Correspondence

Claudication with Normal Pulses

N Engl J Med 1996; 335:1686-1687November 28, 1996

Article

To the Editor:

In the Clinical Problem-Solving article entitled “The Illusion of Certainty” (July 4 issue),1 Dr. Wolinsky provides an informative and constructive critique of the case presentation and the discussant's thoughts. I was disappointed, however, that along with the commentary on what was included, there was no critique of what was not mentioned in the history.

Perhaps the most important aspect of the history was neglected. In differentiating spinal stenosis from vascular insufficiency, or Leriche's syndrome in this case, it is more important to inquire about the position and length of time required for the pain to dissipate on resting than to inquire whether exercise can continue after the pain has begun.2 In patients with spinal stenosis, the pain is usually diminished after exercise has ceased only in the sitting position or when the back is flexed. The pain usually persists, however, at times for hours after resting, and does not begin rapidly after exercise has started. Symptoms of claudication are relieved quickly, usually within one to five minutes, with any kind of rest in a standing, sitting, or leaning position. The pain recurs with the same amount of exercise as before — a point mentioned by the discussant of the case in question.

I realize that with any discriminating questions concerning history-taking and an attempt to differentiate among diagnoses, everything depends on and is invariably reduced to probabilities, as Dr. Wolinsky so elegantly states in his commentary. However, subtle questions and clues should not be ignored. Taken individually, they may be misleading; taken as a whole, they can point to the diagnosis and therapy.

Nicki Panoskaltsis, M.D.
University of Rochester Medical Center, Rochester, NY 14642

2 References

1. 1

   Wolinsky AP. The illusion of certainty. N Engl J Med 1996;335:46-48
   Full Text | Web of Science | Medline

2. 2

   Rutherford RB. The vascular consultation. In: Rutherford RB, ed. Vascular surgery. 4th ed. Vol. 1. Philadelphia: W.B. Saunders, 1995:2, 5.
   

To the Editor:

The treating physician and the discussant seem to ignore the important and likely possibility of cauda equina claudication caused by vascular lesions affecting the blood supply of the cauda equina. The blood supply of the cauda equina is predominantly derived from the lower aorta through the contributions of lumbar arteries. Atherosclerotic occlusion of the lower aorta can diminish this supply, and there can be an associated narrowing of the ostia of lumbar vessels at the origin as well. Another rare vascular cause of similar ischemia is an arteriovenous malformation of the lower spinal canal, which may cause symptoms after exertion as a result of the “vascular steal” phenomenon.

The treating physician failed to note the importance of the symptom of numbness developing after walking, which the patient reported during the second consultation. Did the physician think of performing a neurologic examination after exercise? There could have been sensory or motor abnormalities or diminished tendon jerks. The failure to note the possibility of cauda equina ischemia may be one factor that prompted the discussant to rule out vascular disease early on, despite several risk factors in a young person (smoking, a family history of coronary artery disease, a high total cholesterol level, and a low value for high-density lipoprotein cholesterol).

The possibility of cauda equina ischemia due to small-vessel disease might also explain the poor improvement in symptoms after the aortobifemoral graft.

P. Dileep Kumar, M.D.
Sur Central Hospital, Sur, PB 259 Code 411, Oman

To the Editor:

As Dr. Wolinsky notes, the diagnosis of aortoiliac occlusive disease probably does not explain all the patient's symptoms. In fact, there is a possibility that that diagnosis may not explain any of the patient's symptoms.

The problem may be a somatoform disorder. Where is the objective structural explanation for this man's inability to work? The prior work injury, noted “incidentally,” may not be so incidental. Is this man trying to connect that 10-year-old injury to his present symptoms? Is this a workers' compensation case? Does this man have an attorney? There are psychosocial red flags here, including the patient's depression and anxiety, which although not diagnostic of a somatoform (psychogenic) process, are consistent with it.

Thomas John Michlowski, M.D., M.P.H.
111 East N. Water St., Neenah, WI 54956

To the Editor:

What the patient wants when he or she comes to the doctor with a painful condition is treatment of the problem causing the pain. Thus, it should be stressed that it is “a certainty” that the source of this patient's pain was not peripheral occlusive vascular disease. This is borne out by the fact that even though his arterial system was fixed by an aortobifemoral bypass, his pain persisted. It should be emphasized that in patients with “severe pain at night in bed” and normal pedal pulses, peripheral vascular disease is never a cause of the pain.1 Indeed, for a symptom of pain at rest, “stress testing is not necessary; subtle degrees of arterial obstruction are of no concern.”2

This case shows that with a proliferation of available tests, some anatomical abnormality may be found and corrected by surgery even when another cause of the problem is clearly indicated by the history. There can be little doubt that the diagnosis of a neurologic problem is the correct one. It can only be hoped that additional neurologic studies and treatment have resulted in some pain relief for this unfortunate patient.

Charles C. Paniszyn, M.D.
Tufts University School of Medicine, Boston, MA 02111

2 References

1. 1

   Rutherford RB. The vascular consultation. In: Rutherford RB, ed. Vascular surgery. 4th ed. Vol. 1. Philadelphia: W.B. Saunders, 1995:1-10.
   

2. 2

   Zierler RE, Sumner DS. Physiologic assessment of peripheral arterial occlusive disease. In: Rutherford RB, ed. Vascular surgery. 4th ed. Vol. 1. Philadelphia: W.B. Saunders, 1995:65-117.
   

Author/Editor Response

Dr. Wolinsky replies:

To the Editor: The response to exercise in this patient — the complete disappearance of what were, at rest, bounding pulses, with the simultaneous development of marked cyanosis and coldness of both feet — was so impressive that I have to attribute some of his exercise-induced pain to occlusive vascular disease. I agree with Dr. Paniszyn that the pain at rest did not have an ischemic basis. I do not think that cauda equina claudication, which Dr. Kumar suggests, was a possibility, because the patient had pain at rest, which is not a feature of that syndrome. In response to Dr. Panoskaltsis's comments, this patient's pain was not relieved in the sitting position.

I share Dr. Michlowski's view that at least some portion of this patient's symptoms may have been due to a somatoform disorder.

Arthur P. Wolinsky, M.D.
Texas Tech University Health Sciences Center, Amarillo, TX 79106