Medical Blog

Status Asthmaticus

Introduction
Background

Status asthmaticus is a medical emergency in which asthma symptoms are refractory to initial bronchodilator therapy in the emergency department. Patients report chest tightness, rapidly progressive shortness of breath, dry cough, and wheezing. Typically, patients present a few days after the onset of a viral respiratory illness, following exposure to a potent allergen or irritant, or after exercise in a cold environment. Frequently, patients have underused or have been underprescribed anti-inflammatory therapy. Illicit drug use may play a role in poor adherence to anti-inflammatory therapy. Patients may have increased their beta-agonist intake (either inhaled or nebulized) to as often as every few minutes. Read more…

Histoplasmosis

Introduction
Background

Histoplasma capsulatum is a dimorphic fungus that remains in a mycelial form at ambient temperatures and grows as yeast at body temperature in mammals. Although the fungus can be found in temperate climates throughout the world, it is endemic to the Ohio, Missouri, and Mississippi River valleys in the United States. Internationally, the fungus is predominantly found in river valleys between latitudes 45° north and 30° south in North and Central America. Read more…

Pneumonia, Viral

Introduction
Background

Viral respiratory tract infections are the most common cause of symptomatic human disease among children and adults. They account for more time lost from school and work than any other infection. Approximately 1-3 respiratory tract illnesses occur in adults, compared to 2-7 respiratory tract illnesses in children, each year. These infections may cause a wide variety of diseases, from the common cold to severe pneumonia, and may result in significant morbidity and mortality. Read more…

Milroy Disease

Introduction
Background

Lymphedema is characterized by swelling of the soft tissue secondary to obstruction of lymphatic drainage. Lymphatic obstruction causes an increase in the protein content of the extravascular tissue with subsequent retention of water. The increase in the extravascular protein stimulates proliferation of fibroblasts, organization of the fluid, and development of a “woody feeling” nonpitting swelling of the affected extremity. Fibrosis also obstructs the lymphatic channels and leads to increased protein concentration in the tissues, continuing this cycle. Lymphedema opens channels in the integument and allows bacteria to enter the subcuticular space, which overwhelms host defenses and leads to cellulitis of the extremity. Read more…

Drug-Induced Pulmonary Toxicity

Introduction
Background

More than 380 medications are known to cause drug-induced respiratory diseases. The number of drugs that cause lung disease will undoubtedly continue to increase as new agents are developed. Because the medications that cause drug-induced respiratory diseases are used by a variety of health care providers, including generalists, specialists, and subspecialists, virtually no area of medicine is free from these adverse reactions. To minimize the potential morbidity and mortality from drug-induced respiratory diseases, all health care providers should be familiar with the possible adverse effects of the medications they prescribe. Read more…

Pulmonary Edema, High-Altitude

Introduction
Background

High-altitude illness may result from short-term exposures to altitudes in excess of 2000 m (6560 ft). This illness comprises a spectrum of clinical entities that are probably the manifestations of the same disease process. High-altitude pulmonary edema (HAPE) and cerebral edema are the most ominous of these symptoms, while acute mountain sickness, retinal hemorrhages, and peripheral edema are the milder forms of the disease. The rate of ascent, the altitude attained, the amount of physical activity at high altitude, and individual susceptibility are contributing factors to the incidence and severity of high-altitude illness.
Pathophysiology
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Respiratory Acidosis

Introduction
Background

Respiratory acidosis is a clinical disturbance that is due to alveolar hypoventilation. Production of carbon dioxide occurs rapidly, and failure of ventilation promptly increases the partial arterial pressure of carbon dioxide (PaCO2). The reference range for PaCO2 is 36-44. Alveolar hypoventilation leads to an increased PaCO2 (ie, hypercapnia). The increase in PaCO2 in turn decreases the HCO3 -/PaCO2 and decreases pH. Hypercapnia and respiratory acidosis occur when impairment in ventilation occurs and the removal of CO2 by the lungs is less than the production of CO2 in the tissues. Read more…