Musculoskeletal pain is one of the most common presenting symptoms at the pediatrician’s office. Etiology ranges from benign conditions to serious ones requiring prompt attention. This article addresses entities that present as musculoskeletal pain but are not associated with arthritis. The most common nonarthritic conditions are benign limb pain of childhood (growing pains), hypermobility, overuse syndromes with or without skeletal abnormalities, malignancies, and pain amplification syndromes. The| initial decision process, diagnosis, and treatment options for each of these conditions are discussed.
Musculoskeletal pain is one of the most common presenting symptoms at the pediatrician’s office. Etiology ranges from benign conditions to serious ones requiring prompt attention. This article discusses entities presenting as musculoskeletal pain while not being associated with arthritis, the latter being dealt with in detail in other articles in this issue. The most common nonarthritic conditions are benign limb pain of childhood (growing pains), hypermobility, overuse syndromes with or without skeletal abnormalities, malignancies, and pain amplification syndromes. Fig. 1 shows the possible initial decision process regarding evaluation, after ruling out trauma and infection.
Benign limb pain of childhood
When to Consider
Benign limb pain is a chronic, intermittent, paroxysmal nighttime shin pain without daytime symptoms or limitation.
Background
Benign limb pain is also known as growing pains; a clear misnomer because it usually occurs outside of major growth spurt periods between ages 3 to 5 and 8 to 12 years. Children are characterized by recurrent lower extremity pain, mostly bilateral, occurring at night or in the evenings. The prevalence is variable, between 4% and 37% of studied children, depending on the targeted age groups. Diagnostic criteria were suggested by Naish and Apley in 1951 ( Box 1 ). Their cohort included 721 children attending school clinics, recognizing the existence of 3 groups: (1) children with “ill-defined pains,” vaguely distributed symptoms both daytime and nighttime; (2) the largest group of children, with “diurnal fatigue pains,” whose pain was associated with “emotional disturbance” and postural defects including flat feet, pain being brought on by activities; and (3) the true “paroxysmal nocturnal pains” group, without association with daily activities but with the presence of similar symptoms in 20% of parents, and without any obvious etiology.
- 1.
At least a 3-month history of pain
- 2.
Intermittent pain with symptom-free intervals of days, weeks, or months
- 3.
Pain late in day or awakening child at night
- 4.
Pain not specifically related to joints
- 5.
Pain of significant severity to interrupt such normal activity as sleep
- 6.
Normal physical examination, laboratory data, and roentgenograms
To this day, the etiology remains unknown. A link with restless leg syndrome has been suggested by Rajaram and colleagues, but the concomitant diagnosis of growing pains differed slightly from the criteria by Naish and Appley, the sample size was low (10 children), and some of the children listed had daytime symptoms as well. Limb pain seemed to get better on moving the extremities, which is characteristic for restless leg syndrome but not for growing pains. Hashkes and colleagues showed no association with vascular perfusion changes in affected areas, but there seemed to be decreased bone speed of sound, suggesting a local overuse syndrome. However, this does not explain the paroxysmal character of nighttime appearance only. Interestingly enough, children with this type of pain have decreased pain thresholds, which would suggest that this entity is a form of pain amplification syndrome.
How to Diagnose
The term benign limb pain of childhood likely should be used for children belonging to the third group of Naish and Apley. Episodes are heralded by occurrence at night and wake the child (and subsequently the whole family) from sleep. It is described as very intense pain of mostly the shins with peak intensity of 10 to 15 minutes that slowly regresses over the following hour. It is not joint centered, but young children might not be capable of proper localization. There are no changes of the affected area when examined, such as redness, rashes, or swelling. Massaging might help or at least provide comfort, and nonsteroidal anti-inflammatory drugs (NSAIDs) also seem to provide relief albeit it might be coincidental, considering the time of onset of action of medication and natural resolution of symptoms. Children are well during the day, have no limitations, and there are asymptomatic periods between the episodes lasting from days to weeks.
