Impact of hyponatremia on nerve conduction and muscle strength.

BACKGROUND: Hyponatremia is associated with unstable gait and propensity to falls. The potential contribution of peripheral nervous system dysfunction induced by hyponatremia has not yet been addressed by prospective studies. DESIGN: In the first part of this prospective study, we performed two tests evaluating muscle strength (grip test and quadriceps isometric contraction test) together with a timed up and go (TUG) test in 11 patients with chronic mild-to-moderate hyponatremia before and after the normalization of natremia. In the second part, we measured nerve conduction velocities and F-wave latencies in nine patients with profound hyponatremia (< 125 mmol/L) before and after the normalization of natremia. RESULTS: No significant change in muscle strength was observed when natremia was corrected from 127·7 ± 2·5 to 136·1 ± 1·8 mmol/L, contrary to a significant improvement in TUG from 14·9 ± 5·1 to 12·5 ± 4·7 s (P = 0·006). Nerve conduction velocities and F-wave latencies showed significant improvement in most of the studied nerves when natremia was corrected from 121·9 ± 2·4 to 135·5 ± 3·4 mmol/L (e.g. mean increase of 14·3% for motor nerve conduction and mean decrease of 21·6% for F-wave latency of left peroneal nerve). CONCLUSION: Whereas chronic mild-to-moderate hyponatremia has no impact on muscle strength, we demonstrate for the first time an impact of profound hyponatremia on nerve conduction studies. Further studies are needed to ascertain the contribution of these latter results on gait disturbances, propensity to falls and attention deficits associated with hyponatremia.

Successful treatment of interstitial pneumonia with autoimmune features using rituximab as salvage therapy.

Interstitial pneumonia with autoimmune features is a complex and heterogeneous research classification without clear management and should be discussed on a case-by-case basis in a pluridisciplinary way. Rituximab could be used for severe lung involvement. The coronavirus crisis can hide other pathologies in such a way that a diagnosis can be overlooked.

Sudden Development of Subcutaneous Nodules Shortly after Radioiodine Treatment for Thyroid Cancer Caused by Self-Limiting Sarcoidosis.

BACKGROUND: Sarcoidosis is a multisystemic disease producing non-caseating granulomas. The aetiology and pathogenesis are unknown. We herewith report an atypical case of cutaneous sarcoidosis. CASE PRESENTATION: A 50-year-old female presented with an onset of multiple subcutaneous nodules on her 4 limbs. These nodules appeared concomitantly with the initiation of radioactive iodine therapy for papillary thyroid cancer. These nodules were not obvious on inspection of the skin, but easily felt on palpation.The biopsy of the subcutaneous nodules revealed hypodermic non-caseating granulomas consistent with sarcoidosis. The patient underwent an 18F-fluorodeoxyglucose positron emission tomography (PET) scan study that revealed, besides the subcutaneous nodules, multiple hypermetabolic mediastinal lymphadenopathies and cervical adenopathies. Biopsy of the mediastinal lymphadenopathy showed neither granulomas nor neoplastic cells. Cervical biopsy revealed neoplastic cells of thyroid origin. Laboratory tests were normal. Bronchoalveolar lavage showed a normal CD4/CD8 T-cell ratio.A diagnosis of cutaneous sarcoidosis was established, as well as a recurrence of the cancerous disease. The subcutaneous nodules regressed spontaneously in the absence of any treatment. DISCUSSION AND CONCLUSION: Sarcoidosis is a multisystemic disease of unknown origin. This case illustrates an uncommon occurrence of sarcoidosis, triggered by radioactive iodine therapy. Radioiodine may lead to immunological changes, especially affecting the Th1/Th2 ratio, which may promote the emergence of sarcoidosis in genetically predisposed patients. There is still much to discover to fully understand the pathogenesis of sarcoidosis. LEARNING POINTS: The immunopathogenesis of sarcoidosis is poorly understood, as well as the environmental factors involved.Radioactive iodine therapy for thyroid cancer treatment may be an environmental trigger.The immunological changes induced by radioiodine, especially with respect to the Th1/Th2 ratio, may promote occurrence of sarcoidosis in genetically predisposed patients.

Pituitary Gland and Neurological Involvement in a Case of Hemophagocytic Syndrome Revealing an Intravascular Large B-Cell Lymphoma.

Intravascular large B-cell lymphoma is a rare entity characterized by the proliferation of neoplastic lymphocytes in the lumen of small blood vessels and high mortality. Diagnosis of intravascular lymphoma is often delayed or established postmortem. Here, we report the case of a 48-year-old woman presenting hemophagocytic syndrome, with pituitary gland and neurological involvement. Diagnosis of intravascular large B-cell lymphoma was made on perisplenic vessels, while liver and bone marrow biopsy was noncontributive. This case demonstrates the importance of thorough histopathologic investigations in the setting of high suspicion.