A 26-year-old woman with no past medical history presents to the emergency department (ED) with several days of fatigue, difficulty climbing stairs, and double vision. She has one-word dyspnea and appears to be using accessory muscles of respiration. Her chest radiograph is normal as are all her initial laboratory studies. She mentions having an upper respiratory infection 1 week ago. She does not take any medications and does not have any recent travel. Vital signs: HR 105 bpm, sinus tachycardia, BP 145/90 mm Hg, RR 30 breaths/min, temperature 37.2°C. Examination: The patient is in moderate respiratory distress and using accessory muscles of respiration. She has no rashes. She is drooling and has difficulty clearing her secretions. Her oropharynx is clear. Her neurologic examination is notable for ptosis, bilateral sixth nerve palsy, bilateral facial weakness, neck flexion 3/5, deltoids 3/5, biceps 3/5, triceps 3/5, wrist extensors and intrinsic hand muscles 5/5, iliopsoas 4+/5, quadriceps 4+/5, hamstrings 5/5, tibialis anterior 5/5, gastrocnemius 5/5. Her sensory examination is normal as are her reflexes.
What is the differential diagnosis for this patient?
Acute bilateral weakness can be due to either a central or peripheral lesion. When approaching such a patient, it is advisable to develop a methodology beginning with brain and spinal cord etiologies and moving peripherally, ruling out possibilities based on examination, imaging, and laboratory findings. The acuity of the presentation, symmetry, and pattern of weakness can be helpful. Generalized fatigue due to cardiopulmonary disease, anemia, malignancy, depression, and fibromyalgia, for example, can overlay objective muscle weakness. Similarly, pain can limit the motor examination. A broad overview of possibilities using the mnemonic VINDICATE is listed in Table 6-1.
Table 6-1.Acute Motor and Sensory Weakness Differential Diagnosis ||Download (.pdf) Table 6-1. Acute Motor and Sensory Weakness Differential Diagnosis
| ||Pure motor findings ||Motor and sensory |
|Vascular ||Bilateral motor strip, centrum semiovale, corona radiata, internal capsule infarction, or hemorrhage; azygous ACA with ACA stroke; subdural hemorrhage; bilateral/central pontine infarctions, hemorrhage; MCA-ACA watershed infarction can cause “man in a barrel” syndrome with proximal arm and proximal leg weakness ||Bilateral cortical or subcortical infarction, hemorrhage; bilateral brainstem infarctions, hemorrhage |
|Infection/Inflammation ||Bilateral motor strip, centrum semi- ovale, corona radiata, or internal capsule abscess, demyelinating disease; bilateral/central pontine abscess, demyelinating disease, basilar meningitis, sarcoid ||Bilateral cortical or subcortical infarctions; bilateral brainstem infarctions, abscess, demyelinating disease, basilar meningitis, sarcoid, rhombencephalitis |
|Neoplasm ||Paramedian/falcine tumor; bilateral motor strip, centrum semiovale, corona radiata, internal capsule or pontine tumor, carcinomatous meningitis ||Bilateral cortical, bilateral subcortical infarctions or brainstem tumor, carcinomatous meningitis |
|Drugs ||Accidental ingestion: carbon monoxide poisoning (globus pallidus injury), methanol poisoning (putaminal injury) || |
|Idiopathic/Iatrogenic ||Seizure with Todd paralysis ||Bickerstaff-Cloake brainstem encephalitis |
|Congenital/genetic ||Alternating hemiplegia of childhood, migraine with hemiplegia, progressive bulbar palsy ||Leukodystrophy |
|Autoimmune || ||Bilateral MS lesions, ADEM, acute hemorrhagic encephalomyelitis, tumefactive MS, ...|