Thyrotoxic burden in the ICU and the value of bedside thyroid ultrasound in the diagnosis of thyrotoxicosis and thyrotoxic cardiac emergencies in critically-ill patients

BackgroundThyrotoxicois is not uncommonly suspected in many ICU patients. There are many clinical and laboratory fallacies that may hinder the rapid diagnosis of thyrotoxicosis in ICU patients especially those presenting with cardiac emergencies.AimFirst, to estimate the thyrotoxic burden in the ICU. Second, to assess the usefulness of thyroid ultrasound in early evaluation of suspected thyroid disease in critically ill patients especially those with life threatening cardiac emergencies.Patients and methods854 patients admitted in 2 general intensive care units from Jan to November 2011 were evaluated. All patients suspected to have thyrotoxicosis were assessed by thyroid ultrasound and by measurement of serum levels of Ft3,Ft4,TSH, echocardiography and continuous ECG monitoring. Radioisotope scanning was done in selected cases.ResultsOut of 854 admitted patients, 113 (13.2%) were suspected to have thyrotoxicosis. Thyrotoxicosis was proved in 28 patients (24.7% of suspected cases and 3.3% of all admitted cases): 15% of all suspected cases had Graves’ disease and 9.7% had toxic nodules. Most diagnosed patients (No: 16, 59.3%) had masked thyrotoxicosis. Seventy-six patients (67.3% of suspected patients) were admitted as critically ill cardiac patients and presented mainly by cardiac arrhythmias, heart failure, acute chest pain and malignant hypertension and 21 of these patients (27.6%) were proved to be thyrotoxic.ConclusionThyrotoxicosis and thyrotoxic cardiac emergencies are not uncommon in the ICU and should be thoroughly investigated as most cases are clinically masked. Thyroid ultrasound is a feasible, rapid and accurate bedside diagnostic tool for suspected thyrotoxic emergencies in ICU.