Perthes’ disease
BMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g5584 (Published 23 September 2014) Cite this as: BMJ 2014;349:g5584
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Kannu and Howard’s recent article is genuinely informative and interesting but it’s a great shame that the authors were not able to give some guidance on what to do exactly in primary care. Over the years I can think of many children (commonly age between 4-10yrs) I have seen who have suffered with a painful leg where I have considered Perthes’ disease (PD) as part of the differential diagnosis. Though there seems to be no overall pattern and excluding high-risk cases, there are invariably very few clinical findings and thus it begs the question "how best to manage such a child"?
The obvious management options include a requesting a blood test (full blood count, ESR and an X-ray – as recommended in the above article), referring in to hospital as an ‘emergency’ (usually via paediatric casualty) or asking for a prompt out-patient’s appointment. Of course, in someone who is well it is common for us in general practice to review the child again perhaps in a week or two.
With regard to the original article by Kannu and Howard how promptly should we request an X-ray and, furthermore, would it be safe to exclude Perthes' disease so long as the X-ray was reported as normal? Personally I’d feel slightly nervous about doing just this though presumably it depends on the individual case and the persistence of symptoms. What if the child was to continue to limp - albeit intermittently?
To conclude, what is the optimal management of a child who complains of a painful leg and/or is brought in with a limp? How aggressive should we be in trying to identify Perthes's disease? And, finally, should all these children (c/o pain and/or limp – cause unidentified) be seen by a paediatric orthopaedic surgeon?
I would be genuinely interested in the views of the authors on the above points.
Competing interests: No competing interests
Perthes’ disease versus sickle cell disease hip
The instructive article [1] of Peter Kannu and Andrew Howard (Oct 4, p 32) has presenting clinical features that can equally apply to children with sickle cell disease whose omission in differential diagnosis does not help busy Residents and House Physicians in hospitals anywhere in the world.
RADIOLOGICAL DIFFERENTIATION: PERTHES’ VERSUS SICKLE CELL DISEASE HIP
While clinical presentation - the limp with the physical signs elicited – is identical in Perthes’ and sickle cell disease hip in children the radiological features help in differentiation [2 page 239]. The latter hip differentiation “from Calve-Legg-Perthes’ disease is not difficult” [3] especially when “the significant differences in age of onset, degree and site of epiphyseal involvement and changes in the femoral metaphyses are considered” [4 5]. Like in Perthes’ there was no hip involvement in 157 consecutive children with sickle cell disease aged 4 and below [2 page 239], but between 5 to 9 years of age there was 1 case in 201 consecutive sickle cell disease patients (0.5%) and between 10 to 14 years we had 7 (4%) of 177 consecutive patients [2]. Therefore below the age of 15 years we in Ghana found 8 cases of avascular/aseptic femoral head necrosis in 200 consecutive sickle cell disease patients (2.5%) observed by one clinician (myself). The article of Kannu and Howard [1] states: “The annual incidence of Perthes’ disease among children under 15 ranges from 0.2 to 19.1 per 100,000” which, while quoting the paper of Perry and colleagues on the “racial and geographic factors on the incidence of Legg-Calve-Perthes disease” [6], failed to comment that these so-called “racial factors” could be haemoglobinopathic.
DEFINITION OF SICKLE CELL DISEASE
Sickle cell disease is defined as possession of two beta-globin gene defects at least one of which is the sickle cell gene [1], therefore the phenotypes constituting sickle cell disease are ‘SS’ known as sickle cell anaemia, ‘SC’ known as sickle cell haemoglobin C disease, ‘Sβ-Thal’ which is sickle cell beta-Thalassaemia, ‘SF-HEREDITARY’ for sickle cell Hereditary Persistence of Foetal Haemoglobin which 4 phenotypes comprised the commonest sickle cell diseases seen in Ghana. More ‘SC’ phenotype (6.6% of 603 consecutive patients of all ages) than ‘SS’ (2’8 % of 600) suffered hip necrosis, but no disease phenotype is exempt [2]
ANYWHERE IN THE WORLD
Sickle cell disease occurs in significant measure in White people in Greece, Turkey, Sicily, and in the Middle East, India, and in their descendants in the diaspora [2, pages 76-82]. Canada where this article originates [1] has a good representation of these Mediterranean populations [7] as well as Blacks and though the authors, as part of their investigations carried out for Perthes’ disease mention “a full blood count” there is need to remind Residents and House Physicians anywhere in the world that haemoglobin electrophoresis must always be counted among the tests to be carried out in any tentative clinical diagnosis of Perthes’ disease.
