A 49-year-old female is admitted to the medical intensive care unit with sepsis due to pyelonephritis and acute kidney injury. Prior urinary tract infections have been due to extended-spectrum Blactamase Escherichia coli. Her initial pertinent lab values include creatinine 1.8 mg/dL, BUN 32 mg/dL, WBC 22.4 × 10 9 /L with elevated band percentage (24%). She was resuscitated with 6 L of IV fluids and started on norepinephrine to maintain a mean arterial pressure of 65. Empiric antibiotic therapy was started with imipenem and vancomycin. Over the course of 48 hours she has improvement in her lab values and vitals and was weaned from vasoactive medications. Despite improvement in the above, she has had ongoing alteration in her level of consciousness. She underwent a prolonged EEG monitoring (see figure tbelow).
Standard 10 to 20 electrode placement. This is a standard “double banana” montage with left over right. EEG demonstrates broad, generalized periodic discharges right greater than left hemispheric involvement.
What is the next best step in management?
Correct Answer: D
The EEG above demonstrates triphasic waves. The triphasic wave has a high-amplitude (>70 microV), positive transient followed by a negative deflection with an anterior-posterior gradient and anterior-posterior delay. Triphasic waves were initially described in hepatic encephalopathy but have been described in multiple metabolic derangements, and they can be associated with nonconvulsive seizures. Treatment of triphasic waves with benzodiazepine will result in improvement in the discharges, but it may not change the clinical picture of the patient. A trial of benzodiazepine might help in the diagnosis of nonconvulsive status. A positive benzodiazepine test if there is resolution of potentially ictal EEG pattern and improvement in clinical state or appearance of previously absent normal EEG pattern. If there is demonstration of the above, then treatment with an AED would be appropriate. Imipenem and other carbapenem medications have been associated with increased risk of seizures; with imipenem use, 4/1000 patients have seized.
References:
A 36-year-old female presents with worsening dyspnea, double vision, and dysarthria over the course of the last 3 days, which was preceded by an upper respiratory tract infection that cleared without any treatment. On examination she has mild labial and palatal dysarthria, limited right eye elevation, and abduction with horizontal double vision on right lateral gaze. She is admitted to the neurology service for workup. A nerve conduction study is completed and demonstrates 50% decrement with rapid stimulation. Laboratory workup reveals positive MuSK (muscle specific kinase) antibody.
What is the best treatment plan for this patient?
MuSK is a tyrosine kinase receptor found on muscle which is important in the maintenance of the neuromuscular junction. The repetitive stimulation presented in the question demonstrates the typical findings of myasthenia gravis, a decrement of >33% at 3 Hz cycling. Other findings on electrodiagnostic testing include increased jitter on single fiber electromyography. MuSK-positive myasthenia gravis can present with crisis as their initial presentation and typically have predominately ocular and bulbar symptoms. Treatment of crisis is the same as for other myasthenia gravis patients, which is initial treatment with a rapidly acting intervention, either IVIG or plasmapheresis, and concurrent or shortly after with chronic immunosuppressive therapy. MuSK positive myasthenia patients appear to have improved early response with 93% responding to plasmapheresis and only 61% responding to IVIG. Although initiation of steroids is the mainstay of treatment of other myasthenia gravis patients, MuSK antibody patients do not respond as well. These patients respond better to rituximab for chronic immunosuppressive therapy.
A 55-year-old female with lupus (on hydroxychloroquine) and hypertension was brought to the emergency department for obtundation. She was intubated in the field given agonal respirations. CT angiogram revealed diffuse subarachnoid hemorrhage and an anterior communicating artery aneurysm. The aneurysm was secured with endovascular coiling. On hospital day 8 the patient had worsening of her examination with weakness of the left face, arm, and leg, as well as mild dysarthria. Her transcranial Doppler ultrasound results are shown below. Angiography was done to evaluate for potential cerebral artery vasospasm. Mild-tomoderate right proximal anterior communicating artery vasospasm was found and treated with intra-arterial verapamil resulting in angiographic and clinical improvement of her symptoms.
Which of the comments is true regarding the use of transcranial Doppler ultrasound for cerebral artery vasospasm following aneurysmal subarachnoid hemorrhage?
