Rostrocaudal Deterioration—The Pattern
Rostrocaudal deterioration is a fairly stereotyped SEQUENCE of neurological deterioration which occurs from a mass in the head. It is important to recognize that a comatose patient with a mass lesion will progress from consciousness to impaired consciousness to a reversible state of coma to an irreversible state of coma in a predictable fashion.
This is predictability is important, because it gives you a way of knowing where you are in this sequence of deterioration. You also can figure out how quickly the patient is deteriorating and how loudly you need to shout to get some help before the situation becomes irreversible.
The Usual Disclaimer: No, nothing is 100% and there are exceptions to all rules. But if you know this sequence, you will be able to deal with most deteriorating neurological situations pretty well, and know when things aren't going according to the book.
This info is contained within the supratentorial brains of neurologists and neurosurgeons, and probably should be included in readily-accesible peripheral brains of other docs who may come in contact with patients who can deteriorate neurologically (a set not appreciably smaller than the whole set). You will not be penalized for consulting your pocket brain in emergency situations.
This page we will go over: examination that this sequence is based on the of deterioration itself.
Rostrocaudal deterioration of what?
The examination of the comatose (or rapidly becoming comatose) patient is essentially the examination of the BRAINSTEM. It is tough to do proverbs on someone who is decerebrating, so examinations of cortical function are often impossible and of marginal value. However, without the brainstem and its reticular activating system to act as the clock for our biological computers, no amount of cortex will work. Thus one focuses on the function and preservation of the brainstem in these situations.
The basic examination consists of testing:
In Plum and Posner's Diagnosis of Stupor and Coma (the Bible of rostrocaudal deterioration, and a great book to have, by the way), ventilation is mentioned as another useful aid to examination, although nowadays most patients who are deteriorating will have assisted ventilation.
(thank God (for 10 extra points, WHY thank God?) ).
How do you do this examination?
First: Do the ABC's.
Does the patient have an airway? Is he breathing? Does he have a pulse?
If not, fix this first. Always, always check the ABC's in emergencies.
OK, ABC's good? Now on to the exam.Next:
The examination of the comatose patient.
Level of consciousness
Test and record:
This is the most important part of the exam. Level of consciousness (LOC) integrates all the functions of the brain, and gives you the most predictive "howgozit" in this situation.
Do not use words like "obtunded, stuporous, unresponsive." Nobody (including you) knows what they mean. Discipline yourself to write what you did, what the patient did, and what time it happened.
You have a pretty good idea of what is going on.
If the same sequence had been recorded as "normal, obtunded, unresponsive" you would not have the slightest idea of what is going on or how rapidly it developed. Enough said.
Darken the room or the patient's upper face (use your hand, a towel, whatever), and shine a light into each eye. Record each eye's reaction, shorthand is usually:
right pre / left pre --> right post / left post (e.g. 5/5 --> 4/2 ).
Watch for pupils failing to constrict with a strong light, especially if they constricted well before. This is known in the vernacular as "blowing a pupil" and is an ominous sign to develop.
Like any reflex, brainstem reflexes give you a quick circuit check. If they work, great. If they are absent or abnormal, you pay more attention to the system.Useful brainstem reflexes include:
Cold calorics are the best reflex to check. They test virtually the entire brainstem, from the medulla to the midbrain. They are easy to do. They are quick. They are unambiguous. You get the picture. Do them.
Corneal ReflexAlso a good reflex. Useful even when patient has worn contact lenses. Corneals input via the V1 division of the trigeminal (5th) cranial nerve and output through the facial (7th) cranial nerve, a big span of mid-lower brainstem. A good check on your calorics. You get the picture. Do them.
Cough, gag reflex
This tests the lower medulla and is particularly useful in deeply comatose patients.
Caveat: It is not fair to do this (or any motor test) in a patient who was given muscle relaxants to intubate (e.g. pancuronium, vecuronium). Don't laugh, I almost had a patient declared brain dead when he was really just relaxed. Check the chart.
Patients move their bodies spontaneously or in response to stimulation.
In developing coma, patients deteriorate through a sequence of movement patterns:
There, now. We have gone over the basic neurological examination in the comatose patient. This exam can be done in about 60-90 seconds. It is quick, easy, and very accurate. Repeating this exam will put multiple points on your patient's curve.
If your patient's examination takes a rapid nosedive, you get people mobilized to diagnose and treat him. Do not be timid when you are worried about a rapid neurological deterioration, scream loud and long until someone who can help you shows up and evaluates the situation.
OK, with the examination down, we now can look at the sequence of rostrocaudal deterioration which is based on this exam.
Rostrocaudal deterioration: the sequence
Rostrocaudal deterioration from a laterally placed lesion (e.g. a subdural hematoma, a hemispheric tumor or stroke) follows a predictable and often rapid sequence. Thus, knowing what the examination looks like at each step of the sequence, you can determine where you are and how fast things are deteriorating.
This sequence is based on the examination you just learned above (if you jumped here, jump back and review the examination, please).
The sequence of rostrocaudal deterioration from a laterally placed lesion is:
Comments, a diagram, and a table of characteristic findings will be presented for each stage.
Rostrocaudal deterioration: early third nerve stage
A mass in the left side of the head is moving the medial temporal lobe over, compressing the brainstem. Your patient begins to lose consciousness, and develops the examination characteristic of the "early third nerve stage" of rostrocaudal deterioration. T he ipsilateral third nerve is compressed, dilating the ipsilateral pupil. The ipsilateral cerebral peduncle is compressed, causing contralateral hemiparesis. Brainstem reflexes are intact.
Rostrocaudal deterioration: late third nerve stage
The mass continues to push on the brainstem, seriously compromising the midbrain. The "late third nerve stage" of rostrocaudal deterioration then develops. The cold caloric brainstem reflexes begin to deteriorate. Purposeful movement is lost.
Rostrocaudal deterioration: midbrain-upper pons stage
Deterioration progresses to encompass the upper pons. Reflex movement patterns emerge, either decerebrate or decorticate. Both pupils are involved. Cold caloric brainstem reflexes are absent.
THIS IS THE LAST REVERSIBLE PHASE OF ROSTROCAUDAL DETERIORATION.
This is the line of death: if your patient deteriorates to the next phase, then all theraputic efforts will be fruitless: the patient will be irreversibly damaged.
Rostrocaudal deterioration: lower pons-upper medulla stage
The patient has lost pupil light reflexes, brainstem reflexes, and motor movement. The brain is irreversibly damaged and any theraputic intervention at this point would be futile.