DOI: http://dx.doi.org/10.18203/2320-6012.ijrms20171881

Non-convulsive status epilepticus: an often-overlooked etiology of syndrome of inappropriate antidiuretic hormone secretion

Elizabeth Davis, Rima Chakraborty

Abstract


Altered mental status is a common presenting complaint in adult medicine with a broad differential diagnosis. When found in the context of chronic medical conditions, less common etiologies can be overlooked. We present a case of acute altered mental status thought to be secondary to acute on chronic hyponatremia in the context of syndrome of inappropriate antidiuretic hormone secretion (SIADH), eventually diagnosed as non-convulsive status epilepticus, partial type. We report the case of a 67-year-old patient with known SIADH of unknown etiology, hypertension, chronic pancreatitis and chronic obstructive pulmonary disease (COPD) who presented with fatigue, myalgia, decreased urine output. On presentation patient also had profound acute on chronic hyponatremia. During sodium correction, the patient developed an acute, progressive decline in mental status. Vital signs remained stable and workup including LP and MRI were negative. Initial electroencephalographic (EEG) showed no definitive seizure activity, but did show bifrontal focal continuous slowing. The patient’s mental status continued to decline and upon further evaluation it was suggested that the EEG findings and the patient’s progressive AMS could be compatible with non-convulsive status epilepticus. The patient received loading doses of IV lorazepam and levetiracetam and within 48 hours after initial treatment was back to baseline. Non-convulsive status epilepticus is a common, but heterogeneous subclass of status epilepticus that is difficult to diagnose. This case demonstrates the difficulty of diagnosing normalized corrected Shannon entropy (NCSE) in the context of other chronic medical conditions and the importance of including it on any differential diagnosis for acute change in mental status. 


Keywords


EEG, Hyponatremia, NSCE, SIADH

Full Text:

PDF

References


Ellison DH, Berl T. The Syndrome of Inappropriate Anti-diuresis N Engl J Med. 2007;356:2064-72.

Schwartz WB, Bennett W, Curelop S, Bartter FC. A syndrome of renal sodium loss and hyponatremia probably resulting from inappropriate secretion of antidiuretic hormone. Am J Med. 1957;23:529-42.

Goh KP. Management of Hyponatremia. Am Family Physician. 2002;69:2387-94.

Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med. 2000;342:1581-9.

Lowenstein, DH, Alldredge, BK. Status Epilepticus N Engl J Med. 1998;338:970-6.

Kaplan PW. Nonconvulsive Status Epilepticus. Neurology. 2003;61:1035-6.

Chang AK, Shinnar, S Nonconvulsive Status Epilepticus, Emergency Med Clin N Am. 2011;29:65-7.

Geoghegan P, Harrison AM, Thongprayoon C, Kashyap R, Ahmed A, Dong Y, et al. Sodium Correction Practice and Clinical Outcomes in Profound Hyponatremia. Mayo Clin Proc. 2015;90:1348-55.

Vu T, Wong R, Hamblin PS, Zajac J, Grossman M. Patients Presenting with Severe Hypotonic Hyponatremia: Etiological Factors, Assessment and Outcomes. Hosp Pract. 2009;37:128-36.

DeWitt LD, Buonanno FS, Kistler JP, Zeffiro T, DeLaPaz RL, Brady TJ, et al. Central pontine myelinolysis: demonstration by nuclear magnetic resonance. Neurology. 1984;34:570-6.

Celesia GG, Modern Concepts of Status Epilepticus. JAMA. 1976;235:1571-4.

Dunne JW, Summers QA, Stewart-Wynne EG. Non-convulsive status epilepticus: a prospective study in an adult general hospital. Q J Med. 1987;62:117-126.