The extracranial effects of convulsive status epilepticus

A prolonged uncontrollable seizure is not a consequence-free experience. There is typically a price to pay for such vigorous exercise. A good article, unfortunately trapped behind a paywall, is available to explain the systemic effects of ongoing convulsive seizures. In short, most of the physiological changes can be associated with an excess of sympathetic stimulation, and a massive increase in the body’s metabolic demand.

Respiratory effects of ongoing convulsive seizures

  •  There is likely to be hypoxia. This can be due to aspiration (which is common) or purely due to hypoventilation (due to incoordination of respiratory muscles).
  • There is likely to be hypercapnea, for the same reasons. Additonally, the huge bulk of vigorously contracting muscles is metabolizing a lot more substrate, and thus the net amount of CO2 production is greater.

Cardiovascular effects of ongoing convulsive seizures

  • There is hypertension initially, due to a massive sympathetic release of catecholamines. During this stage cerebral blood flow is also increased. The hypertension can be so severe that neurogenic pulmonary oedema may develop.
  • This sympathetic storm can also induce cardiac arrhythmias.
  • Thereafter, a hypotensive period ensues, when cardiac output is decreased, and the patient is relatively vasodilated.

Acid-base effects of ongoing convulsive seizures

  • Naturally, lactic acidosis is the consequence of sustained muscle contraction.
  • Respiratory acidosis is also observed.

Changes in CS biochemistry

Can one tell that a seizure is occurring simply be analysisng the CSF? Some say that yes, you can. Pleocytosis (that is to say, an elevated WCC in the CSF) is seen in around 60% of patients with status epilepticus, although the author of the linked article cautions that "The most important influence on the CSF WBC count is the underlying cause of the SE".

Changes in intracranial pressure

Owing to the increased intracranial blood flow, there is a period of hyperaemia, and during this period a patient with an ICP monitor will register a sharp increase in ICP.

Rhabdomyolysis

Like any vigorous exercise, seizures can result in the breakdown of individual myocytes, and the myocyte content thus enters the bloodstream. There are case reports of clinically significant rhabdomyolysis following status epilepticus, but more often the elevation of CK is merely a footnote and there is no renal involvement.

 

References

Oh's Intensive Care manual:

Chapter 49   (pp. 549) Disorders  of  consciousness  by Balasubramanian  Venkatesh

Chapter   50   (pp. 560) Status  epilepticus  by Helen  I  Opdam

Meldrum, Brian S., Roger A. Vigouroux, and James B. Brierley. "Systemic factors and epileptic brain damage: prolonged seizures in paralyzed, artificially ventilated baboons." Archives of Neurology 29.2 (1973): 82-87.

Olney, J. W., R. C. Collins, and R. S. Sloviter. "Excitotoxic mechanisms of epileptic brain damage." Advances in neurology 44 (1985): 857-877.

Beal, M. Flint. "Mechanisms of excitotoxicity in neurologic diseases." The FASEB journal 6.15 (1992): 3338-3344.

Yeh, Huei-Ming, et al. "Convulsions and refractory ventricular fibrillation after intrathecal injection of a massive dose of tranexamic acid." Anesthesiology 98.1 (2003): 270-272.

Murkin, John M., et al. "High-dose tranexamic acid is associated with nonischemic clinical seizures in cardiac surgical patients." Anesthesia & Analgesia 110.2 (2010): 350-353.

Tan, R. Y. L., A. Neligan, and S. D. Shorvon. "The uncommon causes of status epilepticus: a systematic review." Epilepsy research 91.2 (2010): 111-122.

Tibussek, Daniel, et al. "Status epilepticus due to attempted suicide with isoniazid." European journal of pediatrics 165.2 (2006): 136-137.

Wyderski, Richard J., W. Grant Starrett, and Alaa Abou-Saif. "Fatal status epilepticus associated with olanzapine therapy." Annals of Pharmacotherapy33.7-8 (1999): 787-789.

