Individuals with talcosis may be asymptomatic and have typically injected thousands of tablets (as many as an estimated 280,000), usually from an average daily use of about 15 to 40 pills over several years. When pulmonary talcosis produces symptoms, the most common complaints are exertional dyspnea and a dry or productive cough. Some patients have substantial weight loss, and fever is occasionally present. Spontaneous pneumothorax may occur, especially as the disease progresses, when chronic respiratory failure, pulmonary hypertension, and cor pulmonale can also develop. Physical examination of the thorax is usually normal, but crackles may be audible, and breath sounds often diminish as emphysema supervenes. Pulmonary function tests show obstruction, restriction, or both, and a reduced diffusing capacity is common. When emphysema is present, airflow obstruction is frequently pronounced, causing air trapping and hyperinflation.