銅筋鐵肋的秘密基地

TEACHING TOPIC

1. Case: Hemoptysis
CLINICAL PROBLEM-SOLVING
A 26-year-old man presented with a 1-month history of persistent cough productive of white sputum, which was occasionally tinged with blood. He reported mild pleuritic chest pain but had no dyspnea, fever, chills, night sweats, or weight loss. The patient had had no epistaxis or episodes of sinusitis. A course of azithromycin did not resolve his symptoms. His medical history was notable for pneumothorax and renal-artery dissection. What single disease could be responsible for these previous illnesses as well as his current hemoptysis?

Clinical Pearls

 Hemoptysis: Differential Diagnosis
Hemoptysis can be caused by diseases of the airways, particularly bronchitis or bronchiectasis. Other causes include bronchogenic carcinoma, metastatic cancer or bronchial carcinoid. Kaposi's sarcoma involving the airways may cause hemoptysis in patients infected with HIV. Hemoptysis can also arise from the lung parenchyma. Autoimmune diseases (such as SLE, mixed connective tissue diseases, etc.), cocaine inhalation, and infections (including tuberculosis, bacterial pneumonia, and lung abscess), as well as pulmonary embolism, pulmonary arteriovenous malformation, mitral stenosis, severe left heart failure, and Wegener's granulomatosis should also be included in the differential diagnosis of hemoptysis.


 Aspergillus in Respiratory Cultures
Aspergillus species are ubiquitous in the environment, and growth in respiratory cultures often represents contamination rather than infection. (A lung biopsy is needed for definitive diagnosis.) Common risk factors for invasive aspergillosis include severe neutropenia, hematopoietic stem-cell and solid-organ transplantation, HIV infection, and chronic granulomatous disease.

Morning Report Questions
Q:		What is the differential diagnosis for a cough that lasts longer than 8 weeks?
A:		A key feature when evaluating a patient with cough is symptom duration. Acute cough lasts less than 3 weeks and is usually caused by respiratory tract infection. Cough lasting longer than 8 weeks is considered chronic and is most often due to postnasal drip, asthma, or gastroesophageal reflux disease.
Q:		What conditions could cause waxing and waning pulmonary nodules?
A:		Waxing and waning pulmonary nodules can occur with several conditions. Sarcoidosis is one possible diagnosis in a patient who also has hilar and mediastinal adenopathy. Patients with rheumatoid arthritis can also have cavitary nodules that relapse and remit in concert with systemic disease activity. Other conditions to consider include Wegener's granulomatosis and chronic thromboembolic disease.

TEACHING TOPIC

2. Neurogenic Orthostatic Hypotension

A 65-year-old man reports a 6-month history of dizziness, light-headedness, weakness, and fatigue while upright. He takes no medication and has no personal or family history of neurologic disease. On physical examination, his supine blood pressure is 160/100 mm Hg, with a heart rate of 72 beats per minute; on standing, his blood pressure falls to 70/40 mm Hg, with no change in heart rate. How should he be evaluated and treated?


Clinical Pearls

 Orthostatic Hypotension
A fall in the systolic blood pressure of at least 20 mm Hg or in the diastolic blood pressure of at least 10 mm Hg after 3 minutes of standing is diagnostic of orthostatic hypotension. The history and physical examination, as well as laboratory testing (complete blood count, electrolytes, blood glucose level, serum immunoelectrophoresis, vitamin B₁₂ level, and a morning cortisol level) should be focused on ruling out non-neurologic causes (e.g., blood loss, dehydration, and cardiovascular or endocrine disorders) and determining whether other features of primary autonomic degenerative disorders (e.g., Shy–Drager syndrome, Parkinson's disease, or Lewy-body dementia) or autonomic peripheral neuropathies (e.g., diabetes, amyloidosis, or Sjögren's syndrome) are present. If the diagnosis remains unclear, additional testing, including autonomic testing and imaging studies, may be useful.

 Drugs that Can Cause Orthostatic Hypotension
The recognition and removal (when possible) of reversible causes of orthostatic hypotension are important. Diuretics, antihypertensive agents, antianginal agents, α-adrenoreceptor antagonists for the treatment of benign prostatic hyperplasia, antiparkinsonism agents, and antidepressants are the most common offending agents.

Morning Report Questions
Q:		What are some nonpharmacologic treatments for orthostatic hypotension?
A:		Nonpharmacologic treatments for orthostatic hypotension include wearing custom-fitted elastic stockings, or an abdominal binder, or both to reduce peripheral pooling in the lower limbs and splanchnic circulation, increasing fluids and salt intake, raising the head of the bed by 10 to 20 degrees, moving from a supine to a standing position gradually, particularly in the morning, and employing physical maneuvers including crossing the legs, stooping, squatting, and tensing the muscles of the leg, abdomen, or buttock or of the whole body to help maintain blood pressure during daily activities. Rapid ingestion (e.g., over a period of 3 to 4 minutes) of approximately 0.5 liter of tap water elicits a marked pressor response and improvement in symptoms in many, but not all, patients with autonomic failure. Midodrine [ProAmatine], a peripheral, selective, direct α1-adrenoreceptor agonist, is the only medication presently approved by the Food and Drug Administration for the treatment of orthostatic hypotension.
Q:		How does standing cause a temporary reduction in blood pressure?
A:		Standing results in pooling of 500 to 1000 ml of blood in the lower extremities and splanchnic circulation. There is a decrease in venous return to the heart and reduced ventricular filling, resulting in diminished cardiac output and blood pressure. These hemodynamic changes provoke a compensatory reflex response, initiated by the baroreceptors in the carotid sinus and aortic arch, that results in increased sympathetic outflow and decreased vagal-nerve activity.