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Seizure: Case discussions & key clinical practice points- Dr. YK Amdekar

M3 India Newsdesk Aug 03, 2020

Dr. Amdekar here discusses 8 varied cases of seizure and pseudo-seizure presentations in children, providing stepwise approach for the evaluation and management of each diagnosis.


Before you begin, take this quiz to test your knowledge on seizures.


Clinical application of basic concepts

A seizure is a paroxysmal event that may mimic non-seizure disorder. Hence one must confirm an event to be a seizure before embarking on its cause. Most seizures are recognised by jerky movements of the limbs and transient loss of consciousness with staring spell. However, seizure also can present without loss of consciousness and it needs to be recognised.

Movement disorders present with typical patterns without a change in sensorium. Syncope occurs mostly in standing position and recovers in seconds. Breath-holding spasm is typically triggered by emotional stress as the child holds the breath during expiration and may turn blue or pale. One must enquire about the sequence of events from a witness and if possible by captured video record. It helps to define the nature of the event. Feeling giddy or rotational movements may suggest vertigo.

Once we know it is a seizure, next is to find out its cause. Preceding events, type of seizure and post-seizure events offer a clue to the diagnosis. Thus, detailed history is important. Age group helps to define common causes, a simple febrile seizure is common in early childhood and so also hypocalcemia due to rickets. Idiopathic epilepsy is diagnosed in children >5 years of age. Physical examination may be totally normal as in the case of simple febrile convulsion, idiopathic epilepsy, or hypocalcemia. Localising neurological signs may represent either a recent or old lesion responsible for the seizure. Thus, it is important to consider whether it is an acute or remote symptomatic seizure.


Case-based discussion

Case 1

A one-year-old infant presented with high fever followed in the next 18 hours by a generalised seizure that lasted for a minute. The child remained a bit dazed thereafter for a few minutes and then recovered completely without any neurological sequelae. He had no prior illness. He had grown well and had achieved normal milestones.

There was no family history of similar or any other neurological disorders. This child has had normal brain development and remained neurologically normal after the seizure that was self-limiting and triggered by high fever. This suggests a typical simple febrile seizure. Physical examination showed no neurological abnormality and the cause of fever was considered to a viral infection that settled within the next two days without any specific therapy. It supported the diagnosis of simple febrile seizure.

This child does not need any investigations – however, it is important not to prescribe an antibiotic to this child. This is because antibiotic may mask bacterial meningitis if started early in the course of illness. And if you find the need for an antibiotic because of suspected bacterial infection, it is a must to order CSF to rule out meningitis even without any neurological findings. On the first day, bacterial meningitis may not show any physical findings.

As this child was clinically diagnosed as a simple febrile convulsion, parents were counseled about possible recurrence during the first 24 hours of the onset of fever. This being the first episode of seizure in this child, one may not prescribe prophylactic clobazam as there is always a chance that the child may not have a second episode. However as such an event is always stressful to parents, one may suggest midazolam nasal spray as an immediate rescue drug to stop a seizure. It can be used by parents at home and seizure stops immediately.

If the child has had a relapse, clobazam can be used in three doses – the first dose at the onset of fever and two further doses at 12 hours intervals to cover the risk period. Simple febrile seizure never occurs beyond the age of 5-6 years and has no relation to future epilepsy.


Case 2

A one-year-old infant presented with high fever followed in the next 18 hours with a generalised seizure that lasted for a few minutes and stopped on its own. It was not followed by any postictal event in the form of drowsiness and he remained totally normal. However, within the next two hours, he had another similar episode that lasted just for a few seconds. He was fine thereafter. Fever disappeared over the next two days. He had normal growth and development. There was no family history of similar disorders. On direct questioning, it was found that he was bottle-fed and consumed about a litre of milk each day with very little solid food – he was bottle addicted.

This seizure did not result in postictal events and it is a clue to the probable diagnosis of hypocalcemic seizure. As he was mainly on a milk diet, he had a risk of developing vitamin D deficiency as milk is a poor source of vitamin D and this infant would not have been exposed to sunlight. So rickets may have contributed to hypocalcemia triggered by a viral infection. Physical examination showed signs of rickets without any neurological abnormality. It supported the diagnosis of hypocalcemia as a cause of the seizure.                                                                                                                                                                                                  
Vitamin D deficiency rickets can be confirmed by bone X-ray and high serum alkaline phosphatase with either low or normal serum calcium and low phosphorous level. Serum calcium may be normal in this child because nature moves available calcium from bone to blood and thereafter to tissues. However, it takes a few hours to replenish calcium at the tissue level and that is the reason that this child had another seizure though it was for a shorter duration. But once calcium is replenished in the neurological tissues, seizure stops. If one saw this child during a seizure, IV calcium could have been administered for quick replenishment. However, if one saw this child after the second seizure, one may consider oral replacement of calcium along with vitamin D.

