Teaching Case

A 45-year-old patient, without significant medical history, presents to the Emergency Department with altered general condition and marked weight loss. The patient was recommended to undergo a contrast-enhanced CT scan of the chest, abdomen, and pelvis. After the CT scan findings, the patient was subjected to the following examinations: HIV testing, hepatitis B and C testing, and screening for tuberculosis.

The CT scan of the chest reveals several round-oval lesions in both lung areas, with peripheral iodophilia, fluid and semi-fluid densities, some holding air, resembling abscesses.

The CT scan of the abdomen reveals kidneys with multiple relatively well-defined areas, irregularly contoured, with fluid and semi-fluid densities, mostly peripheral iodophilia, tending to confluence, indicating bilateral acute pyelonephritis with abscess formation. Similar appearances are noted at the prostate level, with extension into the seminal vesicles.

Hypodense, hypoattenuating images are noted in the bilateral renal veins, left common iliac vein and bilateral internal iliac veins, suggestive of intraluminally thrombosis.

Background

Gram-negative bacteraemia represents a significant public health concern, impacting both healthy individuals and those with underlying comorbidities. Classical Klebsiella pneumoniae causes a variety of infections, including pneumonia, urinary tract infections, and bacteraemia, usually in hosts with comorbidities. The progression of gram-negative bacteraemia occurs in three stages: the invasion or colonisation at the sites of infection, followed by host defences being defeated and adaptation to survive in the blood and organs. After these stages, a localised infection is caused. This triggers an inflammatory response, leading to the accumulation of immune cells, such as neutrophils, at the site of infection. As the immune cells attempt to contain and eliminate the infection, tissue damage occurs, resulting in necrosis (cell death) and the formation of pus. Eventually, the pus becomes encapsulated by surrounding tissue, forming a cavity known as an abscess [1–3].

Clinical Perspective

The clinical symptoms of disseminated abscesses in a patient with Klebsiella infection may include high-grade fever, general malaise, nausea, vomiting, tachycardia, localised pain, fatigue, loss of appetite, and unexplained weight loss [4–6].

Abscesses in the lungs may lead to cough, shortness of breath, chest pain, shivering, night sweats along with productive cough with purulent sputum, and sometimes haemoptysis. Additionally, individuals may experience difficulty breathing, wheezing, and a feeling of tightness or discomfort in the chest [4].

Renal abscesses typically present with symptoms such as flank pain, frequent urination, urgency, dysuria or haematuria [5].

Patients with prostatic abscesses typically present various urinary symptoms, including increased urinary frequency, urgency, dysuria, haematuria, urethral burning, perineal discomfort, difficulty in urination or even acute urinary retention [6].

Imaging Perspective

Imaging is vital for diagnosing thorax, abdominal and pelvic abscesses. CT scan stands out as the most definitive test for detecting abscesses. It provides detailed information about the size, number, extent, and exact location of any abscesses. Radiological appearances of an abscess on CT involve a central area of necrotic inflammatory material surrounded by an iodophilic capsular ring [4–6].

Outcome

Treatment of abscesses depends on their severity and usually involves the administration of antibiotics and percutaneous drainage. When these fail, surgical drainage is performed [3].

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