Thyroid Symptomatology across the Spectrum of Hypothyroidism and Impact of Levothyroxine Supplementation in Patients with Severe Primary Hypothyroidism.

This study aimed to determine the clinical and biochemical profile of patients with severe primary hypothyroidism (SPH) (TSH ≥40 μIU/ml) as compared to milder forms of hypothyroidism and document improvement in hypothyroidism symptoms in SPH.Thyroid symptomatology and biochemistry were evaluated in SPH, non-severe overt primary hypothyroidism (NSOPH; TSH <40 μIU/ml), subclinical hypothyroidism (ScH) and healthy controls. A total of 598 consecutive patients of hypothyroidism were screened of which 461 patients' data were analyzed (91 SPH, 130 NSOPH and 240 ScH). Thyroid symptomatology was re-evaluated at 12 weeks follow-up in SPH following restoration of euthyroidism with levothyroxine.The median (interquartile range) age of patients was 35 (28-42) years with 91.6% female. The commonly noted symptomatology were shortness of breath (93.4%) and fatigueability (91.2%) in SPH, fatigueability (68.46%) and limbs swelling (43.07%) in NSOPH, and fatigueability (56.67%) and shortness of breath (32.92%) in ScH. All symptomatology were significantly higher in SPH. Delayed tendon reflex, carpel tunnel syndrome and meno-metrorrhagia were exclusive in SPH. Occurrence of menstrual irregularities was 73.62%, 28.46% and 16.25% in SPH, NSOPH and ScH, respectively. SPH patients had significantly higher cholesterol and triglycerides. There was significant improvement in symptomatology, reduction in body weight (-2.11 kg), improvement in hemoglobin (+0.64 g/L) with fall in total cholesterol (-18.96%), LDL-cholesterol (-23.46%) and triglycerides (-13.53%) following euthyroidism restoration in subjects with SPH. Common residual symptoms were fatigue (10%), poor memory (8%) and menstrual irregularities (6%).Thyroid symptomatology differs significantly across spectrum of hypothyroidism, being significantly worse in SPH. Euthyroidism restoration is associated with reversal of majority of thyroid symptomatology.