Alteration of lung diffusion capacity in IgA nephropathy

No impairment of pulmonary function in children with Henoch-Schonlein purpura after 4-year follow-up

Henoch-Schonlein purpura (HSP) is a generalized form of IgA-mediated vasculitis that usually spares pulmonary circulation. Nevertheless, it is conceivable that subclinical changes at the HSP onset may lead to lung impairment in the long term. Therefore, we decided to follow a group of HSP patients for 4 years to monitor changes in pulmonary function. A group of 11 children and adolescents diagnosed with HSP without apparent pulmonary involvement was subjected to pulmonary function tests (PFTs), i.e., spirometry, body plethysmography, and diffusing capacity for CO (DLCO); these tests were repeated after 48 months. No significant impairment was observed in variables of spirometry, body plethysmography, and DLCO expressed as % of predicted values (% predicted) after 4 years. Specifically, no significant change in DLCO, corrected for blood hemoglobin concentration was noted, i.e., 79.3 ± 10.1 vs. 81.6 ± 14.7 % predicted at the beginning and the end of the study, respectively. IgA vasculitis seems to spare pulmonary circulation as we found no impairment in PFTs within the study time frame and a median of almost 6 years from the first episode of the disease.

Diffuse alveolar hemorrhage in IgA nephropathy: case series and systematic review of the literature

OBJECTIVES

To describe the spectrum of pulmonary involvement in immunoglobulin A nephropathy (IgAN).

METHODS

We describe two patients with pulmonary renal syndrome related to IgAN and a systematic review of previously reported cases of IgAN and lung involvement.

RESULTS

We identified 23 reports of IgAN-related pulmonary disease, including 19 reports of alveolar hemorrhage and two cases of organizing pneumonia. Dyspnea (84%), hemoptysis (74%), cough (53%) and fever (47%) were common presenting complaints. Simultaneous involvement of kidneys and lung was the most common presentation (42%) but alveolar hemorrhage occurred independent of renal disease in one-fifth (21%). Azotemia was seen in 55.5% at presentation. Mesangio-proliferative glomerulonephritis was the most common biopsy finding and crescentic glomerulonephritis was seen in 27.7%. Among patients undergoing lung biopsy, capillaritis was seen in 72.7%; 37.5% of these had IgA deposits. Steroids with cyclophosphamide, followed by maintenance with methotrexate or azathioprine was used in 44%. Mechanical ventilation, dialysis and plasmapheresis were other adjunctive therapies used. IgAN-related alveolar hemorrhage was associated with a mortality of 26.3% and significant morbidity, with 52.7% having end-stage kidney disease despite immunosuppression. Organizing pneumonia with pulmonary IgA deposition is a well-described association of IgAN.

CONCLUSION

These findings are similar to our previous observations of Henoch-Schonlein purpura (HSP)-related alveolar hemorrhage, highlighting the similarities of these related syndromes. Multicentric studies of IgAN and HSP-related pulmonary renal syndrome with a standard protocol are needed to define their similarities and differences, optimum suppression and its role in preventing renal progression in this setting.

[Berger's disease in childhood]

Berger's disease or IgA nephropathy (NIgA) is the most common form of glomerulonephritis in the world. In children macroscopic haematuria is the first sign in about 80% of the patients. Renal failure appears in 20% of cases after twenty years of follow-up. The most important prognosis indicators are a nephrotic syndrome at the onset, a proteinuria > 1 g/24 hours, diffuse tubulo-interstitial lesions and extracapillary proliferation with crescents in more than 50% of the glomeruli. The pathogenic mechanisms are just emerging and involve a disrupted process of the systemic tolerance to mucosal antigen with abnormal mucosal gamma delta T cell repertoire, abnormally glycosylated IgA1 molecules and a down-regulation of Fc alpha receptors on blood cells. After IgA deposition, the mechanisms of mesangial cell damage and activation involve vascular factors as endothelin/nitric oxide system, cytokines and growth factors such as interleukine-6, platelet derived growth factor and transforming growth factor beta. There is no curative treatment but steroids are useful in diffuse proliferative extracapillary forms, when histological activity score is high with a short delay between diagnosis and treatment, or for moderately severe NIgA with normal renal function.

What is the difference between IgA nephropathy and Henoch-Schönlein purpura nephritis?

Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) are considered to be related diseases since both can be encountered consecutively in the same patient, they have been described in twins, and bear identical pathological and biological abnormalities. Apart from the presence of extrarenal clinical signs found only in HSPN, other differences are noticed between the two diseases. The peak age ranges between 15 and 30 years for a diagnosis of IgAN, whereas HSPN is mainly seen in childhood. Nephritic and/or nephrotic syndromes are more often seen at presentation in HSPN. In contrast to IgAN, HSPN has been described in association with hypersensitivity. Endocapillary and extracapillary inflammations as well as fibrin deposits in the glomerulus are more frequent in HSPN. No major biological differences have been found between the two illnesses, except for a larger size of circulating IgA-containing complexes (IgA-CC) and a greater incidence of increased plasma IgE levels in HSPN. As tissue infiltration by leukocytes is a major feature of HSPN vasculitis, a possible role of a more potent activation of the latter cells by IgA-CC and/or circulating chemokines in HSPN should be considered. Further studies are required to elucidate this possible mechanism as well as the role of hypersensitivity in HSPN.

Reduced lung diffusion capacity after Mycoplasma pneumoniae pneumonia

BACKGROUND

Mycoplasma pneumoniae is a frequent but underdiagnosed cause of community-acquired pneumonia (CAP) in children, and appropriate macrolide treatment is often given late. The aim of this work was to estimate the frequency of pulmonary involvement in children 6 months after a clinical episode of Mycoplasma CAP.

METHODS

We measured carbon monoxide diffusion capacity (TLCO) and conducted spirometric tests in 35 children without asthma or chronic lung disease (ages 4.5 to 15 years), 6 months and 1 year after acute CAP caused by M. pneumoniae (23 children), pneumococci (5 children) or viruses (7 children). Only 11 of 23 patients with M. pneumoniae CAP required hospitalization, whereas all the patients with pneumococcal or viral pneumonia were admitted to hospital.

RESULTS

Lung volumes and spirometric tests were normal for all children. TLCO was normal 6 months after pneumococcal or viral pneumonia (87 to 112% of expected values for height and sex). After acute M. pneumoniae CAP, 11 of 23 patients (48%) had TLCO values <80% of the expected value. The extent of change in lung diffusion capacity was correlated with the delay to diagnosis and treatment: TLCO was low in 8 of 11 patients given macrolide treatment 10 days or more after the onset of acute symptoms vs. only 3 of 10 patients given appropriate treatment in the first 10 days. TLCO was low in 7 of 7 who received macrolide therapy for <2 weeks. TLCO had increased slightly after 1 year in the 5 patients retested after a new course of macrolide treatment. TLCO reached the lower normal range in 2 patients controlled after 3 years.

CONCLUSIONS

The abnormal TLCO values suggest that some children with Mycoplasma pneumonia have reduced pulmonary gas diffusion after recovery from the illness. The reduction is related to delay and short macrolide therapy.