Differential Diagnosis: Whole-Body Pain in a 17-Year-Old Girl (No Fever)

1. Functional / Central Sensitization Disorders (Most Common in This Age Group)

Fibromyalgia / Juvenile Fibromyalgia

• The single most likely diagnosis in an adolescent girl with diffuse pain and no fever
• Characterized by chronic widespread musculoskeletal pain above and below the waist, bilateral, involving the axial skeleton, with no alternative organic cause
• Often co-exists with fatigue, sleep disturbance, headache, irritable bowel, and mood symptoms
• Prevalence of chronic widespread pain: 4-12% of the general population, more common in females
• Goldman-Cecil Medicine, p. 2885

Pain Amplification Syndromes / Central Sensitization

• Broad category including fibromyalgia and nociplastic pain
• The nervous system amplifies pain signals without peripheral tissue damage
• Often follows a physical or psychological stressor (illness, trauma, exam stress)
• Rheumatology (Elsevier, 2022)

Complex Regional Pain Syndrome (CRPS)

• Usually regional but can be widespread in adolescents; 73% female, mean age ~12 years
• Children treated as functional neurological disorder; full recovery with physiotherapy + CBT
• Rheumatology (Elsevier, 2022), CRPS in Children section

Somatic Symptom Disorder / Psychosomatic Pain

• Adolescence is a peak time for somatization
• Pain is real to the patient; driven by psychological/stress factors
• Exclude with psychiatric/psychosocial evaluation

2. Inflammatory / Autoimmune Disorders

Juvenile Idiopathic Arthritis (JIA) - Systemic or Polyarticular

• Can present with widespread arthralgia/myalgia; systemic JIA may initially present without obvious arthritis
• Note: systemic JIA typically has quotidian fever - but early or atypical presentations may lack fever

Systemic Lupus Erythematosus (SLE/Juvenile SLE)

• Arthralgia and myalgia are extremely common presenting features
• Look for: photosensitivity rash, oral ulcers, hair loss, fatigue, family history
• Check: ANA, anti-dsDNA, complement levels, CBC, urinalysis

Juvenile Dermatomyositis

• Proximal muscle weakness + myalgia; often has skin involvement (heliotrope rash, Gottron's papules)
• Elevated CK, aldolase

Mixed Connective Tissue Disease / Undifferentiated Connective Tissue Disease

• Overlap features of SLE, myositis, scleroderma
• Anti-U1 RNP antibody positive

Reactive Arthritis / Post-Infectious Arthralgia

• Follows GI (Salmonella, Campylobacter) or urogenital (Chlamydia) infection
• Pain onset 1-4 weeks after infection, often with no active infection/fever at presentation

Rheumatic Fever (Post-Streptococcal)

• Migratory polyarthritis, carditis; usually follows Group A Strep pharyngitis
• Can present without fever at later stages; check ASO titre

3. Hematologic Disorders

Sickle Cell Disease / Vaso-Occlusive Crisis

• If ethnically relevant; diffuse bone and muscle pain without fever possible in early/mild crisis
• Check CBC, peripheral smear, Hb electrophoresis

Leukemia / Lymphoma

• Must not be missed - bone pain from marrow infiltration can mimic musculoskeletal pain
• Red flags: nocturnal pain, bone tenderness, lymphadenopathy, pallor, weight loss
• Check CBC with differential; LDH; blood film

4. Metabolic / Endocrine / Nutritional

5. Infectious (Afebrile / Post-Infectious)

6. Medications / Substances

• Statins (rare in teenagers), corticosteroid withdrawal, fluoroquinolones
• Drug/substance use - opioid withdrawal causes severe myalgia/pain
• Oral contraceptive pills - occasionally cause musculoskeletal discomfort

7. Hypermobility / Connective Tissue

• Joint Hypermobility Syndrome / Ehlers-Danlos Syndrome (hEDS)
• Very common in adolescent girls; widespread joint and muscle pain, "growing pains"
• Assess with Beighton score
• Rheumatology (Elsevier, 2022)

Systematic Approach / Initial Workup

History Clues to Prioritize

• Duration and pattern - acute vs chronic, constant vs episodic
• Sleep quality, fatigue, mood - supports fibromyalgia/functional
• Recent illness - post-viral, reactive arthritis
• Menstrual history - dysmenorrhea, endometriosis (pelvic component)
• Family history - autoimmune, sickle cell
• Psychosocial stressors - school, relationships, trauma

First-Line Investigations

Priority Summary

Prednisolone 40 mg in a 17-Year-Old Girl with Whole-Body Pain?

Short answer: No - not without a confirmed diagnosis that requires it.

Why 40 mg Prednisolone Is NOT Appropriate Empirically

1. It Would Be Harmful in the Most Likely Diagnosis - Fibromyalgia

• Expose the patient to steroid side effects without benefit
• Delay the correct diagnosis and treatment
• Rheumatology (Elsevier, 2022), Treatment of Fibromyalgia

2. It Could Mask a Dangerous Underlying Diagnosis

• If leukemia is the cause, steroids can cause transient remission, making diagnosis much harder and delaying curative treatment
• If SLE is being evaluated, steroids alter serological markers
• It can mask infection signs if an occult infection is present

3. Serious Side Effects in a 17-Year-Old

4. No Specific Indication Has Been Established Yet

What Should Be Done Instead

1. Complete the diagnostic workup first (CBC, ESR, CRP, ANA, Vitamin D, TSH, CK, urinalysis - as outlined previously)
2. Empirical analgesics that are safe: paracetamol (acetaminophen), NSAIDs (ibuprofen/naproxen with food) for short-term symptomatic relief
3. Refer to rheumatology if autoimmune disease is suspected
4. Replace Vitamin D if deficient - this alone can resolve symptoms in many adolescents
5. If fibromyalgia is confirmed: physiotherapy, CBT, sleep hygiene, and if needed low-dose amitriptyline

Bottom Line

Prednisolone 40 mg without a diagnosis is not appropriate in this patient. It treats no confirmed condition, risks serious harm, and may obscure life-threatening diagnoses like leukemia. Establish the diagnosis first, then treat accordingly.