Podcast
Questions and Answers
Define consciousness.
Define consciousness.
Consciousness may be defined as a state of awareness of self and surroundings.
What are the four points on the continuum of arousal often used to describe a patient's clinical state?
What are the four points on the continuum of arousal often used to describe a patient's clinical state?
Delirium can only occur with a reduced level of consciousness.
Delirium can only occur with a reduced level of consciousness.
False
Patients in the persistent vegetative state (PVS) do not demonstrate ________.
Patients in the persistent vegetative state (PVS) do not demonstrate ________.
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Match the following behavioral states with their definitions:
Match the following behavioral states with their definitions:
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What is a common cause of coma due to an underlying medical illness mentioned in the text?
What is a common cause of coma due to an underlying medical illness mentioned in the text?
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What condition can result in coma if the mean arterial pressure drops below a certain level?
What condition can result in coma if the mean arterial pressure drops below a certain level?
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Patients with Addison disease or sepsis typically have cold skin due to peripheral vasoconstriction.
Patients with Addison disease or sepsis typically have cold skin due to peripheral vasoconstriction.
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Match the following causes of coma with their descriptions:
Match the following causes of coma with their descriptions:
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What term is used to describe a condition in which a patient appears comatose but has no structural, metabolic, or toxic disorder?
What term is used to describe a condition in which a patient appears comatose but has no structural, metabolic, or toxic disorder?
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What percentage of patients in a minimally conscious state were misdiagnosed as PVS due to lack of appreciation of eye tracking in two separate European studies?
What percentage of patients in a minimally conscious state were misdiagnosed as PVS due to lack of appreciation of eye tracking in two separate European studies?
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Emergence from minimally conscious state occurs when patients demonstrate higher-level functions, such as intangible speech.
Emergence from minimally conscious state occurs when patients demonstrate higher-level functions, such as intangible speech.
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A state of muteness, with dramatically decreased motor activity, may result from ________.
A state of muteness, with dramatically decreased motor activity, may result from ________.
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Match the following terms with their corresponding definitions:
Match the following terms with their corresponding definitions:
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What may an unwitnessed arrhythmia warn of?
What may an unwitnessed arrhythmia warn of?
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What does an oral anticoagulant like warfarin often lead to?
What does an oral anticoagulant like warfarin often lead to?
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Fever always results in stupor or coma.
Fever always results in stupor or coma.
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Core temperature is best measured with a ________ probe in a comatose patient.
Core temperature is best measured with a ________ probe in a comatose patient.
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Match the following signs with their respective condition:
Match the following signs with their respective condition:
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Which of the following statements concerning integument examination is correct?
Which of the following statements concerning integument examination is correct?
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_______ is a result of barbiturates but also may be caused by imipramine, meprobamate, glutethimide, phenothiazine, and carbon monoxide.
_______ is a result of barbiturates but also may be caused by imipramine, meprobamate, glutethimide, phenothiazine, and carbon monoxide.
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Abnormal flexion is a possible best motor response according to the Glasgow Coma Scale.
Abnormal flexion is a possible best motor response according to the Glasgow Coma Scale.
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What is the state of consciousness in a patient who is able to vocalize to pain with a grunt?
What is the state of consciousness in a patient who is able to vocalize to pain with a grunt?
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What is the main cause of a unilateral dilated pupil?
What is the main cause of a unilateral dilated pupil?
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What is the term used to describe slow deviation of the eyes from the primary position, with a rapid return to the primary position?
What is the term used to describe slow deviation of the eyes from the primary position, with a rapid return to the primary position?
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Ocular flutter is a manifestation of cerebellar disease.
Ocular flutter is a manifestation of cerebellar disease.
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The __________ reflex is observed by sudden rotation of the head to assess eye motion.
The __________ reflex is observed by sudden rotation of the head to assess eye motion.
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What does contralateral hemiparesis suggest in a patient?
What does contralateral hemiparesis suggest in a patient?
