A 67-year-old woman with an insignificant past medical history presents with her husband who reports that she has become increasingly confused over the past week. The husband reports that she had a “hard fall” down a few stairs 10 days ago and since then has been hesitant to walk. A contrast-enhanced head CT is ordered and is shown below.
Which of the following is the underlying cause of this patient’s condition?
Tearing of the bridging veins. This patient is suffering from a subdural hematoma, which is caused by blunt trauma that tears the bridging veins, which connect the cortical superficial veins to the sagittal sinus in the dura. This blood will slowly extravasate into the subdural space, which is why this patient’s fall was recorded over a week prior to admission. Epidural hematomas, on the other hand, become immediately symptomatic (although the classic description of epidural hematomas is that of a “lucent” phase followed by rapid decline). Subdural hematomas manifest symptomatically with headache and gradual confusion and loss of consciousness. Of note, subdural hematomas are much more common in elderly patients and alcoholic patients (brain atrophy and fragility of vasculature). Radiologic findings of a subdural hematoma include a white crescent on noncontrast CT of the head. Also, a midline shift is commonly appreciated. Treatment is neurosurgic hematoma evacuation. (A) Tearing of the middle meningeal artery is the underlying cause of most epidural hematomas. (C) Ruptured aneurysm is the underlying cause of a subarachnoid hemorrhage. (D) In addition to the radiologic evidence, this particular patient has an insignificant past medical history and therefore hypertensive hemorrhage is not the right answer.
A 57-year-old man presents with new onset left-sided weakness, urinary incontinence, and left leg “heaviness” for the past 5 hours. That patient has a long history of diabetes and is noncompliant with his medications. Neurologic examination reveals 3/5 strength in the left upper extremity and 1/5 strength in the left lower extremity. Sensation to pinprick and fine touch is markedly diminished over the left leg. Visual field testing is within normal limits.
Which of the following is the most likely location of this patient’s stroke?
Right anterior cerebral artery. This patient is suffering from a stroke and this question asks to localize the location of the stroke. Strokes are either hemorrhagic (secondary to subarachnoid hemorrhage or intracerebral hemorrhage) or ischemic (secondary to embolism, thrombosis, or hypoperfusion). This patient is having a stroke of the right anterior cerebral artery. This is characterized by contralateral motor and/or sensory deficits that are particularly symptomatic in the lower limb (as seen in this patient). Another clue to anterior cerebral artery strokes includes urinary incontinence.
(A, B) Middle cerebral artery strokes manifest as contralateral motor and/ or sensory deficits that are particularly symptomatic in the upper limb (rather than the lower limb as seen in this patient). Furthermore, if the dominant lobe (usually left) is involved in the stroke, the patient may present with aphasia. (D) Left anterior cerebral artery strokes would demonstrate symptomatically on the right side.
A 37-year-old woman presents with a severely intense headache that began a few hours ago. The headache has not improved since then and the patient has vomited several times. She reports that it is diffusely painful, and she is unable to recall if any “funny sensations” occurred prior to the headache. She does not report head trauma or fever. The patient is too uncomfortable to tolerate a thorough neurologic examination and a CT scan of the head is ordered (Figure below).
Which of the following is the underlying cause of this patient’s headache?
Ruptured berry aneurysm. This patient is likely suffering from a nontraumatic subarachnoid hemorrhage as evidenced by the noncontrast head CT scan. CT scan findings in a subarachnoid hemorrhage include bright (hyperdense) signals that represent acute bleeding (usually in the cisterns). In the case of nontraumatic subarachnoid hemorrhages, the most common cause is ruptured berry or saccular aneurysms. Rupture is more likely for aneurysms greater than 7 mm. Of note, if this patient presented with a negative head CT and a subarachnoid hemorrhage was still suspected, the next best step is to perform a lumbar puncture, which will demonstrate xanthochromia.
(A) Venous sinus thrombosis typically presents with progressively worsening headache and causes hemorrhage along the major cerebral draining veins. (C) Arteriovenous malformation is also a cause of subarachnoid hemorrhages (and intracerebral hemorrhages), but the most common cause of nontraumatic subarachnoid hemorrhages is a ruptured aneurysm. (D) Amyloid angiopathy is the second most common cause of intracerebral hemorrhage. However, this type of hemorrhage is lobar in its location and results from abnormal β-pleated amyloid protein deposition in the cerebral blood vessels.
A 27-year-old woman presents with fatigue and double vision. The patient reports that these symptoms occur at the end of a “long work day.” The patient also reports that she does not eat “tough” foods anymore such as steak or chicken as it is difficult for her to chew. Neurologic examination is unremarkable and the patient has normal thyroid-stimulating hormone (TSH) and creatine kinase (CK) levels. The diagnosis is confirmed with a special laboratory test.
Which of the following is the next best step in management of this patient?
CT scan of the chest. The patient in this question is suffering from myasthenia gravis (MG), an autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatigue. The main symptom of MG is muscle weakness after a period of muscle use. Extraocular muscles are commonly involved leading to double vision. Jaw fatigue is common as well due to fatigue of the bulbar muscles. The underlying mechanism of MG is circulating antibodies that block acetylcholine receptors at the postsynaptic neuromuscular junction. In contrast, Lambert–Eaton syndrome has autoantibodies directed at presynaptic voltage-gated calcium channels. Of note, about 15% of patients with MG will have a thymoma, so it is critical to perform a CT scan of the chest after the diagnosis is made. (A, C, D) These are not the most appropriate first steps in management after the diagnosis of MG is made. A thymoma must first be excluded since it can become invasive.
A 26-year-old man presents with symmetric ascending weakness of the bilateral lower extremities. The patient also endorses numbness and tingling in his toes and reports that he had a diarrheal episode 7 days ago that lasted for 2 days. Neurologic examination confirms symmetric weakness in the lower extremities with diminished and delayed reflexes. Electrophysiologic studies confirm slowing of nerve conduction velocities.
Which of the following pathogens is likely to be the cause of this patient’s disorder?
Campylobacter jejuni. This patient is suffering from Guillain–Barré syndrome (GBS), an acute polyneuropathy associated with ascending paralysis. The majority of patients will report a respiratory or gastrointestinal infection that preceded the neurologic symptoms. GBS is an autoimmune disease resulting from an immune response to foreign antigens that incorrectly targets host nerve tissues through a mechanism known as molecular mimicry. The most common infectious agent and precipitant of GBS is Campylobacter, so this is likely to be the pathogen causing this patient’s diarrheal episode. (A, B, C) These are pathogens that also cause gastrointestinal infections, but these are not likely to cause GBS. Other precipitants of GBS include herpes simplex virus (HSV), Mycoplasma, and H. influenzae.
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