14 Questions
What are the two main classifications of the causes of coma mentioned in the text?
Structural and metabolic
Which respiratory pattern is usually associated with irregular breathing in coma patients?
Cheyne–Stokes
What may mimic coma according to the text?
Psychiatric disorders
In coma patients, what is the typical status of pupillary size and reaction?
Equal, reactive to light
What can cause unequal or unreactive pupils to light, with fixed midposition?
Epidural hemorrhage
Which type of rigidity implies a destructive lesion of the corticospinal tracts within or very near the cerebral hemispheres?
Decorticate Rigidity
In the context of brain damage, which condition involves a hemiplegia that is flaccid early in its course?
Flaccid Hemiplegia
What does decerebrate rigidity typically involve?
Jaws clenched and neck extended
What does dilated, fixed pupils suggest in the context of anticholinergics or hypothermia?
Brainstem infarct
Which condition is characterized by the arms flexed tight to the sides with internally rotated legs?
Abnormal Flexor Response
What might cause decerebrate rigidity?
Severe metabolic disorders such as hypoxia or hypoglycemia
What type of response is seen in decerebrate rigidity?
Abnormal Extensor Response
Which condition involves sudden unilateral brain damage producing a hemiplegia that is flaccid early in its course?
Flaccid Hemiplegia
What is suggested by unequal or unreactive pupils with fixed midposition?
Epidural hemorrhage
Study Notes
Causes of Coma
- There are two main classifications of the causes of coma: structural and metabolic
Respiratory Patterns in Coma
- Cheyne-Stokes respiration is usually associated with irregular breathing in coma patients
Differential Diagnosis of Coma
- Psychogenic unresponsiveness, catatonia, and Locked-In syndrome may mimic coma
Neurological Examination in Coma
- The typical status of pupillary size and reaction in coma patients is unequal or unreactive pupils with fixed midposition
Pupillary Abnormalities
- Unequal or unreactive pupils to light, with fixed midposition can be caused by midbrain damage or anticholinergics
Types of Rigidity
- Decorticate rigidity implies a destructive lesion of the corticospinal tracts within or very near the cerebral hemispheres
- Decerebrate rigidity typically involves extension of all four limbs and arching of the back
Neurological Conditions
- Spastic hemiplegia involves a hemiplegia that is spastic late in its course, whereas flaccid hemiplegia involves a hemiplegia that is flaccid early in its course
- Middle cerebral artery syndrome involves sudden unilateral brain damage producing a hemiplegia that is flaccid early in its course
Decerebrate Rigidity
- Decerebrate rigidity may be caused by a destructive lesion in the rostral pons or midbrain
- Decerebrate rigidity typically involves an extensor response to stimuli
Ocular Signs
- Dilated, fixed pupils suggest anticholinergics or hypothermia
- Unequal or unreactive pupils with fixed midposition suggest midbrain damage
Test your knowledge of the causes of coma by classifying them as either structural or metabolic. Understand the general guidelines for diagnosing coma and recognize how psychiatric disorders may mimic coma.
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