The Biphasic Phenomenon of Cytokine Storm in COVID Pneumonia

Abstract

COVID-19 is a viral disease that commonly presents with mild symptoms with predominant respiratory system involvement. However, it can cause serious complications such as acute respiratory disease, multi-organ dysfunction, especially in patients with comorbidities. As it is a new disease, the full picture of the disease and its complications are not yet fully understood. Moreover, the patients at risk of complications are not well identified, and the data about the biphasic pattern of cytokine storm syndrome are limited. Here, we report the case of a 64-year-old male having diabetes mellitus, hypertension, ischemic heart disease with triple-vessel coronary artery disease tested positive for severe acute respiratory syndrome coronavirus 2, then complicated with acute respiratory distress syndrome and two waves of cytokine storm in 28 days.

INTRODUCTION

COVID-19 is a pandemic viral illness present with respiratory symptoms and is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).[1] The disease severity extends from mild to critical. The severity and complications are more in patients with comorbidities such as hypertension, diabetes, cardiovascular disease, cerebrovascular disease, chronic pulmonary disease, chronic kidney disease, and immunosuppressive diseases.

The binding of SARS-CoV-2 to ACE2 receptors leads to a widespread inflammatory response with the release of pro-inflammatory cytokines. Anti-cytokine therapy is effective against cytokine storm syndrome (CSS). Repeat anti-cytokine therapy leading to rapid resolution of symptoms also points toward a sustained immune dysregulation in our patient.

CASE REPORT

A 64-year-old male patient, chronic tobacco chewer for 40 years, hypertensive, diabetic for 6 years, and ischemic heart disease (coronary artery disease-triple vessel disease) for 4 years coronary artery bypass grafting recommended but not underwent, already on essential medications. Presented in flu clinic with complaints of low-grade fever without chills, dry cough for 3 days, and nausea, dyspnea on exertion for 1 day (total duration of illness-3 days). He was admitted to the general ward after tested positive for SARS-CoV-2 by Rapid Antigen kit.

His temperature on admission was normal, pulse rate 76 beats/min and regular with blood pressure 124/80 mmHg, respiratory rate 16 breaths/min and regular, SpO₂ 98% on ambient air with bilateral basal crepitation on respiratory system examination, other system examination was normal.

Investigations

Day from symptoms onset

Blood reports have done [Table 1] on admission with normal renal and liver function tests, HbA1C-7.4, ESR-53, TSH-3.9, TROP-I, and NT-PRO BNP were normal, a chest X-ray was suggestive of the bilateral mid zone, lower zone ground-glass opacities (GGO) [Figure 1], HRCT thorax done was suggestive of bilateral extensive GGO with the crazy paving appearance and subpleural patchy consolidation with CTSI-20/25 [Figure 2]. Electrocardiogram was suggestive of anterior wall ischemia, two-dimensional echocardiogram (2D echo on 01/05/20) – ejection fraction-60%, RVSP-35 MMHG, NO RWMA, mild concentric LVH. Repeat 2D-echo on admission was the same as the previous Echo.

Table 1.

Laboratory test results on day 4 of symptom onset and then follow-up reports

Investigations	Day 4	Day 7	Day 9	Day 12	Day 14
Hb 12-18 g/dL	12.3	11.5	12.1	12.6	12.1
WBC count 5.2-12.4 KU/L	8850	11650	6210	9600	15210
Platelet count 130,000-400,000 KU/L	260,000	355,000	458,000	505,000	444,000
NLR 1-3	18.2	14.83	9.2	10.2	47.5
CRP (<5) <5: Negative ≥5 Positive	241.56	63	20.38	11.33	6.66
D-dimer <5: Negative ≥5 Positive	0.93	1.91	0.56	0.20	10.24
Ferritin (<250) 10-282 ng/ml	230	353	241	221	284
LDH (<250) 100-250 U/L	301	382	456	791	685
IL-6 (<5) 0-4.4 Pg/mL	55.6	-	-	-	-
ProCal 0-0.1 ng/ml	-	-	-	0.05	-
FiO2	53	60	80	60	80
P:F ratio >300 mmHg	100	153.3	181	121	140

NLR=Neutrophil-lymphocyte ratio, WBC=White blood cells, CRP=C-reactive protein, IL-6=Interleukin-6, LDH=Lactate dehydrogenase, FiO₂=Fractional inspiratory oxygen, ProCal=Procalcitonin, P:F=PaO₂:FiO₂

Figure 1.