FORGETTING PAST PUBLICATIONS?
One Editor of a prestigious international medical publication once wrote asking me to limit my references to articles published after the year 2000 AD. I wrote back to point out that clinical signs were/are clinical signs and doctors needed reminding of their significance in any generation. As part of their treatment regime Peter Kannu and Andrew Howard list “encouraging swimming” among exercises to be recommended in Perthes’ disease. Well, fifty years ago bar 4 months I named in Lancet swimming among the 17 commonest precipitating causes of sickle cell crisis [8]. Mistake sickle cell disease for Perthes’ disease and this advice to encourage swimming would be misplaced. Fortunately, Obisesan and Bohrer [5] knew how to diagnose Perthes’ disease in Black children in West Africa 42 years ago. Should the present authors have mentioned this? Or were they dismissing anything published before AD 2000 as being of little significance? Just two out of their 13 references are before the 21st Century. The increasing habit of starting articles with a clinical dimension thus: “We did a MEDSEARCH going back 25 years” is neither academic nor helpful, because quite significant clinical material may be missed. In 1972 I discovered and described in The Lancet a new physical sign in sickle cell disease, to the extent of quantifying its incidence in the different sickle cell disease phenotypes, the peripheral mental nerve neuropathy of sickle cell crisis [9] – what came to be known on ward rounds as the “kanumbill sign”. Twenty-five years later Sally Davies and L Oni published in the BMJ a comprehensive article on Sickle Cell Disease (10) limiting their references to cover the previous 25 years, thereby (but not deliberately) omitting a vital physical sign (numb lower lip) that could have drawn the attention of any doctor or nurse to the fact that the person they were confronted with had sickle cell disease.
Competing interests: None declared
Felix I D Konotey-Ahulu MD(Lond) FRCP(Lond) DTMH(L’pool) Kwqegyir Aggrey Distinguished Professor of Human Genetics University of Cape Coast, Ghana and Consultant Physician Genetic Counsellor in Sickle Cell and Other Haemoglobinopathies, 9 Harley Street Ltd, Phoenix Hospital Group, London W1G 9AL (E-mail felix@konotey-ahulu.com Web: www.sicklecell.md)
1 Kannu P, Howard A. Perthes’ disease. BMJ 2014; 349:g5584 (doi:1136/bmj.g5584)
2 Konotey-Ahulu FID. The Sickle Cell Disease Patient: Natural History from a Clinico-epidemiological study of the first 1550 patients of Korle Bu Hospital Sickle Cell Clinic. The Macmillan Press Ltd, London 1991 & 1992 and T-A’D Co Watford, 1996.
3 Golding JSR. The bone changes in sickle cell anaemia. Ann Roy Col Surg Eng 1956; 19: 296-315.
4 Barton CJ, Cockshott WP. Bone changes in Haemoglobin SC disease. Am J Roentgen Rad Ther Nuc Med 1962; 88: 523-532.
5 Obisesan AA, Bohrer SP. Perthes’ disease in Nigerians. Ghana Medical Journal 1972; 11: 298-302.
6 Perry DC, Machin DM, Pope D, Bruce CE, Dangerfield P, Platt MJ, et al. Racial and geographic factors in incidence of Legg-Calve-Perthes’ disease: a systematic review. Am J Epidemiol 2012; 175: 159-166.
7 Ringelhann B, Konotey-Ahulu FID. Hemoglobinopathies & Thalassemias in Mediterranean areas and in West Africa: historical and other perspectives 1910-1997 – A Century Review. Atti del’Accademia della Science di Ferrara 1998; 74: 267-307.
