INTRODUCTION — Recurrent, self-limited extremity pains for which the parents, child, and healthcare provider have no explanation are often called “growing pains.” Such pains were first described in the medical literature in 1823. Subsequent publications attributed these pains to “rheumatism,” a word synonymous with rheumatic fever at the time. Correlations were described with digestive and sleep disorders, loose joints, poor posture, and chronic infection. By the 1930s and 1940s, growing pains were distinguished from rheumatic fever and other pathologic conditions. This distinction remains the focus of the evaluation of children with recurrent limb pain.
Growing pains are benign and usually resolve within a year or two of onset. They must be distinguished from pathologic causes of pain that require additional therapy.
The epidemiology, etiology, clinical features, evaluation, and management of growing pains in children are reviewed here. The evaluation of children with joint pain and limp is discussed separately.
DEFINITION — There is no consensus definition of growing pains, and, as a result, there are no specific inclusion or exclusion criteria that are uniformly applied to studies of children with complaints of growing pains. The key consideration is that clinicians not dismiss as “growing pains” a significant problem for which intervention may be appropriate.
In this regard, it is best to restrict “growing pains” to the description of children with pain awakening them at night (or from naps) who are otherwise without any manifestation of musculoskeletal problems. In contrast, children with unexplained joint pains that occur in association with activity deserve further investigation, which the child with typical “growing pains” may not.
EPIDEMIOLOGY — Growing pains usually begin between 2 and 12 years. The prevalence varies from 4 to 37 percent depending upon the population studied, the age of the children, and the clinical definition used. However, surveys of schoolchildren indicate that as many as 10 to 20 percent have had growing pains. Growing pains are slightly more common among girls than boys.
ETIOLOGY — The etiology of growing pains is not known. Although they occur in growing children, they are not actually caused by growth. Growing pains do not coincide with periods of rapid growth, do not occur at the sites of growth, and do not affect the growth of children who have them. Emotional disturbance and psychogenic illness often are mentioned as possible causes, but have not been studied systematically.
Several other etiologies have been proposed, including fatigue, mild orthopedic and postural abnormalities, restless leg syndrome, and local overuse. Parents of children with growing pains often reveal a pattern of increased complaints following an increased level of physical activity. A study of bone speed of sound (SOS) measured by quantitative ultrasonography provides support for local overuse as a contributing factor. In this study, children with growing pains had decreased SOS compared with control children. Decreased SOS is also seen in patients with local overuse.
In population-based studies, growing pains are consistently associated with other recurrent pains (eg, headache and abdominal pain). In one study, children with recurrent headache (45 percent of whom also had growing pains) were more often described by their parents as having greater sensitivity to pain, greater reaction to stressful situations, and more depressive symptoms. In another study, children with growing pains were found to have a decreased pain threshold compared with control children.
CLINICAL FEATURES — The clinical features of growing pains have been described in several studies. Each of these studies had different inclusion criteria:
- In one study of 721 schoolchildren, cases of growing pains (4.2 percent) were defined by pain of ≥3 months’ duration, pain severe enough to interrupt normal activity, including sleep, and pain not specifically related to the joints.
- In another study of 257 6 to 7 year olds and 419 10 to 11 year olds, children were identified by their parents (13.6 percent of 6 to 7 year olds and 19.8 percent of 10 to 11 year olds).
- In a third study of 2178 children between 6 and 19 years of age, cases of growing pains (18.4 and 12.5 percent of girls and boys, respectively) were defined by intermittent and frequently incapacitating pain of the legs (and sometimes arms) that resolved by morning and were not accompanied by objective changes on physical examination.
Despite the varying case definitions, certain common clinical features emerge, including the following:
- Growing pains occur most commonly in preschool and school-aged children.
- Pain occurs primarily in the lower extremities. Upper-extremity pain occurs, but only in conjunction with lower-extremity pain.
- Pain is bilateral and located deep in the legs, usually the thigh or calf.
- Pain is paroxysmal and may be severe enough to make the child weep. Symptom-free periods of days, weeks, or months occur between episodes.
- In older children (6 to 12 years), the pain may be described as crampy, a creeping sensation, or restless legs.
- Pain occurs primarily in the evening or nighttime hours and may interrupt sleep. It usually resolves by morning, but some patients have isolated daytime complaints.
- Pain is relieved by massage, heat, or first-order analgesics, such as acetaminophen or ibuprofen.