It is ideal to delay starting vitamin D supplement for few days before administration of oral calcium because vitamin D is likely to deposit calcium into the bone from whatever is available in tissues and it may precipitate a seizure. Once rickets is fully cured, there is no risk of hypocalcemia.


Case 3

A 3-year-old infant presented with high fever followed by irritability and vomiting for two days. On day 3, he developed a generalised seizure that lasted for a few minutes and was followed by drowsiness for a few minutes. Fever and irritability continued with occasional vomiting. This child has developed a seizure on day 3 of onset of fever and so this is certainly not a simple febrile seizure or fever-triggered hypocalcemia. Irritability and vomiting suggest probable increased intracranial pressure. Thus, it favours the diagnosis of bacterial meningitis.

Initially, the disease is localised only to meninges, and brain cells are preserved. But if not diagnosed in time, brain cells also get affected and that is the time seizure develops. Physical examination showed a highly febrile, sick-looking child. He was drowsy but when disturbed was irritable. He had meningeal sings in the form of neck stiffness and positive Kernig’s sign. There were no localising signs.

Anterior fontanel was open and bulging. It favours the diagnosis of bacterial meningitis. It was confirmed by CSF showing 400 cells 90% polymorphs, proteins 250 mg%, and sugar 20 mg%. The culture showed pneumococcus sensitive to all antibiotics. This child does not need neuroimaging at this stage. If there were any focal signs, one may have suspected brain abscess or subdural empyema, and a CT scan of the brain would have been justified. This child was treated with IV ceftriaxone and luckily recovered completely.


Case 4

A 2-year-old child presented with high fever and drowsiness followed a day later by generalised seizure. On direct questioning, he was not keeping well over the last two months with recurrent episodes of fever that were treated each time with antibiotics but without diagnosis and would get temporarily better. He had lost 2 kg of weight and felt sick. There were no other significant illnesses prior to the onset of this problem two months ago. There was no significant family history and he denied contact for any contagious disease.

This child has a sub-acute onset of disease with recurrent fever. It suggests continuous disease with recurrent illness as evident by his progressive loss of weight and sickness. So, it is the same disease that suddenly developed a high fever, drowsiness, and seizure. So this neurological manifestation came up acutely in the background of the sub-acute disease. It favours a probable diagnosis of TB meningitis.

Unlike bacterial meningitis, this child has had brain cell affection early in the course of the disease – encephalopathy without much increased intracranial pressure. Physical examination showed malnourished child, drowsy, mild neck stiffness, positive Macewan’s sign – cracked pot sound suggestive of raised intracranial tension, left-sided hemiparesis with left-sided facial palsy with spasticity, brisk, deep tendon reflexes, and extensor plantar reflex. Pathologically, these signs represent meningeal inflammation with hydrocephalus, vasculitis affecting the middle cerebral artery as evident by hemiparesis with facial palsy and brain cell oedema as shown by drowsiness. These pathological findings are typical of TB meningitis.

CSF showed 120 cells, mostly lymphocytes, 120 mg% proteins, and 35 mg% sugar. CT scan showed meningeal enhancement with hydrocephalus and brain oedema. CSF culture for TB was negative and so also GeneXpert. The chest X-ray was normal. Even in the absence of proof, TB meningitis was diagnosed on circumstantial evidence.

Theoretically, fungal infection can also present the same way but it is usually seen in immune-compromised patients. This child was treated with anti-TB drugs and steroids and made a recovery but was left behind with brain damage. This child presented in the late stage of the disease with drowsiness and convulsion with a risk of brain damage. If picked up before developing any change in sensorium or convulsion, there could be complete recovery without damage.


Case 5

A 2-year-old child presented with high fever and drowsiness that worsened over the next 8 hours followed by a generalised seizure that lasted for 10 minutes that came under control with drugs. He was apparently well prior to the onset of present illness. He maintained normal growth and development. There was no significant past or family history or contact with any contagious disease.

This history denotes the fast progression of neurological disease with brain cell affection in the form of progressive brain cell oedema with deepening consciousness and seizure. It could be encephalitis or autoimmune encephalopathy. Both conditions look similar with very small differences that may not be discernable. Autoimmune encephalitis generally precedes with febrile illness by at least 2-3 days with an interval of apparently normal period before the onset of neurological disease. As this child did not have any recent illness, it may favor viral encephalitis.

Physical examination showed febrile child, unconscious responding to painful stimuli with no localising signs. It suggests generalised brain cell oedema, probably due to viral infection. However, any other cause such as autoimmune encephalitis or toxic encephalitis or fever-triggered metabolic encephalopathy cannot be ruled out.

