Rare presentation of lower limb weakness, a case report

Abstract

SUMMARY This is a 53 year old male, who was previously healthy, and who presented to a primary care physician, complaining of from chronic back pain. He was seen multiple times with the same problem, which was treated as Myalgia with pain killers only. After a proper approach and investigation he was found to have ALS Amyotrophic lateral sclerosis. BACKGROUND: Lower limb weakness is a common problem in the primary care setting, with a multiple differential diagnosis. It is defined as loss of muscle strength[1]. The physician should firstly isolate and be sure that the complaint of patient is weakness of the muscle , mainly by investigating other causes that may mimic and overlap with the presentation; the famous and most common cause being fatigue[2]. History and physical examination in addition to investigation will assure that the physician will reach the proper diagnosis and management plan but before that knowing the mechanisms of weakness is the corner stone in approach[3,5], which includes[3,4]: Upper motor neurons, Lower motor neurons, Neuromuscular junction, Muscle. In the primary care setting and because of patient flow, usually common is common, which is exactly what happened to the patient, as he visited the center multiple time because of weakness and mild pain which did not attract the attention of the treating physicians to more serious and complicated disease[6,7]. Amyotrophic lateral sclerosis (ALS), commonly called Lou Gehrig’s disease, is a progressive neurodegenerative disease affecting both upper and lower motor neurons. ALS is a condition characterized by weakness, muscle wasting, fasciculations and increased reflexes[1,2]. The annual incidence rate is one to three cases per 100,000. The disease is mostly diagnosed in middle age and affects more men than women [5]. Over a period of months or years, patients with ALS develop severe, progressive muscular weakness and other symptoms caused by loss of function in both upper and lower motor neurons. Mainly it presents with 2 major categories of symptoms: Upper motor neuron, Lower motor neuron [2]. In the patient’s case it was mainly lower motor neuron symptoms without any symptoms of upper motor which makes the presentation unique and confusing with other differential diagnoses. ALS has a bad prognosis and limited options of treatment. Respiratory failure limits survival to 2-5 years after disease onset. RILUZOLE is the only drug that can affect prognosis [1,7,8,9]. Being rare, difficult to treat and with a bad prognosis, makes us want to share this case with our colleagues as the learning opportunity in this case makes it a valuable one for a case report. Key words: lower limb weakness, case report