Procedure Practice 12/15/99 - Coding Recommendations

Feature Article 12/15/99:

Stroke, a.k.a. Cerebrovascular Accident (CVA)

Ishemic Stroke - Hemorrhagic Stroke - Basic Vocabulary - Therapies - Coding Guidelines
  

Approximately 500,000 cases of stroke occur each year. Stroke is the leading cause of serious, long-term disability, with over one million Americans suffering from residual stroke related neurologic deficits. This month, we review the types of stroke that may occur, signs, symptoms, treatment, and coding guidelines.

Stroke is a term that describes disrupted blood flow to the brain. Stroke most often results from occlusion of a cerebral blood vessel by a thrombus or embolism with subsequent loss of oxygen to part of the brain. Stroke may also refer to the rupture of a vessel with bleeding into the brain or pressure within the skull. These two categories of stroke are referred to as ischemic stroke and hemorrhagic stroke. Ischemic events account for approximately 80% of strokes, but hemorrhagic strokes are more lethal. Stroke is both a disease and a symptom indicating an underlying vascular problem.

Ischemic Stroke

Obstruction of blood flow to the brain causes ischemic stroke. The three types of ischemic stroke are listed below.

• Lacunar infarction is the occlusion of a very small artery in the brain resulting in a small area of dead brain tissue called a lacunar infarct. The term is from the Latin word "lacuna" which means hole and describes the small cavity remaining after the acute infarction has occurred. Lacunar infarctions are often caused by stenosis of the small arterioles within the brain, a condition referred to as small vessel disease. Lacunar infarctions are usually associated with chronic hypertension or poorly controlled diabetes mellitus. The resultant infarct may appear on CT scan as a small hypodense patch within the brain tissue. Some small infarcts do not appear on images of any kind. Neurologic deficits may progress for up to 36 hours before they stabilize. Partial or complete resolution of symptoms occurs over a 4-6 week period.
    
• Cerebral thrombosis is the blocking of blood flow by a blood clot (thrombus) in a large artery that supplies blood to the brain. Large vessel thrombosis is the most frequent cause of ischemic stroke. Most cases of large vessel thrombosis are caused by a combination of long-term atherosclerosis followed by rapid blood clot formation. Thrombotic stroke patients are also likely to have coronary artery disease, and myocardial infarction is a frequent cause of death in patients who have suffered this type of stroke. Thrombosis may occur in an artery within the brain, or it may be a precerebral vessel (e.g., the internal carotid artery) that becomes blocked. One identifying feature of cerebral thrombotic strokes is that they often occur at night or upon waking in the morning, when blood pressure is low. Another feature is that very often these strokes are preceded by transient ischemic attacks (TIAs) or "mini-strokes."
    
• Cerebral embolism occurs when a wandering clot forms in a blood vessel away from the brain, usually in the heart. The clot is carried by the bloodstream until it lodges in an artery in or leading to the brain, blocking the flow of blood. The most common cause of these emboli is blood clots that form during atrial fibrillation. In atrial fibrillation the two small upper chambers of the heart, the atria, quiver instead of beating effectively. Blood is not pumped completely out of them when the heart beats, allowing the blood to pool and clot. About 15 percent of strokes occur in people with atrial fibrillation.
   

In cases of ischemic stroke, if the blood supply is promptly restored, brain tissues recover and symptoms disappear, but if ischemia lasts longer than 1 hour, brain cell death and permanent neurologic damage result.

Ischemic stroke usually can be diagnosed clinically - especially in a person over age 50 with hypertension, diabetes mellitus, or atherosclerosis - or in a person with a condition that produces emboli. Carotid bruits may indicate stenosis and plaque formation, and specific neurologic symptoms and signs can provide clues to the site of arterial blockage.

A CT or MRI scan helps differentiate an ischemic stroke from intracerebral hemorrhage. An MRI scan detects areas of evolving infarction within hours; a CT scan is sometimes negative for up to several days after acute infarction. Arteriography is performed when the diagnosis is in doubt or when a surgically treatable vascular obstruction is suspected. Noninvasive studies, such as carotid duplex, ultrasonography, or magnetic resonance angiography may also be done.

During the first 48 to 72 hours of an ischemic stroke, neurologic deficits may worsen, and the level of consciousness may decrease because of cerebral edema or extension of the infarct. Severe cerebral edema can cause a potentially fatal shift in intracranial structures. However, unless the infarct is large or extensive, function commonly improves early, with further improvement occurring gradually over days to months.

Hemorrhagic Stroke

Hemorrhagic strokes often occur without warning when weakened or defective blood vessels within the brain or on its surface rupture.

• Intracerebral hemorrhage is the flooding of surrounding brain tissue with blood by the burst of a defective artery. About 10 percent of all strokes result from cerebral hemorrhages. The ruptured vessel has often been exposed to chronic arterial hypertension or made ischemic by a small local thrombosis. Occasionally, the cause of hemorrhage is a congenital aneurysm or other vascular malformation.
   
