Dr. YK Amdekar breaks down eight varied cases of leg aches among children and steps taken towards arriving at the right diagnosis for each case, underscoring the importance of smart history taking and physical examination.

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To read other originals by Dr. YK Amdekar, click here.

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It is clear that not every leg ache complaint can be ignored as few diseases may be serious enough requiring urgent management while some may be simply cured by correct diagnosis. However, aetiology is not known in a few of these conditions such as growing pains or fibromyalgia or restless leg syndrome.

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Case 1

A 6-year-old child presented with generalised limb pain and headache for a day followed by high fever. There were no other symptoms. He was temporarily better for a few hours after paracetamol but pain and fever would recur. Three days later, he became well without any specific treatment.

On the first day when there was only pain in limbs, one may not be sure of further development. However accompanied headache suggests pain not restricted only to limbs and so often a forerunner of fever. So, one should wait for fever to appear in such situations. Once fever comes up, one is still not sure about the cause of fever. However as the child looked better for a while after paracetamol, it is mostly a viral infection and one would expect quick improvement.

Of course, viral infection may trigger serious immune response though fortunately rare. Physical examination in this child showed no localising signs and as the child got better without any specific treatment, it was labelled as viral infection with myalgia. There is no need for any investigations in such a case.

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Case 2

A 6-year-old child presented with fever and severe leg ache along with headache lasting two days. Pain was so severe that he could not walk and had to be lifted to reach the doctor. There were no other symptoms. On detailed questioning, this boy had waded through knee-deep water during heavy rains few days prior to onset of this illness.

This history is relevant as one may look carefully for a disease like leptospirosis in this case. Though symptoms are similar to any other viral infection, one must observe further progress as well as note clues if any to suggest leptospirosis. It also illustrates the fact that history-taking is an art and unless one probes into details, one may miss the clue.

Aetiology of febrile illness during rainy season should consider specific diseases such as malaria and typhoid besides common viral infections and leptospirosis. Physical examination showed severe congestion in conjunctiva – almost red eye – characteristic of leptospirosis. One must watch carefully for immune phase involving liver and kidney besides other organs such as brain that may occasionally follow after apparently getting better of fever. Luckily this child did not go through such immune complications.

Diagnosis of leptospirosis was confirmed by the presence of IgM leptospira antibodies. It is important to order liver and renal function tests as these two organs are often involved in immune phase of the disease and one may find abnormal biochemisty before symptoms may ensue. He was treated with doxycycline and recovered completely.

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Case 3

A 3-year-old child presented with fever and excessive irritability that lasted for three days. There were no other specific symptoms. He was apparently well prior to this illness. Fever suggests probable infection or inflammation and excessive irritability denotes pain. Site of pain is not clear in the history as at this age of 3 years, as the child cannot localise pain and so one may not be sure whether pain is localised or generalised. However localised pain is often accompanied with related local symptoms such as vomiting in meningitis, diarrhoea in intestinal pain and nasal discharge in pain due to otitis. So it is likely to be generalised pain in this child.

Generalised pain may be either myalgia or bony pain. It can be decided easily on physical examination. Physical examination in this child showed significant pallor without lymphnode enlargement or bleeding. However, acute onset fever with pallor highly suggests possibility of leukaemia. At times, leukaemia in the early stage may present with fever as the only symptom and physical examination may elicit bony tenderness. There was no bony tenderness in this child though in a crying child, it is not easy to document it. Diagnosis of acute lymphoblastic leukemia was confirmed by blood tests and further referred to specialist for management.

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Case 4

A 3-year-old female child presented with pain on standing and walking that lasted four days. Initially, it was thought to be due to unnoticed fall or injury though the child denied any such accident. There were no other symptoms. As pain persisted, parents noticed that the child resisted movements of the right leg and there was fullness of the right knee joint. This seems to be pain arising from either the knee joint or around the knee joint. One cannot be sure it may be due to periarticular tissue or bone itself besides the joint. As there was no significant fever, acute infection is unlikely. So it may be non-infective inflammation and leukaemia should also be kept in mind.

Physical examination showed knee joint swelling with restricted active and passive movements. This confirms articular involvement. Periarticular disease presents with free passive movements though active movements are restricted. So diagnosis of arthritis is made though aetiology is not evident.Acute infection can be ruled out though tuberculosis remains a possibility. Haematological disorders are also unlikely. One may have to wait to see further progress over days or weeks. Until then, clinical follow-up is the most rational way forward.

On detailed physical examination, few small joints of the hand were also affected, though minimally. So this was not monoarthritis as thought initially, but it was pauciarthritis with three other joints involved. This pointed strongly to juvenile idiopathic arthritis.

The important lesson to learn in this child is a fact that every child presenting with single joint involvement must be properly screened for affection of other joints that is easily missed. Investigations – CBC was within normal limits though ESR was 75 mm that indicated inflammation. It pointed to a probable juvenile idiopathic arthritis. Considering this possibility, one must look for iridocyclitis as it is a common accompaniment.

