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Juvenile Idiopathic Arthritis

Juvenile idiopathic Idiopathic Dermatomyositis arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis (JIA), formerly known as juvenile rheumatoid arthritis Rheumatoid arthritis Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis and chronic, progressive, autoimmune disorder. Presentation occurs most commonly in middle-aged women with joint swelling, pain, and morning stiffness (often in the hands). Rheumatoid Arthritis, is a heterogeneous group of inflammatory diseases characterized by inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of 1 or more joints and is the most common pediatric rheumatic disease. Juvenile idiopathic Idiopathic Dermatomyositis arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis is classified according to its clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor, and diagnosis is made with examination findings as well as confirmatory lab testing showing evidence of inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation and characteristic X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests findings. Treatment is directed at preventing loss of function Loss of Function Inflammation and controlling or limiting joint damage, with a variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables prognosis Prognosis A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas depending on the type.

Last updated: 11 Nov, 2021

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Juvenile idiopathic Idiopathic Dermatomyositis arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis, formerly known as juvenile rheumatoid arthritis Rheumatoid arthritis Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis and chronic, progressive, autoimmune disorder. Presentation occurs most commonly in middle-aged women with joint swelling, pain, and morning stiffness (often in the hands). Rheumatoid Arthritis, is the most common chronic rheumatological disease in the pediatric population. While there are multiple subgroups with distinct pathogeneses, the key feature is arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis

Definition

Juvenile idiopathic Idiopathic Dermatomyositis arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis is a term used to describe a group of inflammatory conditions of the joints affecting children younger than 16 and lasting 6 weeks or longer.

Classification

Classification according to symptomatology Symptomatology Scarlet Fever (as per the International League of Associations for Rheumatology):

  • Oligoarticular JIA: 
  • Polyarticular JIA: 
  • Systemic JIA (previously called Still’s disease):
    • Arthritis in 1 or multiple joints 
    • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever ≥ 2 weeks that happens daily for at least 3 days
    • 1 or more of the following: 
      • Evanescent, erythematous rash Rash Rocky Mountain Spotted Fever
      • Hepatomegaly 
      • Splenomegaly Splenomegaly Splenomegaly is pathologic enlargement of the spleen that is attributable to numerous causes, including infections, hemoglobinopathies, infiltrative processes, and outflow obstruction of the portal vein. Splenomegaly
      • Lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy (LAD)
      • Serositis Serositis Inflammation of a serous membrane. Systemic Lupus Erythematosus
  • Psoriatic JIA:
    • Present with arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis and psoriasis Psoriasis Psoriasis is a common T-cell-mediated inflammatory skin condition. The etiology is unknown, but is thought to be due to genetic inheritance and environmental triggers. There are 4 major subtypes, with the most common form being chronic plaque psoriasis. Psoriasis
    • May present with arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis alone and 1 of the following:
  • Enthesitis Enthesitis Ankylosing Spondylitis arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis (also called pediatric spondyloarthropathy Spondyloarthropathy Ankylosing Spondylitis):
    • Present with arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis and enthesitis (inflammation of the entheses, the sites where tendons or ligaments insert into the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types)
    • May present with only either arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis or enthesitis and 2 of the following criteria:
      • Tenderness of the sacroiliac (SI) joint or lumbosacral pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways due to inflammation
      • Positive HLA-B27
      • 1st-degree relative with acute anterior uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea, ankylosing spondylitis Ankylosing spondylitis Ankylosing spondylitis (also known as Bechterew’s disease or Marie-Strümpell disease) is a seronegative spondyloarthropathy characterized by chronic and indolent inflammation of the axial skeleton. Severe disease can lead to fusion and rigidity of the spine. Ankylosing Spondylitis, inflammatory bowel disease (IBD) with sacroiliitis Sacroiliitis Inflammation of the sacroiliac joint. It is characterized by lower back pain, especially upon walking, fever, uveitis; psoriasis; and decreased range of motion. Many factors are associated with and cause sacroiliitis including infection; injury to spine, lower back, and pelvis; degenerative arthritis; and pregnancy. Ankylosing Spondylitis, or reactive arthritis Reactive arthritis Reactive arthritis is a seronegative autoimmune spondyloarthropathy that occurs in response to a previous gastrointestinal (GI) or genitourinary (GU) infection. The disease manifests as asymmetric oligoarthritis (particularly of large joints in the lower extremities), enthesopathy, dactylitis, and/or sacroiliitis. Reactive Arthritis
      • Acute anterior uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea
      • Onset of arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis in boys > 6 years old
  • Undifferentiated JIA:
    • Patients meeting criteria for more than 1 category
    • Patients not meeting full criteria for another category