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What response is expected when cold water is instilled in the right ear?
What response is expected when cold water is instilled in the right ear?
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Abduction is most reliably reflexive in comatose patients.
Abduction is most reliably reflexive in comatose patients.
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It is important to suspect herniation early because, once advanced changes develop, structural injury is likely to have occurred; sub
It is important to suspect herniation early because, once advanced changes develop, structural injury is likely to have occurred; sub
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What type of respiratory pattern slowly oscillates between hyperventilation and hypoventilation?
What type of respiratory pattern slowly oscillates between hyperventilation and hypoventilation?
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What is the function of the parasympathetic efferent innervation of the pupil?
What is the function of the parasympathetic efferent innervation of the pupil?
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Ataxic breathing is regular in rate and rhythm.
Ataxic breathing is regular in rate and rhythm.
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_______ breathing involves periodic respirations that are irregular in frequency and amplitude.
_______ breathing involves periodic respirations that are irregular in frequency and amplitude.
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Match the following abnormal respiratory patterns with their associated lesions:
Match the following abnormal respiratory patterns with their associated lesions:
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What does the emergence of Cheyne-Stokes respiration in a patient with a unilateral mass lesion suggest?
What does the emergence of Cheyne-Stokes respiration in a patient with a unilateral mass lesion suggest?
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What is the term used to describe rapid downward jerks of both eyes followed by a brief pause in downgaze and a slow return to midposition?
What is the term used to describe rapid downward jerks of both eyes followed by a brief pause in downgaze and a slow return to midposition?
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What is the term used to describe spontaneous eye movements in which an initial slow downward phase is followed by a rapid return into full upward gaze, then slowly back to midposition?
What is the term used to describe spontaneous eye movements in which an initial slow downward phase is followed by a rapid return into full upward gaze, then slowly back to midposition?
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Cold water applied to the tympanic membrane causes currents of _______ flow in the semicircular canal.
Cold water applied to the tympanic membrane causes currents of _______ flow in the semicircular canal.
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Match the following motor responses to their probable causes:
Match the following motor responses to their probable causes:
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Purposeful movements are always a sign of cerebellar fits.
Purposeful movements are always a sign of cerebellar fits.
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What can be a finding on abdominal examination in a patient with an acute abdominal condition?
What can be a finding on abdominal examination in a patient with an acute abdominal condition?
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What is the significance of changing mitral murmurs in a cardiac examination?
What is the significance of changing mitral murmurs in a cardiac examination?
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What is the best motor response according to the Glasgow Coma Scale?
What is the best motor response according to the Glasgow Coma Scale?
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What can an unwitnessed arrhythmia warn of?
What can an unwitnessed arrhythmia warn of?
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What is a possible cause of coma due to an underlying medical illness mentioned in the text?
What is a possible cause of coma due to an underlying medical illness mentioned in the text?
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What is the term used to describe slow deviation of the eyes from the primary position, with a rapid return to the primary position?
What is the term used to describe slow deviation of the eyes from the primary position, with a rapid return to the primary position?
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What is the function of the parasympathetic efferent innervation of the pupil?
What is the function of the parasympathetic efferent innervation of the pupil?
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What is the term used to describe rapid downward jerks of both eyes followed by a brief pause in downgaze and a slow return to midposition?
What is the term used to describe rapid downward jerks of both eyes followed by a brief pause in downgaze and a slow return to midposition?
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What is a contraindication to lumbar puncture?
What is a contraindication to lumbar puncture?
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Why should antibiotics and adjunctive corticosteroids be administered within 1 hour of hospital admission in strongly suspected acute bacterial meningitis?
Why should antibiotics and adjunctive corticosteroids be administered within 1 hour of hospital admission in strongly suspected acute bacterial meningitis?
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What should be avoided in septic shock?
What should be avoided in septic shock?
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What is the importance of serial examinations in a comatose patient?
What is the importance of serial examinations in a comatose patient?
