50. Neurologic examination & other diagnostic procedures

What is the aim of a physical examination in neurological cases?

To rule out other disorders that mimic neurological symptoms

What does a complete neurological examination follow?

Physical examination

What is the purpose of a neurological examination?

To confirm a neurological condition and localise the lesion

What are the steps in a neurological examination?

1. Mentation

2. Posture & gait

3. Cranial nerve examination

4. Postural reactions

5. Spinal reflexes

6. Palpation

7. Nociception

What is mentation?

Observation of the patient's behaviour and consciousness

What do alterations in mentation indicate?

Intracranial disease

What are the different mentation states?

Normal, excitement, depression (apathy, stupor), coma

What are some abnormal postures?

1. Kyphosis: dorsal curvature of spine

2. Lordosis: ventral curvature of spine

3. Scoliosis: lateral deviation

4. Torticollis: head tilt, vestibular system, brain stem

5. Opisthotonus: dorsoflexion of head & neck.

6. Wide-based stance: vestibular or cerebellar lesion

7. Schiff-Sherrington posture: Increased tone in forelimbs, paralysis in hindlimbs. T3-L3 lesion

What are some abnormal gaits?

1. Paralysis: complete and incomplete (paresis) loss of function of muscles

2. Ataxia: no paralysis, by lack of functional coordination

3. Spasm: pathologically exaggerated contraction of muscles

4. Tremor: rapid sequence of limited clonic muscular movement

5. Forced movements: repetition of muscle movements in the same pattern

How is gait evaluated?

On a non-slippery surface

What is the purpose of examining cranial nerves?

To detect abnormalities in cranial nerve function and localise lesions to specific locations in the brain or brianstem

What are the cranial nerves?

I. Olfactory

II. Optic

III. Oculomotor

IV: Trochlear

V: Trigeminal

VI: Abducens

VII: Facial

VIII: Vestibulocochlear

IX: Glossopharyngeal

X: Vagus

XI: Spinal accessory

XII: Hypoglossal

What are some cranial nerve tests?

1. Olfactory: Olfactory nerve (CN I)

2. Menace response: Optic nerve (CN II), Facial nerve (CN VII)

3. Pupillary light reflex: Optic nerve (CN II), Oculomotor nerve (CN III), Abducens nerve (CN VI)

4. Vestibular eye movements: Optic nerve (CN II), Oculomotor nerve (CN III), Abducens nerve (CN VI)

5. Palpebral reflex: Trigeminal nerve (CN V), Facial nerve (CN VII)

6. Corneal reflex: Abducens nerve (CN VI)

7. Nasal mucosa: Trigeminal nerve (CN V)

What is nystagmus?

Jerking movements of the eyeball

What do postural reactions test?

Proprioceptive and motor systems

What do abnormalities in postural reactions indicate?

Lesion in peripheral or central nervous system

What is an early indicator of spinal cord compression?

Abnormal conscious proprioception

What are some postural reaction tests?

1. Knuckling correction: foot is manipulated w/ dorsal surface on table, animal should automatically correct position in 1-2 seconds

2. Placing response

   1. Tactile: sensation of touch when blindly moved toward a table

   2. Visual: when animal sees table, puts feet out to place on ground

3. Hopping reaction: slow to initiate w/ conscious proprioception abnormality. Dysmetria: inaccurate movement

4. Hemi-walking: lift two feet (one fore & one hind) look for balance on remaining feet.

5. Wheel-barrowing: Dog should compensate & perform walking movement.

What is dysmetria?

Inaccurate movement

What is the procedure for testing spinal reflexes?

Lateral recumbency, relaxation

What are some spinal reflexes tested?

1. Biceps reflex (C6-T1): knock biceps tendon → contraction of biceps muscle or twitch in toes

2. Triceps reflex (C7-T1): knock triceps tendon → contraction of triceps muscle

3. Patellar reflex (L4-L6): knock patellar tendon → kick w/ foot

4. Gastrocnemius reflex (L6-L7): knock Achilles tendon → contraction of semimembranosus & semitendinosus muscle

5. Withdrawal reflex (C6-T2, L4-S1, L5-L6, S1-S2): done by squeezing a digit → w/drawal of limb

6. Perineal reflex (S1-S3): touch skin around anus → contraction of sphincter

7. Panniculus reflex (C7-T2): pinch skin at level of tuber coxae along length of vertebrae

Which nerve is involved in the biceps reflex?

Musculocutaneous

Which nerve is involved in the triceps reflex?

Radial

Which nerve and muscle are involved in the patellar reflex?

Femoral nerve. Quadriceps muscle

Which muscles contract when testing the gastrocnemius reflex?

Semimembranosus and semitendinosus

Which nerves are involved in the withdrawal reflex?

C6-T2, L4-S1, L5-L6, S1-S2

Which nerve is involved in the perineal reflex?

Perineal nerve

Which nerves are involved in the panniculus reflex?

Lateral thoracic nerves

What does palpation detect in a neurological exam?

Swelling, atrophy, pain

What is nociception?

Perception of pain

What does loss of deep pain perception indicate?

Poor prognosis (last function to be lost)

How is superficial pain tested?

Cutaneous stimulation

How is deep pain tested?

Periosteal pressure: applying pressure to digits with haemostats/fingernails

What imaging techniques are used in neurological diagnosis?

Radiography, CT scan, MRI, myelography

What does radiography detect?

Spinal fractures, osteophytes, bone loss, subluxations, disc space deviations

What are the advantages of CT scan over radiography in spinal injuries?

More accurate identification of fractures and bone problems

What are the limitations of CT scan in spinal injuries?

Less useful for soft tissue damage detection

What are the advantages of MRI in spinal injuries?

Better for soft tissue damage (spinal cord, discs, ligaments, nerve roots)

What is myelography?

Radiography (or CT) of the spinal cord after contrast medium injection

What does myelography detect?

Spinal canal stenosis

How can orthopaedic and neurological problems be differentiated?

Proprioception tests

What is the difference between coma and stupor?

Stupor means that only vigorous and repeated stimuli will arouse the individual, and when left undisturbed, the patient will immediately lapse back to the unresponsive state.

Coma is a state of unarousable unresponsiveness.