Procedure Practice 04/15/00 - Coding Recommendations

Feature Article 04/15/00

Seizure Disorders

Brain Dysfunction - Etiologies - Epilepsy Syndromes - Types - Treatment - ICD-9-CM Coding Tips
  

More than 2 million people in the United States have experienced an unprovoked seizure or have been diagnosed with epilepsy or other seizure disorder. An isolated seizure usually has an underlying cause that needs to be investigated. Only recurrent seizure activity is classified as a seizure disorder. Idiopathic seizure disorders with no identifiable cause are classified as epilepsy. Because of their various etiologies, coding seizure disorders can be confusing. While some seizures are classified as epilepsy and coded as such, others are not. This month we review seizure disorders and their etiologies and treatments and offer some coding tips and guidelines.

Brain Dysfunction During Seizures

A seizure is the transmission of abnormal signals by clusters of neurons. Neurons normally generate electrochemical impulses that act on other neurons, glands, and muscles to produce thoughts, feelings, and actions. In a seizure, the normal pattern of neuronal activity becomes disturbed, causing strange sensations, emotions, and behavior, or sometimes convulsions, muscle spasms, and loss of consciousness. Neurons may fire as many as 500 times a second, much faster than the normal rate of about 80 times a second. In some people, this happens only occasionally; for others, it may happen up to hundreds of times a day.

Seizures may develop because of an abnormality in brain circuitry, an imbalance of nerve signaling chemicals called neurotransmitters, or a combination of these factors. Researchers believe that some seizures are due to an abnormally high level of excitatory neurotransmitters that increase neuronal activity, or conversely, due to an abnormally low level of inhibitory neurotransmitters that decrease neuronal activity in the brain. Either situation can result in overactive neurons and seizures.

The cell membrane that surrounds each neuron plays an important role in seizure disorders. Cell membranes are crucial for neurons to generate electrical impulses. Recent research has focused on membrane structure, how molecules move in and out of membranes, and how the cell nourishes and repairs the membrane. A disruption in any of these processes may lead to seizures.

Seizure Etiologies

Seizures have many causes. Anything that disturbs the normal pattern of neuron activity, from illness to brain damage to abnormal brain development, can lead to seizures. Given sufficient stimulus, any person may have a seizure. The amount of stimulation required to induce seizure is called the seizure threshold.
 

Febrile Seizures

These seizures are brought on by a high fever in infants or young children. Most seizures last only 1-2 minutes. During the seizure, the child loses consciousness, and extremities on both sides of the body shake. Most children with febrile seizures have fevers of greater than 102 degrees F., with seizures occurring during the first 24 hours of illness. About 4% of children have at least one febrile seizure, and about one-third of these children will have additional febrile seizures before they outgrow them. Usually febrile seizures occur in children between the ages of 6 months and 5 years, and they are particularly common in toddlers.
 

Eclampsia

Eclampsia is a life-threatening condition that can develop during the third trimester of pregnancy. Its symptoms include sudden elevations of blood pressure, proteinuria, generalized edema, headache and visual disturbances, and in severe cases, seizures. Eclampsia requires emergency treatment in a hospital setting and usually does not result in additional seizures or epilepsy once pregnancy is over.
 

Pseudoseizures (Psychogenic Seizures)

These seizures, also called nonepileptic events, mimic seizures in presentation without EEG evidence of true seizure activity in the brain. Pseudoseizures indicate an underlying psychiatric condition.
 

Other Causes

Essentially, any disorder that alters brain function or deprives the brain of oxygen may trigger the onset of a seizure. Once the underlying disorder is treated successfully seizures often stop. However, the odds of becoming seizure-free after the primary disorder is treated vary depending on the type of disorder, the brain region affected, and whether brain damage occurred prior to treatment.

• Cerebrovascular disease reduces the supply of oxygen to the brain and is responsible for about 32% of newly developed seizure disorders in elderly people.
    
• Brain abscess, meningitis, AIDS, viral encephalitis, chronic infections such as neurosyphilis, and other infectious diseases can lead to seizures.
   
• Tumors and other space-occupying lesions may cause seizures at any age. Seizures are often the first symptom of tumor and are most likely to occur with lesions involving the frontal, parietal, or temporal lobe regions of the brain.
   
• Developmental and metabolic disorders, including cerebral palsy, neurofibromatosis, pyruvate deficiency, celiac disease, tuberous sclerosis, Landau-Kleffner syndrome, and autism are often associated with seizure disorder. Other metabolic disorders such as diabetes mellitus, acute renal failure, and phenylketonuria may also be responsible for seizures. These conditions, once diagnosed, are among the most treatable causes of seizures.
    
