This week I am oncall and it is a long weekend, since the CNY was celebrated on Thursday. I am going to Adelaide for Tub's course in two weeks time and I'd better be prepared for that intensive course. I must have a proper study strategy. Apparently, it is very difficult for me to juggle my time to suit for family, social, work, research and department.
The above topic is one that I always review over and over again.
Care of the comatose patient
A: assessment of airway adequacy and the patients gag reflex, all of them at the risk of aspiration and there must be a low threshold for establishing a definitive airway. However, all traumatised patients should be assumed to have a potential cervical spine injury.
B: It is important to ensure optimal gas exchange
C: Goals of circulatory therapy include restoration of appropriate MAP and correction of dehydration/volume resuscitation.
The rest will be divided into SPECIFIC and NON SPECIFIC treatment. I am not going into details of the management.
Differrential diagnosis of coma:
A. coma with focal signs
1. trauma-extradural, subdural and parenchymal haemorrhage, concussions
2. vascular-intracerebral haemorrhage, thromboembolic
3. brain abscess
B. Coma without focal signs but with meningeal irritation
1. infection - meningitis, encephalitis,
2. SAH
C. Coma without focal signs and no meningeal irritation
1. metabolic causes - hypoNa, hypoglycaemia, hyperglycaemia, hypoxia, hypercapnea, hypo and hyperthermia, hypo and hyper osmolar states
2. endocrine causes - myxoedema, adrenal insufficiency, hypopituitarism
3. seizure disorders
4. organ failure - hepatic and renal
5. Toxic/drug - sedatives, narcotics, alcohol, psychotropic
Usefullness of EEG in coma1. Identification of NCSE
2. Diagnosis of hepatic encephalopathy
-Presence of paroxysmal triphasic waves
3. Assessing severity of hypoxic encephalopathy
- Presence of theta activity
- diffuse slowing
-Burst suppression (seen with more severe forms)
-Alpha coma (seen with more severe forms)
4. Herpes encephalitis
-Periodic sharp spikes
Anoxic coma
Cardiac arrest is the third leading cause of coma resulting in ICU admission after trauma and drug overdose. The clinical outcome depends on the severity and duration of oxygen deprivation to brain.
Clinical and labarotary predictors of unfavourable prognosis in anoxic coma:
1. Duration of anoxia (time interval between collapse and initiation of CPR) ===> 8-10 minutes
2. Duration of CPR (time interval between initiation of CPR and ROSC)===> > 30mins
3. Duration of anoxic coma ===> 72 hours
4. Pupillary reaction ===> absent on day 3
5. Motor response to pain (a motor response worse than withdrawal) ===> absent on day 3
6. Roving spontaneous eye movements ===> absent on day 1
7. Elevated neuron specific enolase (cytoplasm of neurons) > 33 microgram/l
8. SSEP recording ===> absent N20
Predictors of death or severe neurological impairment after submersion (near drowning)
1. At site of immersion:
i. immersion duration > 10 minutes
ii. delay in commencement of CPR > 10 minutes
2. In the emergency department
i. Asystole on arrival or CPR duration > 25 minutes
ii. Fixed dilated pupils and GCS < 15
iii. Fixed dilated pupils and arterial pH < 7.0
3. In the ICU
i. No spontaneous, purposeful movements and abnormal brainstem function 24 hours after immersion
ii. Abnormal CT scan within 36 hours of submersion
The above topic is one that I always review over and over again.
Care of the comatose patient
A: assessment of airway adequacy and the patients gag reflex, all of them at the risk of aspiration and there must be a low threshold for establishing a definitive airway. However, all traumatised patients should be assumed to have a potential cervical spine injury.
B: It is important to ensure optimal gas exchange
C: Goals of circulatory therapy include restoration of appropriate MAP and correction of dehydration/volume resuscitation.
The rest will be divided into SPECIFIC and NON SPECIFIC treatment. I am not going into details of the management.
Differrential diagnosis of coma:
A. coma with focal signs
1. trauma-extradural, subdural and parenchymal haemorrhage, concussions
2. vascular-intracerebral haemorrhage, thromboembolic
3. brain abscess
B. Coma without focal signs but with meningeal irritation
1. infection - meningitis, encephalitis,
2. SAH
C. Coma without focal signs and no meningeal irritation
1. metabolic causes - hypoNa, hypoglycaemia, hyperglycaemia, hypoxia, hypercapnea, hypo and hyperthermia, hypo and hyper osmolar states
2. endocrine causes - myxoedema, adrenal insufficiency, hypopituitarism
3. seizure disorders
4. organ failure - hepatic and renal
5. Toxic/drug - sedatives, narcotics, alcohol, psychotropic
Usefullness of EEG in coma1. Identification of NCSE
2. Diagnosis of hepatic encephalopathy
-Presence of paroxysmal triphasic waves
3. Assessing severity of hypoxic encephalopathy
- Presence of theta activity
- diffuse slowing
-Burst suppression (seen with more severe forms)
-Alpha coma (seen with more severe forms)
4. Herpes encephalitis
-Periodic sharp spikes
Anoxic coma
Cardiac arrest is the third leading cause of coma resulting in ICU admission after trauma and drug overdose. The clinical outcome depends on the severity and duration of oxygen deprivation to brain.
Clinical and labarotary predictors of unfavourable prognosis in anoxic coma:
1. Duration of anoxia (time interval between collapse and initiation of CPR) ===> 8-10 minutes
2. Duration of CPR (time interval between initiation of CPR and ROSC)===> > 30mins
3. Duration of anoxic coma ===> 72 hours
4. Pupillary reaction ===> absent on day 3
5. Motor response to pain (a motor response worse than withdrawal) ===> absent on day 3
6. Roving spontaneous eye movements ===> absent on day 1
7. Elevated neuron specific enolase (cytoplasm of neurons) > 33 microgram/l
8. SSEP recording ===> absent N20
Predictors of death or severe neurological impairment after submersion (near drowning)
1. At site of immersion:
i. immersion duration > 10 minutes
ii. delay in commencement of CPR > 10 minutes
2. In the emergency department
i. Asystole on arrival or CPR duration > 25 minutes
ii. Fixed dilated pupils and GCS < 15
iii. Fixed dilated pupils and arterial pH < 7.0
3. In the ICU
i. No spontaneous, purposeful movements and abnormal brainstem function 24 hours after immersion
ii. Abnormal CT scan within 36 hours of submersion
Early studies showed S-100B protein (astroglial cells) to be reliable marker of traumatic brain injury, concerns remain about their sensitivity and specificity for assessment of severity and prediction of outcome.
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