Chapter 26. Neurology/Neurosurgery

Lumbar Punctures

Lumbar punctures provide invaluable information if the local culture allows them to be done and if the laboratory can analyze the specimen. In children <5 years old, consider using a short small-gauge hypodermic needle; a butterfly needle works well in infants. For children >5 years old, use a standard lumbar puncture needle, if one is available. Otherwise, a longer small-gauge hypodermic needle may work, depending on the child's size.

Lumbar puncture needles may need to be reused. While this is potentially dangerous, it may be safer to reuse these needles than to reuse hypodermic needles. The obturator allows large material to be cleaned out of the needle's core. After cleaning, the needles should be steam autoclaved. If that is not possible, high-level disinfection by boiling has been recommended.1 To do this:

1. Put the needles into a pan and cover them with 3 cm of potable water. Put the lid on the pan and bring the water to a boil. Once it begins to boil, keep it boiling for 15 minutes.

2. While holding the lid on the pan, pour out the water without letting the needles fall out. This is not as easy as it sounds; practice this before you boil the needles.

3. Leave the nearly dry needles in the covered pan until they are needed. Never put them anywhere else.

Psychogenic Disorders and Malingering

Patients with psychogenic neurological disorders may present with bizarre motor findings and neurological tests that indicate a functional disorder (described below). They usually will have normal muscle tone, no atrophy or fasciculations, and no ataxia, although they may try to simulate it. The following are a number of quick, easy tests that suggest a patient may be malingering—or not. In resource-poor settings, you will have to rely on these simple tests; in other settings, they can save clinicians time and effort.

The Hoover Crossed-Leg Test is for leg strength. A supine person who tries to lift his straight leg against gravity or resistance will push down (for leverage) with the other heel. To do the test, the examiner asks the patient to lift the affected leg while keeping one hand under the patient's other heel. No or little pressure on the examiner's hand while the person says he is trying to lift his leg signifies malingering—as long as both legs are not affected. A more effective modification is for the examiner to put a thumb over both ankles while doing the test (Fig. 26-1). This provides additional resistance to lifting the leg and also provides information on the relative strength exerted by each leg.

The Crossed-Hand Test (Fig. 26-2) is used to discover whether a complaint of unilateral hand numbness is valid. Have the patient cross his arms at the forearm level, turn the palms facing each other, and interlock the fingers. Then, if the patient is limber enough, he can bring his hands up in front of his face. With the patient watching, test the sensation in the fingers. Visual miscues due to the hand position will cause malingerers to pause before responding to sensation when the examiner touches each finger; they often identify the sensation incorrectly.

"Splitting the tuning fork" identifies patients with psychogenic sensory disturbance. These patients typically have a sharply demarcated loss of sensation to the midface. Use a tuning fork to test vibratory sensation on both sides of the forehead. These patients often complain that they lack vibratory sensation when tested on the affected side of the forehead, but will have intact vibratory sensation on the unaffected side. Of course, that isn't possible, as the vibration is transmitted through the frontal bone to both sides.2

"Opticokinetic testing" is used for individuals who claim to be blind but aren't. To induce opticokinetic nystagmus (vertical, horizontal, or rotational), have the patient look at moving visual stimuli, usually on a special rotating drum. If patients have nystagmus, it means they can see the drum. Improvising opticokinetic testing equipment is easy: Make an opticokinetic drum by attaching a paper with alternating black and white stripes around an empty soda can. Alternatively, use a black sheet of paper with multiple strips of white tape (about 2 cm wide) attached so that there are alternating stripes of black and white. Make a photocopy of this and wrap it around an empty soda can. Extend a straight piece of metal, such as a hanger, through the top and bottom parts of the can as a handle to rotate the drum. Another method of eliciting opticokinetic nystagmus is to pass a vertically striped cloth (such as a striped tie) horizontally across the patient's visual field at about 5 to 10 cm/second. A measuring tape with large markings also works well. This reflex can be elicited starting at about 4 to 6 months of age, and confirms cortical vision.3