Investigations – Hb 11 Gm%, WBC 4000 P 55 L 43 M 2 E 0 Pl 1.8 lakhs, malarial parasites not detected, CSF cells 80 mostly lymphocytes, 60mg% proteins, normal sugar, culture –ve, MRI scan of the brain showed diffuse brain oedema. Diagnosis of viral encephalitis was made and treated with IV acyclovir –anti antibiotic mainly acting against herpes viral infection, though administered empirically. Bacterial infection was ruled out and so was malaria. The child also received anti-oedema measures, including anti-convulsant drugs. He improved luckily though aetiology could not be proved.


Case 6

A 10-year-old child presented with jerky movements of the left upper limb that lasted for 5 minutes and stopped by itself. There was no loss of consciousness. He was well prior to the onset of this event and remained normal thereafter as well. There was no significant past or family history. This history suggests a focal seizure. It is not a movement disorder as it occurred suddenly and also stopped by itself. Cause of this seizure cannot be assessed by history, except a fact that there must be local lesion in the motor cortex.

Physical examination showed no abnormality. It meant an apparently silent lesion that must have manifested suddenly without any obvious trigger factor. Such a lesion may be any local structural malformation that must have existed since birth or it may have resulted from focal swelling that may have resulted from local inflammation or infection. But, its exact cause cannot be guessed at this stage and needs investigations. CT scan of the brain showed ring-enhancing lesion in right motor cortex that had surrounding oedema suggestive of inflammatory origin and not congenital malformation. Such a local inflammatory lesion is commonly due to chronic infection such as tuberculosis or neurocysticercosis – a parasitic infection that gets transmitted from eating uncooked meat.

CT scan often failed to differentiate between these two lesions unless there are multiple similar lesions that favour the diagnosis of tuberculosis – tuberculoma. If CT scan finds a scolex of the parasite, the diagnosis of neurocysticercosis can be confirmed. In the absence of such clues, spectroscopy may be useful to differentiate these two conditions. Without definitive diagnosis, in such a situation, management is debatable.

This child certainly needs anti-convulsant drug; carbamazepine is the drug of choice and one may decide to observe further course. However, there is always a risk of tuberculosis spreading to affected brain cells with dire consequences. On the other hand, treatment of neurocysticercosis is short for a few weeks as against minimum of 6 months for tuberculosis. So, the decision should be taken after discussing with parents and explaining the pros and cons of all options. If this child is purely vegetarian, chances of cysticercosis are very low unless he consumed vegetarian food contaminated by uncooked meat without knowing so. Thus, many such patients end up on anti-TB treatment with steroids. On follow-up, this child had shown the disappearance of lesion – probable tuberculoma.


Case 7

A 10-year-old child presented with sudden onset of generalised seizure that lasted for a few minutes and stopped on its own. He was a healthy child with normal brain development and had no symptoms prior to the onset of this event. History suggests unprovoked generalised seizure and as it is the first episode, one may consider clinical follow-up without any tests. EEG at this stage may not be interpretive as normal EEG does not rule out epilepsy and abnormal EEG may be found in a small number of normal children. Physical examination was normal and so the diagnosis of probable idiopathic epilepsy was considered though not labeled at this stage as the very definition of epilepsy is recurrent seizures. One may have to wait for further course.

There is no great risk even if there was another similar seizure. Though one can be prepared with nasal midazolam spray to control seizure. Most of such seizures are short-lasting and self-limiting without causing any brain damage. EEG may help to rule out focal epilepsy with generalisation as many times, no one else has observed onset of a seizure that may have been focal which spread to all the areas resulting in generalised seizure as presentation. EEG was normal in this child, confirming it to be generalised seizure. CT scan of brain is not justified in this child. Parents were counselled and no treatment was advised.


Case 8

A 13-year-old child suddenly fell down while standing for morning prayers in school. He was well till this event happened. He had arrived at school as usual after normal breakfast, No one had noticed onset of this event as it was only when he fell down that everyone around him noticed. By the time his friends offered help, he had got up, was a bit dazed for a few minutes but became normal quickly. One cannot be sure whether this was a seizure that made him fall down or whether it was pseudo-seizure – syncope. However, the fact that he got up within a few seconds would go in favour of syncope. Though, the difference between the two is evident only if one knows the onset of this event.

Physical examination was normal as expected and so the diagnosis of syncope was considered. As this event occurred without any known provocation, it may be a result of neurogenic syncope – vasovagal attack due to unknown stress, such as fear, starving or lack of sleep, the event that typically occurs in standing position.

It is a clinical diagnosis and does not justify any tests such as the tilt-table tests where the sudden tilt of position may induce changes. However, if such an event occurred while exercising or during sport activities, one may have to take a serious note of it as it may represent cardiogenic syncope. It may be fatal if not diagnosed properly unlike a vasovagal attack. If cardiogenic syncope is suspected, one must order routine tests such as ECG and echo-cardiogram to pick up any structural or functional abnormality – one of the important ones to rule out is long QT – it is often familial and so the history of sudden death in the family should arouse suspicion of cardiogenic syncope.

 

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

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