• Subarachnoid hemorrhage is the rupture of a blood vessel on the surface of the brain with blood leaking into the space between the brain and the skull (but not into the brain itself). Subarachnoid hemorrhages account for about 7% of all strokes. Head trauma is the most common cause of subarachnoid hemorrhage. Other causes of subarachnoid hemorrhage include a ruptured intracerebral aneurysm or arteriovenous malformation.

Intracerebral aneurysms are blood-filled sacs that balloon out from weak spots in the wall of an artery or vein. Aneurysms occur most often at points of arterial branching (bifurcations). The disorder may be due to a congenital defect or to preexisting conditions, such as hypertensive vascular disease and atherosclerosis, or from head trauma. Before an aneurysm ruptures, the individual may experience severe headache, nausea, vision impairment and loss of consciousness, or the individual may be asymptomatic. Onset is usually sudden and without warning.

Arteriovenous malformations (AVMs) are congenital vascular malformations in which an abnormal communication between an artery and vein exists. They may vary in size and sometimes are associated with an arterial aneurysm.
  

In a hemorrhagic stroke, bleeding compresses adjacent brain structures and increases intracranial pressure. Symptoms often begin abruptly with headache, followed by steadily increasing neurologic deficits. Large hemispheric hemorrhages may cause loss of consciousness, nausea, vomiting, delirium, and focal or generalized seizures. Large hemorrhages are fatal within a few days in over 50% of patients. In survivors, consciousness returns and neurologic deficits gradually diminish as the extravasated blood is reabsorbed. Some degree of impairment usually remains, including some dysphasia if the dominant hemisphere was affected, but many patients make a reasonable functional recovery. Small hemorrhages cause focal deficits like those in ischemic stroke.

CT is often used to distinguish hemorrhagic strokes from ischemic infarcts because hemorrhage is easily seen as a hyperintense image. CT scans also aid in determining the size of the hematoma.

Neurologic Effects of Stroke - Basic Vocabulary

Clinicians use a number of objective tools to identify and quantify the neurologic damage caused by stroke. Conversely, the nature of the neurologic deficits can reveal what area/areas of the brain have been damaged by the stroke. Examples of stroke measurement tools include the NIH Stroke Scale, the Barthel Index, the Modified Rankin Scale, Glasgow Outcome Scale, and the Hunt and Hess Classification of Subarachnoid Hemorrhage. Coders see a variety of words and phrases within the medical record, often documented on the stroke assessment forms, that describe types of strokes and their resultant neurologic deficits. The following list includes some of the more frequently used stroke-related terms and their meanings.

Acute completed stroke
an ischemic stroke with symptoms that develop rapidly and become maximal within a few minutes; more common than an evolving stroke. (see below)

Agnosia
a cognitive disability characterized by ignorance of or inability to acknowledge one side of the body or one side of the visual field (synonymous with neglect)

Alexia
a cognitive disability resulting in the loss of the ability to read

Amaurosis fugax
temporary loss of vision due to lack of sufficient blood flow to the retina; this symptom is often indicative of carotid atherosclerotic disease

Aphasia
absence or impairment of the ability to speak, write, or sign due to brain dysfunction

Apraxia
a movement disorder characterized by the inability to perform skilled or purposeful voluntary movements, generally caused by damage to the areas of the brain responsible for voluntary movement

Ataxia
defective muscular coordination

Central stroke pain (central pain syndrome)
an uncommon form of pain caused by damage to the thalamic area of the midbrain. The pain is a mixture of sensations, including heat and cold, burning, tingling, numbness, and sharp stabbing and underlying aching pain

Contralateral
originating in or affecting the opposite side of the body. An infarct in the left side of the brain often causes contralateral muscle weakness or paralysis

Diplegia
paralysis of both arms

Dysarthria
difficult and defective speech due to impairment of the tongue or other muscles necessary for clear speech

Dysphagia
difficulty in swallowing or inability to swallow

Dysphasia
impairment of speech characterized by inability to place words in proper order

Emotional lability
difficulty in controlling emotions, or expression of extreme or inappropriate emotions in certain situations

Hemianesthesia
partial or complete loss of sensation in one half of the body

Hemianopsia/hemianopia
blindness in half the field of vision in one or both eyes

Hemiballism
jerking and twitching movements of one side of the body

Hemiparesis
muscle weakness in one side of the body

Hemiplegia
muscle paralysis in one side of the body

Homonymous hemianopsia/hemianopia
blindness of the nasal half of the visual field in one eye and the temporal half of the visual field in the second eye

Ipsilateral
originating in or affecting the same side of the body. In cases of internal carotid occlusion, vision problems sometimes arise in the ipsilateral eye

Ischemic cascade
a series of events lasting for several hours to several days following initial ischemia that results in extensive cell death and tissue damage beyond the area of tissue originally affected by the initial lack of blood flow