Epidemiology

  • Most common rheumatic disease in children
  • Prevalence varies secondary to disease and patient variables: 
    • Gender Gender Gender Dysphoria:
    • Geographical location:
    • Age (note: by definition, onset must be before 16 years of age):
      • 1–3 years of age: peak incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency of JIA (predominantly girls) 
      • 8–10 years of age: 2nd peak (smaller, and more boys with oligoarticular JIA)
      • Mean Mean Mean is the sum of all measurements in a data set divided by the number of measurements in that data set. Measures of Central Tendency and Dispersion age of onset for both systemic and polyarticular disease: approximately 6 years old 
      • Mean Mean Mean is the sum of all measurements in a data set divided by the number of measurements in that data set. Measures of Central Tendency and Dispersion age of onset for oligoarticular disease: 4 years in girls and 10 years in boys 
Table: Epidemiology of major types of JIA
Oligoarticular Polyarticular Systemic
% of JIA cases 50% 35% 10%
Gender Gender Gender Dysphoria Girls > boys Girls > boys Girls = boys
Age 2–3 years old, rare > 10 years old 2–5 years old, 10–14 years old Any < 16

Etiology and Pathophysiology

Etiology

While genetic susceptibility plays a role in JIA, the exact etiology and pathogenesis of the disease is incompletely understood. Juvenile idiopathic Idiopathic Dermatomyositis arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis is believed to be caused by an interplay between environmental exposures and genetic predisposition.

Environmental component:

  • Possible risk factors:
    • Antibiotic use 
    • C-section birth
    • Exposure Exposure ABCDE Assessment to pathogens (e.g., parvovirus B19 Parvovirus B19 Primate erythroparvovirus 1 (generally referred to as parvovirus B19, B19 virus, or sometimes erythrovirus B19) ranks among the smallest DNA viruses. Parvovirus B19 is of the family Parvoviridae and genus Erythrovirus. In immunocompetent humans, parvovirus B19 classically results in erythema infectiosum (5th disease) or “slapped cheek syndrome.” Parvovirus B19, EBV EBV Epstein-barr virus (EBV) is a linear, double-stranded DNA virus belonging to the herpesviridae family. This highly prevalent virus is mostly transmitted through contact with oropharyngeal secretions from an infected individual. The virus can infect epithelial cells and B lymphocytes, where it can undergo lytic replication or latency. Epstein-Barr Virus, enteric bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology, Chlamydophila pneumoniae, and Streptococcus Streptococcus Streptococcus is one of the two medically important genera of gram-positive cocci, the other being Staphylococcus. Streptococci are identified as different species on blood agar on the basis of their hemolytic pattern and sensitivity to optochin and bacitracin. There are many pathogenic species of streptococci, including S. pyogenes, S. agalactiae, S. pneumoniae, and the viridans streptococci. Streptococcus)
  • Possible protective factors:
    • Breastfeeding Breastfeeding Breastfeeding is often the primary source of nutrition for the newborn. During pregnancy, hormonal stimulation causes the number and size of mammary glands in the breast to significantly increase. After delivery, prolactin stimulates milk production, while oxytocin stimulates milk expulsion through the lactiferous ducts, where it is sucked out through the nipple by the infant. Breastfeeding 
    • Household siblings 

Genetic component:

  • Monozygotic twins Monozygotic twins Result from the division of a single zygote; share the same genetic material Multiple Pregnancy have a 25%–40% concordance rate of developing the disease.
  • Patterns of inheritance are not Mendelian or single gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics (having an affected sibling does not significantly increase risk).
  • Specific HLA alleles as well as non-HLA genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure may be associated with specific JIA subtypes.
  • The more HLA-DR risk alleles a patient has, the more likely they are to develop JIA and the earlier they develop it.

