Rarely, Legionella infection causes atrioventricular block| case sharing

The patient is male, 72 years old
.
The main reason was 6 days of dry cough and 4 days of fever at the peak of the new coronavirus infection pandemic
, and he presented to the emergency department.
Past medical history includes hypertension and is treated with lisinopril 5 mg/day
.
ECG 1 year ago shows normal sinus rhythm
.
The patient denied prodromal symptoms such as vomiting and diarrhea, did not have any cardiac symptoms such as syncope, syncope, chest pain or palpitations, and denied recent travel or exposure to
the new crown.

At the time of admission, the patient had no fever, blood pressure of 145/87 mmHg, heart rate of 84 beats/min, tachypnea, respiratory distress and hypoxia, respiratory rate of 21 breaths/min, and oxygen saturation of 94%
at an oxygen concentration of 3L.
Auscultation of the lungs with equal air intake in both lungs and a very small number of small crackling sounds
at both bases.
There is no elevation in jugular venous pressure, and there is no tenderness or swelling
in the lower leg.
Considering the COVID-19 pandemic, become a presumptive diagnosis
.

Preliminary laboratory results showed neutrophilia (9.
1×10 9/L) and lymphopenia (0.
8×10⁹/L), D-dimer (1135 ng/ml), and C-reactive protein (347 mg/L) elevated
.
Brain natriuretic peptide precursors (354 pg/ml) and troponin (26 ng/L) were elevated
.

Arterial blood gases in room air on admission suggest type 1 respiratory failure
.
ECG shows 2:1 AV block with right bundle branch block (figure 1).

Echocardiography showed good left and right ventricular systolic function, ejection fraction above 60%, and no local wall motion abnormalities
.
Chest x-ray shows a large shadow of the left airspace and a largely clear right lung (Figure 2).

(Figure 1 ECG)

(Figure 2 Chest X-ray)

Because the patient's D-dimer was too high, pulmonary embolism was suspected, and pulmonary angiography CT results excluded it, confirming consolidation in the upper lobe of the left lung, suggesting infection, and a mild effusion in the right chamber (figure 3).

(Figure 3 Chest CT examination)

The patient's community-acquired pneumonia screening and chlamydia test were negative, and no bacterial growth
was seen in blood and sputum cultures.
Recurrent viral tests for COVID-19 infection were negative, and PCR results for influenza A, influenza B, avian influenza, and pigeon immunoglobulin G antibodies were negative
.
Later tested positive
for Legionella urine antigen.

Initial treatment for COVID-19 includes oral steroids, injection combination amoxicillin-clavulanate, and oral clarithromycin for secondary bacterial chest infection
.
After reporting CT pulmonary angiography results and negative COVID-19 test results, steroids and antibiotics were discontinued and doxycycline was started for SARS
.
On the second day of treatment with doxycycline, the patient tested positive
for Legionella antigen in the urine.
Oral doxycycline is given for 14 days
.
The infection resolves and a permanent pacemaker
is planned.
Follow-up chest x-ray showed that a small amount of pleural effusion on the right side remained unchanged, but the consolidation improved, so further follow-up by the respiratory department to check for pleural effusion
.