X-ray: Day 4 of Symptom Onset

Figure 2.

Computed tomography thorax: Day 4 of Symptom Onset

On the next day, the patient became tachypneic, desaturated and hence was kept on 8 L of oxygen with nonrebreather mask (NRBM) with a PaO2/FiO2 ratio of 100. Hence, injections methylprednisolone and remdesivir (with loading dose) along with local standard treatment were started as per the institutional protocol. Because of worsening respiratory condition (required continuous noninvasive ventilation [NIV] support) and raised inflammatory markers, tocilizumab (400 mg) was administered (on day 6 of symptom onset). Afterward, the patient required continuous NIV support for the next 1 week and then alternatively kept on NIV/high flow nasal oxygen (HFNO) (50 L and 80% FiO2) support. On the day 16^th of symptom onset, he was kept on NRBM with 15 L of oxygen support for few hours. Despite NRBM at 15 L of oxygen, he was tachypnic, and hence was kept on alternate NIV/HFNO support. Serial laboratory reports were suggestive of raised white blood cells count, i.e., 17,740/c.mm on the 16^th day of symptom onset, but the patient was afebrile, and procalcitonin was within the normal limit (0.06 ng/ml).

On the day 28^th of symptom onset, the patient's clinical condition worsened and required continuous NIV support with 70% of FiO2. The patient was not even tolerating HFNO during meals. Chest X-ray was also worsened in the form of the bilateral mid zone and lower zone increased haziness [Figure 3]. HRCT thorax [Figure 4] was suggestive of bilateral GGO are regressing in both upper lobes with increased interstitial thickening with traction bronchiectasis in both lower lobes with the changes of early pulmonary fibrosis as a sequel of COVID-19. At that time, inflammatory markers were also worsened [Table 2]. Other differential diagnoses were ruled out, like secondary bacterial infections (blood and urine cultures were negative, procalcitonin is negative), deep-vein thrombosis with pulmonary embolism (Doppler of both lower limbs was normal, 2D-Echo: RA/RV were normal), and pneumothorax. Hence, considering cytokine storm, tocilizumab 400 mg was repeated. In the next 2 days, there was dramatic improvement seen in the patient's clinical condition, and inflammatory markers were also improved. The patient maintained 92% SpO₂ on air after 7 days of a repeat dose of tocilizumab. Reverse-transcription polymerase chain reaction was repeated before discharge but came positive on the 37^th day; hence, again it was sent on day 42, as per the MOHFW guideline and it came negative. The patient was discharged on room air on the 42^nd day. On telephonic follow-up consultation on the 7^th day, the patient responded to his clinical condition better, maintaining SpO2 of 92% on air with only mild coughing.

Figure 3.

X-ray: Day 28 of Symptom Onset

Figure 4.

Computed tomography thorax: Day 28 of Symptom Onset

Table 2.

Laboratory test results on day 25 of symptom onset and then follow-up reports

Investigations	Day 25	Day 28	Day 30	Day 35
Hb 12-18 g/dl	11.3	11.1	10.6	12.2
WBC count 5.2-12.4 KU/L	10,060	9010	4770	6570
Platelet count 130,000-400,000 KU/L	253,000	284,000	284,000	351,000
NLR 1-3	11.1	6.8	7.3	4
CRP (<5) <5: Negative ≥5 Positive	0.77	80.98	8.90	0.01
D-dimer <5: Negative ≥5 Positive	1.35	1.26	0.95	1.07
Ferritin (<250) 10-282 ng/ml	271	421	286	173
LDH (<250) 100-250 U/L	351	337	324	317
IL-6 (<5) 0-4.4 Pg/mL		104
ProCal 0-0.1 ng/ml	0.02	0.02
FiO2	80	70	50	33
P:F ratio >300 mmHg	230	84	400	302

NLR=Neutrophil-lymphocyte ratio, WBC=White blood cells, CRP=C-reactive protein, IL-6 Interleukin-6, LDH=Lactate dehydrogenase, FiO₂=Fractional inspiratory oxygen, ProCal=Procalcitonin, P:F=PaO₂:FiO₂

DISCUSSION

During the span of clinical care, the patient had clinical respiratory worsening along with raised inflammatory markers suggestive of hyper-inflammation twice, which directed us to look for the possibility of two phases of cytokine storms [Figure 5].

