Common neurologic disorders

Below are several common neurologic disorders, along with their causes, pathophysiology, signs and symptoms, diagnostic test findings, treatments, and nursing interventions.

Common neurologic disorders: Arteriovenous malformation

In AVM, a tangled array of dilated vessels forms an abnormal network of communication between the arterial and venous systems. AVMs are usually located in the cerebral hemispheres. Spontaneous bleeding from these lesions into the subarachnoid space or brain tissue causes the patient’s signs and symptoms.

AVMs range in size from a few millimeters to large malformations extending from the cerebral cortex to the ventricles. Most are present at birth; however, symptoms rarely occur before ages 10 to 30. AVMs are more common in men than in women.

What causes it

Most AVMs are caused by congenital defects in capillary development. Traumatic injury is another possible cause of AVM.

Pathophysiology

AVMs lack the structural characteristics typical of normal blood vessels. The vessels of an AVM are very thin; when more than one artery feeds into the AVM, it appears dilated and tortuous. Because vessels are thin, there’s a risk that an aneurysm will develop. If the AVM is large enough, shunting can deprive surrounding tissue of adequate blood flow. In addition, the thin-walled vessels may ooze small amounts of blood or they may rupture, causing hemorrhage into the brain or subarachnoid space.

What to look for

  • Seizures that are initially focal but become generalized
  • Headache that doesn’t respond to treatment

Common neurologic disorders: Mind games

  • Transient episodes of syncope, dizziness, motor weakness, or sensory deficits
  • Tingling, aphasia, dysarthria, visual deficits (usually hemianopsia)
  • Mental confusion
  • Intellectual impairment

What tests tell you

  • Cerebral angiography provides the most definitive diagnostic information by localizing the AVM and enabling visualization of large feeding arteries and large drainage veins.
  • A CT scan can help differentiate an AVM from a clot or tumor, especially when a contrast medium is used.
  • EEG may help localize the AVM.
  • Brain scan immediately after isotope injection will reveal an uptake in the AVM.
  • MRI-magnetic resonance angiography (especially with gadolinium) may provide information that supports a diagnosis of AVM.

How it’s treated

The choice of treatment depends on the size and location of the AVM, the feeder vessels supplying it, and the age and general health of the patient. Possible methods include embolization, proton-beam radiation, Nd:YAG laser surgery, surgical excision, and a combination of embolization and surgery.

What to do

  • Prevent bleeding if hemorrhage hasn’t occurred.
  • Control hypertension and seizure activity, and reduce activities and eliminate stressors that raise the patient’s systemic blood pressure.
  • Maintain a quiet, therapeutic environment.
  • Monitor and control associated hypertension with drug therapy, as ordered.
  • Establish a baseline and then conduct ongoing neuro checks.
  • Monitor the patient’s vital signs frequently.
  • Assess and monitor characteristics of headache, seizure activity, or bruit, as needed.
  • Provide emotional support.
  • Evaluate the patient’s LOC, body temperature, heart rate, respiratory rate, and blood pressure.
  • Assess whether he continues to experience pain or seizures.
  • Provide appropriate pain management.
  • Note whether the patient has expressed feelings of loss to members of the staff, his friends, or his family. Similarly, note whether his family or friends have expressed their understanding of the disease process, treatment options, and outcome. (See AVM teaching tips.)

Common neurologic disorders: AVM teaching tips

  • Tailor your teaching to the surgical procedure chosen by the surgeon.
  • Describe the surgical procedure and all preoperative tests and assessments. Answer all of the patient’s questions, and those of his family, directly and honestly.
  • Describe what the patient can expect upon awakening after surgery.
  • After surgery, focus teaching on helping the patient develop the highest level of independence possible.
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Common neurologic disorders: Bell’s palsy

 

Common Neurologic Disorders

 

Bell’s palsy blocks conduction of impulses along the facial nerve (CN VII), which is the nerve responsible for motor innervation of the facial muscles. This block results from an inflammatory reaction around the nerve (usually at the internal auditory meatus).

Bell’s palsy affects all age-groups, but occurs most commonly in patients under age 60. Onset is rapid and, in 80% to 90% of all patients, it subsides spontaneously, with complete recovery in 1 to 8 weeks. Recovery can take longer in elderly patients. If patients experience only partial recovery, contractures may develop on the paralyzed side of the face. Bell’s palsy may recur on the same or opposite side of the face.

What causes it

Bell’s palsy can be caused by:

  • infection
  • hemorrhage
  • tumor
  • meningitis
  • local traumatic injury

Pathophysiology

Inflammation around CN VII where it leaves bony tissue blocks conduction along the nerve. As a consequence, CN VII can’t adequately stimulate the muscle fibers, and unilateral or bilateral facial weakness or paralysis is the result.

What to look for

Patients may experience incomplete eye closure and Bell’s phenomenon (eye rolling upward as eye is closed). Other signs and symptoms of Bell’s palsy include:

  • unilateral facial weakness or paralysis, with aching at the jaw angle
  • drooping mouth, causing drooling on the affected side
  • distorted taste perception over the affected anterior portion of the tongue
  • markedly impaired ability to close the eye on the weak side
  • inability to raise the eyebrow, smile, show the teeth, or puff out the cheek on the affected side

What tests tell you

Electromyography helps predict recovery by distinguishing temporary conduction defects from a pathologic interruption of nerve fibers.

How it’s treated

Prednisone, an oral corticosteroid, reduces facial nerve edema and improves nerve conduction and blood flow. Specific antiviral agents can also be helpful. After the 14th day of prednisone therapy, electrotherapy may help prevent atrophy of facial muscles.

What to do

  • Apply moist heat to the affected side of the face to reduce pain, taking care not to burn the skin.
  • Massage the patient’s face with a gentle upward motion two to three times daily for 5 to 10 minutes, and teach him how to perform this massage.
  • Apply a facial sling to improve lip alignment. Residual effects
  • Give the patient frequent and complete mouth care. Remove residual food that collects between the cheeks and gums.
  • Provide support, and reassure the patient that recovery is likely within 1 to 8 weeks.
  • Assess the effectiveness of pain medications.
  • Assess the patient’s nutritional status. Bell’s palsy shouldn’t interfere with the patient’s ability to maintain adequate nutrition.
  • Note whether the patient has expressed feelings of loss or fear to staff, friends, or family. (See Bell’s palsy teaching tips.)

Common neurologic disorders: Bell’s palsy teaching tips

  • Advise the patient to protect the eye on the affected side by covering it with an eye patch, especially when outdoors. The eyelid must be taped shut at night using a small piece of hypoallergenic tape. Tell him to keep warm and to avoid exposure to dust and wind. If exposure is unavoidable, instruct him to cover his face.
  • To prevent excessive weight loss, teach the patient how to cope with eating and drinking difficulties. Tell him to chew on the unaffected side of his mouth. Provide a nutritionally balanced diet of soft foods. Eliminate hot foods and fluids (soups, sauces, and purees, for example). Arrange for privacy at mealtimes to minimize embarrassment.
  • When the patient is ready, teach him to exercise facial muscles by grimacing in front of a mirror.
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