Letters to the Editor

Differentiating Foot Fractures from Ankle Sprains

TO THE EDITOR: I enjoyed the article, "Foot Fractures Frequently Misdiagnosed as Ankle Sprains,"¹ in American Family Physician. The article provides an excellent discussion of subtle fractures of the tarsal bones that can be easily missed on examination. However, the article does not discuss one type of fracture that is commonly misdiagnosed as an ankle sprain: an avulsion fracture of the proximal fifth metatarsal.

The article¹ only addresses this fracture indirectly through a description of the Ottawa ankle rules in Figure 10. When evaluating a patient with a potential ankle injury, this fracture merits focused attention. In my experience, it is the most common fracture misdiagnosed as a sprain by primary care physicians. Its mechanism of injury is similar to that of a lateral ankle sprain. Indeed, patients with this fracture often complain of a "twisted ankle."² Furthermore, the area of pain and swelling seen with this fracture may overlap that seen with an ankle sprain. If ankle radiographs are obtained, the fifth metatarsal fracture is often not visible; even if it is visible, it may be overlooked if the physician's attention is focused on the malleoli.

The key to recognizing a proximal fifth metatarsal fracture is to maintain a high index of suspicion for this injury and to apply the Ottawa ankle rules³ when evaluating patients with acute ankle injuries. These rules call for palpation of the proximal fifth metatarsal and navicular in patients with acute ankle injuries and midfoot pain. Radiographs of the foot are recommended if there is tenderness over either of these areas or the patient is unable to bear weight on the foot. Dissemination of these guidelines has helped raise physicians' index of suspicion for this injury. However, many physicians still do not routinely consider this fracture when assessing ankle injuries.

Nondisplaced avulsion fractures of the proximal fifth metatarsal generally heal very well with minimal, conservative treatment. As such, they lend themselves to management by primary care physicians. However, before initiating management, it is important to differentiate this fracture from two other types of proximal fifth metatarsal fractures: a stress fracture of the diaphysis and the so-called "Jones fracture." The latter fractures require different management and are much more prone to complications. Eiff and colleagues² provide a discussion of the diagnosis, referral guidelines, and management of proximal fifth metatarsal fractures.

ROBERT L. HATCH, M.D., M.P.H.
Department of Community Health and Family Medicine
University of Florida
Box 100222
Gainesville, FL 32610

REFERENCES

1. Judd DB, Kim DH. Foot fractures frequently misdiagnosed as ankle sprains. Am Fam Physician 2002; 66:785-94.
2. Eiff MP, Hatch RL, Calmbach WL. Fracture management for primary care. 2d ed. Philadelphia, Pa.: W.B. Saunders; 2003:345.
3. Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Reardon M, et al. Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation. JAMA 1993;269:1127-32.

Management of Risk Factors in Relatives of Patients with SAH

TO THE EDITOR: I read and enjoyed the article, "Intracranial Aneurysms: Current Evidence and Clinical Practice,"¹ in American Family Physician and agree with screening the proposed groups: patients with autosomal dominant polycystic kidney disease and patients with a history of aneurysmal subarachnoid hemorrhage (SAH). I also agree with the consensus of not routinely screening for unruptured intracranial aneurysms in relatives of patients with subarachnoid hemorrhage, because of the increased morbidity and mortality associated with elective surgical intervention/repair of unruptured aneurysms. This is based on the result of the International Study of Unruptured Intracranial Aneurysms (ISUIA)² that shows a decrease in the previously thought rupture rate of intracranial aneurysms: 0.05 percent per year in patients with no previous SAH, and 0.5 percent per year for large (greater than 10 mm diameter) aneurysms, and for all aneurysms in patients with previous SAH, compared with the previously proposed rupture rate of 1 to 2 percent per year.³

Table 1 in the article¹ listed the risk factors for intracranial aneurysm formation and SAH; these risk factors could be diminished or eliminated in at-risk patients. While the evidence is strong against routine screening of all relatives of patients with SAH, the issue of careful history taking to identify additional risk factors that could be prevented or corrected was not addressed in the article.

Siblings appear to be the most frequently affected relatives of patients with aneurysmal SAH.¹ More aggressive management or elimination of risk factors in this population could reduce both risk of formation and rupture until screening in this population can be tested in a randomized trial.³

ROBIN GILLARD, M.D.
Southwest Georgia Family Practice Residency Program
2336 Dawson Rd.
Albany, GA 31707

REFERENCES

1. Vega C, Kwoon JV, Lavine SD. Intracranial aneurysms: current evidence and clinical practice. Am Fam Physician 2002;66:601-8.
2. Unruptured intracranial aneurysms--risk of rupture and risks of surgical intervention. The International Study of Unruptured Intracranial Aneurysms Investigators. N Engl J Med 1998;339:1725-33.
3. Wardlaw JM, White PM. The detection and management of unruptured intracranial aneurysms. Brain 2000;123:205-21.

Evaluation and Treatment of Heat-Related Illnesses

TO THE EDITOR: Dr. Wexler's article, "Evaluation and Treatment of Heat-Related Illnesses,¹" was a valuable review of the complex problem of heat-related illnesses. I would like to emphasize some additional points.

The thermoregulatory system operates around an apparent "set point" that is thermally determined by a dynamic balance between signals from two types of sensors at skin and body core. These sensors have opposite temperature-response characteristics. This concept provides a conceptual framework, which fits a variety of clinical situations.

