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Osteonecrosis, Osteosclerosis/Hyperostosis, and Other Disorders of Bone

Osteonecrosis Definition Osteonecrosis (aseptic, avascular, or ischemic necrosis of bone) refers to skeletal infarction. Bone infarcts may be asymptomatic, cause self-limited discomfort, or engender painful collapse of subarticular bone and resulting joint destruction. Epidemiology and Pathobiology Many conditions are associated with osteonecrosis ( Table 229-1 ). In adults, the most common causes are prior hip fracture, osteomyelitis ( Chapter 251 ), renal dialysis ( Chapter 117…

Paget Disease of Bone

Definition Paget disease of bone is a focal disorder of the skeleton characterized by increased and disorganized bone remodeling. Affected bones enlarge, become deformed, and are at increased risk for pathologic fractures. Epidemiology The prevalence of Paget disease is about 0.5% in the United Kingdom and United States. It also occurs in Western Europe and in people of European descent who have migrated to other parts…

The Parathyroid Glands, Hypercalcemia, and Hypocalcemia

Calcium Metabolism A healthy adult body has a total of 1 kg of calcium, about 99% of which is within the crystal structure of bone mineral and less than 1% of which is in soluble form in the extracellular and intracellular fluid compartments. In the extracellular fluid compartment, about half of the total calcium is ionized, and the remainder is principally bound to albumin or complexed…

Osteomalacia and Rickets

Definition Rickets can no longer be considered a historical disorder limited to third world countries or poor people. The COVID-19 pandemic and the loss of school dairy products in the United States has increased malnutrition and vitamin D deficiency. The primary function of vitamin D is to provide adequate levels of calcium and phosphorus by increasing their intestinal absorption, thereby making them available for normal mineralization…

Osteoporosis

Definition Osteoporosis is defined as a skeletal disorder that is characterized by compromised bone strength and that predisposes to an increased risk for fracture. The pertinent clinical outcomes of this disease include fractures, bone pain, loss of height, and physical deformity. The concept of bone strength is central to understanding the disorder because patients who suffer an osteoporotic or fragility fracture may or may not have…

Intimate Partner Violence

Definition Intimate partner violence is defined as any behavior that is within an intimate relationship or ex-relationship and that causes physical, psychological, or sexual harm. Such behaviors can include physical aggression, such as hitting, kicking, and beating; psychological violence, such as intimidation or constant humiliation; various controlling behaviors, such as isolation from family and friends, monitoring movements, financial control, and restricting access to services; and sexual…

Menopause

Definition Menopause is defined as the permanent cessation of menses and is the culmination of a process of reproductive aging that typically occurs in the fifth to sixth decades of life, with a median age of 52.5 years. Epidemiology Menopause is a universal phenomenon among women, and its lived experience varies by individual. The advent of menopause and the coincident loss of gonadal steroids significantly affect…

Chronic Respiratory Insufficiency

Chronic Respiratory Failure and Long-Term Mechanical Ventilation Denise M. Goodman Steven O. Lestrud Epidemiology There are continual improvements in invasive (ventilation through a tracheostomy) and noninvasive (mask ventilation) devices and management to care for those conditions predisposing to the need for chronic ventilation, such as acute respiratory failure, prematurity, and neuromuscular disease. Although difficult to determine the prevalence of chronic ventilation, estimates range from approximately 4 to 6/100,000…

Skeletal Diseases Influencing Pulmonary Function

Pulmonary function is influenced by the structure of the chest wall (see Chapter 400 ). Chest wall abnormalities can lead to restrictive or obstructive pulmonary disease, impaired respiratory muscle strength, and decreased ventilatory performance in response to physical stress. The congenital chest wall deformities include pectus excavatum, pectus carinatum, sternal clefts, Poland syndrome , and skeletal and cartilage dysplasias . Vertebral anomalies such as kyphoscoliosis can…