- Normal patterns of activity are maintained.
- The physical examination during and after the episodes is normal.
- Associated complaints of recurrent abdominal pain and/or headaches occur in approximately one-third of patients.
- A family history of growing pains or rheumatic complaints is common.
- The pains are chronic but episodic, with an overall duration that often may last years and persist into adolescence.
DIAGNOSIS — With a typical presentation in an otherwise healthy child who remains pain free during the day, the diagnosis can usually be made clinically. It is not necessary to perform radiographs or laboratory tests to make the diagnosis in these children.
The usually accepted criteria for growing pains include:
- Pain typically occurs late in the day or awakens the child.
- Pain must be severe enough to interrupt normal activity, including sleep.
- Pain is not specifically related to the joints.
- Pain occurs at least monthly for at least three months.
- Pain is intermittent, with symptom-free periods of at least days.
- Pain is accentuated by increased activity during the day.
- The physical examination is normal.
- Ancillary studies, if performed, are normal.
DIFFERENTIAL DIAGNOSIS — The differential diagnosis of intermittent lower-extremity pain is extensive. It is important to exclude conditions that may require additional evaluation, therapy, or monitoring. These conditions include:
- Trauma (particularly overuse syndromes and stress fractures)
- Tumors of the blood or bone
- Infection (particularly if partially treated with antibiotics)
- Osteonecrosis (eg, Legg-Calvé-Perthes disease)
- Metabolic disorders (eg, rickets)
- Sickle cell anemia
- Vascular insufficiency
- Rheumatologic disorders (particularly spondyloarthropathies, such as psoriatic arthritis and reactive arthritis, which may cause nighttime pain)
Most of these disorders can be excluded on the basis of history and physical examination. Laboratory studies and/or radiographs may be necessary in others.
Tumors, particularly bone tumors, may be the most difficult to distinguish from growing pains without additional studies because tumor pain often occurs at night.
- Bone tumors – The pain associated with primary bone tumors typically begins as intermittent pain and increases in severity over the course of time. The pain associated with Ewing sarcoma, though, may disappear spontaneously for weeks or months at a time. In contrast to growing pains that are bilateral, the bone pain associated with tumors is unilateral. Patients with bone tumors also may have a palpable mass.
Osteoid osteomas are benign tumors. They may present with pain in one lower extremity, which is intermittent and worse at night.
On physical examination, children with bone tumors will experience tenderness with compression of the bone and/or soft tissue, which is not seen in children with growing pains.
- Leukemia – Children with leukemia usually have systemic symptoms, such as fever, pallor, or weight loss.
EVALUATION — The evaluation of children who complain of recurrent, self-limited lower-extremity pain should include a complete history and physical examination.
History — The history should characterize the pain episodes and include the following questions:
- How often does it occur?
- Where does it occur?
- When does it occur? How long does it last?
- What makes it better?
- Does the pain affect the child’s activity, sleep, or school attendance?
- Are there any associated signs or symptoms (eg, fever, swelling, erythema, malaise, weight loss)?
- Does the child have recurrent headaches or abdominal pain?
- Is there a history of recent illness (eg, viral infection, Group A streptococcal infection)?
- Has there been a recent increase or change in type of exercise or sports activity?
- Is there a family history of medical problems (eg, sickle cell anemia, metabolic disease, rheumatologic disorders)?
- Is there a family history of growing pains?
- Is there the complaint of pain in the night (or naps) or during the day? (See ‘Definition’ above.)
In addition, it is important to determine whether the child is receiving any “secondary gain” from the pain episodes. One must also consider the possibility of child abuse (physical or emotional); however, abused children rarely restrict their complaints to the nighttime.
- What are the current stressors facing the patient and family?
- Do the episodes of pain correlate temporally with events that the child may wish to avoid?
- Who might benefit if the pain prevented some activity?
Physical examination — The physical examination must be carefully performed to exclude other conditions in the differential diagnosis.
- Abnormalities on the musculoskeletal examination (e.g., decreased range of motion, joint swelling, or elicited tenderness upon bone compression) may indicate orthopedic or rheumatologic conditions.
- Abnormal skin findings are sometimes present in children with rheumatologic disease or infection (e.g., dermatomyositis, systemic lupus erythematosus, psoriasis, or syphilis).