Clinical syndromes vary from heat syncope, heat cramps, heat exhaustion, and heat stroke.^2-3 Heat syncope occurs when a person experiences orthostatic dizziness or fainting following exposure to a high environmental temperature. Heat illness is precipitated by long hours of standing, postural changes, or physical activity in hot weather, leading to volume depletion and syncope.

Heat cramps usually occur when the person stops work and is relaxing. They differ from cramps experienced during physical exercise, which tend to last for short periods and resolve spontaneously, and from hyperventilation tetany, which may occur during heat exhaustion.

Heat stroke is a complex clinical disorder characterized by the triad of disturbance of the nervous system, generalized anhydrosis, and rectal temperature above 40.6°C (105.1°F).⁴

Since the temperature of all organs is elevated, the degree of insult to different organs and tissues is related to the absolute rise in core temperature, its duration, and associated metabolic acidosis and hypoxia. It is postulated that major contributors to morbidity and mortality vary with the level of core temperature. Below 40.0°C (104.0°F), the factors are changes in body fluids, electrolytes, and cardiovascular activity. At 40.0°C to 42.4°C (108.3°F), lipopolysaccharide toxicity and cardiovascular demands are incriminated. Above 42.4°C, thermal damage becomes critical, oxidative phosphorylation becomes uncoupled, and enzyme systems are affected. Eventually temperature mechanisms fail and hyperthermia accelerates, leading to dysfunction and organ system failure. Damage to the central nervous system is a hallmark of heat stroke.

Since heat stroke presents different clinical pictures (neurologic, cardiovascular, respiratory, hematologic, renal, and hepatic complications), physicians may fail to recognize and treat it promptly. Heat stroke should be considered if a patient presents with the triad of hyperpyrexia, altered mental status, and hot dry skin.

Various modalities for cooling the body have been used: ice-water immersion; evaporative cooling using large circulating fans and skin wetting; ice packs; peritoneal, rectal, or gastric lavage; alcohol sponge bath; and cardiopulmonary bypass. An alternative efficient method uses evaporative cooling from the warm skin.⁵

One article² cites seven objections to ice-water immersion: (1) intense peripheral vasoconstriction shunting blood away from the skin and perhaps causing a paradoxic increase in core temperature; (2) inducing shivering may increase heat production significantly above basal level; (3) extreme discomfort to patients; (4) discomfort to medical attendants; (5) difficulty performing cardiopulmonary resuscitation; (6) difficulty monitoring vital signs; and (7) unpleasant and unhygienic conditions should vomiting or diarrhea occur.

We strongly advise against immersion in ice water or using ice packs especially when managing children. Other supportive measures should be applied jointly with evaporative cooling.

MUSTAFA KHOGALI, M.D.
Department of Family Medicine
American University of Beirut Medical Center
P.O. Box 113-6044
Beirut, Lebanon

REFERENCES

1. Wexler RK. Evaluation and treatment of heat-related illnesses. Am Fam Physician 2002;65:2307-14.
2. Khogali M. Heat stroke and heat exhaustion. Travel Traffic Med Int 1983;1:166-9.
3. Knochel JP. Heat stroke and related heat stress disorders. Dis Mon 1989;35:301-77.
4. Khogali M, Hales JR. Heat stroke: an overview. In: Khogali M, Hales JR, eds. Heat stroke and, temperature regulation. Sydney: Academic Press; 1983.
5. Khogali M, Weiner JS. Heat stroke: report on 18 cases. Lancet 1980;2:276-8.

IN REPLY: Dr. Khogali emphasizes some very important points regarding the physiologic changes the body undergoes during heat-related illness that were not discussed in the article.¹ I understand Dr. Khogali's concerns regarding cold-water immersion versus evaporative cooling techniques. The article acknowledges that some literature demonstrates the superiority of evaporative cooling techniques compared with cold-water immersion techniques. In fact, the evaporative cooling technique recommended in the article¹ was Dr. Khogali's.

Heat stroke is a serious life-threatening emergency that needs prompt attention. Few institutions in the United States have the capability to provide the type of evaporative technique described by Dr. Khogali and used by those who deal with this problem with greater frequency based on their geographic location. The risks associated with ice water immersion are widely recognized; however, a system without other therapeutic options must take immediate action to reduce core temperature by any means possible, and ice water immersion is one such technique.

The most important thing for the patient is that immediate core body temperature reduction is achieved by whatever technique. If the options are ice water immersion or nothing, then ice water immersion should be utilized. If other techniques are available, then they may be utilized as dictated by the experience of the treating physician and the clinical circumstance.

I thank Dr. Khogali for emphasizing these important points, and his input is much appreciated.

RANDY WEXLER, M.D.
The Ohio State University
21 E. State St.
Suite 250
Columbus, OH 43215

REFERENCE

1. Wexler RK. Evaluation and treatment of heat-related illnesses. Am Fam Physician 2002;65:2307-14.

Send letters to Jay Siwek, M.D., Editor, American Family Physician, 11400 Tomahawk Creek Pkwy., Leawood, KS 66211-2672; fax: 913-906-6080; e-mail: afplet@aafp.org. Please include your complete address, telephone number, and fax number. Letters should be submitted on disk, double-spaced, fewer than 500 words, and limited to one table or figure and six references. Please submit a word count. Letters submitted for publication in AFP must not be submitted to any other publication. Possible conflicts of interest must be disclosed at time of submission. Submission of a letter will be construed as granting the AAFP permission to publish the letter in any of its publications in any form. The editors may edit letters to meet style and space requirements.