Bronchopulmonary Dysplasia

Bronchopulmonary Dysplasia Bronchopulmonary dysplasia (BPD) is a chronic lung disease of infancy and childhood that occurs primarily in preterm infants born at less than 32 wk gestation. BPD is characterized by alveolar hypoplasia, often with concomitant small airway dysfunction and impaired pulmonary vascular growth. Contributing factors to the development of BPD may include early gestational age, low birth weight, lung barotrauma, exposure to hyperoxia, lung inflammation, and…

Chylothorax

Chylothorax is a pleural collection of fluid formed by the escape of chyle from the thoracic duct or lymphatics into the thoracic cavity. Etiology Chylothorax in children occurs most frequently because of thoracic duct injury as a complication of cardiothoracic surgery (post Fontan surgery) ( Fig. 443.1 ). Other cases are associated with chest injury ( Fig. 443.2 ), extracorporeal membrane oxygenation, or with primary or…

Hemothorax

Hemothorax, an accumulation of blood in the pleural cavity, is rare in children. Etiology Bleeding into the chest cavity most commonly occurs after chest trauma, either blunt or penetrating. It can be the result of iatrogenic trauma, including surgical procedures and venous line insertion. Hemothorax can also result from erosion of a blood vessel in association with inflammatory processes such as tuberculosis and empyema. It may…

Hydrothorax

Hydrothorax is a transudative pleural effusion; typically, it is caused by abnormal pressure gradients in the lung. Etiology Hydrothorax is most often associated with cardiac, renal, or hepatic disease. It can also be a manifestation of severe nutritional edema and hypoalbuminemia. Rarely, it results from superior vena cava obstruction by neoplasms, enlarged lymph nodes, pulmonary embolism, or adhesions. It may occur from a ventriculoperitoneal shunt, central…

Pneumomediastinum

Air or gas in the mediastinum is called pneumomediastinum. Etiology Pneumomediastinum is typically caused by alveolar rupture which can be due to either a spontaneous or traumatic cause. A spontaneous pneumomediastinum can either be primary without an underlying etiology or can occur secondary to an underlying cause. Primary pneumomediastinum can be due to increases in intrathoracic pressure as is seen with a Valsalva maneuver, vomiting, Boerhaave…

Pneumothorax

Pneumothorax is the accumulation of extrapulmonary air within the chest, most commonly from leakage of air from within the lung. Air leaks can be primary or secondary and can be spontaneous, traumatic, iatrogenic, or catamenial ( Table 439.1 ). Pneumothorax in the neonatal period is also discussed in Chapter 122.1 . Table 439.1 Causes of Pneumothorax in Children Adapted from Noppen M. Spontaneous pneumothorax:epidemiology, pathophysiology and…

Atelectasis

Atelectasis is the incomplete expansion or complete collapse of air-bearing tissue, resulting from obstruction of air intake into the alveolar sacs. Segmental, lobar, or whole lung collapse is associated with the absorption of air contained in the alveoli, which are no longer ventilated. Pathophysiology The causes of atelectasis can be divided into 5 groups ( Table 437.1 ). Respiratory syncytial virus (see Chapter 287 ) and…

Pulmonary Embolism, Infarction, and Hemorrhage

Pulmonary Embolus and Infarction Mary A. Nevin Keywords pulmonary hemorrhage pulmonary embolism deep venous thrombosis air embolism thrombophilia partial thromboplastin time hemosiderin bronchoalveolar lavage acute idiopathic pulmonary hemorrhage of infancy (AIPHI) Venous thromboembolic disease (VTE) has become an increasingly recognized critical problem in children and adolescents with chronic disease, as well as in patients without identifiable risk factors ( Table 436.1 ). Improvements in survival with chronic…

Pulmonary Hemosiderosis

Pulmonary hemorrhage may be characterized as focal or diffuse based on the location(s) of bleeding. A detailed review of pulmonary hemorrhage is in Chapter 436.2 . The diagnosis of pulmonary hemosiderosis refers to the subset of patients with diffuse alveolar hemorrhage (DAH) . Bleeding in DAH occurs as a result of injury to the microvasculature of the lung and may be slow and insidious due to…