Legionella: The complications of Pneumonia

Journal of Medical Case Reports

Case Presentation

A 53-year-old African American man presented to the hospital with a complaint of difficulty in breathing. He complained of having a fever along with chills for 3 days. He also had fatigue and muscle weakness, however, there was no muscle pain.

There was no history of travel. However, he had a history of tobacco, cocaine, alcohol, and cannabis addiction. At the time of presentation to the hospital, he was continuing to take these drugs. He recalled that he had recently moved into a new house and had cleaned the bathtub in the basement filled with stagnant water. After this, he started experiencing fatigue, which progressively worsened.

On examination, the patient didn’t have a fever. His heart rate was 130 beats per minute, his respiratory rate was 22 breaths per minute. Doctors admitted him to the hospital, where he developed a fever of 102 ℉ (38.9 ℃).

His oxygen levels were low (86% to 88%) on room air, however, they improved to 94% to 96% on receiving 2 litres of oxygen via a nasal cannula. Cardiovascular examination was unremarkable, as doctors could not hear any abnormal sounds or heart murmurs. A respiratory examination revealed wheezing sounds and decreased breath sounds in the lower left lung. Doctors did not notice any engorged neck veins or limbs. Abdominal examination was also normal. His neurological examination revealed that his muscle strength was 4 out of 5 in his arms and legs, and he had normal reflexes, and sensations.


Doctors upon performing investigations, found that his white cell count was 12.1 × 109/L, with 80% of those cells being neutrophils. His haemoglobin level was 15.5 g/dL. Other results showed abnormal values, including a procalcitonin level of 34.3 ng/mL, sodium level of 128 mmol/L, potassium level of 3.9 mmol/L, calcium level of 8.1 mmol/L, glucose level of 246 mg/dL, blood urea nitrogen (BUN) level of 75 mg/dL, creatinine level of 3.32 mg/dL (which was higher than his usual level of 0.7 mg/dL), alanine aminotransferase (ALT) level of 496 U/L, aspartate aminotransferase (AST) level of 1393 U/L, and lactate dehydrogenase (LDH) level of 412 U/L. Urine analysis revealed hematuria. His urine toxicology test was positive for cannabinoids and cocaine. Creatine kinase was extremely high, exceeding 25,000 U/L. A chest X-ray showed consolidation in the lower left lung. An electrocardiogram revealed tachycardia.


The doctors diagnosed the patient with sepsis secondary to community-acquired pneumonia. This was complicated by respiratory failure with low oxygen levels and acute kidney injury, which was due to rhabdomyolysis. The doctors suspected the patient may have had a Legionella infection as he had low sodium levels, high levels of LDH, elevated levels of hepatic transaminases, confusion, and possible exposure to contaminated water. The doctors commenced treatment with IV fluids at a rate of 125 cc per hour. They also administered IV antibiotics, including azithromycin (500 mg daily) and ceftriaxone (1 g daily).

On the second and third days of his hospital stay, the sputum culture showed no growth, and the test for Streptococcus pneumoniae in the urine was negative. However, the test for Legionella pneumophila in the urine was positive. The respiratory investigations came back negative for all pathogens. The blood culture showed no growth throughout his time in the hospital. The doctors stopped giving him ceftriaxone and extended the course of azithromycin to a total of 14 days, which was switched from IV to the oral route.


Although the patient’s white blood cell count, serum creatinine, creatine kinase, AST, and ALT levels gradually decreased from the time he was admitted. However, fever, tachycardia, rapid breathing, and low oxygen levels remained until the fourth day of his hospital stay. The doctors carefully evaluated him for any secondary infections or complications related to Legionella pneumonia, however, they found none. Finally, on the fifth day, the patient began to show signs of improvement. He didn’t need a ventilator or hemodialysis. By the tenth day, his kidney function had returned to normal, and he no longer required oxygen.

Doctors discharged him from the hospital with a course of antibiotics. The doctors did a follow-up with the patient a year after, and he had not experienced a recurrence of rhabdomyolysis.

Discussion: Legionella-associated pneumonia

This case highlights the association of Legionella infection with rhabdomyolysis and acute kidney injury. Early detection and sufficient treatment can reduce the risk of complications and death. Usually, patients with these complications need a long hospital stay and may require dialysis, invasive ventilation, or intensive care. However, this patient didn’t need any of these interventions. Doctors discharged him from the hospital after just 10 days, and he didn’t experience rhabdomyolysis on the follow-up.

Rhabdomyolysis occurs when muscles break down, releasing substances like myoglobin and creatine kinase into the bloodstream. The typical symptoms are muscle pain, weakness, and dark-coloured urine. However, less than 10% of patients develop this symptom triad, and more than half of patients may not have any muscular symptoms. Laboratory tests show high levels of creatine kinase in the blood and myoglobin in the urine, which leads to a false positive result of hematuria in the urine. Electrolyte imbalances are common, as well as elevated levels of liver enzymes, particularly AST. Acute kidney injury can occur in up to 50% of patients.

Rhabdomyolysis can be caused by various factors, such as trauma, metabolic disorders, electrolyte imbalances, toxins, and medications. Influenza is the most common viral cause, followed by HIV and enteroviruses. Legionella is the most common bacterial cause, followed by Streptococcus, Francisella, and Salmonella. Bacterial causes are associated with significant morbidity and mortality, with 57% of cases resulting in acute renal failure and 38% leading to death.

Management of Legionella Community-acquired Pneumonia

The management strategy for acute kidney injury caused by rhabdomyolysis is aggressive fluid resuscitation to compensate for fluid loss from muscles and promote kidney filtration. The treatment for community-acquired pneumonia typically involves a 3 to 5-day course of antibiotics, such as quinolones alone or a combination of a macrolide and a beta-lactam. In some cases, like Legionella infection, a longer course of up to 2 weeks may be necessary. Azithromycin or fluoroquinolones are the preferred antibiotics for Legionella.


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