Background: We report a case of a 30-year-old patient who presented with acute Mycoplasma pneumoniae infection that was complicated by reactive arthritis and asymmetric proximal myopathy and progressed to chronic spondyloarthropathy. Reactive arthritis and sacroiliitis are unusual extrapulmonary manifestations of M. pneumoniae infection, which is a common condition. Case presentation: A 30-year-old Greek previously healthy man presented to our emergency department with fever, progressively worsening bilateral lower limb weakness, and asymmetric oligoarthritis. Our diagnosis was based on a positive polymerase chain reaction test for M. pneumoniae using blood and cerebrospinal fluid and magnetic resonance imaging findings that suggested sacroiliitis. Our patient was also found to be human leukocyte antigen B27 positive. His infection was successfully treated with a 14-day course of doxycycline; the arthritis was treated with naproxen and corticosteroids. His arthritis, which restricted his mobility, improved progressively, and he was discharged without any neurological symptoms. Conclusions: In our case, an acute M. pneumoniae infection eventually progressed to chronic spondyloarthropathy. In our patient, M. pneumoniae infection may represent a random event, or it might be a necessary factor for the development of reactive arthritis, asymmetric proximal myopathy, and sacroiliitis, always in combination with the appropriate genetic background. Extrapulmonary manifestations of M. pneumoniae may occur even in the complete absence of respiratory symptoms, and the diagnosis of unusual complications, such as reactive arthritis, requires high clinical suspicion and extensive investigation.

Tuberculous vertebral osteomyelitis (TVO) is an extrapulmonary tuberculosis form characterized by difficulty and delay in diagnosis. PET/CT is a valuable, well-established tool in the diagnostic workup of cancer and fever of unknown origin, which is increasingly appreciated in the management of infectious diseases. We report a TVO case where PET/CT had a valuable contribution towards diagnosis and monitoring of treatment response, highlighting its advantages and future perspectives when dealing with infectious diseases.

Background and Clinical Significance: Acquired angioedema (AAE) is a rare and potentially life-threatening condition characterized by acquired deficiency of C1-inhibitor (C1-INH) resulting in hyperactivation of the classical complement pathway. AAE occurs in association with malignancies or autoimmune diseases. Infectious triggers are rarely encountered, and the underlying mechanisms have yet to be completely clarified. Case Presentation: This case involves a previously healthy 19-year-old male who was admitted with Mycoplasma pneumonia and oral ulcers, subsequently developing unilateral facial angioedema. Laboratory studies demonstrated reduced C4, decreased levels and activity of C1-INH, and reduced C1q, all consistent with acquired C1-INH deficiency. These findings were attributed to the presence of cold agglutinins, which are frequently observed in Mycoplasma pneumoniae infections. Following treatment with icatibant, a bradykinin B2 receptor antagonist, the patient’s angioedema resolved rapidly. An exhaustive workup found no evidence of underlying systemic disorders, and the patient did not experience any angioedema attacks following resolution of the infection. Conclusions: The presence of cold agglutinins, commonly associated with Mycoplasma infections, can precipitate a decline in C1-INH levels, resulting in complement pathway dysregulation. This disruption leads to an excess of bradykinin, followed by increased vascular permeability and localized edema.

Introduction: We present a case of anion gap euglycemic diabetic ketoacidosis (EuDKA) in a patient with COVID-19 infection. Patients with diabetes mellitus are at increased risk of severe illness, and hyperglycaemia is associated with higher morbidity and mortality in patients infected with COVID-19. Case Description: A 76-year-old male with diabetes mellitus treated with SGLT2 inhibitor tested positive for COVID-19 infection on day 3 after his admission. In the emergency room he had a high anion gap metabolic acidosis and a blood glucose of 248 mg/dl. His urine tested strongly positive for ketones. A diagnosis of euglycemic diabetic ketoacidosis was made and he was treated with intravenous insulin and normal saline; his antidiabetic medications were stopped. His metabolic acidosis gradually resolved, and he was discharged. Discussion: Euglycemic diabetic ketoacidosis is a rare complication of COVID-19 infection. It is defined by the American Diabetes Association as the triad of anion gap metabolic acidosis with arterial pH <7.3, serum bicarbonate <18 mmol/l and ketonuria or ketonemia. It is a life-threatening complication which usually occurs in type 1 diabetes mellitus patients but may also occur in type 2 diabetes mellitus patients. As described earlier, it is associated with hyperglycaemia but if blood glucose is low or near normal but <250 mg/dl it is then named euglycemic diabetic ketoacidosis. Patients treated with SGLT2 inhibitors are at increased risk of euglycemic diabetic ketoacidosis. Conclusions: COVID-19 infection precipitated euglycemic diabetic ketoacidosis in our patient. SGLT2 inhibitors must be stopped when this adverse reaction occurs. As their use increases, the risk of this adverse reaction is higher as well. Their prescription should be restricted to trained physicians who are able to educate their patients and treat them appropriately in situations that may arise.