Acute pneumonia evolution

Clinical History

A previously healthy patient presented with a 2-day history of high fever, skin lesions, non-productive cough, and dyspnoea.
Physical examination revealed non-pruritic skin lesions in different stages, bilateral basal lung crackles, and hypotension. Viral pneumonia was suspected and the patient was started on acyclovir treatment.

Imaging Findings

The emergency room chest X-ray showed a bilateral nodular pattern, consisting of numerous 5 to 10 mm poorly defined nodules that were confluent in some areas (Figs. 1 and 2).
Some hours later, the patient experienced respiratory failure and was transferred to the intensive care unit. Portable chest X-ray revealed bilateral interstitial oedema (Fig. 3). PCR testing of the cutaneous exudate was positive for varicella zoster complex.
The patient received respiratory support and treatment with intravenous acyclovir and ceftriaxone, with a favourable response.
Nine days later, his clinical status had improved, oxygen was not required, and he was discharged from the hospital. On chest plain films, interstitial oedema had resolved but the nodular pattern persisted (Fig. 4).
The follow-up chest X-ray at 10 days after discharge showed no changes (Fig. 5).

Discussion

Viral pneumonia in adults can be divided into two groups: atypical pneumonia that affects healthy hosts and viral pneumonia in immunocompromised hosts [1].

Varicella-zoster virus (VZV) is the causal agent of chickenpox, the initial manifestation of infection by this pathogen [2]. The incidence of VZV infection in adults has doubled in the last few years (2.3 cases per 400 individuals) [3], with increases in the associated hospitalization and mortality rates [4].

Varicella pneumonia, the most serious complication of disseminated VZV, affects healthy adults much more often than children [4, 5]. The incidence of varicella pneumonia in healthy adults ranges from 5% to 50%, depending on the series [6]. The respiratory symptoms (dyspnoea, chest pain, tachypnoea, cyanosis, haemoptysis and fever) usually develop after the typical skin rash, which helps to establish the diagnosis [2, 4]. In some cases these symptoms are severe and lead to respiratory failure with signs of oedema on chest radiography [2, 4, 6–8].

In adults, varicella pneumonia tends to develop 10-21 days after the primoinfection during the viremia period [2]. Histologic examination of the lung shows diffuse alveolar damage and scattered fibrotic capsular nodules with central necrosis [1, 5, 9].

The key findings of varicella pneumonia on conventional chest radiography are small scattered nodules in both lungs that may coalesce [1, 5, 6]. CT shows multiple, small, ill- or well-defined nodules (1-10 mm) that may have a ground-glass halo, scattered in both lungs, patchy ground-glass attenuation, and coalescent lesions. Lymphadenopathy and pleural effusion are not commonly seen [1, 5, 10, 11].

The small nodules usually resolve within one week after the skin lesions disappear, but they may persist for months. The lesions may calcify, and multiple, scattered, 2 to 3 mm well-defined calcifications are sometimes seen lifelong on chest radiographs [1, 5, 10, 11] (Fig 7, 8).

Antiviral treatment (acyclovir) is used in patients in risk for severe disease and in patients with complications such as varicella pneumonia [2, 3, 7, 8]. Other treatments such as assisted ventilation and corticosteroids may be necessary in respiratory insufficiency [7].

Viral pneumonia is the most common complication of primoinfection with VZV.
- The diagnosis is made based on the typical skin rash associated with respiratory symptoms, which may be severe
- Chest radiography shows a diffuse nodular pattern with nodule coalescence
- On CT the nodules are associated with a ground-glass halo or patchy ground-glass attenuation

Differential Diagnosis List

Final Diagnosis

Acute varicella pneumonia

URL:	https://www.eurorad.org/case/13878
DOI:	10.1594/EURORAD/CASE.13878
ISSN:	1563-4086