Pathophysiology

  • Pathogenesis varies related to the subtype:
    • Autoimmune or autoinflammatory disease
    • Imbalance between the overactivation (both innate and adaptive) and regulation of the immune system Immune system The body’s defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs
  • Synovium is the primary target of the inflammatory response:
    • Immune system cells are activated and secrete proinflammatory cells, such as tumor Tumor Inflammation necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage factor ( TNF TNF Tumor necrosis factor (TNF) is a major cytokine, released primarily by macrophages in response to stimuli. The presence of microbial products and dead cells and injury are among the stimulating factors. This protein belongs to the TNF superfamily, a group of ligands and receptors performing functions in inflammatory response, morphogenesis, and cell proliferation. Tumor Necrosis Factor (TNF))–alpha, IL-6 cells, and IL-1 cells.
    • T- lymphocytes Lymphocytes Lymphocytes are heterogeneous WBCs involved in immune response. Lymphocytes develop from the bone marrow, starting from hematopoietic stem cells (HSCs) and progressing to common lymphoid progenitors (CLPs). B and T lymphocytes and natural killer (NK) cells arise from the lineage. Lymphocytes: Histology and B- lymphocytes Lymphocytes Lymphocytes are heterogeneous WBCs involved in immune response. Lymphocytes develop from the bone marrow, starting from hematopoietic stem cells (HSCs) and progressing to common lymphoid progenitors (CLPs). B and T lymphocytes and natural killer (NK) cells arise from the lineage. Lymphocytes: Histology are involved in the development of the inflammatory state of the joint.
    • The synovium proliferates and becomes inflamed, increasing blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure to the joint, which leads to edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema and swelling Swelling Inflammation of the joint:
      • Increased amount of synovial fluid
      • Decreased viscosity of synovial fluid
    • Persistent synovitis Synovitis Inflammation of the synovial membrane. Rheumatoid Arthritis ultimately causes joint destruction.
    • Eventually, bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types, tendon, and ligament destruction is also produced.

Clinical Presentation

The presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor of JIA is variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables secondary to the heterogeneous nature of the various subgroups, but there are some common features.

Common features

  • Progressive pattern of symptoms and findings:
  • Arthritis present for at least 6 weeks before diagnosis
  • Long-standing joint pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways (25% may not have pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, only swollen joints)
  • Morning stiffness or, after a long period of inactivity, gelling
  • Limping, which may improve during the day with activity
  • Eye redness Redness Inflammation and pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways suggestive of uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea: can have significant impact on vision Vision Ophthalmic Exam-related quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement of life in children

Clinical presentations unique to each subtype

  • RF RF Rheumatoid Arthritis-positive polyarticular and systemic subtypes: destructive arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis 
  • Psoriatic arthritis Psoriatic Arthritis A type of inflammatory arthritis associated with psoriasis, often involving the axial joints and the peripheral terminal interphalangeal joints. It is characterized by the presence of hla-b27-associated spondyloarthropathy, and the absence of rheumatoid factor. Psoriasis
    • Swelling of fingers, wrists, and ankles 
    • Nail involvement/pitting 
  • Systemic JIA:
    • Rash on the trunk and extremities 
    • Fevers occurring once or twice each day at about the same time of day
    • Macrophage activation Macrophage activation The process of altering the morphology and functional activity of macrophages so that they become avidly phagocytic. It is initiated by lymphokines, such as the macrophage activation factor (maf) and the macrophage migration-inhibitory factor (mmif), immune complexes, C3b, and various peptides, polysaccharides, and immunologic adjuvants. IL-12 Receptor Deficiency syndrome (MAS): rare complication involving severe hematological changes, a medical emergency
  • Enthesitis Enthesitis Ankylosing Spondylitis-related arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis: post-exercise pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
Table: Clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor of major types of JIA
Oligoarticular Polyarticular Systemic
Number of joints affected Fewer than 5 > 5 Any
Types of joints affected
  • Medium and large joints
  • Asymmetric
  • Rare in hips
  • Less destructive arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis
Systemic features
  • Appear well without significant systemic features
  • If ANA+, more likely to develop uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea
Less frequent uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea
  • The child appears ill.
  • Daily high fevers
  • Evanescent salmon-pink rash Rash Rocky Mountain Spotted Fever, hepatosplenomegaly Hepatosplenomegaly Cytomegalovirus, large LAD, heart/lung/ liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy involvement

Long-term complications

  • Growth disturbance
  • Osteopenia Osteopenia Osteoporosis
  • Functional disability Disability Determination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits. ABCDE Assessment ( leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy length discrepancies, flexion Flexion Examination of the Upper Limbs contracture of joints, loss of cervical spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy extension Extension Examination of the Upper Limbs)
  • Long-term visual changes secondary to uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea

Diagnosis

Diagnosis of JIA is primarily based on history and physical exam findings. The laboratory data and imaging contribute to the confirmation of the diagnosis and the exclusion of other diseases.