Tunnel vision may be another manifestation of psychogenic visual disturbance. Patients may complain that they can see only a tiny part of the visual field in the center of vision, not unlike looking through a soda straw. To test whether such a complaint is legitimate, do the following: Make a small hole (about the diameter of a pencil) in a piece of paper. Have the patient close one eye and hold the paper with the hole positioned over their open eye. Move your face in front of the paper such that the patient can see only your nose and then move back 3 to 6 feet from the patient and ask them what they see. If they say that they can see only your nose, they are feigning, because the degree of visual arc subtended has increased. In other words, they should see your whole face (at the very least). (Geoffrey Ahern, MD, PhD, University of Arizona, Tucson. Personal written communication received September 1, 2008.)

If the patient complains of being blind, but you do not think he is, leave some money on the floor and see how the patient reacts when he enters the room. (Joseph Miller, MD, PhD, University of Arizona, Tucson. Personal written communication received September 8, 2008.)

Another simple test is the "hand–face drop" test, used in patients with psychogenic coma who appear flaccid. When the patient's hand is held over their face and dropped, the patient in psychogenic coma typically avoids letting the hand hit their face by making subtle movements to the side.2

Monocular diplopia that does not correct using a pinhole device is almost always a functional problem.4 And eyelids that flutter when a person is in "coma" means that they are completely awake. If you don't have time to wait for their spontaneous awakening, break two or three ammonia capsules and hold them under their nose.

Neuropathies

An early sign of a peripheral neuropathy is the inability to feel vibration. If a low-pitched tuning fork is not available, use a pager or a cell phone (set on vibratory mode) to see if a patient feels vibrations over bony prominences.5

If concerned about polyneuropathy in a patient, test their Achilles tendon reflex. Patients with normal Achilles reflexes rarely have a clinically significant polyneuropathy.6

Migraine Treatments

A large number of patients, especially when populations are under stress, will come in with the complaint of headache, often a "migraine." Historical and physical findings usually can differentiate their headaches from more serious problems. If a migraine is diagnosed, and if medications are limited, try using a medication from Table 26-1.

Migraine headaches may also be treated with paraspinal injections of local anesthetic and steroids, as described in Chapter 14, Anesthesia—Local and Regional.

Cluster headaches, often considered the most painful type of headache, can be aborted with oxygen by face mask, if it is available. Various medications, including corticosteroids, can suppress attacks during cluster periods. Two "street drugs," the ergot derivative lysergic acid diethylamide (LSD) and the related drug, psilocybin, have been the only ones to induce remissions of a cluster period. In "sub-hallucinogenic doses," LSD aborted the cluster period after one dose; psilocybin generally took three doses.11

Stroke Syndrome ("Brain Attacks")

Predicting a Stroke after a Transient Ischemic Attack

If a patient with a transient ischemic attack (TIA) presents, how many resources must you devote to this patient? In other words, what is the chance of this patient developing a stroke in the next seven days? Use a scoring system, such as the one below, to help determine the answer.

The six-point ABCD Scale uses a score calculated on the basis of the patient's Age, Blood pressure (BP), and Clinical features, as well as the Duration of symptoms. Assign points according to the list below and then add them to get the ABCD score:

In one validation study of 274 consecutively enrolled patients with TIA (based on World Health Organization [WHO] standards), no patient with an ABCD score ≤3 had a stroke within 30 days. Of the patients suffering a stroke within 7 days, 20% had an ABCD score of 4, 40% scored 5, and 40% scored 6.12

Stroke Diagnosis

Nearly one-third of patients presenting with a possible stroke have a different diagnosis. With limited imaging and consultation, rapid clinical differentiation becomes especially important. It saves resources and can guide therapy and diagnostic measures in the correct direction.

