case_images: PMC11824883_01
case_images: (Case 1) Neuroimaging. (A) Non-contrast CTH demonstrates wedge-shaped hypoattenuation in the right MCA territory, consistent with acute infarction.
  (B) CTP quantitative analysis reveals a core infarct (CBF < 30%, volume = 31 mL) with no significant ischemic penumbra (tissue at risk volume (Tmax > 6 seconds) = 27 mL).
  (C) DWI, performed one day later, shows diffusion restriction abnormalities indicative of multiple acute cortical infarcts bilaterally, with the largest involving the posterior right MCA territory.. CBF: Cerebral blood flow; CTH: CT of the head; CTP: CT perfusion; DWI: Diffusion-weighted MRI; MCA: Middle cerebral artery
case_images: cureus-0017-00000077436-i01.jpg
case_images: PMC11824883_01_cureus-0017-00000077436-i01.jpg
case_images: FIG1
case_images: CT of the head (CTH) confirmed wedge-shaped areas of hypoattenuation in the RMCA territory, compatible with acute infarcts involving the perirolandic cortex, lateral aspect of the right parietal lobe, dorsal aspect of the right superior temporal lobe, and adjacent posterior insular cortex (Figure 1A). CT angiography of head and neck demonstrated a distal right M3 occlusion with a matched perfusion deficit (Figure 1B). MRI performed one day later revealed multiple acute embolic infarcts in both cerebral hemispheres with the largest involving the posterior right MCA territory associated with gyral swelling and mild local mass effect (Figure 1C).
case_images: CAPE pattern in EEG and QEEG trends (Case 1). EEG and QEEG (eight-hour segment from 10:00 to 18:00) illustrating CAPE with two distinct states. State changes are evident in the rhythmicity and FFT spectrograms. State 1 shows increased spectral power density in the delta range frequencies (0-4 Hz), while State 2 demonstrates higher spectral power density in the theta-beta range frequencies (4-16 Hz).. CAPE: Cyclic alternating pattern of encephalopathy; FFT: Fast Fourier transform; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i02.jpg
case_images: PMC11824883_01_cureus-0017-00000077436-i02.jpg
case_images: FIG2
case_images: State 1 (Figure 2) was characterized by a continuous diffuse delta range (0.5-3.5 Hz, 30-60 uV) semi-rhythmical slow wave activity. State 2 (Figure 2) was characterized by continuous diffuse theta-alpha range (7-12 Hz, 20-45 uV) activity. Figure 2 displays an eight-hour QEEG (from 10:00 to 18:00) demonstrating the CAPE pattern.
case_images: PMC11824883_02
case_images: CAPE pattern in EEG and QEEG trends (Case 2). EEG and QEEG (15-minute segment from 00:20 to 00:35) demonstrating the CAPE pattern with two distinct states. State changes are highlighted by red arrows in the FFT spectrograms. In State 1, semi-rhythmic slowing is observed in the theta range (4-7 Hz). In State 2, there is increased spectral power in the delta range (1-4 Hz), corresponding to quasi-periodic triphasic waves. State changes are also evident in the aEEG trends, where amplitude is more than 50% higher in State 2 compared to State 1.. aEEG: Amplitude-integrated EEG; CAPE: Cyclic alternating pattern of encephalopathy; FFT: Fast Fourier transform; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i03.jpg
case_images: PMC11824883_02_cureus-0017-00000077436-i03.jpg
case_images: FIG3
case_images: She was transferred to the ICU and intubated for anesthesia to manage status epilepticus. cEEG monitoring was initiated to evaluate for non-convulsive status epilepticus (NCSE) and titration of anti-seizure medications (ASM). cEEG demonstrated a CAPE pattern with two abnormal states: State 1 (Figure 3) was characterized by continuous generalized theta range (4-7 Hz, 20-40 uV) semi-rhythmical slowing, and State 2 (Figure 3) was characterized by continuous generalized delta-theta range (1-5 Hz, 20-50 uV) semi-rhythmical slowing. Figure 3 presents a 15-minute QEEG segment (from 00:20 to 00:35) illustrating the CAPE pattern.
case_images: CAPE pattern in QEEG, extended temporal resolution (Case 2). QEEG (eight-hour segment from 00:00 to 08:00) illustrating prolonged stable states lasting up to 2.5 hours, followed by periods of rapid state fluctuation. Black boxes highlight the rapid fluctuation periods, where state changes occur every 30 to 60 seconds.. CAPE: Cyclic alternating pattern of encephalopathy; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i04.jpg
case_images: PMC11824883_02_cureus-0017-00000077436-i04.jpg
case_images: FIG4
case_images: Figure 3 presents a 15-minute QEEG segment (from 00:20 to 00:35) illustrating the CAPE pattern. These were followed by periods of rapid state fluctuation, during which state changes occurred every 30 to 60 seconds and persisted for up to 1.5 hours (Figure 4).
case_images: Neuroimaging (Case 3). (A) CTH demonstrating bilateral basal ganglia hypodensities.