Laboratory findings

  • Inflammatory markers may be elevated in systemic JIA and polyarticular JIA:
  • Corticobasal degeneration Corticobasal Degeneration Atypical Parkinsonian Syndromes (CBC): 
    • Neutropenia Neutropenia Neutrophils are an important component of the immune system and play a significant role in the eradication of infections. Low numbers of circulating neutrophils, referred to as neutropenia, predispose the body to recurrent infections or sepsis, though patients can also be asymptomatic. Neutropenia is uncommon.
    • When it is associated with thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia, consider acute lymphocytic leukemia.
  • ANA: 
    • Up to 70% of oligoarticular JIA children have positive ANA.
    • +ANA increases the prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency of uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea and these children require regular Regular Insulin slit lamp Slit Lamp A microscope with a light source that can be projected into a linear beam. It allows cross-sectional viewing of the aqueous humor; conjuncteiva; cornea; eyelids; iris; and lens of the eye. Ophthalmic Exam screening Screening Preoperative Care.
  • RF RF Rheumatoid Arthritis and anti-cyclic citrullinated peptide (CCP) antibody: important in defining subtype and prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas
  • HLA-B27: may be positive in enthesitis-related arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis

Radiology

Variable findings related to severity and type of disease; often used to evaluate for other diagnoses:

  • Plain radiographs:
    • Limited utility, particularly as early signs are not detectable on X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests
    • May demonstrate:
    • Cervical spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy radiographs: atlantoaxial subluxation Subluxation Radial Head Subluxation (Nursemaid’s Elbow)
  • MRI:
    • Gold standard
    • Particularly sensitive for evaluating synovitis Synovitis Inflammation of the synovial membrane. Rheumatoid Arthritis
    • Evaluate synovial hypertrophy Hypertrophy General increase in bulk of a part or organ due to cell enlargement and accumulation of fluids and secretions, not due to tumor formation, nor to an increase in the number of cells (hyperplasia). Cellular Adaptation and bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types and cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology erosions Erosions Corneal Abrasions, Erosion, and Ulcers
  • Ultrasonography:

Management

The primary goal in the management of JIA is to limit Limit A value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lung Invasive Mechanical Ventilation the extent of joint damage and restrict the loss of function Loss of Function Inflammation. Juvenile idiopathic Idiopathic Dermatomyositis arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis is a chronic disease, and inducing remission Remission A spontaneous diminution or abatement of a disease over time, without formal treatment. Cluster Headaches with the least amount of toxicity Toxicity Dosage Calculation is essential.

Overall management

  • Pharmacological therapy:
    • NSAIDS NSAIDS Primary vs Secondary Headaches
    • Disease-modifying antirheumatic drugs Disease-modifying antirheumatic drugs Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs) ( DMARDs DMARDs Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs))
    • Biologic agents
    • Intra-articular and oral steroids Steroids A group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. Benign Liver Tumors
  • Nutrition: addressing bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types health and anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types ( iron Iron A metallic element with atomic symbol fe, atomic number 26, and atomic weight 55. 85. It is an essential constituent of hemoglobins; cytochromes; and iron-binding proteins. It plays a role in cellular redox reactions and in the transport of oxygen. Trace Elements deficiency anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types ( IDA IDA Iron deficiency anemia is the most common type of anemia worldwide. This form of anemia is caused by insufficient iron due to a decreased supply, an increased loss, or an increased demand. Iron deficiency anemia is seen across all ages, sexes, and socioeconomic strata; however, children, women of childbearing age, and patients from lower socioeconomic strata are at higher risk. Iron Deficiency Anemia)) with diet 
  • PT and occupational therapy Occupational Therapy Skilled treatment that helps individuals achieve independence in all facets of their lives. It assists in the development of skills needed for independent living. Fetal Alcohol Spectrum Disorder:
    • Joint protection and optimizing function
    • Consider orthoses to protect the joint.
  • Psychosocial: family, school issues
  • Medical therapy/medications for JIA are best guided by a pediatric rheumatologist.