Upper extremity or joint pain, daytime complaints, limping, systemic symptoms including fevers, weight loss, and decreased energy/activity are not part of the presentation and require further workup. Pain presentation later in the day and in the evening, especially associated with increased activities, suggests overuse syndromes, and common skeletal variations such as femoral anteversion, genua valga, flat feet, and hypermobility need to be assessed. Again, children should be asymptomatic during the day, with normal physical examination. Otherwise, radiographic imaging and, if indicated, complete blood count (CBC) and erythrocyte sedimentation rate (ESR) should be performed to look for other entities. Table 1 lists findings that suggest benign limb pain.
| Likely Benign Limb Pain | Unlikely Benign Limb Pain |
|---|---|
| Shin pain | Joint pain |
| Paroxysmal night time occurrence | Daytime |
| Episodic with asymptomatic periods | Constant/fluctuating |
| Well otherwise | Systemic symptoms |
| Normal physical examination | Findings on physical examination |
How to Treat
Initially reassurance is important, although parents might find it unsatisfactory. Massaging and NSAIDs can provide help. Considering the asymptomatic intervals, daily prophylactic NSAID administration might be more harmful than beneficial in the long run.
What to Expect
There are few studies addressing long-term evolution of this condition. Five-year follow-up suggests resolution of symptoms in half of the patients, but the remainder seem to have persistent complaints even in adulthood.
Malignancy
When to Consider
It is paramount to consider an underlying malignancy when there is daytime and nighttime joint pain, arthritis without morning stiffness, systemic symptoms including fever, weight loss, and night sweats. Infections and systemic inflammatory conditions should also be part of the differential diagnosis.
Background
Fewer than 1% of patients presenting with musculoskeletal complaints will end up being diagnosed with malignancy whereby leukemia, lymphoma, Ewing sarcoma, and neuroblastoma are the most common entities ( Table 2 ). Although a rare event, symptoms can overlap with those of juvenile idiopathic arthritis (JIA), overuse syndrome, or the previously mentioned benign limb pain of childhood, which can lead to a delay in the diagnosis. Symptoms are due to either local tissue destruction or the paraneoplastic effect.
| Cabral and Tucker, 1999 | Trapani et al, 2000 | Gonçalves et al, 2005 | |
|---|---|---|---|
| Total number of patients | Approximately 8400 | 1254 | 3528 |
| Patients with malignancies (%) | 29 (0.35) | 10 (0.8) | 9 (0.25) |
| Most common | Leukemia, lymphoma, neuroblastoma, Ewing sarcoma | Leukemia, Ewing sarcoma, lymphoma | |
| Presentation (%) | |||
| Musculoskeletal pain | 82 | 80 | 88 |
| Fever | 54 | 80 | 100 |
| Fatigue | 50 | 50 | 22 |
| Weight loss | 42 | 20 | 33 |
| Hepatosplenomegaly | 29 | 30 | — |
| Lymphadenopathy | 18 | 30 | — |
| Arthritis | 25 | 50 | 55 |
| Night sweats | 14 | 30 | — |
| Bruising | 14 | — | — |
| Laboratory findings (%) | |||
| Abnormal CBC | 31 | 20–80 | 11–66 |
| Abnormal WBC | — | 20 | 11 |
| Anemia | — | 80 | 66 |
| Abnormal platelets | — | 70 | 50 |
| Elevated ESR | 26 | 80 | 75 |
| Elevated LDH | 24 | 10 | 50 |
How to Diagnose
Clinical evaluation
The most common presentation is monoarthritis of the large joints, musculoskeletal pain, night sweats, and fevers. Malignancy as an underlying diagnosis should be considered every time systemic symptoms or an atypical presentation of a diagnosis is present (solitary elbow arthritis without morning stiffness diagnosed as JIA). Possible red flags appearing during workup are summarized in Table 3 . The physical examination may be noncontributory besides the overall chronically ill appearance. However, bony tenderness, decreased strength, hepatosplenomegaly, and lymphadenopathy are clear indications for further workup.
| Pain | Disproportionate to physical examination |
| Not joint centered | |
| Migratory | |
| Night time pain (except for growing pains) | |
| Arthritis | No morning stiffness |
| Atypical onset: elbow, back | |
| Systemic symptoms | Night sweats |
| Weight loss | |
| Fever |
Laboratory evaluation
Laboratory indicators can be normal (see Table 2 ). Nevertheless, CBC (leukopenia or leukocytosis, anemia, thrombocytopenia), and elevated ESR, C-reactive protein (CRP), uric acid, lactate dehydrogenase (LDH), and urine vanillylmandelic acid (especially in a young child with back pain) can be helpful. Diseases with systemic inflammation such as systemic lupus erythematosus (SLE) or systemic JIA might present with similar findings. Cytopenias with elevated ESR and normal CRP can occur in SLE; leukocytosis with anemia may occur in systemic JIA, polyarteritis nodosa, and Kawasaki disease, although in the latter 2, thrombocytosis rather than thrombocytopenia is more usual. Elevated uric acid can occur in kidney diseases but primary gout is almost unheard of in childhood. A high LDH seems to be the best predictor for leukemia, but it also can be elevated in hemolysis and myositis. Nevertheless, Coombs negative anemia with thrombocytopenia, and elevated ESR, CRP, LDH, and uric acid should lead to imaging and bone marrow biopsy.