• Trauma is an important cause of seizures at any age. In some cases, the brain’s attempts to repair itself after a head injury may inadvertently generate abnormal nerve connections that induce seizure activity. A severe head injury may result in traumatic hydrocephalus, a condition of excess fluid accumulation in the brain, which also may lead to seizures.
   
• Congenital abnormalities and perinatal injury due to maternal infections, poor nutrition, maternal substance abuse, or fetal oxygen deficiencies may result in seizures presenting in infancy or early childhood.
    
• Poisoning from lead exposure, carbon monoxide, and other environmental contaminants can result in seizures. Exposure to street drugs, alcohol withdrawal, and overdoses of antidepressants and other medications can also cause seizures.
    
• Environmental or lifestyle factors such as sleep deprivation, alcohol consumption, stress, or the hormonal changes of pregnancy may trigger seizures. Smoking cigarettes also can trigger seizures. The nicotine in cigarettes acts on receptors for the excitatory neurotransmitter acetylcholine in the brain, which increases neuronal firing.

Epilepsy Syndromes

Hundreds of different epilepsy syndromes have been identified. Some of these syndromes appear to be hereditary. For other syndromes the cause is unknown. Epilepsy syndromes are frequently described by their symptoms or by where they originate in the brain.
  

Absence Epilepsy (Petit Mal Seizures)

This epilepsy syndrome is characterized by repeated partial seizures called absence seizures that cause momentary lapses of consciousness. Seizures almost always begin in childhood or adolescence, and they tend to run in families. Some people with absence seizures have purposeless movements during their seizures, such as a jerking arm or rapidly blinking eyes. If the attack occurs during conversation, the individual may miss a few words or stop speaking for a few seconds. Loss of muscle tone may cause a person to fall ("drop attacks"). The impairment of consciousness is so brief that the individual is unaware of it. Full recovery occurs immediately after the seizure with no post-seizure confusion. However, these seizures sometimes occur so frequently that they impede concentration in school or other situations.
  

Photosensitive Epilepsy

In this syndrome, seizures are triggered by flashing lights or flickering computer or television screens. It also may be called photic epilepsy or photogenic epilepsy.
  

Psychomotor Epilepsy

This term refers to recurrent partial seizures. "Psychomotor" refers to the strange sensations, emotions, and behavior seen with these seizures.
  

Temporal Lobe Epilepsy (TLE)

TLE is the most common epilepsy syndrome with partial seizures. These seizures are often associated with auras and usually begin in childhood. Repeated temporal lobe seizures can cause a brain structure called the hippocampus to shrink over time. The hippocampus is important for memory and learning. While it may take years of temporal lobe seizures for measurable hippocampal damage to occur, this finding underscores the need to treat TLE early and as effectively as possible.
 

Frontal Lobe Epilepsy

This syndrome usually involves a cluster of short seizures with a sudden onset and termination. Symptoms of the varied subtypes of frontal lobe epilepsy depend on where in the frontal lobe the seizures occur.
  

Occipital Lobe Epilepsy

These seizures usually begin with visual hallucinations, rapid eye blinking, or other eye-related symptoms. Otherwise, they resemble temporal or frontal lobe epilepsy.
  

Parietal Lobe Epilepsy

The symptoms of parietal lobe epilepsy closely resemble those of other types of epilepsy. This situation may reflect the fact that parietal lobe seizures tend to spread and involve other areas of the brain.
 

Infantile Spasms

Several types of epilepsy begin in infancy. The most common type of infantile epilepsy is infantile spasms, clusters of seizures that usually begin before the age of 6 months.
 

Status Epilepticus

Status epilepticus is a life-threatening condition in which a person either has prolonged seizures or does not fully regain consciousness between seizures. The amount of time in a prolonged seizure that must pass before a person is diagnosed with status epilepticus is a subject of debate. Many doctors diagnose status epilepticus if a person has been in a prolonged seizure for 5 minutes. However, other doctors use more conservative definitions of this condition and may not diagnose status epilepticus unless the person has had a prolonged seizure of 10 minutes or even 30 minutes.
 

Other Epilepsy Syndromes

Many other types of epilepsy exist, each with its own characteristic set of symptoms. Many of these conditions, including Lennox-Gastaut syndrome and Rasmussen’s encephalitis, begin in childhood. Children with Lennox-Gastaut syndrome have severe epilepsy with several different types of seizures. This severe form of epilepsy can be very difficult to treat effectively. Rasmussen’s encephalitis is a progressive type of epilepsy in which half of the brain shows continual inflammation. Some childhood epilepsy syndromes, such as childhood absence epilepsy, tend to go into remission or stop entirely during adolescence, whereas other syndromes are usually present for life once they develop. Seizure syndromes do not always appear in childhood. For example, Ramsay Hunt syndrome type II is a rare and severe progressive type of epilepsy that generally begins in early adulthood and leads to reduced muscle coordination and cognitive abilities in addition to seizures.

