Traumatic Coronary Artery Damage

(Australia—Australian Family Physician, March 2000, p. 243.) Acute compression of the heart between the sternum and spine during a motor vehicle crash or following a blow to the chest wall may damage the coronary arteries. While the left descending artery is most vulnerable, shearing forces may damage the right coronary artery at its origin. The patient may appear more profoundly hypotensive than expected from the injury. Abnormal findings on electrocardiography (ECG) include changes in ST and T waves, and ventricular arrhythmias and conduction delay. Elevations of cardiac enzymes are common because of direct arterial damage and contusion of the myocardium. Echocardiography is recommended for any patient with ECG changes following chest trauma, and early angiography should be considered. Patients who appear to do well initially may develop serious complications later from arterial damage or associated cardiac ischemia.

Morton's Neuroma

(Australia—Australian Family Physician, April 2000, p. 363.) Morton's neuroma occurs in the third intermetatarsal space and may be related to foot conditions or the use of shoes that cause excessive angulation of the metatarsals. Pain is usually felt in the lateral forefoot, often with paraesthesiae shooting into the toes. Walking exacerbates the pain and tingling. The differential diagnosis of Morton's neuroma includes stress fracture, synovitis, proximal nerve entrapment or metatarsalgia. The patient may limp and have increased pain when raising the calf. Local tenderness can be elicited over the neuroma, and the mass may be appreciated on examination by a “click” as it moves between the metatarsal heads. A plain radiograph can rule out fracture, tumor and infection, but ultrasound may be the best investigation to visualize the neuroma. Symptoms often can be controlled with conservative therapy based on avoidance of pressures on the foot and the use of pads to separate the metatarsal heads. Pain can be alleviated with localized injection of steroids. Surgery is indicated only if conservative therapy fails.

Diagnosing Acute Dyspnea

(Great Britain—The Practitioner, May 2000, p. 478.) The most common causes of acute shortness of breath are acute left ventricular failure, asthma, exacerbations of chronic obstructive pulmonary disease, pneumonia, pulmonary embolism and pneumothorax. Many other pulmonary and systemic conditions may present as acute dyspnea, including inhaled foreign object and hyperventilation. Assessment may have to be curtailed if the patient is severely hypoxic, but the history and physical examination of the patient are the most useful factors in diagnosis. Most causes of acute dyspnea cause sinus tachycardia. Electrocardiography may also help to diagnose myocardial infarction, left or right ventricular failure or strain, pulmonary embolism and other conditions. A chest radiograph is essential if pneumothorax is suspected and can provide useful information about other conditions. When selecting and prioritizing other investigations, the severity of the patient's condition and the most probable diagnosis should be considered. Indicators of severe or life-threatening dyspnea include a respiratory rate of more than 25 breaths per minute, tachycardia greater than 110 beats per minute or bradycardia, a peak expiratory flow of less than 40 percent of predicted value, lower partial pressure of oxygen and elevated partial pressure of carbon dioxide, confusion or exhaustion, and difficulty in completing sentences.