A 52year yearold Caucasian female presented with history of wide based ataxic gait for four days. Head CT showed possible pontine stroke, however the MRI was interpreted as normal. Patient denied any dyspnea with pulse oxygenation of 79% and ABG revealed pH of 7.33, CO2 of 53, and HCO3 of 31. Her medical history included diabetes mellitus, hypothyroidism, pneumonia, hyperlipidemia, obstructive sleep apnea, multiple falls, cataract surgery, uvulopalatopharyngoplasty, and thyroidectomy. Family history was significant for CAD. Physical exam was remarkable for hypoxemia, hyporeflexia in all extremities, temporal wasting, mild frontal balding, and mild bilateral ptosis. Her labs were normal except for ABG. A chest xray showed a right hemidiaphragm elevation with markedly reduced lung volumes. Chest fluoroscopy showed bilateral minimal excursion of the diaphragm, and pulmonary function testing demonstrated reduced vital capacity at 34%. Neurology was consulted for evaluation of the bilateral diaphragm paralysis. Neck MRI was negative. Further questioning revealed family history of the recurrent falls, progressive weakness and ptosis of unknown etiology in siblings. Her myotonic reflex at both thumb pads and grip release test were positive. This warranted further work up for possible Myotonic Dystrophy(DM. EMG revealed widespread myotonic discharges, with prominence in the distal muscles consistent with DM. Subsequently genetic testing confirmed Myotonic Dystrophy Type I (DM1) with a full expansion size repeat of 695. Discussion: DM1 is an autosomal dominant inherited disorder due to an expansion of a trinuclotide (CTG) repeat on chromosome 19q13.3 with a prevalence of one in 8,000. It is a multisystem disorder that affects vision (cataracts), respiratory (chronic hypoxemia and hypercapnia due to diaphragmatic weakness, sleep apnea, aspiration) endocrine (diabetes, hypothyroid) cardiovascular (conduction disorders, cardiomyopathy) gastrointestinal (dysphagia, IBS, chronic infections) musculoskeletal (weakness, atrophy) and reproductive (uterine weakness, low testosterone levels) organ systems. Most patients present between 15 and 35 years of age. Genetic testing for the presence of CTG expansion repeat is a diagnostic gold standard, and EMG is helpful as an initial test. Presently, there are no disease modifying therapies for DM1 and treatment is symptomatic. Genetic counseling is crucial. Periodic respiratory function and cardiac assessments are recommended in clinical follow up as a complication preventive measure along with physical therapy.
This case demonstrates a rare etiology of a relatively common presenting problem in hospitalized patients. It also emphasizes the importance of a detailed history and physical exam. Early recognition of the disease creates an opportunity for preventive follow up and family genetic counseling.
To cite this abstract:Romano A, Kirillova L. Chronic Hypoxemia with Ataxic Gait. Abstract published at Hospital Medicine 2012, April 1-4, San Diego, Calif. Abstract 97767. Journal of Hospital Medicine. 2012; 7 (suppl 2). https://www.shmabstracts.com/abstract/chronic-hypoxemia-with-ataxic-gait/. Accessed March 31, 2020.