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What should be obtained prior to antibiotic administration in acute bacterial meningitis?
What should be obtained prior to antibiotic administration in acute bacterial meningitis?
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Why is it important to document the behavioral state of a comatose patient at different points in time?
Why is it important to document the behavioral state of a comatose patient at different points in time?
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What is a potential complication of lumbar puncture that may be avoided by performing a CT scan of the head first?
What is a potential complication of lumbar puncture that may be avoided by performing a CT scan of the head first?
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What should be considered in a patient with strongly suspected acute bacterial meningitis when CSF collection cannot be obtained in a timely fashion?
What should be considered in a patient with strongly suspected acute bacterial meningitis when CSF collection cannot be obtained in a timely fashion?
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What is the primary purpose of starting with verbal stimuli when assessing a patient's level of consciousness?
What is the primary purpose of starting with verbal stimuli when assessing a patient's level of consciousness?
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What is the implication of respiratory noise in a patient's breathing pattern?
What is the implication of respiratory noise in a patient's breathing pattern?
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What is the location of the brainstem mechanism that controls normal respiration?
What is the location of the brainstem mechanism that controls normal respiration?
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What is the term used to describe a breathing pattern characterized by slow oscillations between hyperventilation and hypoventilation?
What is the term used to describe a breathing pattern characterized by slow oscillations between hyperventilation and hypoventilation?
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Which of the following abnormal respiratory patterns is associated with lesions of the dorsomedial part of the medulla?
Which of the following abnormal respiratory patterns is associated with lesions of the dorsomedial part of the medulla?
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What is the significance of a patient's response to taking their hand and advancing it toward their face?
What is the significance of a patient's response to taking their hand and advancing it toward their face?
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What is the implication of a patient's failure to respond to verbal stimuli?
What is the implication of a patient's failure to respond to verbal stimuli?
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What is the purpose of assessing a patient's respiratory pattern in coma?
What is the purpose of assessing a patient's respiratory pattern in coma?
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What is the primary distinction between coma and pseudocoma?
What is the primary distinction between coma and pseudocoma?
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What is the most critical component of the rapid initial examination of a comatose patient?
What is the most critical component of the rapid initial examination of a comatose patient?
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What is the primary goal of the neurological examination in a comatose patient?
What is the primary goal of the neurological examination in a comatose patient?
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What is the term used to describe a patient who appears comatose but has no underlying structural, metabolic, or toxic disorder?
What is the term used to describe a patient who appears comatose but has no underlying structural, metabolic, or toxic disorder?
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What is the primary difference between a patient in a persistent vegetative state and a patient in a minimally conscious state?
What is the primary difference between a patient in a persistent vegetative state and a patient in a minimally conscious state?
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What is the most common cause of non-traumatic coma?
What is the most common cause of non-traumatic coma?
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What is the primary role of laboratory studies in the evaluation of a comatose patient?
What is the primary role of laboratory studies in the evaluation of a comatose patient?
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What is the term used to describe the dynamic and changing behavioral states that range from alert to comatose?
What is the term used to describe the dynamic and changing behavioral states that range from alert to comatose?
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What is the characteristic of Cheyne-Stokes respiration?
What is the characteristic of Cheyne-Stokes respiration?
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What is short-cycle periodic breathing similar to?
What is short-cycle periodic breathing similar to?
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What is the correct description of Biot breathing?
What is the correct description of Biot breathing?
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What is the location of the lesions associated with short-cycle periodic breathing?
What is the location of the lesions associated with short-cycle periodic breathing?
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What is the function of the brainstem mechanisms responsible for respiratory rhythm generation?
What is the function of the brainstem mechanisms responsible for respiratory rhythm generation?
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What is the correct description of the medullary junction?
What is the correct description of the medullary junction?
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What is the significance of Cheyne-Stokes respiration in a patient with a unilateral mass lesion?
What is the significance of Cheyne-Stokes respiration in a patient with a unilateral mass lesion?