Epilepsy syndromes that do not seem to impair cognitive functions or development are often described as benign. Benign epilepsy syndromes include benign infantile encephalopathy and benign neonatal convulsions. Other syndromes, such as progressive myoclonic encephalopathy, include neurological and developmental problems. However, these problems may be caused by underlying degenerative processes rather than by the seizures. Epilepsy syndromes in which the seizures and/or the person’s cognitive or motor abilities get worse over time are called progressive epilepsy.

Types of Seizures

Doctors have described more than 30 different types of seizures. Seizures are divided into two major categories, partial and generalized, with many different types of seizures in each of these categories. As coders, we need to remember that, although the type of seizure activity is often an important clinical detail for treatment, it does not clarify the presence or absence of epilepsy as a diagnosis.
 

Partial Seizures

Partial seizures occur in just one part of the brain. These seizures are frequently described by the area of the brain in which they originate. For example, someone might be diagnosed with partial frontal lobe seizures.

In a simple partial seizure, also known as a jacksonian seizure, the person remains conscious but may experience unusual feelings or sensations, such as sudden inexplicable feelings of joy, anger, or sadness. He or she also may hear, smell, taste, see, or feel things that are not real.

In a complex partial seizure, the person has a change in or loss of consciousness. People having a complex partial seizure may display strange, repetitious behaviors such as blinks, twitches, mouth movements, or walking in a circle. These repetitious movements are called automatisms. They also may fling objects across the room or strike out at walls or furniture as though they are angry or afraid. These seizures usually last just a few seconds.

Some people with partial seizures, especially complex partial seizures, may experience auras, unusual sensations that warn of an impending seizure. Auras are actually simple partial seizures in which the person maintains consciousness. The symptoms an individual person has and the progression of those symptoms tends to be stereotyped or similar every time.
  

Generalized Seizures

Generalized seizures are a result of abnormal neuronal activity in many parts of the brain. These seizures may cause loss of consciousness, falls, or massive muscle spasms.

Many types of seizures fall into this category. Tonic seizures cause stiffening of muscles, most often in the back, legs, and arms. Clonic seizures cause repeated jerking movements of muscles on both sides of the body. Myoclonic seizures cause jerks or twitches of the upper body, arms, or legs. Atonic seizures (drop attacks) cause a loss of normal muscle tone. The affected person will fall down or may nod his or her head involuntarily. Tonic-clonic seizures (grand mal seizures) cause a mixture of symptoms, including stiffening of the body and repeated jerks of the arms and/or legs as well as loss of consciousness.

Treatment Methods
  

Medications

By far the most common approach to treating seizures is the prescription of anticonvulsive drugs. More than 20 such drugs are available, all with different benefits and side effects. The choice of which drug to prescribe at what dosage depends upon many different factors, including the type of seizures a person has, the person’s lifestyle and age, how frequently the seizures occur, and, for a woman, the likelihood that she will become pregnant. Commonly prescribed anticonvulsants include carbamazapine, valproate, phenytoin (Dilantin), clonazepam, phenobarbital, primidone, tiagabine, lamotrigine, gabapentin, ethosuxamide, felbamate, topiramate, Tegretol, and carbazapine.
 

Surgery

Doctors generally recommend surgery only after patients have tried two or three different medications without success or if an identifiable brain lesion -a damaged or abnormally functioning area- is believed to cause the seizures. In cases where seizures are caused by a brain tumor, hydrocephalus, or other condition that can be treated surgically, doctors may operate to treat these underlying conditions. In many cases, once the underlying condition is successfully treated, seizures will stop as well.

• Stereotactic radiosurgery employs the precise delivery of a single high dose of radiation to destroy a discrete seizure focus within the brain. Three different technologies may be used to perform this procedure, the source of radiation being the key differentiating factor. Methods include single photon source linear accelerators (LINAC), multi-source photon (cobalt-60) technology, and high energy particulate (particle beam) technology.
   
• Lobectomy is appropriate for partial seizures that originate in just one area of the brain. In general, people have a better chance of becoming seizure-free after surgery if they have a small seizure focus. The most common type of lobectomy is a temporal lobe resection, which is performed for people with temporal lobe epilepsy.
   
• Multiple subpial transection is performed if seizures originate in part of the brain that cannot be removed. In this operation, surgeons make a series of cuts that are designed to prevent seizures from spreading into other parts of the brain while leaving the person’s normal abilities intact.
   
• Corpus callosotomy, or severing the network of neural connections between the right and left hemispheres of the brain, is done primarily in children with severe seizures that start in one half of the brain and spread to the other side. Corpus callosotomy can end drop attacks and other generalized seizures. However, the procedure does not stop seizures on the side of the brain where they originate, and in fact, these partial seizures may even increase after surgery.
   
