Der Internist
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Four types of hereditary haemochromatosis have been identified. Type 1 is due to a point mutation in the HFE gene (C282Y) and leads via an increase in intestinal iron absorption to iron overload and organ damage. Type 2 is a juvenile form with manifestation before age 30; it affects both gender and is associated with severe cardiomyopathy and hypogonadism. ⋯ In contrast to types 1 and 3 iron deposits in type 4 are seen predominantly in macrophages; in type 4 serum ferritin is significantly increased although transferrin saturation is only slightly abnormal. The prognosis of haemochromatosis is normal when phlebotomy therapy is started prior to manifestation of cirrhosis or diabetes. Screening strategies should be implemented to improve early detection.
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Corresponding to the two compartments of the respiratory system (lungs and ventilatory pump), two different forms of respiratory insufficiency can be distinguished on a pathophysiologic basis: disturbances of gas exchange with primary oxygenation failure (hypoxemia) due to pulmonary diseases and reduced ventilation of the lungs (hypoventilation) with primary elevated arterial carbon dioxide partial pressure (hypercapnia) and secondary hypoxemia due to disorders of the ventilatory pump. Different methods can be employed in the diagnosis of respiratory insufficiency, e.g., spirometry, blood gas analysis, nocturnal monitoring with capnography, or transcutaneous pCO2 registration and measurement of mouth occluding pressure. ⋯ The indication for long term ventilation depends on subjective complaints, objective measurement parameters, disease course, and other disease symptoms. The most frequent indications for home mechanical ventilation are diseases with restrictive ventilatory defects, especially chest wall disorders and neuromuscular disorders.