Oligoarticular JIA

  • Low disease activity: NSAIDs and/or intra-articular steroid therapy as indicated
  • High disease activity:
    • NSAIDS NSAIDS Primary vs Secondary Headaches, intra-articular steroid therapy, and escalate to DMARDs DMARDs Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs) ( MTX MTX An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy initially)
    • Folic acid (with MTX MTX An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy therapy)
  • TNF TNF Tumor necrosis factor (TNF) is a major cytokine, released primarily by macrophages in response to stimuli. The presence of microbial products and dead cells and injury are among the stimulating factors. This protein belongs to the TNF superfamily, a group of ligands and receptors performing functions in inflammatory response, morphogenesis, and cell proliferation. Tumor Necrosis Factor (TNF) inhibitors used if not responding after 3 months

Polyarticular JIA

  • DMARD DMARD Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs) is recommended at the time of diagnosis (rare for NSAIDS NSAIDS Primary vs Secondary Headaches alone to control the inflammation).
  • MTX MTX An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy is the initial DMARD DMARD Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs) choice: folic acid (with MTX MTX An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy therapy).
  • Corticosteroids Corticosteroids Chorioretinitis for moderate or high disease activity:
    • Oral initially
    • Injected into joint if resistant to therapy after 3 months
  • Consider biologics ( TNF TNF Tumor necrosis factor (TNF) is a major cytokine, released primarily by macrophages in response to stimuli. The presence of microbial products and dead cells and injury are among the stimulating factors. This protein belongs to the TNF superfamily, a group of ligands and receptors performing functions in inflammatory response, morphogenesis, and cell proliferation. Tumor Necrosis Factor (TNF)-alpha initial choice)

Systemic JIA

  • Mild disease (or during initial workup): NSAIDS NSAIDS Primary vs Secondary Headaches as an initial trial 
  • More severe disease and evidence of systemic manifestations:
    • Glucocorticoids Glucocorticoids Glucocorticoids are a class within the corticosteroid family. Glucocorticoids are chemically and functionally similar to endogenous cortisol. There are a wide array of indications, which primarily benefit from the antiinflammatory and immunosuppressive effects of this class of drugs. Glucocorticoids and NSAIDS NSAIDS Primary vs Secondary Headaches
    • DMARDS or biological agents are both used by pediatric rheumatologists.

Psoriatic JIA

  • NSAIDS NSAIDS Primary vs Secondary Headaches initially
  • Intra-articular glucocorticoids
  • DMARDS as indicated ( MTX MTX An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy is the most frequently used)
  • Biologics as indicated

Remission

American College of Rheumatology criteria for complete remission Remission A spontaneous diminution or abatement of a disease over time, without formal treatment. Cluster Headaches:

  • No inflammatory joint pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • No fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia
  • No synovitis Synovitis Inflammation of the synovial membrane. Rheumatoid Arthritis
  • No morning stiffness
  • Normal ESR ESR Soft Tissue Abscess and CRP levels

