Acute leg ischaemia
BMJ 2013; 346 doi: https://doi.org/10.1136/bmj.f2681 (Published 08 May 2013) Cite this as: BMJ 2013;346:f2681All rapid responses
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Brearley’s article(1) makes for sobering reading, given that acute leg ischaemia is so commonly missed. This matches my experience in orthopaedics, where of the six acutely ischaemic limbs I recall seeing, five were initially missed.
Failure to consider the diagnosis is identified as a leading reason. However sometimes it is missed even when the diagnosis is considered, and this requires further explanation. Simply put, wishful thinking can be the culprit. The doctor’s fears and wishes affect his perception of the absent pulses and other signs. Either the doctor does not want to admit that he cannot palpate the pulse and that he is worried, or he does not wish to give the patient or his consultant bad news, especially when uncertain. Uttam Shiralkar’s book(2) explains common cognitive errors that doctors make. He might invoke “anchoring bias”, although none of his categories of bias quite describes wishful thinking.
The solution, I believe, is to include cognitive skills in medical training. Patient psychology now takes pride of place in the medical curriculum, but the doctor’s own psychology, as applied to differential diagnosis, is still neglected. Unless we are taught how to deal with uncertainty and how to face up to the fact that there is a potential emergency, then we will continue to learn, too late, from the disasters described in Brearley’s article.
Regarding pulses specifically, medical students must be taught not only how to feel pulses, but how to “own up to” absent or doubtful pulses, and of course perform rapid handheld Doppler assessment as needed.
References
1. Brearley S. Acute leg ischaemia. BMJ 2013;346:36-37
2. Uttam Shiralkar. “Smart surgeons, sharp decisions; Cognitive skills to avoid errors and achieve results”. 2011, tfm Publishing Ltd.
Competing interests: No competing interests
The excellent account of acute leg ischaemia(1) would not be complete without mention of the fact that, in some instances, acute leg ischaemia may have a pain-free presentation(2)(3)(4).
In his report of 330 unselected cases of peripheral arterial embolism (ie "embolism of the extremities") Haimovici noted that 52 of his patients had "sudden numbness and coldness without initial pain"(2). This observation led him to conclude that "the common belief that arterial embolism is always charcterised at onset by severe pain may be misleading"(2).
In a previous study comprising 100 cases of sudden occlusion of arteries in the extremities (including 46 with embolism, and 54 with thrombosis) McKechnie and Allen noted that numbness was the initial symptom in eight of the patients with an embolic aetiology, and this was also the initial symptom in another eight with a thrombotic aetiology)(3). Their own comment was that "dogmatic adherence to the old criterion [of presentation with abrupt excruciating pain]...contributes to inadequate or inaccurate diagnosis and the poor treatment which invariably follows"(3).
The effects of acute ischaemia were documented by personal observation in a study conducted by Richards in 52 patients with peripheral arterial embolism. He noted that, among 48 cases in whom data regarding onset was adequate, the onset was sudden in 37. The initial symptom was often pain, "but numbness or coldness of the extremity, either sudden or progressive, precede[d] pain in about a third of cases"(4).
Accordingly, in addition to invoking baseline documentation of all peripheral pulses as a prerequisite to good clerking (for comparison with subsequent clinical findings in the event of a suspected embolic episode), patients at risk of peripheral embolism (such as those with atrial fibrillation, and recent myocardial infarction, for example) should be instructed to seek urgent medical attention in the event of experiencing new-onset abnormal sensations in the extremities.
References
(1) Brearley S. Acute leg ischaemia. BMJ 2013;346:36-37
(2)Haimovici H. Peripheral arterial embolism. Angiology 1950;1:20-45
(3) McKechnie RE., Allen EV. Sudden occlusion of arteries of the extremities. Surg., Gyn. and Obst., 1936;63:231-240
(4) Richards RL. The effects of peripheral arterial embolism. Q J Med New Series XXIII, No 89, January 1954 p 73-90
Competing interests: No competing interests
Excellent article - particularly regarding the mantra that a pulse that you can't count is to be regarded as absent. I pride myself on being good at palpating pulses having done a vascular job in my younger days but even I know what it is to have ones that I "think" are present.
Message to all GP's out there: should we all be getting a Doppler with a vascular probe for the surgery (in addition to the ante-natal one)?