Martínez-Rodríguez, Jose E., et al. "Nonconvulsive status epilepticus associated with cephalosporins in patients with renal failure." The American journal of medicine 111.2 (2001): 115-119.

De Sarro, A., et al. "Relationship between structure and convulsant properties of some beta-lactam antibiotics following intracerebroventricular microinjection in rats." Antimicrobial agents and chemotherapy 39.1 (1995): 232-237.

Johnson, Herbert C., and A. Earl Walker. "Intraventricular penicillin: a note of warning." Journal of the American Medical Association 127.4 (1945): 217-219.

Johnson, Nicholas, et al. "Anti-NMDA receptor encephalitis causing prolonged nonconvulsive status epilepticus." Neurology 75.16 (2010): 1480-1482.

Barry, Elizabeth, and W. Allen Hauser. "Pleocytosis after status epilepticus."Archives of neurology 51.2 (1994): 190.

Singhal, P. C., K. S. Chugh, and D. R. Gulati. "Myoglobinuria and renal failure after status epilepticus." Neurology 28.2 (1978): 200-200.

Collins, W. C., O. Lanigan, and N. Callaghan. "Plasma prolactin concentrations following epileptic and pseudoseizures." Journal of Neurology, Neurosurgery & Psychiatry 46.6 (1983): 505-508.

Towne, A. R., et al. "Prevalence of nonconvulsive status epilepticus in comatose patients." Neurology 54.2 (2000): 340-340.

Brophy, Gretchen M., et al. "Guidelines for the evaluation and management of status epilepticus." Neurocritical care 17.1 (2012): 3-23.

Ma, Xiaoping, et al. "Neurosurgical treatment of medically intractable status epilepticus."  Epilepsy research 46.1 (2001): 33-38.

Sass, K. J., et al. "Corpus callosotomy for epilepsy. II. Neurologic and neuropsychological outcome." Neurology 38.1 (1988): 24-24.

Chen, James WY, and Claude G. Wasterlain. "Status epilepticus: pathophysiology and management in adults." The Lancet Neurology 5.3 (2006): 246-256.

Treiman, David M., et al. "A comparison of four treatments for generalized convulsive status epilepticus." New England Journal of Medicine 339.12 (1998): 792-798.

Meierkord, Hartmut, and Martin Holtkamp. "Non-convulsive status epilepticus in adults: clinical forms and treatment." The Lancet Neurology 6.4 (2007): 329-339.

Borris, Douglas J., Edward H. Bertram, and Jaideep Kapur. "Ketamine controls prolonged status epilepticus." Epilepsy research 42.2 (2000): 117-122.

Slovis, Corey M. "Lidocaine in the treatment of status epilepticus." Academic emergency medicine 4.9 (1997): 918-925.

Storchheim, Frederic. "Status epilepticus treated by magnesium sulphate, injected intravenously." Journal of the American Medical Association 101.17 (1933): 1313-1314.

Kluger, G., et al. "Pyridoxine-dependent epilepsy: normal outcome in a patient with late diagnosis after prolonged status epilepticus causing cortical blindness." Neuropediatrics 39.5 (2008): 276-279.

Mirsattari, Seyed M., Michael D. Sharpe, and G. Bryan Young. "Treatment of refractory status epilepticus with inhalational anesthetic agents isoflurane and desflurane." Archives of neurology 61.8 (2004): 1254-1259.

Hamani, Clement, et al. "Deep brain stimulation of the anterior nucleus of the thalamus: effects of electrical stimulation on pilocarpine-induced seizures and status epilepticus." Epilepsy research 78.2 (2008): 117-123.

Cervenka, Mackenzie C., et al. "The ketogenic diet for medically and surgically refractory status epilepticus in the neurocritical care unit." Neurocritical care15.3 (2011): 519-524.

Corry, Jesse J., et al. "Hypothermia for refractory status epilepticus."Neurocritical care 9.2 (2008): 189-197.