Differential Diagnosis

  • Gonococcal arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis: an infection due to Neisseria gonorrhoeae. Disseminated disease can present similar to JIA with an acute, inflammatory, asymmetric arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis with urethritis Urethritis Inflammation involving the urethra. Similar to cystitis, clinical symptoms range from vague discomfort to painful urination (dysuria), urethral discharge, or both. Urinary tract infections (UTIs). Diagnosis is based on the clinical history, synovial fluid analysis Synovial Fluid Analysis Rheumatoid Arthritis, and culture results. Management includes antibiotics. 
  • Reactive arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis: a seronegative, autoimmune spondyloarthropathy Spondyloarthropathy Ankylosing Spondylitis that is often precipitated by a GI or genitourinary infection. Patients present with an asymmetric oligoarthritis Oligoarthritis Ankylosing Spondylitis, enthesopathy Enthesopathy Reactive Arthritis, dactylitis, and/or sacroiliitis Sacroiliitis Inflammation of the sacroiliac joint. It is characterized by lower back pain, especially upon walking, fever, uveitis; psoriasis; and decreased range of motion. Many factors are associated with and cause sacroiliitis including infection; injury to spine, lower back, and pelvis; degenerative arthritis; and pregnancy. Ankylosing Spondylitis. The diagnosis is clinical, and a negative synovial Gram stain Gram stain Klebsiella and culture will help rule out septic arthritis Septic arthritis Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. Septic Arthritis. Management includes NSAIDs, DMARDS, and treatment of an active infection.
  • Osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis ( OA OA Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis): an arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis due to cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology destruction and changes of the subchondral bone Subchondral Bone Osteochondritis Dissecans. Patients develop gradual joint pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, stiffness lasting < 30 minutes, and decreased range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs (ROM). Physical exam may reveal crepitus Crepitus Osteoarthritis with joint motion and osteophyte Osteophyte Bony outgrowth usually found around joints and often seen in conditions such as arthritis. Osteoarthritis formation. The diagnosis is clinical. Synovial fluid will be noninflammatory, which differentiates OA OA Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis from septic arthritis Septic arthritis Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. Septic Arthritis. Management includes analgesics, glucocorticoid intra-articular injections, and surgery for advanced disease. 
  • Osteomyelitis Osteomyelitis Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus. Osteomyelitis: an infection of the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types, most commonly caused by Staphylococcus Staphylococcus Staphylococcus is a medically important genera of Gram-positive, aerobic cocci. These bacteria form clusters resembling grapes on culture plates. Staphylococci are ubiquitous for humans, and many strains compose the normal skin flora. Staphylococcus aureus. Patients present with pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, redness Redness Inflammation, and swelling Swelling Inflammation of the affected site and may have associated symptoms such as fever and chills Chills The sudden sensation of being cold. It may be accompanied by shivering. Fever. Laboratory values will demonstrate elevated WBC, CRP, and ESR ESR Soft Tissue Abscess in most cases. The most sensitive and specific imaging modality to diagnose osteomyelitis is MRI. Management requires long-term antibiotics and potential surgical debridement Debridement The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Stevens-Johnson Syndrome.
  • Lyme disease Lyme disease Lyme disease is a tick-borne infection caused by the gram-negative spirochete Borrelia burgdorferi. Lyme disease is transmitted by the black-legged Ixodes tick (known as a deer tick), which is only found in specific geographic regions. Patient presentation can vary depending on the stage of the disease and may include a characteristic erythema migrans rash. Lyme Disease: a tick-borne infection caused by the Gram-negative spirochete Spirochete Treponema is a gram-negative, microaerophilic spirochete. Owing to its very thin structure, it is not easily seen on Gram stain, but can be visualized using dark-field microscopy. This spirochete contains endoflagella, which allow for a characteristic corkscrew movement. Treponema Borrelia Borrelia Borrelia are gram-negative microaerophilic spirochetes. Owing to their small size, they are not easily seen on Gram stain but can be visualized using dark-field microscopy, Giemsa, or Wright stain. Spirochetes are motile and move in a characteristic spinning fashion due to axial filaments in the periplasmic space. Borrelia burgdorferi. Patients with late disease may develop a migratory polyarthritis Polyarthritis Rheumatoid Arthritis, particularly in large joints. An erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion migrans rash Rash Rocky Mountain Spotted Fever as well as neurologic, cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR), and ocular manifestations may also be present. Synovial fluid analysis and serologic testing can confirm a Lyme infection and will differentiate the disease from septic arthritis Septic arthritis Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. Septic Arthritis. Antibiotic therapy is used for treatment.

References

  1. Wu, EY, & Rabinovich, CE. (2020). Juvenile idiopathic arthritis. In Kliegman, RM, et al. (Eds.), Nelson Textbook of Pediatrics, pp. 1258–1268, 1st Ed. Elsevier. Retrieved October 20, 2021, from https://www.clinicalkey.es/#!/content/3-s2.0-B9780323529501001802
  2. Ritchey, AK, O’Brien, SH, & Keller, FG. (2018). Hematologic manifestations of childhood illness. In Hoffman, R, et al. (Eds.), Hematology: Basic Principles and Practice, pp. 2215–2237, 7th Ed. http://dx.doi.org/10.1016/B978-0-323-35762-3.00152-9
  3. Macaubas, C, et al. (2009). Oligoarticular and polyarticular JIA: Epidemiology and pathogenesis. Nature Reviews Rheumatology, 5(11), pp. 616–626. https://doi.org/10.1038/nrrheum.2009.209
  4. Weiss, JE, & Ilowite, NT. (2005). Juvenile idiopathic arthritis. Pediatr Clin North Am, 52(2), 413–42. https://pubmed.ncbi.nlm.nih.gov/15820374/
  5. Macaubas, C, et al.  (2012). Alternative activation in systemic juvenile idiopathic arthritis monocytes. Clinical Immunology (Orlando, Fla.), 142(3), pp. 362–372. https://doi.org/10.1016/j.clim.2011.12.008
  6. Dimitriou, C, et al. (2017) Imaging of juvenile idiopathic arthritis. Radiologic Clinics of North America, 55(5), pp. 1071–1083. https://pubmed.ncbi.nlm.nih.gov/28774449/
  7. Beukelman, T, et al. (2011). 2011 American College of Rheumatology recommendations for the treatment of juvenile idiopathic arthritis: Initiation and safety monitoring of therapeutic agents for the treatment of arthritis and systemic features. Arthritis Care & Research, 63(4), pp. 465–482. https://doi.org/10.1002/acr.20460

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