8 Konotey-Ahulu FID. Sicklaemic Human Hygrometers. Lancet 1965; 1: 1003-1004.
9 Konotey-Ahulu FID. Mental nerve neuropathy: a complication of sickle cell crisis. Lancet 1972; 2: 388 [The so-called kanumblll sign (Konotey-Ahulu Numb Lower Lip Lancet sign)]
10 Davies Sally C, Oni L. Management of patients with sickle cell disease. BMJ 1997; 315: 656-660.
Competing interests: No competing interests
Kannu and Howard`s Key Points begin with the child who presents with a limp. But what of those children whose families, for whatever reason, fail to see a GP when symptoms first emerge? They, like clinicians, can easily miss the problem, attributing the limp to the rough and tumble of their youngsters` lives. And then, after a time, symptoms disappear: all is well.
Families from lower socioeconomic groups, whose children are more likely to be of low birth weight, may be frequently be under-monitored by health services. Case finding to prevent later osteoarthritis is particularly important given Perthes affects boys more frequently, and their employment is more likely to require physical labour. Could greater awareness on the part of teachers be helpful?
How many children might there be who do not even get to the first base of a timely diagnosis for Perthes Disease?
Competing interests: No competing interests
Re: Perthes’ disease - Author's response
I appreciate Dr. Singh’s commentary including important pointed questions about what to do in the primary care setting. I can provide my views, as requested, recognizing that there is a gap in evidence about the sensitivity and specificity of history and physical exam against diagnostic tests like blood tests and plain radiographs.
What is the optimal management of the child who complains of a painful leg and/or is brought in with a limp? How aggressive should we be in trying to identify Perthes's disease?
We know from a Dutch family practice cohort (Krul Family Practice 2009) that the overwhelmingly common diagnosis is transient synovitis (52 of 101 hips) followed by symptom diagnosis (39 hips) with perthes (6 of 101 hips) and slipped capital femoral epiphysis SCFE (4 of 101 hips) being quite rare diagnoses in primary care settings. Septic arthritis of the hip did not present among the 101 hip pain presentations from a 70,000 child base population over one year. Most transient synovitis and symptom diagnosis patients will settle within two weeks.
If the differential diagnosis has been narrowed to transient synovitis/symptoms vs. perthes by history and physical findings I think primary care followup in two weeks with instructions to return early for worsening symptoms is sensible. I find the prone internal rotation test pictured the most sensitive way to detect unilateral hip pathology on clinical examination. Those with ongoing symptoms or persistent clinical findings could have a radiograph at two weeks. A two week delay in the diagnosis of perthes is not likely to change the outcome, perthes is not likely to go away in two weeks, and radiography could be used more parsimoniously if reserved for those with ongoing symptoms.
A fracture, a septic joint, or a slipped epiphysis should ideally be identified on first presentation as prompt surgical referral will change the outcome. A child who is systemically unwell or a child who is refusing to walk at all warrants blood tests and radiographs. A child over ten with unilateral hip findings warrants a radiograph, including a lateral, to rule out slipped epiphysis as progression can lead to complications more rapidly. Heavier children are at more risk of slipped epiphyses, as are those with endocrinopathies.
Should all these children (c/o pain and/or limp – cause unidentified) be seen by a paediatric orthopaedic surgeon?
No. The majority with transient synovitis or symptom only diagnoses are better managed in a primary care setting. Those with persistent symptoms or identified surgical diagnoses are best referred. A child with acute, severe symptoms who is unable to bear weight is appropriate as an emergency referral.
I appreciate Dr. Konotey-Ahulu’s reminder that osteonecrosis of the hip is one of the myriad presentations of sickle disease. Sickle disease needs to be considered as a potential aetiology of osteonecrosis in patient populations at genetic risk. I am unaware of how commonly osteonecrosis of the hip would be the first presenting symptom of sickle disease in a child not otherwise diagnosed. Most patients in my practice with sickle disease have diagnoses made early in childhood for presentations which may include acute bone pain or dactylitis. They rarely present with childhood hip pathology alone. Osteonecrosis of the hip is a difficult and challenging clinical problem for some of these patients and typically presents and progresses in the older teenage and early adult years. Milner (NEJM 1991) presents a study outlining the incidence of osteonecrosis of the femoral head among patients with sickle disease, which is about 1% below the age of 5, 5% between the ages of 5 and 9, and rises monotonically to over 30% in patients 45 years old and older. Timely diagnosis of sickle disease likely crosses many areas in clinical medicine and both specialists and generalists are well to keep the entity in mind.
Competing interests: No competing interests