Imaging
Localized constant bone pain, especially if not joint centered, warrants imaging. Unfortunately, positive findings including metaphyseal growth arrest lines on radiographic studies occur late during the disease process and are often nonspecific. Hepatosplenomegaly, lymphadenopathy, systemic symptoms, and elevated uric acid and LDH should prompt computed tomography scans of the chest, abdomen, and pelvis. Multiple sites of involvement can be assessed by whole-body tri-phase bone scan, but this is nonspecific as is magnetic resonance imaging, because misinterpretation of the image as osteomyelitis can delay diagnosis.
In summary, being a relatively rare entity, the presentation of childhood malignancy can be misleading. In the study by Gonçalves and colleagues, all 9 affected patients had relief from pain either spontaneously or with massage and analgesics, and 2 had benign laboratory findings.
Malignancy
When to Consider
It is paramount to consider an underlying malignancy when there is daytime and nighttime joint pain, arthritis without morning stiffness, systemic symptoms including fever, weight loss, and night sweats. Infections and systemic inflammatory conditions should also be part of the differential diagnosis.
Background
Fewer than 1% of patients presenting with musculoskeletal complaints will end up being diagnosed with malignancy whereby leukemia, lymphoma, Ewing sarcoma, and neuroblastoma are the most common entities ( Table 2 ). Although a rare event, symptoms can overlap with those of juvenile idiopathic arthritis (JIA), overuse syndrome, or the previously mentioned benign limb pain of childhood, which can lead to a delay in the diagnosis. Symptoms are due to either local tissue destruction or the paraneoplastic effect.
| Cabral and Tucker, 1999 | Trapani et al, 2000 | Gonçalves et al, 2005 | |
|---|---|---|---|
| Total number of patients | Approximately 8400 | 1254 | 3528 |
| Patients with malignancies (%) | 29 (0.35) | 10 (0.8) | 9 (0.25) |
| Most common | Leukemia, lymphoma, neuroblastoma, Ewing sarcoma | Leukemia, Ewing sarcoma, lymphoma | |
| Presentation (%) | |||
| Musculoskeletal pain | 82 | 80 | 88 |
| Fever | 54 | 80 | 100 |
| Fatigue | 50 | 50 | 22 |
| Weight loss | 42 | 20 | 33 |
| Hepatosplenomegaly | 29 | 30 | — |
| Lymphadenopathy | 18 | 30 | — |
| Arthritis | 25 | 50 | 55 |
| Night sweats | 14 | 30 | — |
| Bruising | 14 | — | — |
| Laboratory findings (%) | |||
| Abnormal CBC | 31 | 20–80 | 11–66 |
| Abnormal WBC | — | 20 | 11 |
| Anemia | — | 80 | 66 |
| Abnormal platelets | — | 70 | 50 |
| Elevated ESR | 26 | 80 | 75 |
| Elevated LDH | 24 | 10 | 50 |
How to Diagnose
Clinical evaluation
The most common presentation is monoarthritis of the large joints, musculoskeletal pain, night sweats, and fevers. Malignancy as an underlying diagnosis should be considered every time systemic symptoms or an atypical presentation of a diagnosis is present (solitary elbow arthritis without morning stiffness diagnosed as JIA). Possible red flags appearing during workup are summarized in Table 3 . The physical examination may be noncontributory besides the overall chronically ill appearance. However, bony tenderness, decreased strength, hepatosplenomegaly, and lymphadenopathy are clear indications for further workup.
