methimazole and Ischemia

A 62-year-old woman with a history of partially treated Graves disease and hypertension presented with approximately 3 weeks of worsening fatigue, lower extremity myalgias, and shortness of breath. Her medical history included a thyroid radiofrequency ablation several years earlier. Following the ablation, she was found to have some residual thyroid activity, negating the need for therapy. She was lost to follow-up after months of normal thyroid-stimulating hormone values. On this presentation, the patient was noted to be in atrial fibrillation with a rapid ventricular rate, and although she presented alert and oriented initially, she developed progressive inattentiveness and confusion while in the ED. The patient was transferred to the medical ICU for further management of her rapid heart rate and progressive delirium.

Topics: Anti-Arrhythmia Agents; Anti-Inflammatory Agents; Anticoagulants; Antithyroid Agents; Atrial Fibrillation; Delirium; Disseminated Intravascular Coagulation; Dyspnea; Fatal Outcome; Fatigue; Female; Femoral Artery; Graves Disease; Heparin; Humans; Hydrocortisone; Ischemia; Lower Extremity; Methimazole; Middle Aged; Myalgia; Pneumoperitoneum; Popliteal Artery; Potassium Iodide; Propranolol; Radiofrequency Ablation; Thrombosis; Thyroid Crisis; Tibial Arteries; Venous Thrombosis

The protective effect of hypothyroidism against ischemic or toxic conditions has been shown in various tissues. We investigated the effect of propylthiouracil (PTU)/methimazole (MMI)-induced hypothyroidism and acute local effect of MMI on the outcome of lethal ischemia in random-pattern skin flaps.. Dorsal flaps with caudal pedicles were elevated at midline and flap survival was measured at the seventh day after surgery. The first group, as control, received 1 mL of 0.9% saline solution in the flap before flap elevation. In groups 2 and 3, hypothyroidism was induced by administration of either PTU 0.05% or MMI 0.04% in drinking water. The next four groups received local injections of MMI (10, 20, 50, or 100 μg/flap) before flap elevation. Local PTU injection was ignored due to insolubility of the agent.. Hypothyroidism was induced in chronic PTU- and MMI-treated groups, and animals in these groups showed significant increase in their flap survival, compared to control euthyroid rats (79.47% ± 10.49% and 75.48% ± 12.93% versus 52.26% ± 5.75%, respectively, P < 0.01). Acute local treatment of skin flaps with MMI failed to significantly affect the flap survival.. This study demonstrates for the first time that hypothyroidism improves survival of random-pattern skin flaps in rats.

Topics: Animals; Antithyroid Agents; Dermatologic Surgical Procedures; Disease Models, Animal; Hypothyroidism; Ischemia; Male; Methimazole; Plastic Surgery Procedures; Propylthiouracil; Rats; Rats, Sprague-Dawley; Skin; Surgical Flaps; Thyroid Gland

Hindlimb ischemia for 4 h, followed by reperfusion, resulted in necrosis of most soleus muscle in euthyroid rats, whereas only slight damage occurred in hypothyroid rats. Muscle repair after transection of the tibialis anterior muscle of hypothyroid rats showed delayed debris removal, initial retardation of myotube formation, and a higher incidence of aberrant sarcomeres in newly formed muscle fibers by electron microscopy. The protective mechanism against ischemia in hypothyroid muscles can probably be attributed to decreased degradation of high-energy phosphates, reduced formation of substrates for xanthine oxidase during ischemia, and attenuated generation of harmful oxygen free radicals during reperfusion. Initial delay of myotube formation seems to reflect retarded proliferation of muscle precursor cells. Prolonged occurrence of aberrant sarcomeres in hypothyroidism is perhaps due to a delay or imbalance in the synthesis of proteins that assemble sarcomeres. These findings demonstrate the significant roles of thyroid hormones in ischemic injury and muscle repair.

Topics: Animals; Antithyroid Agents; Body Weight; Hindlimb; Hypothyroidism; Ischemia; Male; Methimazole; Microscopy, Electron; Muscle Fibers, Skeletal; Muscle, Skeletal; Rats; Rats, Wistar; Regeneration; Thyroid Gland; Wound Healing

We present a case of a 40-years-old woman with an acute posterior multifocal placoid pigment epitheliopathy (APMPPE) associated with recent instauration hyperthyroidism symptoms. A Graves' disease was diagnosed and the patient was initially controlled with antithyroid drugs. The epitheliopathy evolution was relatively favourable without relapse. Two years later a thyroidectomy was performed.. We have not found in the literature any APMPPE case associated with Graves' disease. We only found an APMPPE case associated with a subacute thyroiditis. Little is known about the APMPPE causes, it could be that placoid epitheliopathy and Graves' disease had a common autoimmune origin. We can not forget that our finding could be only a matter of chance.

Topics: Acute Disease; Adult; Antithyroid Agents; Choroid; Combined Modality Therapy; Female; Fluorescein Angiography; Graves Disease; Hormone Replacement Therapy; Humans; Ischemia; Methimazole; Pigment Epithelium of Eye; Radiography; Retinal Diseases; Thyroidectomy; Thyroiditis, Subacute; Thyroxine

Selective thromboxane inhibitors were evaluated as a pharmacological agent in the prevention of progressive dermal ischemia after burning. Standardized partial-thickness burns were inflicted on guinea pigs. Burned guinea pigs were separated into four groups: one served as a control, one was treated with Imidazole, one with dipyridamole, and the other with methimazole. Histology and depth of dermal perfusion were evaluated by the India ink perfusion technique. Untreated controls showed progressive dermal ischemia with complete absence of India ink-filled vessels in the dermis by 24 hours. Imidazole, dipyridamole, and methimazole improved dermal perfusion as suggested by relative levels of India Ink filling. Preservation of dermal appendages was seen secondarily to improved dermal microcirculation with an eight-fold increase in hair follicles in treated guinea pigs compared with controls. This study suggest that thromboxane plays a role in progressive dermal ischemia. Selective inhibition of thromboxane avoids the side effects associated with complete suppression of the metabolism of arachidonic acid.

Topics: Animals; Burns; Dipyridamole; Female; Guinea Pigs; Heterocyclic Compounds; Imidazoles; Ischemia; Methimazole; Microcirculation; Skin; Thromboxanes