**4. Clinical evaluation**

#### **4.1. History**

We must begin with a complete history of the patient, asking about preexisting diseases that may be a direct cause of the neuropathy or may exacerbate it like diabetes, hypothyroidism, alcoholism, rheumatologic or orthopedic problems and any history of trauma or surgeries that may explain his or her symptoms.

The symptoms we may find in our patients will depend on diverse factors, mainly in the nature of the nerve involved, if it is primary motor, sensitive or both, and the anatomic location of the site of compression. The principal affections we will find will be hypoesthesia of the territory of the sensitive nerve or a complete anesthesia in more chronic conditions. In case of motor nerve compression, symptoms will be related to a progressive loss of function to a complete muscular atrophy in severe cases.

We need to investigate when did the symptoms began, if they were progressive or sudden, which movements are limited or impaired, if hypoesthesia or complete loss of sensation is present, accompanying symptoms, and if they have improved with time or with a particular action taken by the patient.

### **4.2. Physical exam**

Besides these pathologies, the differential diagnosis must include painful rheumatologic and orthopedic disorders; and other psychological entities, such as somatoform and

104 Peripheral Neuropathy - A New Insight into the Mechanism, Evaluation and Management of a Complex Disorder

When nerve fibers undergo compression, the response depends on the force applied at the site and the duration. Acute, brief compression results in a focal conduction block as a result of local ischemia, being reversible if the duration of compression is transient. On the other hand, if the focal compression is prolonged, ischemic changes appear, followed by endoneurial edema and secondary perineurial thickening. These histological alterations will aggravate the changes in the microneural circulation and will increase the sensitivity of the neuron sheath to ischemia. If the compression continues, we will find focal demyelina‐ tion, which typically results in a greater involvement of motor than sensory nerve fibers. Even at this point clinical and electrophysiologic signs can resolve within a period of weeks

As the duration of compression increases beyond several hours, more diffuse demyelination will appear, being the last event an injury to the axons themselves. This process begins at the distal end of compression or injury, a process termed wallerian degeneration. These neural changes may not appear at a uniform fashion among the whole neural sheath depending on the distribution of the compressive forces, causing mixed demyelinating and axonal injury resulting from a combination of mechanical distortion of the nerve, ischemic injury, and

We must begin with a complete history of the patient, asking about preexisting diseases that may be a direct cause of the neuropathy or may exacerbate it like diabetes, hypothyroidism, alcoholism, rheumatologic or orthopedic problems and any history of trauma or surgeries that

The symptoms we may find in our patients will depend on diverse factors, mainly in the nature of the nerve involved, if it is primary motor, sensitive or both, and the anatomic location of the site of compression. The principal affections we will find will be hypoesthesia of the territory of the sensitive nerve or a complete anesthesia in more chronic conditions. In case of motor nerve compression, symptoms will be related to a progressive loss of function to a complete

We need to investigate when did the symptoms began, if they were progressive or sudden, which movements are limited or impaired, if hypoesthesia or complete loss of sensation is

factitious disorders.

to months.

**4.1. History**

impaired axonal flow [2].

**4. Clinical evaluation**

may explain his or her symptoms.

muscular atrophy in severe cases.

**3. Pathophysiology**

Besides a complete history of our patient, a thorough nerve exam needs to be addressed based on the knowledge of the upper extremity nerves anatomy in order to determine the possible site of compression. Our physical exam must include a sensitive and a motor evaluation of the complete upper extremity, beginning with the evaluation of specific movements of the shoulder, arm, forearm, elbow, wrist and digits to determine which muscles are affected and the range of motion of each of these muscles. Next, the sensitivity must be tested, light touch, pain, pressure, vibration and two-point discrimination among the specific distribution of the main nerve involved. There are some complementary tests we may apply in order to guide our exam according to the nerve we think is involved. These specific tests will be discussed further in the chapter [3].