ANA may be positive or negative in such a child and in fact ANA should be ordered only if one suspects lupus and not otherwise. It is a non-specific test for other conditions. This child showed eye involvement and so diagnosis of juvenile idiopathic arthritis with iridocyclitis was made. Such children must be referred to a specialist.

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Case 5

A one-year-old, severely malnourished infant presented with excessive irritability and paucity of limb movements that lasted two days. There was no fever or any other significant symptoms. This child was fed with dilute milk without any solid food till date. He had past history of two episodes of loose stools.

Paucity of movements may suggest neurological disease but excessive irritability may denote possibility of severe painful conditions affecting all limbs that has resulted in pseudo-paralysis. So it may represent generalised limb pain. In the absence of fever, it is less likely to be infection or non-infective inflammation, though a severely malnourished infant may not respond with fever despite serious infection or inflammation. Leukemia is a possibility and so also scurvy as this child is severely malnourished.

Physical examination showed severe malnutrition – weight 4.5 kg, length 65 cm, head O 43 cm, significant pallor, painful movements of all limbs, no purpura or bleeding gums, no hepatosplenomegaly or lymphadenopathy. Other systems were normal including the nervous system. Absence of enlargement of liver, spleen or lymph nodes favour diagnosis of scurvy in this child. Bleeding gums are seen only when many teeth erupt and as this child had only two teeth, this sign may not appear so early.

Bony tenderness is seen in both scurvy and leukaemia but is difficult to note in a crying infant and so not dependable. Investigations ruled out leukaemia and so diagnosis of scurvy was made. It can be proved by low serum vitamin C levels though such a test is not routinely available. So, the best diagnostic test is radiological demonstration of periosteal haemorrhage along with other epiphyseal changes.

This child was confirmed to be suffering from scurvy besides multiple nutritional deficiencies. He was treated with 500 mg of vitamin C per day and within three days, the pain had disappeared and he could move his limbs well and was no more irritable. This is also a therapeutic test for scurvy as improvement after large dose of vitamin C is quickly seen.

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Case 6

A 10-year-old male child presented with pain and swelling of the left knee joint for two days. He was apparently well prior to the present problem. He started experiencing pain in the left knee region within half an hour after a trivial fall while walking. It was considered to be a sprain, but got worse over the next two days. There was no fever. Apparently, it would look like a traumatic injury but it is worth noting that the fall was trivial though the outcome of injury was much more severe. It suggests underlying pathology. Such preexisting pathology may be congenital malformation in the joint itself or functional disorder like haemophilia or acquired condition like leukaemia.

On detailed history, it was revealed that he would bleed easily after an injury that would take time to control. This in a male child suggested haemophilia and further confirmed by history of similar disease in the maternal uncle. Physical examination showed significant swelling of the left knee joint with tenderness and restriction of movements – both active and passive – but without warmth or redness. This suggests diagnosis of haemophilia. It was confirmed by blood tests showing very low levels of factor 8.

Management consists of factor 8 replacement to stop further bleeding and thereafter cautious physiotherapy to prevent damage to the joint. Such a child is prone to deep bleeding on trivial injury and so should be advised not to participate in physical sports.

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Case 7

An 8-year-old child presented with history of pain and paucity of movements of both legs that lasted four days. There were no other significant symptoms. He had suffered from simple viral infection few days prior to this illness but had recovered completely without any specific drugs. It is important to decide whether this is true paresis or pseudoparesis due to severe pain. On direct questioning, it was revealed that he could not move his limbs at all and so it was true paresis.

Neurological condition that presents with pain may be due to affection of nerve roots or also due to spasm of affected muscles as a result of anterior horn cell irritation as in case of polio or polio-like viral infection. So, either could be possible though physical examination should be able to differentiate between these two conditions.

Physical examination showed lower motor neuron involvement with symmetrical affection of both lower limbs without involvement of upper limbs or other areas. Further, on raising the leg straight, pain was exaggerated suggesting root involvement. Anterior horn cell disease is usually patchy. This child did not show any sensory involvement and so it was pure motor paresis. This favoured diagnosis of ascending polyneuritis – autoimmune disease (GBS) This disease may worsen over the next few days and involve respiratory muscles along with upper limbs. He was treated with IV gamma-globulin and recovered completely without any further worsening.

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Case 8

A 10-year-old child presented with history of pain in both legs mainly in the evenings lasting two months. Through the day, he would remain active without pain but by late evening, especially just before going to bed, he would complain of aches in both legs. Pain would get relieved with massage and he would fall asleep to get up and remain normal through the next day.

There was no relief with pain killers though massage made him feel relieved. This history is typical of growing pain. This is the pain that is relieved with massage and the child may feel much more comfortable with vigorous massage. It rules out any inflammatory condition. It suggest tired muscles with accumulation of metabolic products that are absorbed following increase in blood supply with massage or application of heat.

The exact cause is not known though growing pain is a benign condition and gets well by itself over time. One must avoid repeated use of analgesics that may lead to renal damage. Physical measures are good enough to offer relief. Physical examination in this child was totally normal. There is no need for any investigations in such a child. Parents were counselled about diagnosis of growing pain.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.