Monoplegia
paralysis affecting a single extremity or a single group of muscles

Neglect
lack of knowledge of one side of the body or one side of the visual field (synonymous with agnosia)

Paraplegia
paralysis of both legs

Stroke in evolution (evolving stroke)
an enlarging brain infarct manifested by neurologic deficits that worsen over 24 to 48 hours. Progression is usually interrupted by periods of stability, but it may be continuous

Tetraparesis
muscle weakness in all four extremities

Tetraplegia (Quadriplegia)
paralysis of all four extremities
 

Therapies

• Medication or drug therapy is the most common treatment for stroke. The most popular classes of drugs used to prevent or treat stroke are antithrombotics (antiplatelet agents and anticoagulants), thrombolytics, and neuroprotective agents.

Antithrombotics prevent the formation of blood clots that can become lodged in a cerebral artery and cause strokes. Antiplatelet drugs prevent clotting by decreasing the activity of platelets, blood cells that contribute to the clotting property of blood. These drugs reduce the risk of blood-clot formation and, thus, the risk of ischemic stroke. In the context of stroke, physicians prescribe antiplatelet drugs mainly for prevention. The most widely known and used antiplatelet drug is aspirin. Other antiplatelet drugs include clopidogrel and ticlopidine. Anticoagulants reduce stroke risk by reducing the clotting property of the blood. The most commonly used anticoagulants include warfarin, heparin, and aspirin.

Thrombolytic agents are used to treat an ongoing acute ischemic stroke caused by arterial blockage. These drugs halt the stroke by dissolving the blood clot that is blocking blood flow to the brain. Recombinant tissue plasminogen activator is a genetically engineered form of t-PA, a thrombolytic substance made naturally by the body. It can be effective if given intravenously within 3 hours of stroke symptom onset, but it should be used only after a physician has confirmed that the patient has suffered an ischemic stroke. Thrombolytic agents can increase bleeding and therefore must be used only after it is clear that the patient has not suffered a hemorrhagic stroke.

Neuroprotectants are medications that protect the brain from secondary injury caused by stroke. Although only a few neuroprotectants are FDA-approved for use, many neuroprotectants are in clinical trials. Several different classes of neuroprotectants show promise for future therapy, including calcium antagonists, glutamate antagonists, opiate antagonists, antioxidants, and apoptosis inhibitors. One of the calcium antagonists, nimodipine, also called a calcium channel blocker, has been shown to decrease the risk of neurologic damage from subarachnoid hemorrhage. Calcium channel blockers, such as nimodipine, reduce cerebral vasospasm, a dangerous side effect of subarachnoid hemorrhage in which the blood vessels in the subarachnoid space constrict erratically, cutting off blood flow.
 

• Surgery can be used to prevent stroke, to treat acute stroke, or to repair vascular damage or malformations in and around the brain. The two prominent types of surgery for stroke prevention and treatment are carotid endarterectomy and extracranial/intracranial (EC/IC) bypass.

Carotid endarterectomy is a surgical procedure in which the surgeon removes plaque within one of the carotid arteries located in the neck. The carotid arteries are the main suppliers of blood to the brain. Carotid endarterectomy is a safe and effective stroke prevention therapy for most people with over 50% stenosis of the carotid arteries.

EC/IC bypass surgery is a procedure that restores blood flow to a blood-deprived area of brain tissue by rerouting a healthy artery in the scalp to the area of brain tissue affected by a blocked artery. Although this procedure does not appear to prevent recurrent strokes in patients with atherosclerosis, it is sometimes performed for patients with aneurysms, some types of small vessel disease, and some arteriovenous malformations.
 

• Rehabilitation of the stroke patient often requires a team of health care specialists. The goal of rehabilitation is to reduce dependence and improve physical ability. Often old skills have been lost and either need to be relearned and/or new ones need to be required. It is also important to maintain and improve a patient's physical condition if possible.
   
  Multiple therapeutic modalities are used to assist the stroke patient in achieving optimal independence. Physical therapy uses training, exercises, and physical manipulation of the stroke patient’s body to restore movement, balance, and coordination. Occupational therapy employs exercise and training to assist patients in relearning daily activities such as eating, drinking and swallowing, dressing, bathing, cooking, reading and writing, and using the bathroom. Speech therapy helps patients relearn language and speaking skills, or assists the patient in learning other forms of communication. Many stroke victims need psychological help after a stroke. Depression, anxiety, frustration, and anger are common post-stroke problems. Psychological counseling is often helpful to families of stroke patients as well.

Coding Guidelines

The range of ICD-9-CM codes for stroke and stroke-related neurologic deficits covers codes 430 through 438.9 and code V12.59.

Practice Makes Perfect!

Are you ready for some hands-on practice?

Read the patient report(s) on our procedure practice page. Assign the appropriate codes and then compare your answers with our coding recommendations. Good luck!
 

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