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What is the term used to describe the respiratory pattern with one or two waxing breaths, followed by two to four rapid breaths, then one or two waning breaths?
What is the term used to describe the respiratory pattern with one or two waxing breaths, followed by two to four rapid breaths, then one or two waning breaths?
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What is the response expected when a patient's head is rotated to the left during the oculocephalic reflex?
What is the response expected when a patient's head is rotated to the left during the oculocephalic reflex?
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What does a bilateral symmetrical limitation of upgaze suggest during the oculocephalic reflex?
What does a bilateral symmetrical limitation of upgaze suggest during the oculocephalic reflex?
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What is the significance of a unilateral eye movement abnormality during the oculocephalic reflex?
What is the significance of a unilateral eye movement abnormality during the oculocephalic reflex?
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What is the response expected when a patient's head is rotated to the right during the oculocephalic reflex in a patient with unilateral pontine gaze palsy?
What is the response expected when a patient's head is rotated to the right during the oculocephalic reflex in a patient with unilateral pontine gaze palsy?
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What is the stimulus that causes endolymph flow in the semicircular canal?
What is the stimulus that causes endolymph flow in the semicircular canal?
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What is the result of cold water instillation in the right ear?
What is the result of cold water instillation in the right ear?
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What is the term used to describe the reflex observed by sudden rotation of the head to assess eye motion?
What is the term used to describe the reflex observed by sudden rotation of the head to assess eye motion?
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What is the significance of no movement in either eye during the oculocephalic reflex?
What is the significance of no movement in either eye during the oculocephalic reflex?
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What is the cause of a unilateral dilated pupil?
What is the cause of a unilateral dilated pupil?
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What is the significance of asymmetry in pupillary size or reactivity in a comatose patient?
What is the significance of asymmetry in pupillary size or reactivity in a comatose patient?
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What is the purpose of the doll’s eye maneuver or cold caloric testing in a comatose patient?
What is the purpose of the doll’s eye maneuver or cold caloric testing in a comatose patient?
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What is the characteristic of a conjugate lateral eye deviation in a comatose patient?
What is the characteristic of a conjugate lateral eye deviation in a comatose patient?
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What is the difference between a sixth nerve palsy and a fourth nerve palsy in a comatose patient?
What is the difference between a sixth nerve palsy and a fourth nerve palsy in a comatose patient?
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What is the significance of a partial third nerve palsy in a comatose patient?
What is the significance of a partial third nerve palsy in a comatose patient?
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What is the characteristic of pupillary function in lesions above the thalamus and below the pons?
What is the characteristic of pupillary function in lesions above the thalamus and below the pons?
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What is the significance of the pupillary reactivity to light in differentiating a third nerve palsy from Horner syndrome?
What is the significance of the pupillary reactivity to light in differentiating a third nerve palsy from Horner syndrome?
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What is the result of warm-water irrigation in the ear in an awake person or a patient in pseudocoma?
What is the result of warm-water irrigation in the ear in an awake person or a patient in pseudocoma?
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What is the term used to describe the bilateral extensor posture, with extension of the lower extremities and adduction and internal rotation of the shoulders and extension at the elbows and wrist?
What is the term used to describe the bilateral extensor posture, with extension of the lower extremities and adduction and internal rotation of the shoulders and extension at the elbows and wrist?
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What is the result of simultaneous bilateral cold water application in the ears?
What is the result of simultaneous bilateral cold water application in the ears?
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What is the significance of external rotation of the lower limb?
What is the significance of external rotation of the lower limb?
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What is the mnemonic used to remember the direction of the fast phase of nystagmus?
What is the mnemonic used to remember the direction of the fast phase of nystagmus?
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What is the result of warm-water irrigation in the ear in an awake person or a patient in pseudocoma, in terms of the eye movement?
What is the result of warm-water irrigation in the ear in an awake person or a patient in pseudocoma, in terms of the eye movement?
