Case Presentation: A 20-year-old Caucasian male presents to the emergency department (ED) with acute onset of right leg weakness and lower back pain. Apart from two prior visits to the ED for atypical chest pain and mild traumatic right foot pain, his past medical history is unremarkable, and no other neurological symptoms are revealed. There are no preceding flu-like symptoms, vaccination, illicit drug use, or trauma. Examination in the ED shows complete inability to move the right leg. Initial labs show no abnormalities and Lumbar spine MRI shows mild degenerative changes. Consultation with neurology over the phone suggests that it is possibly conversion disorder, ED physician concurs, but the patient was admitted for observation. Upon admission, further detailed neurological examination by the admitting hospitalist confirms motor power of 0/5 in the right leg but also reveals a sensory level below the umbilicus and hyperesthesia below the knees bilaterally. The admitting hospitalist also performs Hoover test on both legs: Both heels are lifted off the bed; when the patient was asked to flex the left “normal” leg against resistance with the knee extended, no downward extension movement is felt in the heel of the right “weak” leg; when he was asked to extend the right “weak” leg he cannot do that but a downward extension movement was felt on the left heel. This exam finding suggests organic, rather than psychogenic, cause of the weakness, and together with the sensory level below umbilicus (suggesting thoracic, rather than lumbar, pathology) the differential diagnosis is broadened to consider transverse myelitis, neuromyelitis optica, multiple sclerosis, and acute demyelinating myelitis among others. MRI with and without contrast of the Thoracic spine is ordered and it shows focal abnormalities in the cord at the level of T11. Lumbar tap shows elevated protein and WBC count. After consultation with neurology he was treated empirically with pulse steroids with some improvement. He was discharged with outpatient physical therapy and follow-up with primary care and neurology.
Discussion: With the growing concern of declining physical examination skills, it is important to perform careful neurologic examination in patients suspected to have functional symptoms. Charles Hoover, American physician, described the “Hoover sign” in 1908. The basis of the exam relies on the crossed extensor reflex where a patient cannot flex one extremity without the extension of the other, a normal physiologic phenomenon in the absence of organic disease. This exam is a useful tool to support a diagnosis of functional weakness (specificity approaches 100%) but does not differentiate conversion from malingering, nor does it alienate from a combination of organic and functional weakness. Pain can also interfere with this exam as pain can cause greater force of flexion/extension than baseline and can be interpreted as an increased effort to aid movement. Patients also could be consciously reluctant to move painful leg as well. There is also concern of manipulation of the exam by patients to make physicians believe that there is a significant deficit. Sensory level also should raise concern for corresponding spinal cord disease and can be helpful to determine where the pathology is.
Conclusions: Careful physical exam is invaluable in excluding organic causes of symptoms thought to be functional. Neurological exam is also crucial to try to localize where the pathology is to guide investigations and determine the type of imaging studies to order.
