The musculoskeletal manifestations started simultaneously with the first symptoms of hypothyroidism, and disappeared with L-thyroxine administration [1]. The musculoskeletal manifestations are muscle pain and stiffness, arthralgia, synovial thickening with effusion, hypothyroid myopathy, acroparesthesia and carpal tunnel syndrome.

The muscle manifestations in hypothyroidism are proximal weakness, fatigue, slowed movements and reflexes, stiffness, myalgia, and less commonly, cramps and muscle enlargement. The muscle manifestations can occur at any time in hypothyroidism which can be replaced by thyroid hormone replacement therapy [2].

Arthropathy in hypothyroidism is non-inflammatory arthralgia, stiffness and arthritis. Arthritis is non-inflammatory, highly viscous joint effusions primarily affecting the knees, wrists and hands. The symptoms may mimic rheumatoid arthritis. Arthropathy can be treated with thyroid hormone replacement therapy [3]. Adhesive capsulitis, also known as frozen shoulder, is a regional skeletal problem reported in association with thyroid disorders.

Neuropathy of hypothyroidism includes carpal tunnel syndrome, and thyroid abnormalities are generally sought in patients with this syndrome, may be occur before clinical hypothyroidism is apparent, thyroid replacement is complete relief of neuropathy, thus avoiding surgery [4].

Hypothyroidism can be confused with fibromyalgia; the estimated incidence of hypothyroidism in FMS is higher than in the general public [5].

Patients with rheumatic diseases, such as rheumatoid arthritis or systemic lupus erythematosus, may have an increased association with hypothyroidism on an autoimmune basis. Patients with connective tissue diseases suffering with increasing fatigue in the absence of increased inflammation should have their thyroid function checked [6]. Our purpose was clinical assessment the effect of L-thyroxine therapy on musculoskeletal symptoms.

The study was conducted on 7^th October 2011 at University Hospital till October 2012. Follow up study, which included patients diagnosed with hypothyroidism and musculoskeletal symptoms. They were interviewed with a structured questionnaire about their past and current musculoskeletal complaints, who visited the outpatient clinic of rheumatology, follow-up assessment 3 and 12 months from baseline. The data are analyzed statistically. The correlation between recovery musculoskeletal symptoms on L-thyroxine therapy and various variables factor in hypothyroidism the effect on musculoskeletal symptoms. It was calculated by Pearson's correlation coefficient and its statistical significance was defined as p<0.05.

Seventy-five patients diagnosed with hypothyroidism were included in the study. Patients’ clinical characteristics are shown below (Table 1). The age of the study patients ranged from 20-85 years, M=30 ± 55 years. 68 (90.7%) were females and Duration of the disease ranged from 4 months-25 years (mean M=12 ± 13years). The frequencies of co-morbid conditions in the study patients were as follow: diabetes mellitus (DM) (16%), hypertension (HTN) (13.3%), Obesity (BMI ≥ 30 kg/m²) (46.7%), cardiovascular disease (2.7%) and chronic renal failure (CRF) (2.7%) the musculoskeletal of hypothyroidism, most patients had arthralgia (72%), carpal tunnel syndrome (61.3%), frozen shoulder (37.3%), myalgia (36%), myopathy (12%) and arthritis (10.6%) the connective tissue disease association with hypothyroidism, patients had rheumatoid arthritis (14.7%), osteoarthritis (17.3%), fibromyalgia (13.3%) and systemic lupus erythematosus (2.7%). The management of musculoskeletal symptoms patients were start l-thyroxine therapy (33.3%), patients were on same dose of l thyroxine (20%), patients were increase dose of l-thyroxine (46.7%). The patients were use nonsteroidal anti-inflammatory drugs (49.3%), patients were do physiotherapy (38.7%) and patients were under go reduction of weight (25.9%). It disappeared musculoskeletal symptoms on follow-up was (66.7%), where unrecovered musculoskeletal symptoms (33.3%). We demonstrated (Figure 1 and Table 2) a significant positive stronger correlation between recovery musculoskeletal symptoms of hypothyroidism and various variable factors like age, duration of hypothyroidism disease, co morbidity diseases and level TSH.

Table 1: Patients’ clinical characteristics, co-morbidities, musculoskeletal symptoms, and concomitant medications.

Table 2: Correlation between recovery musculoskeltal symptoms on Lthyroxine therapy and variable factors that effect on recovery musculoskeltal symptoms in hypothyroidism.

Figure 1: Response of musculoskeletal symptoms with L-thyroxine therapy.

Recently it has been accepted that patients with hypothyroidism may show a variety of musculoskeletal symptoms well before the obvious features of hypothyroidism have appeared [7]. Higher prevalence arthropathy and carpal tunnel syndrome in our study can be attributed to high BMI (body mass index) observed and comorbid disease like Diabetes mellitus in our study population. In our study there is agreement with previous studies, we found the recovery or disappearance of musculoskeletal symptoms with L thyroxine therapy on follow-up (66.7%). They reached complete response between 6 to 9 months [8,9].

We observed increase response with age of patients less than 60 years old, duration of hypothyroidism less than 5 years, musculoskeletal symptoms less than 2 years, no comorbidity disease like diabetes mellitus, obesity, control level TSH and physiotherapy.

A follow-up study for these rheumatic manifestations will be better; it was improved by L-thyroxine treatment, reach complete response between 6 to 9 months, statistical significance strong relation between the recovery musculoskeletal symptoms with L-thyroxine therapy.

The variable factors that effect on recovery musculoskeletal symptoms in hypothyroidism like age, duration of hypothyroidism and musculoskeletal symptoms, comorbidity disease, and TSH level which were interfering on recovery musculoskeletal symptoms in hypothyroidism.