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.

The examination

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:

FIRST THINGS FIRST
Level of consciousness<
Pupil reaction to light
Brainstem reflexes
Motor pattern

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:

Examiner's stimulus
Patient's response
Time of exam

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.

Example: If you see a sequence like:

time: 21.00
stim: normal speech
resp: normal speech

time: 21.15
stim: shouting
resp: moaning and flailing all 4 extremities

time: 21.20
stim: sternal rub
resp: bilateral decerebrate posturing, left greater than right

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.

Pupil reaction

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.

WHY?)

Brainstem reflexes

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
Corneal reflex
Cough, gag

Cold calorics

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.

Technique:

Do not do calorics in an awake patient (who will vomit all over you and then punch you).
Look in the ears first (in trauma, the patient may not have an eardrum and you may do a direct brainstem stimulation, don't laugh...)
Then get a 20-30 cc syringe with an 18 gauge angiocath, fill it with ice water and squirt the entire syringe into the ear, having you or your assistant hold the eyelids open.

Normal response:

Eyes conjugately deviate towards the cold ear, then snap back to midline

Record any response, either normal, abnormal (describe), or absent
Repeat in the other ear

Corneal Reflex

Also 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.

Technique:

Open the eye and touch the lateral lower corner of the cornea. DO THIS LIGHTLY and with a wisp of cotton teased from a Q-tip. If you grind your finger or a 4x4 into the cornea, you may damage it and make it useless to your patient (if patient survives) or your transplant recipient (if patient does not survive). Be gentle.
Stay lateral in the cornea or you will get a looming "blink" reflex instead.

Normal response:

ipsilateral eye blinks

Record any response, either normal, abnormal (describe), or absent
Repeat in the other eye

Cough, gag reflex

This tests the lower medulla and is particularly useful in deeply comatose patients.

Technique:

jiggle the endotracheal tube or NG tube to stimulate the larynx or pharynx

Normal response:

patient coughs or gags

Record any response, either normal, abnormal (describe), or absent

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.

Motor pattern

Patients move their bodies spontaneously or in response to stimulation.

In developing coma, patients deteriorate through a sequence of movement patterns:

Normal spontaneous and stimulated movement (e.g. "raise your right hand")
Purposeful movement to pain (they grab your hand when you do a sternal rub)
Nonpurposeful movement to pain (they get near your hand, but never grab it)
Decorticate posturing (flex arms, extend legs)
Decerebrate posturing (extend arms, extend legs)
No response (when stimulated, either nothing or very weak and ineffective flexion of extremities)

Look at ALL the extremities. Is the patient moving one side (right or left) more than the other? Is the patient moving his upper extremities but not his lowers? Is the patient moving his lower extremities but not his uppers? Use all the information you have in front of you, there is usually a lot more there than you are aware of until you look for it.

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:

Early third nerve stage
Late third nerve stage
Midbrain-Upper pons stage
Lower pons-upper Medulla stage

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.

Early 3rd Nerve Stage

Level of consciousness	Pupils	Brainstem reflexes	Motor pattern
responds to deep pain with purposeful movement	IPSILATERAL pupil dilates	full EOMs on calorics	CONTRALATERAL hemiparesis

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.

Level of consciousness	Pupils	Brainstem reflexes	Motor pattern
responds to deep pain with decorticate or decerebrate movement ipsilaterally	IPSILATERALpupil fixed and dilated	EOMs dysconjugate on calorics	contralateral hemiparesis, bilateral posturing

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.

Level of consciousness	Pupils	Brainstem reflexes	Motor pattern
responds to deep pain with decorticate or decerebrate movement contralaterally	BOTH pupils dilated or mid-fixed	EOMs impaired or dysconjugate on calorics	posturing bilaterally

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.

Level of consciousness	Pupils	Brainstem reflexes	Motor pattern
deep pain elicits no response or weak flexion	BOTH pupils fixed-dilated or mid-fixed	no EOMs on calorics	flaccid or weak flexion