system-

atic physical and neurological examination. Meanwhile,

medical information should be gathered from family

members, friends or the rescue team, searching for data