- The neurologic examination, including gait, may be abnormal in children with spinal cord tumors.
- The finding of lymphadenopathy or splenomegaly should prompt consideration of malignancy, infection, or rheumatic disease.
- An abnormal gait may be seen in a variety of musculoskeletal disorders, but should not be present in a child with growing pains.
Further evaluation — Additional evaluation may be necessary to exclude more serious conditions in the differential diagnosis and usually is warranted in all children who have:
- Systemic symptoms (e.g., unexplained fever, weight loss, decreased activity)
- Persistent, increasing, or unilateral limb pain
- Pain during the day
- Limp or limitation of activities
- Localized findings on examination (decreased range of motion, warmth, tenderness, swelling, erythema)
- Pain that is isolated to the upper extremity, back, or groin
The additional evaluation may include, but is not limited to, complete blood count (CBC) and differential, erythrocyte sedimentation rate (ESR) (or C-reactive protein), and/or plain radiographs. Abnormal results in any of these tests exclude a diagnosis of growing pains.
Paediatricians, family practitioners, paediatric orthopedic surgeons, and paediatric rheumatologists were surveyed regarding the diagnostic evaluation of a child with typical growing pains. Depending upon the speciality, between 19 and 51 percent of clinicians would order CBC and differential, between 30 and 58 percent would order an ESR, and 37 to 52 percent would order radiographs. Diagnostic tests were more likely to be ordered if the patient was >12 years of age or if the clinician felt the need to reassure the parents.
While parental concern is not always a reliable indicator of disease, it is easily assessed during the office visit. When parents seem particularly concerned and difficult to reassure, thorough diagnostic evaluation is an effective way to both exclude a significant underlying problem and provide the necessary reassurance. However, the evaluation must be clinically appropriate since there is potentially no limit to the concerns that families may express or the studies they may request. Clinicians who are confident of their diagnosis can usually reassure reasonable families of the appropriateness of their recommendations, even without an extensive diagnostic evaluation.
TREATMENT — Little is written about the treatment of growing pains in children, and few controlled trials have been performed. The management must include recognition of the child’s pain and its effects on his or her functioning. Education of the patient and family is a crucial component of the management plan. An understanding of the benign nature of the disorder may alleviate unnecessary concern, fear, and suffering.
Acute pain relief may be achieved with massage, analgesics (e.g., aspirin, acetaminophen, ibuprofen), and heat in various forms. Often, episodes that awaken the child at night cluster in groups of nights and follow days of increased physical activity. In a child who has been appropriately evaluated, acetaminophen or ibuprofen given at bedtime may prevent awakening following a day of increased activities or break the cycle of repeated complaints. At times, a longer-acting analgesic given after dinner, such as naproxen, may be needed for the child to be able to sleep through the night. However, none of these medications should be continued beyond a few days.
The pain should not be allowed to interfere with usual childhood activities and social experiences. Discontinuation of normal activities does not prevent growing pains and may in fact make the pain a focus for the child and family.
Muscle stretching exercises may relieve chronic symptoms. In one unblinded study of 36 children with growing pains, children who were treated with a muscle stretching regimen had more rapid resolution of their symptoms than controls (average of zero episodes per month at 9 months versus one to two episodes per month at 18 months). However, it is not clear whether the improvement was a result of the exercise or the increased parental attention required for the twice-daily routine.
The author provides education and reassurance for children who are having growing pains fewer than three to four times per week. He treats children who have more than four episodes of pain per week prophylactically.
The child should be seen in follow-up at periodic intervals to evaluate the course of the disease. Children who have pain that increases in frequency or severity may require additional evaluation.
- Growing pains are defined as pain awakening a child at night (or from naps) who is otherwise without any manifestation of musculoskeletal problems.
- Although growing pains are a common musculoskeletal condition, occurring in approximately 15 percent of children, their etiology is not known.
- It is important that appropriate evaluation is performed to differentiate growing pains from other, more serious conditions.
- If the child appears ill, complains of pain during the day or with activity, or if pain worsens or persists, the diagnosis is unlikely to be growing pains. A thorough evaluation (e.g., complete blood count [CBC] and differential, erythrocyte sedimentation rate [ESR] or C-reactive protein, and/or plain radiographs) is required in children who meet any of these conditions. Abnormal results in any of these tests exclude a diagnosis of growing pains.
- Treatment is usually symptomatic and must include education and reassurance.