The likelihood that the patient had an acute stroke increases dramatically if there is a definite history of focal neurological symptoms (odds ratio = 7.21), if you know the exact time that symptoms began (odds ratio = 2.59), or in the presence of any cardiovascular abnormality (systolic BP >150 mm Hg, atrial fibrillation, valvular heart disease, or absent peripheral pulses; odds ratio = 2.54).13 On presentation, a stroke is more likely if the patient has facial paresis, arm drift, or abnormal speech (odds ratio = 5.5). If none of these symptoms are present, it is unlikely that the patient had a stroke (odds ratio = 0.39).14

Head Injury

Determining True Coma/Level of Consciousness

Is the patient unconscious? Hysteria, psychological disease, drugs, or alcohol may all make patients seem unconscious when they are not. The following are simple, rapid methods to test for the level of wakefulness in these patients:

• Sternal rub: Use your knuckles and progressively increase pressure as you rub.
• Ammonia capsules: Break three or four and cup them in your hand. Place your cupped hand firmly over the patient's mouth and nose.
• Supraorbital nerve pressure: Similar to a sternal rub; be careful that your finger doesn't slip and injure the eye.
• Jaw pull: Place your second and third fingers behind the ascending ramus of the mandible and pull the patient's jaw forward.
• Nose-hair tickle: Use cotton strands (e.g., from a cotton swab) and gently stimulate the hair inside the nares.
• Rectal exam: Part of the normal full exam for unconscious patients, this procedure may arouse the hysteric. When done in unconscious patients who are about to be chemically paralyzed for intubation, the absence of tone means they are paralyzed from a spinal injury.
• Foley catheter (especially males): This stimulation will usually awaken any male who can be awakened by external stimuli.

The simplest way to transmit information about the level of head injury is by using the Glasgow Coma Score (GCS; also known as the Glasgow Coma Scale). An alternative is the AVPU scale widely used in prehospital care: A = alert; V = responsive to verbal stimuli; P = responsive to painful stimuli; and U = unresponsive. Neurological consultants will want to know this critical information, especially when you ask for their advice or when you want to transfer head-injured patients to them.

Common Mistakes

Do not rely on the ophthalmoscopic exam to show evidence of acute rises in intracranial pressure. These changes appear only in chronic conditions, but retinal hemorrhages can be seen in infants with head injuries from child abuse.

In the midst of turmoil, be careful not to let easily salvageable head-injured patients die because (a) you confused a bad scalp laceration with an open skull fracture or (b) you did not control significant scalp bleeding. Control scalp hemorrhage by simply wrapping a tourniquet-type bandage around the head above the eye line. (Remember that all vessels to the scalp travel up from the neck.) When the bleeding slows, quickly use scalp clips, staples, or big sutures to stop the bleeding; then remove the tourniquet. Do a better closure later, if necessary.

Unsalvageable Head Injuries

Knowing which patients will not survive is the key to maximizing the use of limited resources to treat hordes of multiple and severely injured patients. As the US military recognizes, "the prognosis of brain injuries is good in patients who respond to simple commands, are not deeply unconscious, and do not deteriorate. The prognosis is grave in patients who are rendered immediately comatose (particularly those sustaining penetrating injury) and remain unconscious for a long period of time."15

Similarly, Dr. Husum and colleagues, in their book, War Surgery, write about patients who are "beyond salvation," saying that "bilateral dilated pupils that do not improve after a few hours in a comatose [head-injured] patient are a sign of major brain injury which normally will not respond to treatment. Operation in such cases is wasted."16 In a similar vein, the US military writes that "a GCS ≤ 5 indicates a dismal prognosis despite aggressive comprehensive treatment, and the casualty should be considered expectant [comfort care provided, but not treatment]."17

Head Injury Decision Rules

In austere situations where computed tomographic (CT) scans are not readily available, it may be an extremely weighty and costly decision to send patients for a CT scan. The question is: How much chance of making an error is reasonable in your situation?

In resource-poor environments, the best option may be to use the Canadian Rules (Adult and Child), since these will detect more patients who actually need neurosurgical intervention.