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What is the term used to describe bilateral flexion at the elbows and wrists, with shoulder adduction and extension of the lower extremities?
What is the term used to describe bilateral flexion at the elbows and wrists, with shoulder adduction and extension of the lower extremities?
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What is the probable cause of decerebrate posturing?
What is the probable cause of decerebrate posturing?
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What is the level of the spinal cord where the first-order neuron of the sympathetic efferent innervation travels to reach the ciliospinal center of Budge?
What is the level of the spinal cord where the first-order neuron of the sympathetic efferent innervation travels to reach the ciliospinal center of Budge?
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What type of pupils are often referred to as diencephalic pupils?
What type of pupils are often referred to as diencephalic pupils?
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What is the result of lesions along the sympathetic pathway, including hypothalamic lesions?
What is the result of lesions along the sympathetic pathway, including hypothalamic lesions?
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What type of pupillary abnormality is produced by dorsal tectal lesions in the midbrain?
What type of pupillary abnormality is produced by dorsal tectal lesions in the midbrain?
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What is the term used to describe the pupillary findings in many toxic-metabolic conditions resulting in coma?
What is the term used to describe the pupillary findings in many toxic-metabolic conditions resulting in coma?
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What is the significance of absent bowel sounds in an abdominal examination?
What is the significance of absent bowel sounds in an abdominal examination?
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What is the inherent risk of atrial fibrillation confirmed by cardiac auscultation?
What is the inherent risk of atrial fibrillation confirmed by cardiac auscultation?
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What is the site of the second-order neuron of the sympathetic efferent innervation?
What is the site of the second-order neuron of the sympathetic efferent innervation?
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What is the significance of changing mitral murmurs in a cardiac examination?
What is the significance of changing mitral murmurs in a cardiac examination?
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What is the result of midbrain lesions, depending on the location of the lesion?
What is the result of midbrain lesions, depending on the location of the lesion?
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What is the best motor response according to the Glasgow Coma Scale?
What is the best motor response according to the Glasgow Coma Scale?
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What is the effect of a mydriatic agent placed by the patient or a prior observer wearing off unevenly?
What is the effect of a mydriatic agent placed by the patient or a prior observer wearing off unevenly?
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What is the significance of abnormal flexion in a patient's motor response?
What is the significance of abnormal flexion in a patient's motor response?
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What is the significance of constant murmurs in a cardiac examination?
What is the significance of constant murmurs in a cardiac examination?
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What can be a finding on abdominal examination in a patient with an acute abdominal condition?
What can be a finding on abdominal examination in a patient with an acute abdominal condition?
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What is the significance of a verbal response of 'oriented' in a patient?
What is the significance of a verbal response of 'oriented' in a patient?
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Study Notes
Stupor and Coma
- Stupor and coma are two types of altered consciousness that affect arousal.
- Consciousness is defined as a state of awareness of self and surroundings.
- Alterations in consciousness can be categorized into two types: one affecting arousal and the other affecting cognitive and affective mental function.
Definitions
- Delirium is a disturbance in attention and awareness that can occur with or without a reduced level of consciousness.
- Delirium is classified as a disorder of arousal or mental function depending on the context.
- Coma is a state of complete unresponsiveness to arousal.
Conditions that May Mimic Coma
- Locked-in syndrome: a condition where patients are alert and aware but quadriplegic and able to move only their eyes.
- Persistent vegetative state: a condition where patients are awake but unaware of their surroundings and have no purposeful behaviors.
- Abulia: a severe apathy in which patients have blunted feeling, drive, mentation, and behavior.
- Catatonia: a state of muteness with decreased motor activity.
- Pseudocoma: a condition where patients feign coma.
Approach to the Patient in Coma
- The initial approach to a patient in coma is to treat the condition as a life-threatening emergency until vital functions are stabilized.
- Urgent steps may be necessary to avoid or minimize permanent brain damage.