• Hemispherectomy removes half of the brain’s cortex, or outer layer, and is used only for children who have severe damage to one brain hemisphere and who also have seizures that do not respond to medication. While this type of surgery is very radical and is performed only as a last resort, children often recover very well from the procedure, and their seizures usually are greatly reduced or may cease altogether. Intense postsurgical rehabilitation is required in order for the child to regain normal function and cognitive abilities.
    

Devices

The vagus nerve stimulator (VNS) was approved by the U.S. Food and Drug Administration (FDA) in 1997 for use in people with seizures that are not well-controlled by medication. The VNS is a battery-powered device that is surgically implanted under the skin of the chest, much like a pacemaker, and attached to the vagus nerve in the lower neck. This device delivers short bursts of electrical energy to the brain via the vagus nerve. On average, this stimulation reduces seizures by about 20-40 percent. Patients usually cannot stop taking epilepsy medication because of the stimulator, but they often experience fewer seizures and they may be able to reduce the dose of their medication.
 

Diet

In some cases children may experience fewer seizures if they maintain a strict diet rich in fats and low in carbohydrates. This ketogenic diet creates ketosis and causes the body to metabolize fats instead of carbohydrates to survive. Researchers are not sure how ketosis inhibits seizures. One study showed that a byproduct of ketosis called beta-hydroxybutyrate (BHB) inhibits seizures in animals. If BHB also works in humans, researchers may eventually be able to develop drugs that mimic the seizure-inhibiting effects of the ketogenic diet.

ICD-9-CM Coding Tips

Now that we know seizures may be associated with a wide variety of diseases, it is clear that not all seizures should be coded to the epilepsy subheading of 345.xx.

	If chart documentation is unclear, always consult the attending physician for clarification of the exact nature of the seizure disorder.
	Do not code a seizure disorder as epilepsy unless the physician has specifically documented epilepsy in the medical record
	Remember to assign the appropriate 5th digit of 0 or 1 to codes 345.0, 345.1, and 345.4 through 345.9 in the epilepsy subcategory to denote presence or absence of intractable epilepsy.
	Intractable epilepsy refers to epilepsy that is not effectively controlled by medication. Do not automatically code recurrent epileptic seizures as intractable, since all seizures in an epileptic patient are recurrent.
	Status epilepticus not otherwise specified is assigned 345.3.
	Codes 780.31 and 780.39 are from Chapter 16, Signs, Symptoms and Ill-Defined Conditions. As with all codes within this chapter, these codes should be used as principal diagnoses only if a related definitive diagnosis (i.e., underlying etiology) has not been established. If the underlying cause is known, the cause is coded first. Either of these codes may then be used as secondary diagnosis.

• In cases of recurrent seizures with no mention of epilepsy or other cause, assign 780.39, Other convulsions.
   
• Code febrile seizures to 780.31, Febrile convulsions.
   
• Assign 779.0, Convulsions in newborn, for seizures in newborn infants.
   

	Pseudoseizures, also sometimes known as psychogenic seizures, are coded 300.11, Conversion disorder.
	Progressive myoclonic epilepsy is coded 333.2, Myoclonus.
	Seizures associated with pregnancy eclampsia are assigned to either 642.6, Eclampsia, or 642.7, Pre-eclampsia or eclampsia superimposed on pre-existing hypertension, with the appropriate 5th digit 0, 1, 2, 3, or 4. 780.39 may be assigned as a secondary diagnosis.
	Seizures due to scarlet fever are coded 034.1, Scarlet fever. Use 780.39 as a secondary code if desired.
	Code seizures due to neurosyphilis 094.1, General paresis. Again, 780.39 may be used as a secondary diagnosis.
	Seizures due to malignancy are coded to the malignancy with 780.39 as a secondary diagnosis.

	Seizures due to trauma are coded to the specific trauma and thus are assigned a code from the Injury and Poisoning chapter. Code 780.39 may be used as a secondary code.
	Alcohol withdrawal with seizures is coded to the appropriate code from subcategory 291, Alcoholic psychosis with 780.39 as a secondary diagnosis.
	Seizures due to an overdose or administration of an incorrect substance are assigned a code from the 960-979 range with 780.39 as a secondary diagnosis code and an E-code to identify the circumstances involved.
	Seizures due to an adverse effect of a properly administered medication are coded 780.39 with the appropriate code from range E930-E949 to identify the drug.

Practice Makes Perfect!

Are you ready for some hands-on practice? Read the patient reports on our Procedure Practice page. Assign the appropriate codes and then compare your answers with our coding recommendations. Good luck!

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