Canadian Adult Rule (≥16 Years Old; GCS 13 to 15)

• GCS <15 within 2 hours after injury
• Suspected open or depressed skull fracture
• Any sign of basilar skull fracture (hemotympanum, raccoon eyes, otorrhea, rhinorrhea, Battle's sign)
• ≥ 2 episodes of emesis
• >65 years old
• Moderate risk of brain injury on CT scan
• Retrograde amnesia ≥ 30 minutes
• Dangerous injury mechanism (pedestrian struck by motor vehicle, ejection from motor vehicle, fall from 3 feet/1 meter or ≥ 5 stairs)

The Canadian Adult Rule has a sensitivity of 100% and a specificity of 38% for detecting any lesion requiring neurosurgical intervention, and a sensitivity of 87% and a specificity of 39% for detecting any clinically important CT abnormality.18

Canadian Child Rule

• Age <2 years
• GCS <15
• Mental status change
• Sensory deficit
• Palpable skull defect
• Any sign of basilar skull fracture (hemotympanum, raccoon eyes, otorrhea, rhinorrhea, Battle's sign)

The Canadian Child Rule has >95% sensitivity and ~49% specificity, with a negative predictive value of >99% and a positive predictive value of >11%.19

Head Injury Treatment in Austere Situations

Skull radiographs are still valuable in head injury management if other imaging is not available. Radiopaque foreign bodies, usually bullets, can be located using both postero-anterior (P-A) and lateral or stereoscopic films (see Chapter 18, Radiology/Imaging). Also, finding a skull fracture is useful because: (a) a patient with a simple skull fracture and no abnormal signs has a 1:30 chance of developing an intracranial hematoma; (b) if there are abnormal signs with the fracture, the risk rises to 1:4; and (c) an intracranial hematoma nearly always will be on the side of, and at the site of, the fracture.20

Spinal Injury

Positioning

Patients with facial injuries or who are not fully conscious should, as previously mentioned, be placed in the lateral decubitus or "recovery" position to preserve their airway. If a spinal injury is suspected, the method of rolling them into the recovery position, and the recovery position itself, should be slightly altered.

The HAINES (High Arm IN Endangered Spine) modified recovery position (see Fig. 8-1) has the patient's dependent arm (the one nearest the ground) extended above his head before he is rolled into the lateral decubitus position. When on his side, his head rests on that arm. This reduces lateral neck flexion to less than half of what it is when the dependent arm extends away from the body and the head droops down, as is normally the case. For patients in the HAINES position, flex their legs so the patients are supported on their side.21

Spinal Immobilization

Critical Decisions

In remote or dangerous locations or in disaster settings when resources are minimal, decisions must be made about whether to follow standard field guidelines, that is, to immobilize the spine of anyone with a possible spinal injury.

As the National Association of Emergency Medical Services Physicians wrote, "Full-spine immobilization, if it is not required, can be unnecessarily difficult, impractical, impossible, and even dangerous during prolonged evacuation, especially in severe environments or when using improvised equipment."22 That is not to say that you shouldn't make a reasonable effort to protect the patient's spine, but other factors may take precedence. Using the cervical spine decision rule as described under "C-Spine Decision Rule," later in this chapter, may help, but a situational assessment must accompany its use. Note that even after a decision about immobilization is made, it is necessary to reassess the patient over time, as the clinical picture may change.

C-Collar/Spine Immobilizers

While only bilateral sandbags held together with tape over the forehead has been proven to immobilize the spine in the prehospital and emergency department setting,23 in emergency situations, cervical immobilization collars can be fashioned from a sleeping pad; a padded hip belt from a pack; any cloth, padding, or clothing; a tarp; or a tent flap. They may also be made from cotton and gauze and bandages (Schanz collar), newspapers, cardboard, blankets, plaster of Paris, or polyvinyl chloride (PVC) pipe, as described below.

Gauze (Schanz) Collar

To make a Schanz collar, wind a 5-inch-wide strip of cotton around the patient's neck several times. Over this, apply gauze to compress the cotton. Add additional layers of cotton and gauze, winding the gauze tighter as the collar's thickness increases. To get the desired effect, this collar should fill the entire submental space. As the collar loosens over time, apply additional cotton under the edges, with a tighter gauze bandage over it.24 Although similar to a commercial "soft collar," a Schanz collar provides considerably more support.

