A 38-year-old, right-handed woman is brought to the emergency department after a brief seizure witnessed by her husband. The patient has never before had a seizure but has had headaches for several weeks. Her husband says that she has acted strangely for several months. The patient used to be quite social, but lately, she is not motivated to participate in any social activities and has lost interest in everyday activities. She will not talk unless directly spoken to and has impaired memory. The patient has no significant medical or psychiatric history. There is no family history of neurologic disorders. Temperature is 36 C (96.8 F), blood pressure is 130/78 mm Hg, and pulse is 86/min. On examination, the patient is somnolent but wakes to voice and follows commands. The pupils are equal and reactive. Funduscopy reveals bilateral papilledema. Bilateral upper and lower extremity muscle strength is normal. Neuroimaging is most likely to reveal which of the following findings in this patient?
This patient's presentation is most consistent with a frontal lobe tumor. Brain tumors can be asymptomatic or minimally symptomatic until increased intracranial pressure (ICP) causes headache (classically worse with recumbency), with ICP transmission to the optic nerve sometimes leading to papilledema. Other common manifestations include an unprovoked first seizure (as seen in this patient), focal deficits, and cognitive dysfunction (eg, impaired memory).
Specific deficits, which are sometimes subtle and present for weeks to months, help with tumor localization. Frontal lobe involvement can affect personality, language, motor, or executive functions (eg, planning, inhibition, attention). This patient's personality changes (eg, acting strangely) over the past few months likely reflect a frontal lobe mass. Although frontal lobe damage classically causes disinhibition and impulsiveness, it may also lead to depressive symptoms, including decreased motivation and/or lack of concern regarding the diagnosis (ie, abulia) and loss of interest (ie, anhedonia), as seen in this patient.
(Choice A) Frontotemporal dementia, which preferentially affects the frontal lobe, is often characterized by personality changes and executive dysfunction. However, it typically has a hereditary component, is most common in patients age 50-70, and does not classically cause headaches or papilledema.
(Choice B) Although it can cause seizures and increased ICP due to cerebral edema, ischemic brainstem infarction classically presents with acute cranial nerve deficits accompanied by contralateral hemiparesis or hemisensory loss (ie, crossed signs). It would not explain weeks of headaches and personality changes.
(Choice C) Lesions in the nondominant (ie, right hemisphere in a right-handed patient) parietal lobe affect nonverbal spatial mapping and orientation, causing neglect and/or distortions in position sense (eg, feeling of floating) or visual interpretation (eg, object size). Lesions in the dominant parietal lobe cause Gerstmann syndrome, characterized by difficulties with writing, performing calculations, distinguishing fingers, and left-right disorientation.
(Choice D) Mesial temporal (ie, hippocampal) lobe sclerosis is the most common cause of focal epilepsy, which can subsequently generalize. However, seizures due to temporal lobe epilepsy are often preceded by a distinct aura (eg, epigastric uneasiness, olfactory hallucinations) rather than subacute personality changes. Signs of increased ICP would also be unexpected.
Educational objective:
Headaches, increased intracranial pressure, and an unprovoked first seizure are concerning for a brain tumor. Frontal lobe tumors may cause personality changes, abulia, and anhedonia.