- A basic understanding of the mechanisms leading to impaired arousal is necessary to develop a diagnostic and therapeutic routine.
Common Causes of Coma
- Diffuse and metabolic brain dysfunction (more than half of all cases)
- Drug poisoning (almost half of diffuse and metabolic brain dysfunction cases)
- Supratentorial mass lesions (101 cases in Plum and Posner's study)
- Subtentorial lesions (65 cases in Plum and Posner's study)
- Psychiatric coma (8 cases in Plum and Posner's study)
Initial Examination
-
Check general appearance, blood pressure, pulse, temperature, respiratory rate, and breath sounds.
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Stabilize the neck in cases of trauma.
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Protect the airway and place an intravenous line.
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Consider a CT scan of the abdomen or peritoneal lavage in cases of trauma.
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Hypotension, hypertension, bradycardia, and signs of cerebral herniation require immediate therapeutic intervention.
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Hyperthermia or meningismus prompts consideration of urgent lumbar puncture.
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Examination of the fundus of the eye for papilledema and a CT scan of the brain should be performed before lumbar puncture.
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Infection at the site of lumbar puncture, papilledema, decerebrate posturing, and thrombocytopenia and other bleeding diathesis are contraindications to lumbar puncture.### Coma and Stupor
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Coma can be a predictable progression of an underlying illness, an unpredictable event in a patient with known medical conditions, or a sudden event in a patient with unknown medical history.
Initial Examination and Therapy
- A rapid initial assessment is essential to ensure the patient's medical and neurological stability before conducting a more detailed investigation.
- Urgent and sometimes empirical therapy is necessary to prevent further brain damage.
- Empirical use of supplemental oxygen, intravenous thiamine, and intravenous 50% dextrose in water may be necessary.
- A baseline serum glucose level should be obtained before glucose administration.
Acute Bacterial Meningitis
- When acute bacterial meningitis is strongly suspected, antibiotics and adjunctive corticosteroids should be administered within 1 hour of hospital admission.
- Blood cultures and throat swabs should be obtained before antibiotic administration.
- Corticosteroid administration should be avoided in the presence of septic shock.
Lumbar Puncture
- Lumbar puncture should be performed with caution, as it poses a risk of herniation in patients with increased intracerebral pressure.
- Multiplex nucleic acid amplification tests may be helpful in diagnosing CNS infections.
- Measurements of prothrombin time, partial thromboplastin time, and platelet count should precede lumbar puncture in cases of coagulation abnormality or thrombocytopenia.
Causes of Coma
- Toxins, metabolic disorders, and infections are common causes of coma (Table 5.4).
- Structural causes include supratentorial and infratentorial lesions, and asymmetrical presentations.
Common Presentations
- Coma may present as a sudden, unexpected event, or as a predictable progression of an underlying illness.
- Comatose patients may have a history of psychiatric disease, previous similar episodes, or unusual responses to stress.
- Family members or friends may be able to provide valuable information about the patient's medical history and circumstances surrounding the coma.
General Examination
- A systematic, detailed general examination is essential in the approach to the comatose patient.
- Blood pressure, pulse, respiratory rate, and temperature should be evaluated.
- Special care must be taken not to be misled by an apparently predictable progression of an underlying illness.
Blood Pressure Evaluation
- Hypotension may result in coma if the mean arterial pressure decreases to less than 60 mm Hg.
- Causes of hypotension include hypovolemia, massive external or internal hemorrhage, myocardial infarction, cardiac tamponade, and intoxication with alcohol or other drugs.
Heart Rate
- Bradycardia can result from the Kocher-Cushing reflex, myocardial conduction blocks, certain poisonings, and effects of drugs such as beta-blockers.
- Tachycardia can result from hypovolemia, hyperthyroidism, fever, anemia, and certain toxins and drugs.
Respiration
- Decreased respiratory rate can result from metabolic or toxic causes, such as carbon dioxide narcosis or drug overdose.