Newspaper Collar

To fashion a useable c-collar from newspaper and socks, stack 10 open sheets of newspaper. Fold the stack in half along its longest dimension. Then fold it in thirds. The width should be appropriate for an adult. For a child, use seven sheets and fold them in half until the correct width for that child is found. Then slip a heavy sock over each end, pass the collar around the patient's neck, and secure it with tape, a scarf, a necktie, or bandage material.

Cardboard/Plastic Collar

The framework for this c-collar is made either from a corrugated cardboard box, such as that in which stores receive merchandise, or by cutting off the top of a plastic bucket. Cut an 18- × 6-inch piece and cut an indentation in the middle of one long edge to accommodate the chin; cut two shallower pieces from the sides where the collar passes over the shoulders. Finally, cut a shallow indentation on the upper (chin) side at each end of the piece to accommodate the occiput.

If using cardboard, bend it at multiple sites along its length so that it will easily encircle the neck. Next, wrap the cardboard with cotton, socks, or other soft padding materials. Then slip it into a stockinet or long sock, or wrap it with a tight elastic or gauze bandage (Fig. 26-3). Secure it around the neck with additional bandaging, tape, a belt, or a similar tie. The tightness of these ties determines how much stability the collar will have.24

Blanket Collars

Blanket rolls can be made and easily stored for use as cervical collars for patients who are supine, who are prone, or who must be kept on their sides. Blankets can also be used to make a collar for a seated patient. First, fold a heavy blanket lengthwise once. Then tightly roll it toward the middle from both ends. When the two rolls meet, tape the entire package together for storage. Experience shows that it needs two layers of tape. When a collar is needed, the tape can be cut and the rolls opened as far as necessary.

For a cervical collar (patient supine, prone, or on his side), open the two rolls wide enough to accommodate the patient's head and position the back of the roll behind the head (Fig. 26-4). Then put tape around the package. This is often easiest if the patient is on a backboard. For a seated patient, unroll the package, but keep the blanket folded. Roll it tightly lengthwise and wrap it around the patient's neck, with the ends overlapping across his chest. Tightly tape the two ends of the blanket together (Fig. 26-5).25

Plaster of Paris Collar

Plaster of Paris has long been used as a c-collar. It can be placed over virtually any type of padding as a primary collar, or can be used to hold other materials (such as clothing being used as a c-collar) in place.26 A c-collar made totally of plaster is heavy, so it is not generally used in ambulatory patients.

The cast must extend the entire length of the c-spine. It must have a broad weight-bearing base over the shoulders and support the jaw and occiput. Unless the patient is already in cervical traction, someone must maintain traction while the plaster is applied and until it sets. To apply it, put thick padding over the shoulders, jaw, and occiput. Next apply two broad plaster slabs—one anteriorly and the other posteriorly. Then apply the plaster around the neck to secure these slabs.27 The problem with this collar is that once applied, it is difficult to adjust. "After the first day, or two, a certain amount of play will develop from compression of the padding material."24

PVC Pipe Collars

More durable cervical collars can be made from pieces of a large plastic (PVC) drain pipe. Although these collars take some time to make, PVC pipe is ubiquitous and the collars last a long time.

Use a piece of pipe that has an internal diameter of the neck(s) you want to stabilize, and saw the piece in half. Drill 0.25- to 0.5-inch holes in it so air can pass through to the neck for comfort. Drill smaller holes along the edges that fit together and use lacing to close the two halves around the neck (Fig. 26-6). Making multiple rows of holes for lacing material allows this collar to be used on various sized patients.

Shape the collar so that it will fit better around the neck, chin, and occiput by placing it in boiling water or by using a welding torch or other low-intensity flame to soften it. If a flame is used, take care not to burn the plastic.28 (See Chapter 27, Ophthalmology, for more information on making medical equipment using PVC pipe.)

