Viclinical Considerations

A. Respiratory distress syndrome is caused by a deficicncy of surfactant, which may oc cur due to prolonged intrauterine asphyxia, premature birth, or in infants of diabetic mothers.

1. Thyroxine and Cortisol treatment increase production of surfactant.

2. Not only is immediate asphyxiation a concern in these infants, but also repeated gasping inhalations can damage the alveolar lining, leading to hyaline membrane disease.

B. Bronchogenic carcinoma is classified histologically into the following types:

1. Squamous cell carcinoma is associated with a smoking history, arises in large bronchi, and has a high rate of growth. Well-differentiated forms of squamous cell carcinoma produce keratin.

2. Adenocarcinoma is associated with a nonsmoking history. Well-differentiated forms of adenocarcinoma have obvious glandular elements that contain mucin.

3. Small cell carcinoma is associated with a smoking history. This highly malignant tumor contains small, oval-shaped cells with neurosecretory granules (oat cells) that may produce ectopic hormones.

C. Cystic fibrosis (CF) is caused by production of abnormally thick mucus by epithelial cclls lining the respiratory (and gastrointestinal) tract. This results clinically in obstruction of airways and recurrent bacterial infections.

1. CF is due to autosomal recessive mutations of the CF gene, which is located on the long arm of chromosome 7 (7q).

2. The CF gene encodes for a protein called cystic fibrosis transporter (CFTR), which functions as a chloride ion channel.

3. In North America, 70% of CF cases are due to a deletion of three bases that normally code for the amino acid phenylalanine at position 508, such that phenylalanine is missing from CFTR.

D. Lung infections

1. Staphylococcus aureus produces lung abscesses and is a common secondary infection in rubeola or influenza.

2. Chlamydia trachomatis produces pneumonia that is contracted as a newborn infant passes through the birth canal.

3. Candida albicans produces pneumonia that is associated with an indwelling catheter and immunodeficiency states.

4. Coxiella burnetii is a respiratory pathogen that is commonly found in individuals who have close association with cows, sheep, or goats.

5. Histoplasma capsulatum is a fungus that causes an infection characterized by multiple granulomas with calcification in the lung. It is acquired by inhalation of spores and is the most common systemic fungal disease in the midwest United States.

6. Aspergillus fumigatus is a fungus that resides in old tuberculous cavities.

7. Coccidioides immitis (valley fever) is a fungus acquired by inhalation of spores and is most common in the southwest United States (San Joaquin Valley).

8. Pneumocystis carinii is an opportunistic fungus that causes an infection that is a common initial presentation of AIDS.

Capillary endothelial

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The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.

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