Subsegmental consolidation masquerading as extralobar bronchopulmonary sequestration presenting as pyrexia of unknown origin

Mashkura Riyazuddeen; Sudhagar Mookkappan; Nayyar Iqbal

doi:10.4103/jcrsm.jcrsm_18_17

CASE REPORT

Year : 2017 | Volume : 3 | Issue : 1 | Page : 60-63

Subsegmental consolidation masquerading as extralobar bronchopulmonary sequestration presenting as pyrexia of unknown origin

Mashkura Riyazuddeen, Sudhagar Mookkappan, Nayyar Iqbal
Department of General Medicine, Pondicherry Institute of Medical Sciences, Puducherry, India

Date of Submission	03-May-2017
Date of Acceptance	20-May-2017
Date of Web Publication	12-Jul-2017

Correspondence Address:
Nayyar Iqbal
Department of General Medicine, Pondicherry Institute of Medical Sciences, Puducherry
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jcrsm.jcrsm_18_17

Abstract

Acinetobacter baumannii infection is common among inpatients and is a major cause of hospital-acquired or ventilator-associated pneumonia. It is rare for this pathogen to cause community-acquired pneumonia. Eighty percent of the patients with community-acquired Acinetobacter present with lobar consolidation. Bronchopulmonary sequestration is a rare congenital disorder with incidence of 1 in 10,000–35,000 live births. Intralobar sequestration is more common than extralobar. Affected individual generally presents with respiratory distress at an early age. Late manifestation with the lower respiratory tract infection has also been reported. We report an interesting case of subsegmental consolidation masquerading as extralobar sequestration of the lung in an adult who presented with pyrexia of unknown origin.

Keywords: Community-acquired Acinetobacter, extralobar bronchopulmonary sequestration, pyrexia of unknown origin, subsegmental consolidation

How to cite this article:
Riyazuddeen M, Mookkappan S, Iqbal N. Subsegmental consolidation masquerading as extralobar bronchopulmonary sequestration presenting as pyrexia of unknown origin. J Curr Res Sci Med 2017;3:60-3

How to cite this URL:
Riyazuddeen M, Mookkappan S, Iqbal N. Subsegmental consolidation masquerading as extralobar bronchopulmonary sequestration presenting as pyrexia of unknown origin. J Curr Res Sci Med [serial online] 2017 [cited 2023 May 28];3:60-3. Available from: https://www.jcrsmed.org/text.asp?2017/3/1/60/210340

Introduction

Community-acquired pneumonia (CAP) is one of the most common cause of life-threatening infections and a major cause of mortality among elderly and in individuals with chronic diseases. Streptococcus pneumoniae is the most common causative agent followed by Gram-negative bacilli and Mycoplasma pneumoniae. Among Gram-negative bacilli, Klebsiella pneumoniae is frequently found in sputum culture.^[1]Acinetobacter baumannii is common etiological agent among nosocomial infections. Community-acquired Acinetobacter pneumonia is rare but has been reported from Asia and Australia.^[2] Lobar consolidation is common in CAP. Subsegmental consolidation is a rather rare presentation of CAP. Sequestration of the lung is a rare congenital anomaly of the lower respiratory tract. The incidence is 1 in 10,000–35,000 live births reported worldwide. It is the pathoembryologic remnant of diverticular outgrowth of the esophagus. It is nonfunctioning lung tissue without any connection with main tracheobronchial tree and it has separate arterial supply.^[3] The 75%–90% of sequestrations are intralobar and rest is extralobar.^[4] We report an interesting case of subsegmental consolidation masquerading as bronchopulmonary sequestration and presenting as pyrexia of unknown origin (PUO).

Case Report

An 18-year-old male presented with the history of fever for the past 3 weeks with chills and dry cough with no history of breathlessness or chest pain. Fever was continuous and high-grade which subsided with tablet paracetamol. He was treated with oral antibiotics by private practitioner but symptom persisted; hence, he was admitted in our hospital.

He had history of similar episode 2 years ago for which he was treated with antibiotics and recovered. On examination, the patient was febrile with 101°F, blood pressure-110/70 mmHg, pulse-110 beats/min, respiratory rate-20 breaths/min, and SpO₂ at room air was 98%. There was no pallor, icterus, cyanosis, clubbing, lymphadenopathy, and edema. Respiratory system examination revealed decreased breath sound in the left infrascapular area. Other systemic examinations were within normal limits. On the basis of history and physical examination, the patient was admitted with a provisional diagnosis of pulmonary or extrapulmonary tuberculosis or lymphoma.

