Clinical and Laboratory Test Findings
The average age of the 30 patients in MP group was 43.7±10.6 years (range, 26–64 years), younger than the non-MP group (51.2±14.0 years, range, 26–74 years, p = 0.02). All the patients of the MP group lived in Wuhan. The most common complaints were fever (26/30, 87%), fatigue (16/30, 53%) and cough (13/30, 43%). Other complaints included diarrhea (3/30, 10%), dyspnea (3/30, 10%), headache (3/30, 10%) and muscle soreness (3/30, 10%). Some patients of MP group had reduced white blood cell count (12/30, 40%) and reduced lymphocyte count (14/30, 47%), increased C-reactive protein (CRP, 18/30, 60%), increased erythrocyte sedimentation rate (ESR, 9/30, 30%), and increased lactate dehydrogenase (LDH, 12/30, 40%). However, the CRP, ESR and LDH levels were lower than those of the non-MP group (p<0.05). More demographic data, laboratory tests and symptoms of the MP and non-MP groups are listed in Table 1.
Initial CT Features
Data of the initial and follow-up chest high-resolution CT findings of the MP group were listed in Table 2. In the first CT exams from disease onset, opacities were one-lobe involved (12/30, 40%), or multiple and bilaterally (17/30, 57%) distributed (one patient had no obvious opacities in her first CT), and commonly located in the subpleural (14/30, 47%), peribronchial (8/30, 27%), and diffuse area (7/30, 23%). In 23/30 cases (77%), the right and/or left lower lobes were involved. In some cases, consolidation (10/30, 33%), interstitial thickening or reticulation (10/30, 33%), air bronchograms signs (6/30, 20%) and pleural effusion (1/30, 3.3%) could also be seen (Fig. 1). These features were also observed in the non-MP group (detailed in Table 2).
In the MP group, the days from illness onset to first CT exam ranged from 1 to 11days (3.3±2.5 days), less than the non-MP group (1 to 10days, 4.7±2.8 days, p = 0.042). The Sum Score of opacities ranged from 0–16 (4.8±4.0) scores, less than that of the non-MP group (1–20 scores, 9.5±5.1 scores, p = 0.0016). Before admission in hospital and regular treatments, the Sum Score of the opacities was positively correlated with the days from illness onset to initial CT, in both the MP and non-MP groups (with age and gender as covariates, R = 0.624 and 0.602, p<0.01, respectively). After regular and individualized treatments, the correlations were not all significant (Fig. 2A, B).
Changes on Follow-up CT
All the patients in both MP and non-MP groups underwent 1–4 follow-up CT exams in our institution. Follow-up CT exams in both MP and non-MP patients usually demonstrated mild, moderate or severe progression of disease in approximate 11.8±4.6 days, as measured by Sum Score of the total dataset, which represent an increased extent of pulmonary opacities. As disease progressed, severe cases could have more consolidation and air bronchograms in the relevant lobes (Fig. 3 and Fig. 4). The diffuse lesions, showed as “white lungs” were seen in the most severe patients. The days from disease onset to the date when the CT showed most obvious pulmonary opacities, were similar in the MP group (11.5±5.9 days) and the non-MP group (12.2±3.1 days, p = 0.55). However, at this “peak stage of opacities”, the average Sum Score of the MP group (10.2±4.7 scores) was less than the non-MP group (14.2±4.2 scores, p = 0.0069) (Table 2 and Fig. 2 C, D). It suggested that although the disease duration, from onset to peak opacities were observed, were similar in both groups, the extent of severity was relatively mild in the MP group.
Until 16th, Feb, 2020, we observed 22 patients (22/30, 73%) in the MP group get better in CT manifestations with decreasing extent and/or density of the opacities. Five patients were still showing a progressive progress in the latest CT. Two patients didn’t undergo the third time CT, including one patient was transferred into ICU. Twenty-eight patients (28/33, 85%) in the non-MP group also exhibited less extent and/or density of the opacities in the follow-up CT exams. Three patients were still progressing, including a very seriously ill female patient, who died 18 days after the disease onset. One patients in the MP group and two patients in the non-MP group had been transferred to another hospital. Among these patients who were getting better according CT manifestations, the days from disease onset to the date when CT began to show decreased extent and density of the opacities, was less in the MP group (16.0±4.4 days) than that in the non-MP group (20.2±3.8 days) (Table 2 and Fig. 2 C, D). Fibrous stripes could be a common sign during the remission stage (17/22 cases in MP group and 23/28 cases in the non-MP group).
Anxiety and Depression Assessments
The Hamilton anxiety scale (HAMA) and Hamilton depression scale (HAMD) [11] were applied in a small portion of mild patients (10/30 cases in the MP group and 11/33 cases in the non-MP group). The HAMA scores were 14.5±2.8 and 15.3±2.7 in the MP and non-MP groups; the HAMD scores were 13.4±2.6 and 14.1±2.7, respectively (p = 0.50 and 0.55). In this limited study group, mild to moderate anxiety and depression were observed in both MP and non-MP patients.