- Increased respiratory rate can result from hypoxia, hypercapnia, acidosis, hyperthermia, hepatic disease, toxins or drugs, sepsis, and pulmonary embolism.
Head Trauma
- Laceration or edema of the scalp is indicative of head trauma.
- Raccoon eyes and Battle sign are indicative of basilar skull fracture.### Rhythm in a Comatose Patient
- Neck stiffness may be a sign of infectious or carcinomatous meningitis, subarachnoid hemorrhage, or central or tonsillar herniation.
- Absence of neck stiffness does not rule out coma from any cause.
Temperature
- Core temperature is best measured with a rectal probe in a comatose patient.
- Pyrexia is often a sign of infection.
- Absence of elevated temperature does not rule out infection.
- Pure neurogenic hyperthermia is rare and usually due to subarachnoid hemorrhage or diencephalic (hypothalamus) lesions.
Eye Examination
- Examination of the eyes includes observation of the cornea, conjunctiva, sclera, iris, lens, and eyelids.
- Edema of the conjunctiva and eyelids may occur in congestive heart failure and nephrotic syndrome.
- Congestion and inflammation of the conjunctiva may occur in the comatose patient from exposure.
- Enophthalmos indicates dehydration.
- Scleral icterus is seen with liver disease.
Head and Neck Examination
- Palpation for depressed skull fractures and edema should be attempted.
- Signs of trauma should be carefully examined.
- Infections of the middle ear, mastoid, and paranasal sinuses are the most common sources of underlying infection in brain abscess.
General Appearance
- The general appearance of the patient may provide further clues to the diagnosis.
- Torn or disheveled clothing may indicate prior assault.
- Vomiting may be a sign of increased ICP, drug overdose, or metabolic or other toxic cause.
- Urinary or fecal incontinence suggests an epileptic seizure or may result from a generalized autonomic discharge.
Integument Examination
- Systematic examination of the integument includes inspection of the skin, nails, and mucous membranes.
- Hot, dry skin is a feature of heat stroke.
- Sweaty skin is seen with hypotension or hypoglycemia.
- Drugs may cause macular-papular, vesicular, or petechial-purpuric rashes or bullous skin lesions.
Cardiac Examination
- Cardiac auscultation will confirm the presence of arrhythmias such as atrial fibrillation.
- Changing mitral murmurs are heard with atrial myxomas and papillary muscle ischemia.
Abdominal Examination
- Abdominal examination may reveal abnormal bowel sounds, organomegaly, masses, and ascites.
- Bowel sounds are absent in an acute abdominal condition, as well as with anticholinergic poisoning.
- Hyperactive bowel sounds may be a consequence of increased gastrointestinal motility.
Neurological Examination
- The neurological examination of a comatose patient serves three purposes: to aid in determining the cause of coma, to provide a baseline, and to help determine the prognosis.
- The examination should include the state of consciousness, respiratory pattern, pupillary size and response to light, spontaneous and reflex eye movements, and skeletal muscle motor response.
Glasgow Coma Scale
- The Glasgow Coma Scale is used to assess the initial severity of traumatic brain injury.
- The scale assesses three separate aspects of a patient's behavior: the stimulus required to induce eye opening, the best motor response, and the best verbal response.
- Degrees of increasing dysfunction are scored.
Respiratory Patterns
- Cheyne-Stokes respiration is a respiratory pattern that oscillates between hyperventilation and hypoventilation.
- It was first described by Cheyne in 1818.
- Short-cycle periodic breathing is a respiratory pattern with a shorter cycle than Cheyne-Stokes respiration, with one or two waxing breaths, followed by two to four rapid breaths, then one or two waning breaths.
- It is seen with increased ICP, lower pontine lesions, or expanding lesions in the posterior fossa.
Brainstem Mechanisms
- Respiratory rhythm generation is regulated by a brainstem mechanism located between the midpons and cervical medullary junction.
- Forebrain influences also play a role in regulating metabolic needs and behavioral needs such as speech production.
