A 40 year-old woman presents with onset of shortness of breath and lower extremity weakness for one week. On the morning of her presentation, she was unable to stand up and was experiencing difficulty breathing upon waking up. She denies chest pain, dyspnea on exertion, orthopnea, diaphoresis, fever and chills. She previously presented a few months ago with loss of vision in her left eye and diminished vision on her right. Her past medical history is significant for end stage renal disease on peritoneal dialysis. Physical exam was significant for loss of light sensation on the left eye and 20/800 on the right. Additionally, horizontal nystagmus was present during right and upward gaze. Her motor and sensory exams on the upper extremities were normal, but in the lower extremities she scored 1/5 for left and right hip flexion and 1/5 for pain stimuli. Reflexes were 0 for patellar and Achilles tendons bilaterally. Her head CT ruled out any acute vascular changes or CVA. MRI revealed small lesions in the subcortical region of frontal lube, a new tumefactive lesion in the right centrum semiovale, and worsening demyelination in the Pons suggestive of NMO. Bedside punch biopsies of her skin vesicles were Tzanck smear positive with multinucleate giant cells. Her constellation of symptoms combined with lesions and demyelination pattern seen on imaging was suggestive of neuromyelitis optica (NMO). NMO- antibody returned positive. She was admitted to the ICU for 1-hour neurologic and 4-hour negative inspiratory force (NIF) checks. She was started on high dose IV steroids, IV ganciclovir and plasma exchange.
Hospitalists frequently encounter neurologic complaints such as lower extremity weakness. A methodical approach to the causes of extremity weakness is important in identifying the less common causes of these symptoms. Recognition of demyelinating disease requires good history gathering, a systematic physical exam and appropriate imaging.
Neuromyelitis optica is an autoimmune, demyelinating disease of the nervous system. Patients who suffer from this disease form IgG autoantibodies against aquaporin channels (AQP4) of the astrocytes causing rapid demyelination of neurons. However, this demyelination is specific to optic and spinal nerves. Patients usually present with visual changes, shortness of breath and upper or lower extremity symptoms. The severity of the symptoms depends on the extent of demyelination. Viruses, namely HSV, VZV and EBV, can cause acute NMO flare-ups.
NMO and MS are both autoimmune nervous system disorders, which attack myelin yet the pathophysiology of these diseases is different. MS is T-cell mediated, whereas NMO is IgG mediated. Treatment recommendations are primarily reached from data obtained from observational studies and from experience of experts of this field. For acute attacks and relapses of NMO, recommended treatment is with high-dose intravenous steroids for three to five consecutive days. For patients suffering from severe symptoms, plasma exchange is recommended with high dose IV steroids. Patients with NMO have poor prognosis with high rates of long-term disability and mortality, mostly secondary to neurogenic respiratory failure. The natural history is that of stepwise decline due to visual, sensory and motor deficits.
NMO is a demyelinating disease that specifically attacks the optic and spinal nerves. Treatment with IV steroids and/or plasma exchange is indicated in acute flares to decrease morbidity and mortality from the disease.
To cite this abstract:Huq T, Mohiuddin A. Distinguishing Diagnoses to Determine the Deficit. Abstract published at Hospital Medicine 2016, March 6-9, San Diego, Calif. Abstract 565. Journal of Hospital Medicine. 2016; 11 (suppl 1). https://www.shmabstracts.com/abstract/distinguishing-diagnoses-to-determine-the-deficit/. Accessed February 25, 2020.