Regarding vertigo in an elderly man, which ONE of the following statements is TRUE?
Answer: B: Vertebrobasilar insufficiency causes a ‘positional vertigo’ of central origin. It may or may not cause neurological deficits such as diplopia, dysarthria and bilateral long tract signs. The transient ischaemia to the brainstem that occur in this condition may present as a posterior circulation TIA. If the reticular activating system is sufficiently affected, presyncope or syncope may occur. In 85% of the patients with BPPV, the posterior semicircular canal is affected unilaterally with free-floating particles (canalolithiasis hypothesis). In these patients Dix-Hallpike manoeuvre will be positive. The horizontal semicircular canal is affected in approximately 15% of patients in BPPV. In these patients Dix-Hallpike manoeuvre is negative and diagnosis can be made with a supine roll test. Although hearing loss and tinnitus is associated with conditions causing a peripheral type of vertigo such as Ménière’s disease, vestibular neuronitis, or viral or bacterial labyrinthitis, in BPPV these symptoms are not present. In BPPV examination of the middle ear is usually normal; alternatively, in labyrinthitis changes in the middle ear due to otitis media is a significant finding.
Reference:
Regarding generalised convulsive status epilepticus, which ONE of the following statements is TRUE?
Answer: A: Generalized convulsive status epilepticus has been traditionally defined as a seizure lasting more than 30 minutes or two or more seizures without full recovery of consciousness between seizures. This traditional definition has been questioned by some authors and Lowenstein and Cloyd suggest 5 minutes of continuous seizure activity to be taken as status because it is less likely for the seizure to terminate spontaneously and more likely for neuronal damage to occur after this duration. Generalized convulsive status epilepticus is more common in children in whom over 50% of the cases occur. In children, it is most common in those younger than 2 years. In adults, the incidence is proportionately higher in the elderly in whom cerebrovascular disease is often the cause.
As the duration of seizures progresses, permanent neurological damage becomes more common. Brain compensatory mechanisms remain intact during the early phases of seizures. However, they begin to fail as the duration prolongs despite attempts at adequate delivery of oxygen and nutrients during resuscitation. The brain injury is exacerbated by the contributory hypoglycaemia, hypotension, hypoxia and hypercarbia due to failing brain mechanisms. The longer the seizure duration, the less refractory it becomes to treatment. Mortality increases from <5% when the status epilepticus lasts <1 hour to over 30% when seizures continue beyond 1 hour.
References:
Regarding the use of phenytoin for a young adult presenting with generalised convulsive status epilepticus, which ONE of the statements is TRUE?
Answer: B: Phenytoin is generally effective in seizure control in a dose of 15–20 mg/kg body weight given as an intravenous infusion. One of the important limitations with phenytoin is the safe rate of delivery, which is 50 mg/min. This should be reduced to 25 g/min in the elderly and patients with significant cardiovascular disease. At faster rates it is known to cause cardiac arrhythmias secondary to prolonged QT interval as a result of sodium channel blocking effect and hypotension due to the diluent (propylene glycol) used in the phenytoin preparation. The dose of 1 g intravenously is not adequate in controlling seizure in most adults and correct dosage calculated according to actual or approximate body weight should be infused (usually no more than 1.5 g).
The adverse effects associated with a full loading dose are thought to be minimal in a patient with status epilepticus who is on regular oral phenytoin. In these patients, the drug levels are often subtherapeutic. Therefore, full loading dose is indicated.
Regarding a patient with a known history of alcohol abuse presenting with generalised seizures, which ONE of the following is TRUE?
Answer: C: Both minor and major alcohol withdrawal can cause alcohol-related seizures in a patient with or without previous seizure history. However, delirium tremens occurs at least 3 days after abstinence and it is uncommon (5% of the patients). Patients who continue to have seizure activity with a reduced level of consciousness often require intubation and ventilation. During rapid sequence intubation a suitable muscle relaxant such as suxamethonium or rocuronium can be used; however, further use of paralytic agents should be avoided because ongoing seizure activity cannot be recognized without electroencephalogram (EEG) if paralytic agents are given. Patients’ ventilation should be facilitated with adequate use of sedation. The diagnosis of non-convulsive status is usually made by the EEG during the suspicious activity. These patients often present with a prolonged unconsciousness or postictal period following a convulsive seizure. The subsequent course is typically with a fluctuating level of consciousness, subtle motor signs such as eye deviations and blinking without obvious seizure activity.
Regarding absence seizures, all of the following statements are true EXCEPT:
Answer: C: Absence seizures are generalized seizures that typically occur in childhood and resolve as the child matures into adulthood (similar seizures in adults are complex partial seizures). Sudden loss of consciousness is a feature but the patient does not fall to the ground (there is no loss of postural tone). The patient suddenly stops the activity he/she is performing at that time and will appear to be not focusing (inattention). There is no response to voice or other stimuli, no motor activity (except blinking of the eyes), no urinary incontinence and no tongue biting during the episodes. The seizure activity terminates abruptly and there is no postictal phase. Absence seizures can occur many times a day and can go unrecognized. These seizures can occur in patients presenting to the ED with other types of seizures or they can occur alone.
Intact consciousness and mentation is a hallmark of simple partial seizures where seizure activity remains localized.
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