Thoracic and Lumbar Spine

A number of makeshift litters are described in Chapter 20, Patient Transport/Evacuation. However, many are not rigid enough to provide optimal support for suspected thoracic or lumbosacral spine injuries. Ideally, patients with a suspected thoracic spine injury should be immobilized from head to pelvis, with their hips adjusted for comfort. Patients with potential lumbar-pelvic injuries should have their thoracic spine, pelvis, and hips (in a position of comfort) splinted. This generally requires using a backboard, which can be made from a flat door, a piece of wood or metal (usually too heavy), or another strong flat object.

C-Spine Decision Rule

NEXUS C-Spine Rule

The NEXUS C-Spine Rule (Table 26-2) uses five very subjective criteria. If the patient meets all five criteria, he has a low probability of a clinically significant ("likely to result in any harm to patient") cervical spine injury. The NEXUS C-Spine Rule has a sensitivity of 99% and a negative predictive value of 99.8%.29

Removing the Collar

In austere medical situations when the patient cannot be imaged, you will need to make a decision at some point to remove the collar—or to leave it on long term. Remove spinal immobilization (without imaging) if the patient meets the c-spine rules for not applying a collar and the patient (a) is conversant, alert, and not inebriated on any substance; (b) has no spontaneous complaint of neck or back pain; (c) has no major distracting (painful) injury; and (d) has no neurological compromise on exam (i.e., can move all extremities, no tenderness on palpation of spine).

Traction

Reasons for Use

Cervical spine injury with neurological signs indicates the need for cervical traction.30 For unstable c-spines, surgery or braces are generally used rather than traction. However, in austere circumstances, traction may be the only option. The problem is that unless traction is being used only symptomatically for cervical disc pain or to reduce a subluxation, prolonged traction, long-term c-collar use, or surgery may have to follow at some point. Traction used for fractures of subluxations nearly always needs to be followed using radiographs. That is the only way to determine if there is sufficient weight pulling in the correct direction.

Halter Traction

Halter or sling traction is the easiest and least-invasive traction method; it can be used not only for unstable c-spines and subluxations, but also for cervical disc pain. If used for disc pain, it can be applied intermittently as an outpatient or used in the patient's home. When using this method, do not exceed 5 kg of weight (which may not be sufficient in spinal injuries). If used for spinal injury, attempt to replace it with a more formal traction method within 24 hours.31

Halter traction equipment can be easily and inexpensively made from local resources. The basic parts of the system are the pulleys, cord, head harness, and weights.32 Pulleys are made from small pipes grooved to allow passage of the cord. These can be taken from orthopedic traction devices and attached to the end of the bed or stretcher. Any cotton or nylon rope is suitable, as long as it is strong enough to hold the weights and fits in the pulley grooves.

The head harness should be well padded with a soft cloth. It can be made from cow leather and sandal buckles. It could also be made from jeans or khaki clothing material, or from canvas (Fig. 26-7). Remember, the hole between the two strips must be wide enough to slip over the head.

Weights can be fashioned from 5-L heavy-plastic bags (irrigation bags), large jars, or plastic bottles. They should be calibrated in kilograms by water weight: add 1 L of water at a time and mark them at each level (1 L water = 1 kg). Hooks can be made from 0.25-inch metal rods shaped into an S.

Cervical Traction Management

These rules apply to most cases where cervical traction is being applied for acute trauma.33,34

1. Traction is strictly neutral—the patient's neck should be neither in flexion nor in extension.

2. Apply counter-traction by elevating the head of the bed about 4 cm for each kilogram of weight applied (as with femoral traction).

3. Traction weight for adults (larger individuals may need more): C1, use 2.5 to 5 kg; C2, 3 to 5 kg; C3, 4 to 7 kg; C4, 5 to 10 kg; C5–6, 7 to 15 kg.

4. Increase the weight stepwise, adding 2 kg every 4 to 6 hours. Use lateral c-spine radiographs at each step. The spinal deformity will gradually reduce under traction.

5. Analgesia prevents muscle spasms and makes the traction more effective.

6. Most c-spine fractures are in the correct position within 24 hours. The traction weights are then gradually reduced under radiographic control.

7. Displaced neck fractures >1 week old may require several days to reduce.

8. Displaced neck fractures >3 weeks old may not respond to traction. Stabilize them in a cast or a collar.