Differential Diagnosis
- The patient's symptoms of progressive weakness on one side, facial weakness, slurred speech, and visual disturbances suggest a lesion in the brain, likely in the left hemisphere given the right-sided symptoms.
Single Most Likely Diagnosis
- Cerebral tumor (e.g., metastasis from breast cancer): The patient's past history of breast cancer and the gradual onset of focal neurological deficits over one week are highly suggestive of a metastatic brain tumor. The combination of right-sided weakness, facial weakness, homonymous hemianopia, and difficulty with naming objects (anomia) points towards a lesion in the left hemisphere of the brain, which could be a metastasis given her history.
Other Likely Diagnoses
- Ischemic stroke: Although the onset over a week is less typical for a stroke, which usually presents acutely, stroke should always be considered in the differential diagnosis for sudden or progressive focal neurological deficits. The presence of brisk reflexes and an upgoing plantar response on the right side supports an upper motor neuron lesion, consistent with a stroke.
- Glioma or other primary brain tumors: These could present similarly to metastatic disease with progressive focal neurological deficits, though typically over a longer timeframe.
Do Not Miss Diagnoses
- Cervical spine injury or disease (e.g., cervical spine tumor, infection): Although less likely given the specific pattern of deficits, a high cervical spine lesion could potentially cause similar symptoms, including weakness and reflex changes. Missing such a diagnosis could lead to significant morbidity or mortality.
- Infectious or inflammatory conditions (e.g., brain abscess, encephalomacia): These could present with focal neurological signs and are critical to identify as they require urgent treatment.
Rare Diagnoses
- Multiple sclerosis (MS): Although MS can present with a wide range of neurological symptoms, the specific pattern of progressive unilateral weakness, facial weakness, and visual disturbances over a short period is less typical. MS usually presents with relapsing-remitting episodes of neurological dysfunction.
- Vascular malformations or moyamoya disease: These conditions could potentially cause progressive neurological deficits due to ischemia or hemorrhage but are less common and might not fit as well with the patient's history and specific pattern of deficits.
Differentiating Upper from Lower Motor Neuron Facial Palsy
- Upper motor neuron (UMN) facial palsy involves the upper part of the facial nucleus or its motor pathway and typically spares the forehead due to bilateral innervation of the frontalis muscle. It is characterized by a mild weakness, often without significant impairment of facial movements.
- Lower motor neuron (LMN) facial palsy involves the lower part of the facial nucleus or the facial nerve itself and affects all muscles of facial expression on the same side, including the forehead. It results in a more pronounced weakness or paralysis of the face.
Gerstmann Syndrome
- Gerstmann syndrome is a neurological disorder characterized by a constellation of symptoms including:
- Agraphia (inability to write)
- Alexia (inability to read)
- Acalculia (inability to perform mathematical calculations)
- Finger agnosia (difficulty identifying fingers)
- Right-left disorientation
- It is typically associated with lesions in the dominant (usually left) parietal lobe of the brain. While the patient's difficulty naming objects (anomia) and the presence of a right homonymous hemianopia might suggest a left hemisphere lesion, the full syndrome of Gerstmann is not clearly present in this case.