Correct Answer: C
Transcranial Doppler ultrasound (TCD) is a noninvasive, easily reproducible test that can be used to monitor for cerebral artery vasospasm following aneurysmal subarachnoid hemorrhage. It can be used for other disease evaluation including emboli detection, brain death evaluation, and sickle cell disease. TCD uses low-frequency (2 MHz) pulse Doppler to evaluate velocity of blood flow through the proximal intra- and extracranial arteries. Although a good screening tool, it has limited sensitivity (90%), specificity (70%), and positive predictive value (57%) when compared to digital subtraction angiography. Early studies using TCD evaluated the diameter of blood vessels and the mean velocity. Mean velocities >120 cm/s correlated with decrease in blood vessel diameter by 50%. The patient’s transcranial Doppler ultrasounds are normal despite having angiographic and clinical vasospasm which can be seen given the sensitivity of the testing. More importantly, there are limitations in the ability to TCD to detect vasospasm in major blood vessels other than the middle cerebral and basilar arteries. Although not present here, elevated velocities may not be a sign of vasospasm. At times there can be hyperemia resulting in increased velocities throughout. The advent of the Lindegaard ratio can be used to further evaluate elevation in velocities by comparing the mean velocity in the middle cerebral artery with that of the ipsilateral extracranial internal carotid artery (MEANmca/MEANeica) with ratios of 3 to 6 consistent with mild spasm and >6 moderate spasm while a ratio of <3 meaning there is increased flow throughout the vascular system. Lindegaard ratio >3 and mean velocity >120 cm/s correlated with clinical vasospasm 85% and angiographic vasospasm 83.2%. There are many treatment options for angiographic vasospasm and verapamil works by blocking L-type calcium channels and results in relaxation of smooth muscle. Following treatment with verapamil mean TCD velocities will decrease rather than increase.
A 73-year-old woman with schizophrenia on lithium was found unresponsive by her husband in the bathroom. EMS was called, and on arrival she was unresponsive, intubated in the field, and brought to the ED. Her initial vital signs were stable and within normal limits. Off sedation, her eyes remained closed, minimally reactive pupils, no corneal or cough but intact gag reflex, and no movement to painful stimulation. A head CT, and CTA head and neck were completed (see figures below).
What is the patient’s Hunt and Hess and modified Fisher grade?
The patient presents with a subarachnoid hemorrhage in the setting of a basilar tip aneurysm which is seen on the sagittal reformatted images shown. The description of the patient’s presentation is best described by scales that have been previously developed that assist with long-term outcome as well as anticipated complications during the hospitalization. The Hunt and Hess score was developed as a tool for assessment of death. There are five grades with the lowest scores having better prognosis and higher having worse prognosis (Hunt and Hess Grade table). With the course of time and improved treatment strategies, the prognosis has improved, but those with the highest grade have a high mortality (71%). The Hunt and Hess grading system is based on the clinical exam of the patient. The second commonly used grading system for subarachnoid hemorrhage (SAH) is the modified Fisher scale (Modified Fisher Grade table). This is a radiographic-based scale which uses the thickness of subarachnoid blood and intraventricular extension to predict clinically relevant vasospasm. Vasospasm is a well-defined complication of subarachnoid hemorrhage which results in vasoconstriction of the cerebral vasculature through both calcium-dependent and calcium-independent pathways and results in cerebral ischemia.
A 68-year-old female is brought to the emergency department from home for increased confusion, nausea, and emesis. She was in her usual state of health until the morning of presentation. She was last known well at 9:15 am when her husband saw her getting dressed. He heard a thud at 9:30 am and found her on the ground in the bedroom confused. EMS was called and en route she had an episode of emesis. Her initial head CT demonstrated a cerebellar hemorrhage. A follow-up MRI was completed 5 days following admission (see figures below).
What is the most likely underlying etiology of her intraparenchymal hemorrhage?
Correct Answer: B
Given the findings on MRI, the most likely cause of her cerebellar hemorrhage is hypertension. This location is one of the common places for hypertensive bleeds (other being thalamus, basal ganglia, and pons). This is thought to be due to degeneration of the internal elastic lamina and resultant lipohyalinosis of the small vessels of the brain. The MRI of patients with hypertensive angiopathy will demonstrate areas of microhemorrhage within the same vascular regions as macrohemorrhages. Cerebral amyloid angiopathy is the most common cause of lobar intraparenchymal hemorrhage in older adults. This is the result of betaamyloid protein deposition within the intima and media of the large and medium-sized intracranial vasculature. Autoimmune vasculitis is another important etiology of intraparenchymal hemorrhage. The typical imaging finding is both ischemic and hemorrhagic infarcts of varying age. The clinical presentation of autoimmune vasculitis can mimic the presentation above, but there is typically a prodromal phase with progressive symptoms. Lastly, infective endocarditis results in intraparenchymal hemorrhage from formation of mycotic aneurysms. Infected embolic material from the affected valve will embolize and can result in formation of microhemorrhages at the sites as well as macrohemorrhages if the aneurysms rupture. Vessel imaging with CT angiography, MR angiography, or digital subtraction arteriogram are best for evaluating an aneurysm.
Click to expand