| Pain | Disproportionate to physical examination |
| Not joint centered | |
| Migratory | |
| Night time pain (except for growing pains) | |
| Arthritis | No morning stiffness |
| Atypical onset: elbow, back | |
| Systemic symptoms | Night sweats |
| Weight loss | |
| Fever |
Laboratory evaluation
Laboratory indicators can be normal (see Table 2 ). Nevertheless, CBC (leukopenia or leukocytosis, anemia, thrombocytopenia), and elevated ESR, C-reactive protein (CRP), uric acid, lactate dehydrogenase (LDH), and urine vanillylmandelic acid (especially in a young child with back pain) can be helpful. Diseases with systemic inflammation such as systemic lupus erythematosus (SLE) or systemic JIA might present with similar findings. Cytopenias with elevated ESR and normal CRP can occur in SLE; leukocytosis with anemia may occur in systemic JIA, polyarteritis nodosa, and Kawasaki disease, although in the latter 2, thrombocytosis rather than thrombocytopenia is more usual. Elevated uric acid can occur in kidney diseases but primary gout is almost unheard of in childhood. A high LDH seems to be the best predictor for leukemia, but it also can be elevated in hemolysis and myositis. Nevertheless, Coombs negative anemia with thrombocytopenia, and elevated ESR, CRP, LDH, and uric acid should lead to imaging and bone marrow biopsy.
Imaging
Localized constant bone pain, especially if not joint centered, warrants imaging. Unfortunately, positive findings including metaphyseal growth arrest lines on radiographic studies occur late during the disease process and are often nonspecific. Hepatosplenomegaly, lymphadenopathy, systemic symptoms, and elevated uric acid and LDH should prompt computed tomography scans of the chest, abdomen, and pelvis. Multiple sites of involvement can be assessed by whole-body tri-phase bone scan, but this is nonspecific as is magnetic resonance imaging, because misinterpretation of the image as osteomyelitis can delay diagnosis.
In summary, being a relatively rare entity, the presentation of childhood malignancy can be misleading. In the study by Gonçalves and colleagues, all 9 affected patients had relief from pain either spontaneously or with massage and analgesics, and 2 had benign laboratory findings.
Hypermobility syndromes
When to Consider
Hypermobility syndromes need to be considered when there is mostly lower extremity joint pain toward the afternoon or end of the day, pain is worse with activities, and resting helps. Also, it should be suspected in children with repeated joint subluxations, loose skin, and capillary fragility because it can be part of complex genetic syndromes ( Table 4 ).
| Syndrome | Notable Associated Pathology |
|---|---|
| Marfan | MVP, aortic dilatation, dissection |
| Ehlers-Danlos | MVP, aortic dilatation, dissection |
| Stickler | Myopia, glaucoma, cataract, hearing loss |
| Williams | Supravalvular aortic stenosis |
| Osteogenesis imperfecta | Recurrent fractures, blue sclerae |
| Trisomy 21 | VSD |
Background
Range of motion of the joints is variable; it is increased in childhood and decreases with aging. There are syndromes in which molecular defects of connective tissue such as collagen disorder in Ehlers-Danlos or fibrillin mutations in Marfan syndrome have been proved, but in the majority of cases one cannot identify the biochemical defect. Prevalence varies between various races but, in general, 1 of 5 girls and 1 of 10 boys are hypermobile and up to 75% of these children present with musculoskeletal pain. Increased range of motion of ankles or knees can result in repeated microtrauma of the tendons, asymmetric or abnormal muscle involvement, and even frequent clumsiness. Impaired proprioception is seen in those with knee hypermobility but not in those with hypermobility of the shoulder girdle. Recurrent joint subluxations, loose skin, increased capillary fragility, thin scars, or lens abnormalities should alert for further workup, especially considering the various cardiac abnormalities that can be associated with these symptoms.
How to Diagnose
There have been multiple attempts to classify abnormal range of motion, and one of the most commonly used methods is the Beighton scale ( Table 5 ). Nevertheless, cutoff values for positivity (4–6 of 9), the choice of joints tested, and validity and reproducibility of the testing are still undergoing scrutiny.
| Movement Assessed | Score |
|---|---|
| Passive apposition of the thumb to the flexor side of the forearm | 1 for each side |
| Passive dorsiflexion of the little finger >90° | 1 for each side |
| Passive hyperextension of the elbow >10° | 1 for each side |
| Passive hyperextension of the knee >10° | 1 for each side |
| Forward flexion of the trunk with straight knees and palms resting on the floor | 1 |
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