Competing interests: No competing interests
limb loss from delayed or missed diagnosis of acute ischaemia is not as uncommon as some might think and so this review is much welcome.
my residency days in surgical training had comparatively less easy access to doppler diagnostic tools at the time and so clinical acumen with regards to high index of suspicion was very crucial at the time.
but even with all of the 6 Ps of pulselessness, paraesthesias, pain, pallor/cyanosis, paralysis, poikilothermia,
there were always then
some who would come with such local or regional polymorbidities
of say
1. florid varicosities with saphenous insufficiencies and orthostatic oedema making pulse identification difficult if not impossible with a risk of false negative diagnosis of pulselessness
or
2
a. cases of neurospinal claudications making pain analysis more difficult in the context of ischemia and muscle response
or for the same reason,
b. making sensory or motor deficits difficult to contextualise in a patient otherwise simultaneously smitten with acute ischaemia.
the potential pitfalls then were naturally more real.
today, ready availability of doppler facilities have removed most of these confounders at the point of contact and the only thing really necessary is not to forget to have ischaemia in mind in painful limbs.
the point also becomes needful of making, that in environments where peripheral vascular diseases are common
either cos of de facto high incidence/prevalence of vasculopathies,
or
prevalence of risk factors ( hypertension, diabetes, smoking etc),
doppler facilities must become part of minimum diagnostic tools available to all clinicians likely to intertface with these cases.
though not immediately within this current purview, i find it interesting to also recall how acute testicular ischaemia in cases of testicular torsions used to be sometimes so very difficult to distinguish from primary inflammatory conditions like epididymo-orchitis,
so much so sometimes, that many registrars used to be embarrased when at exploration, they realised they have fallen for false positives of acute ischaemia on displaying the testis during operation only to find it was epididymo-orchitis.
doppler of the testicular artery has also come to the rescue in nearly all of these cases.
it is therefore increasingly difficult to defend missed or delayed diagnosis with doppler simplifications around.
Competing interests: No competing interests
Acute leg ischaemia: Can they wiggle their toes?
Acute leg ischaemia: Can they wiggle their toes?
In response to Mr Brearley’s excellent article, I would like to add from my personal practical experience as a retired consultant vascular surgeon, the most important question I ask when I am referred a patient with acute leg ischaemia.
Acute lower limb ischaemia (ALI) is a serious condition, which is frequently missed with delay in diagnosis and treatment.
ALI can affect patients at any age [1] and should be considered in the differential diagnosis of all patients presenting with leg pain of sudden onset irrespective of age and risk factors.
The current acronym of "the six Ps" (Pain, Pallor, Perishing cold, Pulselessness, Paraesthesia, and Paralysis) summarises the different and evolving stages of the clinical presentation of ALI.
The mere presence of the first three Ps, (sudden severe pain, pallor and perishing coldness) should trigger the alarm, alerting the clinician to this possibility, so to diagnosis at this early stage, before the progression to sensory motor deficit [1].
The most urgent action is the immediate intravenous administration of 5,000 international units of unfractionated heparin to prevent propagation of thrombosis to the small vessels, this in addition to the involvement of a vascular surgeon.
A vascular surgeon's decision is based on the stage at which they find the limb in.
Rutherford et al [2] in 1997 classified ALI to three stages: viable, threatened and irreversible. In Stage 1 there is no sensory or motor deficit and the limb is not immediately threatened and still viable.
In Stage 2 the limb is either marginally threatened (2A) or immediately threatened (2B). The difference being that in Stage 2A the patient can usually wiggle their toes meaning that there is time to request arterial imaging and definitive treatment can be performed by either interventional radiology or surgery. However in Stage 2B immediate revascularisation is required to save the limb and this is usually by surgery, in the form of an emergency thromboembolectomy under local anaesthesia. If this is not successful, then on table angiogram and catheter directed thrombolysis should be performed.
A limb presenting in Stage 3 with profound paralysis and anaesthesia of the foot and fixed mottled skin, is sadly unsalvageable and revascularisation can be dangerous. The only option is to perform primary amputation to save the patient's life. After all, life is more precious than a limb.
Professor MI Aldoori, PhD, FRCP, FRCS
Retired Consultant Vascular Surgeon, Calderdale and Huddersfield NHS Foundation Trust, Acre Street, Huddersfield, HD3 3EA
mikaldoori@gmail.com
References
[1] Brearley S. Acute leg ischaemia. BMJ 2013; 346: 2681
[2] Rutherford R B, Baker J D, Ernst C, et al. Recommended standards for reports dealing with lower extremity ischemia :Revised version. J Vasc Surg 1997; 26: 517-38
Competing Interests Statement
The author has no competing interests to declare
Competing interests: No competing interests