Growing pains: making an accurate diagnosis
The term ‘growing pains' is used to describe a consistent group of symptoms with no
definite pathological basis. True growing pains are entirely benign and have no sequelae or implications with regard to future skeletal development.
However, the diagnosis is ultimately one of exclusion and as the symptoms can also indicate serious childhood illness, the diagnosis must be made with care.
In particular, acute bone or joint infection, along with slipped upper femoral epiphysis (SUFE) and tumours are differential diagnoses that must be identified and referred immediately. A delay in diagnosing these conditions may result in rapid deterioration leading to significant and potentially avoidable
Awareness of the typical presentation, and the more significant differential diagnoses that must be considered, reduces the risk of misdiagnosis.
A typical picture suggestive of benign growing pains is the child aged between four and eight years, who has an active day and then wakes in the night crying with cramp-like pain, typically affecting both legs, localised to the shin, calf, foot or knee, but not involving the joints. The pains ease in 10 to 20 minutes, either spontaneously or by rubbing the painful area, and the child returns to sleep. The child wakes the following morning
as if nothing has happened – unlike the tired parents.
There are no daytime symptoms, no limp and no reduction in the child's functional level. If either clinical signs or daytime symptoms are present, the diagnosis should not be accepted and an alternative underlying pathology sought.
The frequency of the painful episodes is widely variable, but they generally resolve fully over a period of six to 24 months from onset. Even the most prolonged cases have stopped by 11 years in girls or 13 years in boys. Estimates of childhood prevalence vary from 5 per cent to 25 per cent, depending on the degree of adherence to the diagnostic criteria used, and represent up to 7 per cent of all paediatric GP consultations. Certain authors have included upper-limb pains in the criteria for growing pains but this is unusual and it is safer to regard growing pains as a predominantly lower-limb condition.
The cause of growing pains remains unknown. The nominal relationship of the pain to growth is purely speculative and probably erroneous, particularly since the age of peak incidence coincides with a period of relatively slow growth. There is, however, a documented relationship between growing pains and frequency of non-specific headaches, abdominal pains and behavioural disorders.1,2 In addition, clustering is seen in families with a prevalence of pain syndromes and abnormal illness behaviour.
These observations suggest a psychological component to the condition, but other authors regard growing pains as a syndrome of abnormal muscle fatigue and tension. They have reported more rapid resolution of symptoms by actively treating children with muscle stretches and exercises when compared with purely symptomatic treatment.3
There is no proven association between the presence of growing pains and physical growth disturbances, inflammatory conditions or body weight.
Making an accurate diagnosis remains
the main challenge in the management of the condition, as it is one of exclusion. The alternative, less benign diagnoses can usually be excluded on clinical grounds, but there will be incidences that merit further investigation or specialist opinion.
The nocturnal nature of the pain is one feature that is of concern, as the pain of musculoskeletal infection or neoplasia is typically worse at night. In a GP's professional lifetime, cases of benign growing pains will markedly outnumber these more serious diagnoses, increasing the potential for error. As a simple screening tool, if any of the following features are present, a diagnosis of growing pains should not be made without more detailed assessment and investigation:
• Systemic symptoms, night or day
• Pain during the day, even if caused by activity
• Limp or restriction of functional level
• Localising signs – tenderness, swelling, wasting, redness or warmth
• Reduction in the range of motion at adjacent joints.
Subsequent management will obviously be determined by the clinical picture and the potential differential diagnoses.
The list of possible alternate diagnoses is reasonably long, but the outcome of only a few of these will be adversely affected by a delay of a few days, or even weeks, while appropriate observation or investigation occurs. The exceptions to this are SUFE, acute joint or bone infections and malignancy, which require immediate recognition, prompt referral and early treatment to achieve the
SUFE typically affects children approaching the prepubertal growth spurt. Many are overweight and some have an underlying endocrine disorder. The common pitfall with SUFE is that the child often complains of pain in the knee, leading to a normal knee X-ray and subsequent false reassurance and misdiagnosis.
The onset of pain is variable, and only sometimes follows a fall or sporting activity and is present day and night. In the presence of a small slip, the only apparent clinical sign may be some irritability of the hip on passive motion.
At this early stage, surgical stabilisation is relatively straightforward and the prognosis is good. With greater degrees of slip, the affected leg lies in a position of increased external rotation, stabilisation becomes more difficult and the prognosis worsens. A percentage of cases are bilateral, although not necessarily synchronous, and prophylactic pinning of the unaffected side in those cases with underlying endocrine disorders is recommended.