On investigation, his complete blood count showed leukocytosis with increased neutrophils [Table 1]. His blood and urine culture showed no growth. Two-dimensional echocardiography and chest X-ray were also within normal limits [Figure 1]. Since patient had continuous fever and dry cough, he was taken up for computed tomography (CT) scan of the thorax which showed a mass in posterior segment of the left lower lobe [Figure 2]. Further, his bronchoscopy was done which showed normal airways without any intraluminal lesions. His bronchoalveolar lavage (BAL) fluid analysis was negative for Gene Xpert or atypical cells. BAL fluid culture was also negative. Hence, provisional diagnosis of infected bronchopulmonary sequestration was made. His CT-guided biopsy of affected lung showed few inflammatory cells and areas of necrosis [Figure 3]. Later, tissue biopsy showed growth of Acinetobacter baumanii sensitive to injection ceftriaxone and amikacin. He was initially treated with intravenous ceftriaxone 1 g twice daily. In view of nonresolution of symptoms, injection amikacin 500 mg once daily was added. He responded to the treatment and was discharged after 2 weeks of antibiotics. He was later planned for CT angiography and excision of sequestered lung. On follow-up, his contrast-enhanced CT scan (CECT) showed complete resolution of pneumonia without aberrant blood supply to the affected area of the lung [Figure 4].

Table 1: Result of investigations

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Figure 1: Chest X-ray

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Figure 2: Computed tomography scan showing area of sequestered lung in the left lower lobe

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Figure 3: Histopathological slide of lung tissue showing area of necrosis

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Figure 4: Review computed tomography scan thorax shows resolved consolidation (arrow)

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Discussion

Sequestration is the aberrant formation of segmental lung tissue that has no connection with the bronchial tree. It is of two types - extralobar and intralobar. It has 0.1% of incidence and predominantly occurs in males (male:female ratio = 4:1).^[2] Extralobar sequestration usually has its own visceral pleura and arterial supply. It usually occurs between the left lower lobe and hemidiaphragm.^[5],[6] Extralobar sequestrations are most commonly found in the left thorax although 10%–15% can be found in the abdomen. Males are predominantly affected by sequestration of the lung. Hemoptysis, fever, and dry cough are common clinical manifestations.^[7]

Subsegmental consolidation also has similar complaints of fever and dry cough. Subsegmental atelectasis is another differential diagnosis. The etiological factor associated with subsegmental atelectasis is pulmonary embolism, foreign body, tumor, mucus plug, etc.

In our case, the patient presented with fever for more than 3 weeks and classified as PUO according to Petersdorf and Beeson definition of PUO.^[8] Infections are the most common cause of PUO worldwide followed by collagen vascular diseases and malignancy.^[9] Among infections, extrapulmonary tuberculosis, abdominal abscess, infective endocarditis, osteomyelitis, fungal, enteric fever, and kala azar generally present as PUO. Adult-onset Still's disease presenting as PUO is more common among connective tissue disorders. In our patient, only localizing sign was dry cough; hence, extrapulmonary tuberculosis and lymphoma were provisional diagnosis. In the most cases of infection-associated PUO, histological tissue culture helps in diagnosis.^[9] In our case, also the diagnosis was reached after the tissue culture.

Diagnosis of pulmonary sequestration requires demonstration of abnormal artery feeding the sequestered segment. Spiral CT of the chest and magnetic resonance imaging are the key diagnostic tools.^[10] The most common CT scan findings described in the literature are consolidation or soft tissue opacity, bronchiectasis, and cystic or cavitary lesion. In our case, the patient had consolidation in the left lower lobe. Bronchoscopy is generally normal in case of extralobar sequestration of the lung even in the patients with complications such as hemoptysis.^[11] In our case, bronchoscopy along with BAL fluid analysis was normal, suggests that the affected area of the lung was subsegmental.

In recent literature, Polymyxin B or colistin is the mainstay of the treatment of nosocomial Acinetobacter pneumonia.^[2] In a study from Northern Australia, it was found that all the isolates of Acinetobacter from CAP were sensitive to aminoglycosides and resistant to the 3^rd generation cephalosporins.^[12] Although, in our case, Acinetobacter was sensitive to both ceftriaxone and amikacin, patient only responded when injection amikacin was added to injection ceftriaxone. Treatment of bronchopulmonary sequestration is excision of the sequestered segment which was avoided with subsequent CECT thorax in this case.

Conclusion

Subsegmental consolidation, especially of the left lower lobe, may mimic bronchopulmonary sequestration. Normal chest X-ray does not exclude the possibility of respiratory tract infection. Early intervention with CT scan and CT-guided biopsy of the affected segment may help in reaching the diagnosis early. Follow-up CECT scan may help to differentiate these two conditions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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