Deciphering disproportionate dyspnoea in a young patient with overlap sclerodermatomyositis.

Sharrack, S.; Nadin, T.; Wong, N.; Musat, C.; Sabkar, M.; Weatherley, N.; Carter, S.

Deciphering disproportionate dyspnoea in a young patient with overlap sclerodermatomyositis.

All Authors

Sharrack, S.

Nadin, T.

Wong, N.

Musat, C.

Sabkar, M.

Weatherley, N.

Carter, S.

LTHT Author

Sharrack, Sana

LTHT Department

NIHR Leeds Biomedical Research Centre

Publication Date

2025

Item Type

Conference Abstract

Abstract

Introduction: We present the case of a 25-year-old female patient who presented to rheumatology with a myriad of symptoms and was diagnosed with overlap connective tissue disease in the form of sclerodermatomyositis. Appropriate treatment was started and up-titrated; however, symptoms worsened and the patient was subsequently admitted due to significant breathlessness and tachycardia on minimal exertion. Through this case, we hope to illustrate the multiple potential causes for breathlessness in patients with inflammatory myositis and the investigations one may wish to consider when deciphering the most likely cause. This case highlights the importance of understanding respiratory physiology in interpreting relevant investigations. Case description: Our patient presented to us at the age of 25 with no significant past medical history of note, having recently qualified as a nurse. She presented with a six-month history of widespread joint pain, stiffness and myalgia, also describing tightening of the skin of the hands with symptoms of recent-onset Raynaud's. On examination, she had evidence of sclerodactyly (modified Rodnan Skin Score 10), Raynaud's stigmata with abnormal capillaroscopy, and synovitis of the small joints of the hands. In addition, she had evidence of typical peri-orbital heliotrope rash. Initial investigations revealed ANA, PM-Scl-75/100 and anti-Ku antibody positivity, an elevated creatine kinase (CK) of 2670 U/L and normal kidney function. A diagnosis of overlap connective tissue disease (CTD) in the form of sclerodermatomyositis was made and mycophenolate mofetil in combination with oral prednisolone was commenced. Treatment improved joint symptoms and peripheral oedema (only appreciated retrospectively). However, the patient started describing breathlessness with tachycardia on minimal exertion. Chest radiograph was normal; however, a transthoracic echocardiogram revealed a moderate-sized pericardial effusion without features of tamponade or haemodynamic compromise, and estimated pulmonary pressures were normal. Initial pulmonary function testing (PFTs) showed a restrictive pattern and subsequent high-resolution computed tomography of the thorax revealed nonspecific interstitial pneumonia (NSIP) pattern of lung fibrosis. Electromyography showed evidence of mild generalised patchy myopathy and cardiac magnetic resonance imaging was equivocal for myocarditis. Troponins I and T were both elevated, but only marginally so for I, making the diagnosis of myocarditis less likely. It was felt that the investigation findings did not explain the degree of dyspnoea our patient was experiencing. A specialist respiratory opinion was sought, and respiratory muscle weakness was considered very likely to be contributing. Subsequent nasal sniff testing and blood gas analysis ultimately revealed the diagnosis and guided treatment decisions. Discussion(s): This patient's case highlights the multiple potential causes for breathlessness in someone with inflammatory myositis, and the important investigations to consider when deciphering the cause. Cardio-respiratory causes include myocarditis causing left ventricular failure, pulmonary arterial hypertension, inflammatory serositis causing pleuro-pericardial effusion(s), CTD-related interstitial lung disease (ILD), and respiratory muscle weakness due to myositis. Of course, other important differentials should also be considered in the clinical context (e.g. infection, pulmonary embolism or anaemia). Through joint rheumatology-respiratory-cardiology discussions, it was clear that our patient's degree of dyspnoea was disproportionate to preliminary investigation findings. In particular, although ILD was identified, the breathlessness and volume loss on spirometry was disproportionate to the extent of radiological findings (Table 1). This raised the possibility of respiratory muscle weakness as a cause of symptoms, and the expert respiratory team therefore arranged Maximal Inspiratory/Expiratory Pressure Sniff testing (MIPS/MEPS) (Table 1). The MIPS are as close to a specific test of diaphragmatic function as possible and indicated here that our patient was close to complete ventilatory failure. This prompted urgent treatment with intravenous cyclophosphamide and routine FVC and capillary gas monitoring with the option of overnight transcutaneous CO2 monitoring (TOSCA). Key learning points: There are multiple learning points from this case. Firstly, this case demonstrates the way that young patients can often compensate for a substantial degree of physiological loss and be critically ill before standard tests or early warning scores reveal the extent of their disease. This patient was on the verge of requiring urgent mechanical ventilation, and yet was not needing oxygen with a National Early Warning Score of only three. Secondly, this case has reminded us of the wide differentials for breathlessness in a patient with inflammatory myositis and the investigations available to help decipher the cause. It is also an excellent case to train correct PFT interpretation, an essential skill for all rheumatology trainees and consultants (Table 1). Finally, this case clearly illustrates the impact of our rheumatological diseases on patients. This patient, a newly qualified nurse, was having to face a life-changing diagnosis at a very young age. She understandably felt overwhelmed at diagnosis, facing uncertainty about her prognosis and whether she could ever work as a nurse. We are pleased to say that after treatment with intravenous cyclophosphamide, she was able to interview for a nursing job and is now working without significant delay. She still has intermittent fatigue with her shift patterns, and it can take her longer than normal to draw up intravenous medications, but she is very grateful to be able to work and function at the level she is. At the conference, I would be interested to learn how often rheumatologists consider respiratory muscle weakness as a cause of breathlessness in their inflammatory myositis patients, and how familiar colleagues are in requesting and interpreting both PFTs and MIPS/MEPS as a way to diagnosing this. PFTs and MIPS/MEPS pre- and post-treatment with intravenous cyclophosphamide, illustrating significant improvements, particularly in the MIPS, post-treatment. All units as per standard units of measurements for PFTs.