  (B) MRI shows T2-FLAIR hyperintensities throughout the deep supratentorial white matter, posterior limbs of the internal capsules, subcortical white matter in the occipital lobes, and cerebellar white matter bilaterally, compatible with acute toxic leukoencephalopathy.. CTH: CT of the head
case_images: cureus-0017-00000077436-i05.jpg
case_images: PMC11824883_03_cureus-0017-00000077436-i05.jpg
case_images: FIG5
case_images: Admission CTH showed diffuse loss of grey-white matter differentiation and bilateral symmetric hypodensities within basal ganglia concerning for hypoxic ischemic injury (Figure 5A). Subsequent MRI of the brain was consistent with toxic leukoencephalopathy with symmetrical white matter T2-FLAIR hyperintensities and restricted diffusion, sparing the subcortical U-fibers but with significant mass effect and cortical vasogenic edema (Figure 5).
case_images: CAPE pattern in EEG and QEEG trends (Case 3). EEG and QEEG (15-hour segment from 00:00 to 15:00) demonstrating the CAPE pattern with two distinct states. State changes are visible in the rhythmicity and FFT spectrograms. State 1 exhibits higher spectral power density in the delta range (0-2 Hz). State 2 exhibits higher spectral power density in the alpha range (10-12 Hz).. CAPE: Cyclic alternating pattern of encephalopathy; FFT: Fast Fourier transform; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i06.jpg
case_images: PMC11824883_03_cureus-0017-00000077436-i06.jpg
case_images: FIG6
case_images: State 1 (Figure 6) was characterized by continuous diffuse delta-range (0.5-1.5 Hz, 40-140 microV) slow-wave activity. State 2 (Figure 6) was characterized by continuous diffuse delta-range (0.5-1.5 Hz, 30-60 microV) slow-wave activity with superimposed diffuse alpha-range activity (11-12 Hz, 10-40 microV). Figure 6 displays a 15-hour QEEG segment (00:00 to 15:00) illustrating the CAPE pattern.
case_images: CAPE pattern in EEG and QEEG trends (Case 4). EEG and QEEG (10-minute segment from 02:14 to 02:24) illustrating the CAPE pattern with two distinct states. State changes are visible in the rhythmicity and FFT spectrograms. Red arrows indicate an upward deflection of theta-alpha activity in State 1. Black arrows highlight increased spectral power in the delta range (1-4 Hz) during State 2, correlating with triphasic waves.. CAPE: Cyclic alternating pattern of encephalopathy; FFT: Fast Fourier transform; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i07.jpg
case_images: PMC11824883_04_cureus-0017-00000077436-i07.jpg
case_images: FIG7
case_images: State 1 (Figure 7) was characterized by continuous generalized theta-alpha (6-7 Hz, 20-40 microV) semi-rhythmic slowing. State 2 (Figure 7) was characterized by continuous generalized delta-theta range (0.5-5 Hz, 40-75 microV) slowing, intermixed with generalized periodic discharges with triphasic morphology. Figure 7 presents a 10-minute QEEG segment (02:14 to 02:24) illustrating the CAPE pattern.
case_images: CAPE pattern in QEEG, extended temporal resolution (Case 4). QEEG (six-hour segment from 00:00 to 06:00) demonstrating extended periods of alternating states. The black box highlights periods of rapid state fluctuations, with changes occurring every 10 to 120 seconds.. CAPE: Cyclic alternating pattern of encephalopathy; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i08.jpg
case_images: PMC11824883_04_cureus-0017-00000077436-i08.jpg
case_images: FIG8
case_images: Figure 7 presents a 10-minute QEEG segment (02:14 to 02:24) illustrating the CAPE pattern. Periods of rapid state fluctuation, with changes occurring every 10 to 120 seconds, were also observed (Figure 8).
case_images: PMC11824883_03
case_images: Neuroimaging (Case 3). (A) CTH demonstrating bilateral basal ganglia hypodensities.
  (B) MRI shows T2-FLAIR hyperintensities throughout the deep supratentorial white matter, posterior limbs of the internal capsules, subcortical white matter in the occipital lobes, and cerebellar white matter bilaterally, compatible with acute toxic leukoencephalopathy.. CTH: CT of the head
case_images: cureus-0017-00000077436-i05.jpg
case_images: PMC11824883_03_cureus-0017-00000077436-i05.jpg
case_images: FIG5
case_images: Admission CTH showed diffuse loss of grey-white matter differentiation and bilateral symmetric hypodensities within basal ganglia concerning for hypoxic ischemic injury (Figure 5A). Subsequent MRI of the brain was consistent with toxic leukoencephalopathy with symmetrical white matter T2-FLAIR hyperintensities and restricted diffusion, sparing the subcortical U-fibers but with significant mass effect and cortical vasogenic edema (Figure 5).