The required X-ray views are AP pelvis and ‘frog lateral' of both hips – these should be specifically requested. Early radiographic changes can be subtle, but are diagnostic in the vast majority of cases. Once the diagnosis is suspected, weight bearing should be restricted to prevent deterioration and arrangements made for immediate specialist review.
Acute septic arthritis (see figure 2, page 31) and acute osteomyelitis are usually associated with febrile illness and are unlikely to be mistaken for growing pains. However, a classical clinical picture may be absent if the infection has been partially treated with oral antibiotics, which may mask the systemic features, improve the limp, diminish the clinical features, prevent isolation of the causative organism and yet fail to cure the infection. The pain of infection may be worse during the night, but will also be present throughout the day and local signs of inflammation will
The child is extremely reluctant to
move the affected limb (so-called pseudoparalysis), which may lead to a fracture being suspected in some individuals. The rigid joint arises due to protective muscle spasm. During examination, the child resists any passive movements of the affected joint.
Inflammatory markers (most notably CRP) rise early, but X-ray changes, which are essentially those of a chronic osteitis, are late, and definitive treatment should be well in place before the latter occurs.
If the diagnosis of musculoskeletal infection is suspected, there should be immediate referral to an orthopaedic specialist.
Chronic bone infection comes in several guises that can simulate growing pains. These include Brodie's abscess and the rare, sclerosing forms of chronic osteomyelitis. Plain radiographs and bone scans are useful to localise the pathology in these cases, but blood tests such as
ESR are normal and a causative organism is rarely isolated. There will usually be daytime symptoms, including a reduction in functional level or subtle localising signs.
The other pertinent diagnoses to consider are not necessarily benign, but once it is established that the picture differs from the typical pattern of growing pains, there is an opportunity for observation or investigation. The alternative possibilities and the means by which they can be excluded are listed below. In some cases, it can be appropriate for the GP to initiate first-line investigations and in others acute orthopaedic or paediatric referral will be more appropriate.
Perthe's disease (see figure 3, page 32) typically affects children from five to nine years of age and presents with exertional hip pain, often referred to the knee. The child limps and the joint is irritated by passive movements but there is no systemic illness.
There are characteristic radiographic changes of sclerosis and collapse of the femoral head, although early appearances may be normal. Treatment is aimed at maintaining the range of hip motion and may require surgical intervention to improve joint congruency and containment of the injured femoral epiphysis.
Transient or reactive synovitis of the hip is often associated with an upper respiratory tract infection or gastroenteritis, but the child, commonly aged from two to eight years, is otherwise systemically well.
There is hip pain, often referred to the knee, with a reduction in the range of hip abduction in flexion (the ‘frog' position), along with a limp during the day. A joint effusion is demonstrable on ultrasound, but imaging is not usually required to make the diagnosis. It is important to remember that septic arthritis of the hip, partially treated with antibiotics, can present with the features of a transient synovitis.
Primary bone malignancy (see figures 1, 4 and 5, pages 28, 34 and 37) is thankfully rare, with only one or two cases presenting over a GP's career on average. Pain is classically deep-seated and gnawing in quality, being worse at night.
However, there is usually some daytime pain and some degree of functional loss. There are often localising signs, especially swelling and subtle buttock or quadriceps wasting and the radiographic features are usually diagnostic.
Osteoid osteoma is a benign neoplasm that produces a deep, nagging pain, especially at night. The pain is dramatically relieved by NSAIDs and
the lesion appears sclerotic on X-ray with a central ‘nidus'. It appears very ‘hot' on a technetium bone scan. Treatment is usually by surgical excision to relieve pain.
Once the diagnosis of growing pains
has been made by exclusion, treatment
is based around alleviation of symptoms. Simple analgesics or NSAIDs are occasionally used, but individual episodes frequently settle quickly without treatment and the necessity of these medications is questionable. If the symptoms are more intrusive, or the episode more protracted, a course of physiotherapy with muscle stretching can prove beneficial. Reassuring both the parents and the child that the condition is self-limiting and benign in nature is the other essential aspect of treatment.
1 Aromaa M, Sillanpaa M, Rautava P et al. Pain experience of children with headache and their families: A controlled study. Pediatrics 2000;106(2):270–5
2 Lavigne JV, Schulein MJ, Hahn YS. Psychological aspects of painful medical conditions in children. II. Personality factors, family characteristics and treatment. Pain 1986;27(2):147–69
3 Baxter MP, Dulberg C. Growing pains in childhood – a proposal for treatment. J Pediatric Orthopedics 1988;8(4):402–6