Consciousness
- Consciousness is a state of awareness of self and surroundings.
- Alterations in consciousness can be conceptualized into two types, affecting arousal and cognition.
- These states are dynamic and may change with time.
Coma
- Coma is a state of altered consciousness characterized by a lack of awareness of self and surroundings.
- It is a dynamic state that may change with time.
- Differentiating toxic-metabolic coma from structural coma is important for diagnosis and treatment.
Neurological Examination
- A thorough neurological examination is necessary to determine the level of consciousness and identify potential structural lesions.
- The examination should include a rapid initial examination, history, general examination, and neurological examination.
Respiratory Examination
- Normal breathing is quiet and unlabored.
- The presence of any respiratory noise implies airway obstruction, which must be dealt with immediately to prevent hypoxia.
Glasgow Coma Scale
- The Glasgow Coma Scale is a tool used to assess the level of consciousness.
- It consists of three components: best motor response, verbal response, and eye opening.
Lumbar Puncture
- Lumbar puncture is a diagnostic tool used to collect cerebrospinal fluid.
- Contraindications to lumbar puncture include infection at the site of the lumbar puncture, papilledema, decerebrate posturing, and thrombocytopenia and other bleeding diathesis.
- In cases of suspected acute bacterial meningitis, antibiotics and adjunctive corticosteroids should be administered within 1 hour of hospital admission, even if cerebrospinal fluid collection cannot be obtained in a timely fashion.
Pupil Size and Reactivity
- Pupil size in a comatose patient depends on the level of illumination and the state of autonomic innervation.
- Thalamic lesions cause small, reactive pupils (diencephalic pupils).
- Hypothalamic lesions or lesions along the sympathetic pathway result in Horner syndrome.
- Midbrain lesions produce three types of pupillary abnormalities, depending on the location of the lesion.
Pupillary Asymmetry
- Asymmetry in pupillary size or reactivity is important, even if minor.
- Asymmetry may be due to dilation (mydriasis) of one pupil or contraction (miosis) of the other.
- Pupillary reactivity to light and associated neurological signs can help differentiate the causes.
Eye Deviation
- Spontaneous eye deviation may be conjugate or dysconjugate.
- Conjugate lateral eye deviation usually indicates an ipsilateral lesion in the frontal eye fields.
- Dysconjugate eye deviation may indicate a lesion in the brainstem or elsewhere in the pathway.
Oculocephalic Reflex
- The oculocephalic reflex is used to assess brainstem function.
- Normal response: eyes move in the opposite direction of the head movement.
- Abnormal responses: no movement, one eye moves, or bilateral limitation of upgaze.
Glasgow Coma Scale
- The Glasgow Coma Scale assesses the severity of coma based on motor response, verbal response, and eye opening.
- Motor response: obeys, localizes, withdraws, flexion, extensor response, or nil.
- Verbal response: oriented, confused, inappropriate, or nil.
Cardiac Examination
- Cardiac auscultation can confirm the presence of arrhythmias, such as atrial fibrillation.
- Changing mitral murmurs may indicate atrial myxomas or papillary muscle ischemia.
- Constant murmurs may indicate valvular heart disease.
Abdominal Examination
- Abdominal examination may reveal abnormal bowel sounds, organomegaly, masses, or ascites.
- Bowel sounds are absent in acute abdominal conditions or anticholinergic poisoning.
Brainstem Function
- Cold water caloric testing can help diagnose brainstem lesions.
- Ipsilateral paralysis indicates a probable brainstem lesion.
- Decerebrate posturing: bilateral extensor posture, with extension of the lower extremities and adduction and internal rotation of the shoulders.
- Decorticate posturing: bilateral flexion at the elbows and wrists, with shoulder adduction and extension of the lower extremities.
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Description
This quiz covers the definitions, differentiations, and approaches to diagnosing coma and stupor, including laboratory studies and emergency therapy.