case_images: CAPE pattern in EEG and QEEG trends (Case 3). EEG and QEEG (15-hour segment from 00:00 to 15:00) demonstrating the CAPE pattern with two distinct states. State changes are visible in the rhythmicity and FFT spectrograms. State 1 exhibits higher spectral power density in the delta range (0-2 Hz). State 2 exhibits higher spectral power density in the alpha range (10-12 Hz).. CAPE: Cyclic alternating pattern of encephalopathy; FFT: Fast Fourier transform; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i06.jpg
case_images: PMC11824883_03_cureus-0017-00000077436-i06.jpg
case_images: FIG6
case_images: State 1 (Figure 6) was characterized by continuous diffuse delta-range (0.5-1.5 Hz, 40-140 microV) slow-wave activity. State 2 (Figure 6) was characterized by continuous diffuse delta-range (0.5-1.5 Hz, 30-60 microV) slow-wave activity with superimposed diffuse alpha-range activity (11-12 Hz, 10-40 microV). Figure 6 displays a 15-hour QEEG segment (00:00 to 15:00) illustrating the CAPE pattern.
case_images: CAPE pattern in EEG and QEEG trends (Case 4). EEG and QEEG (10-minute segment from 02:14 to 02:24) illustrating the CAPE pattern with two distinct states. State changes are visible in the rhythmicity and FFT spectrograms. Red arrows indicate an upward deflection of theta-alpha activity in State 1. Black arrows highlight increased spectral power in the delta range (1-4 Hz) during State 2, correlating with triphasic waves.. CAPE: Cyclic alternating pattern of encephalopathy; FFT: Fast Fourier transform; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i07.jpg
case_images: PMC11824883_04_cureus-0017-00000077436-i07.jpg
case_images: FIG7
case_images: State 1 (Figure 7) was characterized by continuous generalized theta-alpha (6-7 Hz, 20-40 microV) semi-rhythmic slowing. State 2 (Figure 7) was characterized by continuous generalized delta-theta range (0.5-5 Hz, 40-75 microV) slowing, intermixed with generalized periodic discharges with triphasic morphology. Figure 7 presents a 10-minute QEEG segment (02:14 to 02:24) illustrating the CAPE pattern.
case_images: CAPE pattern in QEEG, extended temporal resolution (Case 4). QEEG (six-hour segment from 00:00 to 06:00) demonstrating extended periods of alternating states. The black box highlights periods of rapid state fluctuations, with changes occurring every 10 to 120 seconds.. CAPE: Cyclic alternating pattern of encephalopathy; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i08.jpg
case_images: PMC11824883_04_cureus-0017-00000077436-i08.jpg
case_images: FIG8
case_images: Figure 7 presents a 10-minute QEEG segment (02:14 to 02:24) illustrating the CAPE pattern. Periods of rapid state fluctuation, with changes occurring every 10 to 120 seconds, were also observed (Figure 8).
case_images: PMC11824883_04
case_images: CAPE pattern in EEG and QEEG trends (Case 4). EEG and QEEG (10-minute segment from 02:14 to 02:24) illustrating the CAPE pattern with two distinct states. State changes are visible in the rhythmicity and FFT spectrograms. Red arrows indicate an upward deflection of theta-alpha activity in State 1. Black arrows highlight increased spectral power in the delta range (1-4 Hz) during State 2, correlating with triphasic waves.. CAPE: Cyclic alternating pattern of encephalopathy; FFT: Fast Fourier transform; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i07.jpg
case_images: PMC11824883_04_cureus-0017-00000077436-i07.jpg
case_images: FIG7
case_images: State 1 (Figure 7) was characterized by continuous generalized theta-alpha (6-7 Hz, 20-40 microV) semi-rhythmic slowing. State 2 (Figure 7) was characterized by continuous generalized delta-theta range (0.5-5 Hz, 40-75 microV) slowing, intermixed with generalized periodic discharges with triphasic morphology. Figure 7 presents a 10-minute QEEG segment (02:14 to 02:24) illustrating the CAPE pattern.
case_images: CAPE pattern in QEEG, extended temporal resolution (Case 4). QEEG (six-hour segment from 00:00 to 06:00) demonstrating extended periods of alternating states. The black box highlights periods of rapid state fluctuations, with changes occurring every 10 to 120 seconds.. CAPE: Cyclic alternating pattern of encephalopathy; QEEG: Quantitative EEG
case_images: cureus-0017-00000077436-i08.jpg
case_images: PMC11824883_04_cureus-0017-00000077436-i08.jpg
case_images: FIG8
case_images: Figure 7 presents a 10-minute QEEG segment (02:14 to 02:24) illustrating the CAPE pattern. Periods of rapid state fluctuation, with changes occurring every 10 to 120 seconds, were also observed (Figure 8).