I thought it was pneumonia, but various treatments were ineffective. This rheumatism was actually the first case in the world!

*It is only for medical professionals to read for reference.
Is it so difficult? It’s a good idea to take a good look at a man who developed pneumonia symptoms such as dry cough and dyspnea.
However, the treatment was ineffective and his condition progressed rapidly
.

After a series of examinations, it was discovered that it was rheumatism
.

At this time, the patient's lung symptoms worsened, what should the doctor do to pull him back from the death god? Case brief introduction An elderly man was admitted to the hospital with dry cough and pleuritic chest pain for 2 months, progressively worsening dyspnea and myalgia in the proximal upper extremity
.

No dry mouth, enlarged glands, dental caries, fever, rash, joint pain, Raynaud's phenomenon, dysphagia, dysarthria and other symptoms
.

Before this visit, the chest radiograph showed that bilateral pneumonia had been treated with antibiotics for 2 weeks, but the symptoms had not improved
.

Past history: have a history of hypertension; have dry eye, the result does not suggest Sjogren’s syndrome
.

Denied history of surgery, history of drug allergy, and history of statin use
.

Personal history: Born in the Dominican Republic and moved to the United States six years ago
.

Construction workers, exposed to dust, no other potential occupational exposure
.

Family history: deny family history of autoimmune diseases, family history of myopathy
.

Physical examination: fever, tachycardia to 111 beats/min
.

The blood oxygen saturation is 95% at rest, and drops to 86% after walking for a few meters
.

Crackling sounds can be heard at the base of both lungs
.

Nervous system examination showed that the proximal muscle strength of both upper and lower limbs was grade 4-5, and the muscle strength of the distal muscles was normal
.

Nailfold capillary examination and skin examination were normal
.

Auxiliary examination: mild eosinophilia, mild C-reactive protein increase, aminotransferase increase, creatine kinase CK: 4618 U/L
.

There were no ischemic changes in the electrocardiogram, and no local wall motion abnormalities in the echocardiogram
.

Chest CT showed multi-lobed ground glass infiltration and patchy changes in bilateral lower lobes
.

Figure 1: Chest CT shows multi-lobed ground glass infiltration and patchy changes in the lower lobes on both sides.
Is it just pneumonia? mistaken! Originally, the doctor thought it was just a simple pneumonia, but the patient's white blood cell did not increase, and antibiotic treatment was ineffective.
It was not so simple, unlike ordinary pneumonia
.

In order to explore the true appearance of lung lesions, the patient further did a bronchoscopy, and the results showed that there were 45% eosinophils in the bronchoalveolar lavage fluid
.

Doctors began to evaluate the underlying causes of eosinophilic pneumonia, such as fungal infections and parasitic infections, but found nothing, all of which were negative
.

Symptoms and examinations grasped with both hands, the truth gradually emerged.
The patient had no history of asthma-like symptoms.
His shortness of breath was mainly caused by fatigue
.

Bronchial biopsy revealed alveolar lung parenchyma with tissue pneumonia
.

The lung function test is consistent with restrictive lung disease
.

So based on the patient’s lung imaging findings, mild proximal muscle weakness, and elevated CK, doctors began to look for answers in inflammatory myopathy and interstitial lung disease (ILD)
.

The first thing to consider is autoimmune rheumatism, and start immune-related examinations
.

Key points: antinuclear antibody positive, SSA/Ro-52 antibody positive! The aldolase was 42.
8 U/L, and the results of the remaining myositis were negative
.

MRI of the legs showed the most obvious muscle edema in the bilateral hip area, quadratus femoris and lateral femoris muscle
.

The electromyogram of the right iliopsoas muscle suggests myositis
.

Skeletal muscle biopsy revealed a large number of chronic microvascular disease in the form of "tubular" capillaries and abnormal deposition of membrane attack complex (MAC) C5b-9 in intramuscular capillaries
.

Rare scattered necrotic muscle fibers suggest necrotizing myopathy
.

Figure 2: (Left image) Chronic microvascular disease in the form of "tubular" capillaries (arrow); (right image) Abnormal deposition of MAC C5b-9 in intramuscular capillaries (star) and finally diagnosed as SSA antibody-related necrosis Myopathy is associated with ILD and tubular capillaries
.

Just hearing the name of this disease, it feels so complicated~ Necrotizing myopathy is a unique form of idiopathic inflammatory myopathy.
Necrotizing myopathy (NM) refers to obvious necrosis and regeneration of muscle fibers, with no or very little inflammation.
Sex cell infiltration is a pathological feature of skeletal muscle disease
.

Necrotizing myopathy related to autoimmunity is called immune-mediated necrotizing myopathy (IMNM)
.

In recent years, people have gradually begun to recognize IMNM and believe that it is a unique form of idiopathic inflammatory myopathy (IIM).
The pathological features are obvious necrosis and regeneration of muscles, increased intramuscular macrophages, blood vessels or perifascicular lymph.
Cell infiltration is not obvious [2]
.