Figure 5.

Picture: Case progress-1

Cytokine storm-definition

The elevated circulating levels of cytokines due to any type of infection or immune-mediated condition are usually known as a cytokine storm, usually, it is a pathological condition that leads to vascular damage, hyper inflammation, capillary leakage, and worsening clinical condition.

In mild SARS-CoV-2 illness, once the virus enters endothelial cells and pneumocytes through ACE-2 receptors, there is more release of anti-inflammatory cytokines such as platelet-derived growth factor, endothelial growth factor, vascular endothelial growth factor, etc. These protective cytokines do not damage endothelial cells and pneumocytes, so there is less activation of macrophages and less release of pro-inflammatory cytokines.[2]

While in severe disease, excess release of inflammatory cytokines with thrombin generation and fibrin production leading to the microthrombi formation. Excess activation of macrophages and release of inflammatory cytokines in pneumocytes and capillaries leading to ARDS and cytokine storm.[1] In both mild versus severe illness in the initial phase viral load is high but as time passes beyond the 10^th day of illness viral load still remains high in severe cases while not in mild cases. In severe cases, viral shedding is also prolonged for days that explain more severity of the illness.[3] In mild COVID-19 illness, low viral load results in early viral clearance, and CD8+ T cell response is more dominant than CD4+ T cell response. While in severe COVID-19 illness, high viral load results in delayed viral clearance, and CD4+ T cell response is more dominant and it persists for a longer period. It suggests broader and stronger T-cell response correlates with strong antibody response later on.[4] In the initial phase of COVID-19, detection of the virus is 100% in mild or severe illness, but at the end of 4 weeks, only 44% of respiratory samples are positive for virus detection in mild illness, while 56% in severe illness. In the age group of >60 years, viral shedding continues for a longer period in severe illness as compared to mild illness.[5]

SARS-CoV-2 enters alveoli through ACE 2 receptors that activate dendritic cells and macrophages leading to the release of proinflammatory cytokines like interleukin (IL)-1β, IL-2, IL-6, IL-7, IL-10, tumor necrosis factor-alpha, interferon-gamma, granulocyte-colony stimulating factor, granulocyte macrophage colony-stimulating factor, MCP1, and various chemokines into circulation. However, in stage-1 that is the initiation stage (0–4 days), only a minimal amount of cytokines are released with the presence of neutralizing chemokine activity leading to cytokine blockage with minimal symptoms. However, in severe illness, it progresses to the stage-2-Amplification stage (5–14 days) where excess activation of dendritic cells, macrophages, neutrophils, monocytes, and natural-killer cells leading to massive cytokine secretion, it suggests high chances of ICU transfer. Moreover, the stage-3 that is the consummation stage (15 days onwards) suggests massive cytokine release in circulation leading to cytokine storm in which IL-6 is predominant and that suggests high mortality.[6]

As Clay et al.[7] showed that the virus is replicated in the lungs until day 10 of postinfection, but lung inflammation is more intense even after viral clearance, reaching its peak at day 14 and may remain up to day 28 in severe illness. An early phase of the hyperinflammatory response (cytokine storm) is dependent on viral replication while a later phase is viral-independent but immune dependent due to exacerbated inflammatory response leading to prolonged tissue destruction. These demonstrate two-phase cytokine storm occurs in course of severe COVID-19. In the first 10 days of symptoms onset patients with severe or moderate disease display a similar correlation in intensity and overall core COVID-19 signature markers. After the 10^th day, markers are declined steadily in patients with moderate disease. While patients with severe disease maintain an elevated level of core signature markers for a prolonged period which is responsible for the 2^nd phase of the cytokine storm.[8,9]

CONCLUSION

The virus persists longer with high viral load and peaks later in the respiratory tissue of patients with severe disease. Although there is a lack of robust data, LATE CYTOKINE RELEASE SYNDROME is present in our patient. Repeat anti-cytokine therapy leading to the rapid resolution of symptoms also points toward a sustained immune dysregulation in our patient. Age, multiple comorbidities, addictions, peripheral blood cell morphology, and elevation of inflammatory markers can be used as SURROGATE MARKERS to monitor patients closely for the development of severe disease spectrum and thus requires timely aggressive management. Not every patient who survived day 14 is free from developing complications of COVID-19.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.