We describe the development of rheumatoid factor-positive migratory polyarthritis in a 5-year-old male who had been administered bidaily oral mineral oil as a laxative since birth. Minor respiratory symptoms, radiographic and bronchoscopic findings were consistent with chronic lipoid pneumonia. We speculate that immune sensitization to mineral oil promoted the clinical syndrome of juvenile idiopathic arthritis.
Juvenile idiopathic arthritis (JIA) is an autoimmune disorder characterized by chronic inflammation and destruction of cartilage and bone. JIA is caused by both genetic and environmental triggers. There are 17 genes which are linked to the development of the disease [
A 5-year-old Caucasian boy presented with worsening, episodic leg, and ankle pains since two years of age. Painful episodes lasted several days and were typically intermittent, about every four to six weeks. Increasing frequency and new symptoms in feet and hands prompted referral to our facility. Past medical history was notable for difficulty to gain weight, complex partial seizure disorder, and long-term constipation. The constipation was managed with 5 mL oral mineral oil administered bidaily by syringe since postnewborn age. At age of 5 years, he weighed 19.7 kg (49th percentile) and was 113.2 cm tall (69th percentile). Examination was normal, including lung exam, except for swelling of the dorsum of wrists with decreased dorsiflexion, extension, and pain with motion. Hemoglobin, white blood count, and morphology were all identified within normal ranges. He had elevated rheumatoid factor (RF) at >802 IU/mL, anti-cyclic citrullinated peptide antibody 121 U (strongly positive > 60), positive anti-histone antibody 1.3 U (nl < 1.0 U), erythrocyte sedimentation rate at 27 mm/h, and C-reactive protein (CRP) < 3 mg/L. There were no known cardiac, pulmonary, or renal abnormalities, but outside chest radiography “opacifications” during an evaluation for “pneumonia” were noted.
Magnetic resonance imaging of the right wrist showed diffuse mottled edema and hazy enhancement of carpal bones. There was moderate thickening and enhancement of the synovium and soft tissue surrounding the carpus. Soft tissue wrist biopsy of the extensor sheath showed fibrovascular and synovial tissue with moderate lymphoplasmacytic inflammation. A routine chest radiogram showed a left lower lobe infiltrate. Subsequently, a chest computed tomography scan (Figure
High resolution CT image of lower lobes. Arrows show diffuse hazy mixed alveolar interstitial infiltrates involving much of the left lower lobe and medial portions of the lingula, right middle lobe, and medial right lower lobe.
The diagnoses were consistent with chronic lipoid pneumonia, a silent complication of chronic occult mineral oil aspiration and inflammatory arthritis consistent with RF positive JIA. Discontinuance of mineral oil and initiation of hydroxychloroquine (100 mg/day) and methotrexate (12.5 mg/week) lead to a moderate improvement in frequency and severity of symptoms. At age of 7 years he has not achieved clinical remission and he continues to have episodic flairs of joint pain leading to school absence and restricted activity.
RF positive JIA is a chronic autoimmune disorder eliciting inflammation and destruction of joints [
It is generally accepted that the development of JIA is a consequence of the environmental triggers in a genetically susceptible individual [
In 1956, Pearson demonstrated that complete Freund’s adjuvant caused arthritis in animal models [
Exogenous lipoid pneumonia occurs due to the inhalation or aspiration of fatty substances, chiefly mineral oil. Clinical symptoms include cough, dyspnea, chest pains, hemoptysis, or periodic fevers. These symptoms are likely due to direct an inflammatory response or coexisting infection. Common substances aspirated to cause lipoid pneumonia include petroleum jelly, that is, Vaseline, mineral oils, navel drops, and animal fats. Lip balm, lip-gloss, olive oil, and sesame oils are also risk factors despite being less common. In adults some cases of lipoid pneumonia [
In the past chronic childhood constipation was often managed with regular administration of mineral oil. However, this routine practice has been abandoned due to the high incidence of lipoid pneumonia [
Mineral oil entering the tracheobronchial tree does not promote the cough reflex, inhibits mucociliary transport system, and becomes long-term resident within alveoli. As macrophages are incapable of metabolizing the mineral oil this results in lipid granulomatous inflammation and alveolar fibrosis.
In our case the chest CT showed a dependent lung zone “crazy-paving” pattern consistent with lipoid pneumonia. Moreover, the bronchoalveolar lavage showed significant oil red O within alveolar macrophages consistent with chronic mineral oil aspiration. The history of long-term bidaily mineral oil use was undoubtedly the cause of the lipoid pneumonia. Indeed we speculate that the sustained long-term use of mineral oil elicited an autoimmune JIA. We suggest that clinicians continue to strongly discourage mineral oil use as a cathartic and investigate its possible occult use in very young children with JIA.
There was no honorarium, grant, or other forms of payment given to anyone to produce the paper.
The authors declare that they have no conflict of interests.