The pathogenesis of IMNM is not yet clear, and it is considered to be related to specific autoantibodies
.

The role of two different autoantibodies: anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) antibody and anti-signal recognition particle peptide (SRP) antibody in the pathogenesis of IMNM is a hot spot in current research
.

The anti-PM-Scl75 antibody and anti-Ro52 antibody have also been reported [3]
.

What are the clinical features? IMNM myopathy is more serious than other IIM subtypes, with more extensive muscle involvement and higher CK levels in radiology
.

Serum CK level reflects the activity of the disease and the degree of muscle necrosis, which is different from other IIM subtypes
.

Myalgia and dysphagia are common, and limb weakness is the most common clinical manifestation.
Critically ill patients may be associated with myocardial involvement, distal muscle weakness, facial muscle weakness, fatigue, and weight loss
.

Some IMNM patients have mild ILD
.

6-point diagnostic criteria: The 2016 ENMC consensus on the IMNM pathological diagnostic criteria experts agreed: (1) Necrotic muscle fibers scattered in the muscle bundle; (2) Necrosis, phagocytosis, muscle cell regeneration and other stages can be seen pathologically; (3) " Phagocyte-based inflammation” or “less inflammation”; (4) MHC-I molecules must be expressed on the muscle cell membrane that is not necrotic or regenerated; (5) MAC patch-like deposition on the muscle cell membrane; (6) may be accompanied by intramuscular Membrane fibrosis and telangiectasia
.

Among them, 1-3 are the main features, and 4-6 are other features
.

With tubular capillaries, what are the characteristics? In some NM cases, the endomysial capillaries have local or systemic capillary depletion, complement MAC deposition, and thickened and transparent capillaries, which are called tubular capillaries
.

In 1991, Emslie and Engel first described NM with tubular capillaries as the following characteristics: less inflammation, tubular capillaries, MAC deposition and capillary loss [4]
.

What are the characteristics of the world's first case? At present, this is the first case in the world diagnosed with SSA antibody-related necrotizing myopathy combined with tubular capillaries and ILD.
The diagnosis and treatment process are extremely challenging.

.

What are the characteristics of this case? Case characteristics: The patient has symptoms such as dry cough, dyspnea, myalgia, etc.
, antibiotic treatment is ineffective; CK is elevated, SSA/Ro-52 antibody is positive; EMG shows myositis, muscle biopsy shows tubular capillaries and necrotic muscle fibers; lungs There was a crackling sound on auscultation, chest CT and lung biopsy showed ILD or fibrosis
.

According to the characteristics of the above cases, the patient's diagnosis is clear! Will the patient be saved after diagnosis? It seems that there is no 1.
Intravenous high-dose steroids-the patient's shortness of breath, myalgia and muscle weakness have not improved significantly, the CK level is still elevated, and the chest CT shows continuous bilateral infiltration
.

2.
Intravenous immunoglobulin therapy-no significant improvement, pulmonary symptoms worsened
.

3.
Immunosuppressant therapy-muscle symptoms improved, CK decreased from 2609 U/L to 1136 U/L
.

However, eosinophilia did not completely disappear, and the lung symptoms persisted
.

4.
Finally, only lung transplantation can be considered
.

It should be noted that patients have increased eosinophils in serum and BAL samples, the significance of which is unclear
.

Summary of key points: The patient continues to have shortness of breath, and chest X-ray findings suggest pneumonia, but no symptoms of systemic infection.
The possibility of other causes, such as ILD, needs to be evaluated
.

If CK is increased by 5000 U/L without any heart disease, the possibility of inflammatory myopathy should be suspected
.

Patients with myositis with tubular capillaries are difficult to treat and respond poorly to traditional treatments
.

This requires further research to clarify the specific pathophysiology of this disease and obtain therapeutic targets from it
.

References: [1] Ramu A,et al.
Rare case of Sjögren's syndrome antibody(SSA-Ro52kDA)-associated interstitial lung disease and myositis with pipe stem capillariesBMJ Case Rep 2021;14:e244133.
doi:10.
1136/bcr-2021- 244133.
[2] Senecal JL, Raynauld JP, Troyanov Y.
Editorial: a new classification of adult autoimmune myositis [J].
Arthritis Rheumatol, 2017, 69 (5): 878-884.
[3] Lim J, Rietveld A, Debleecker JL,et al.
Seronegative patients form a distinctive subgroup of immune-mediated necrotizing myopathy[J].
Neurol Neuroimmunol Neuroinflamm, 2019, 6(1): e513.
[4]Emslie-Smith AM,Engel AG.
Necrotizing myopathy with pipestem capillaries, microvascular deposition of the complement membrane attack complex (MAC), and minimal cellular infiltration.
Neurology 1991;41:936–9.