Acute chest syndrome and COVID‐19 in hydroxyurea naïve sickle cell disease patient in a low resource setting

Abstract Acute chest syndrome (ACS) is a severe complication of sickle cell disease (SCD) and one of the leading causes of mortality in SCD patients. The management of ACS is challenging and requires prompt intervention to halt clinical deterioration. With the outbreak of the Coronavirus Disease 2019 (COVID‐19) pandemic, which also primarily results in acute respiratory illness, the clinical picture and treatment outcome in SCD patients with ACS remain unknown. We present a case of a 30‐year‐old male who came in with features of painful vaso‐occlusive episode and haemolysis that later evolved to acute chest syndrome. Chest X‐ray showed pneumonic changes and mild bilateral pleural effusion, and nasal Reverse Transcription‐Polymerase Chain Reaction (RT‐PCR) for COVID‐19 test came out positive. He was managed supportively with simple transfusion, antibiotics, dexamethasone and oxygen support with a good clinical outcome. Presenting with non‐specific symptoms and similar respiratory symptoms and signs, the clinical picture of COVID‐19 can prove difficult to discern from that of ACS due to other causes. This report emphasizes a need for a higher index of suspicion whenever a SCD patient presents with symptoms of acute respiratory distress.


CASE DESCRIPTION
A 30-year-old male, a resident of Dar es Salaam, Tanzania, with a known history of sickle cell anaemia (HbSS), was referred to our hospital with fever and generalized bone pains. The fevers were of low grade, associated with excessive night sweats, and subsided with parac- The blood count at presentation showed leukocytosis, microcytic anaemia, and normal platelet count. The reticulocyte count was significantly raised ( Table 1). The peripheral blood smear showed sickled red blood cells, neutrophilia with a left shift and toxic granulation; features consistent with sickle cell anaemia and an ongoing infective process ( Figure 1A,B). Total and unconjugated bilirubin, lactate dehydrogenase and liver enzymes were all raised. Urea and creatinine levels were within the normal range. The rapid malaria antibody test was negative ( Table 2). The proportion of sickle or fetal haemoglobin levels could not be measured due to the unavailability of the test at our facility at the time of admission.
The patient was started on IV Paracetamol 1 g, 6 hourly for 2 days, and IV Ceftriaxone-sulbactam 1.5 g 12 hourly for 5 days. Since the patient presented with fever and had signs of dehydration, we placed the patient on intravenous normal saline equivalent to 1.5 times the normal maintenance fluid dose over 24 hr. Daily folic acid was continued at 5 mg daily, and oral Hydroxyurea 1 g once daily was initiated to prevent future episodes of vaso-occlusive events. He also received a top-up transfusion with two units of packed red cells to reach a haemoglobin level of above 8 g/dl.
By the third day of admission, the fever had subsided but the patient    (Tables 1 and 2).
Nevertheless, a repeat nasopharyngeal swab for SARS-CoV-2 was F I G U R E 2 A chest X-ray image (PA view) with features of pneumonic process with mild bilateral pleural effusion. The film shows bilateral consolidation that is more on the middle and lower zones. Vascular markings and the horizontal fissure are prominent, and the right costophrenic angle is blunted F I G U R E 3 A repeat chest X-ray image (PA view) done after 6 weeks shows significant improvement with resolved pleural effusion and decreased interstitial lung markings negative, and with the continued improved clinical state, he was discharged home after 17 days of hospitalization. A repeat chest X-ray that was done after 6 weeks showed resolved features of consolidation and pleural effusion ( Figure 3). Further, the patient's clinical symptoms had completely resolved and had normal respiratory examination findings.
The baseline blood count (Table 1) in our patient showed a low mean cell volume, mean cell haemoglobin and red cell distribution width, all features suggestive of iron deficiency anaemia. We could not use serum ferritin to confirm the iron deficiency state because of the low sensitivity of these tests in patients with sickle cell anaemia (SCA) and a setting of acute infection [22]. In our case, serum ferritin, which is also an acute-phase reactant was elevated, hence not useful in the diagnosis of iron deficiency. Transferrin saturation assay was not available for further comparison [23]. Iron deficiency though uncommon in patients with SCA has been reported in studies done in Tanzania and other regions with a high prevalence of irondeficiency anaemia [24][25][26]. The possibility of the concomitant existence of thalassemia could not be ruled out due to the lack of genetic studies.
Regarding the management of ACS, there is a lack of randomized trials to inform standard therapy. Nevertheless, transfusion (simple and/or exchange) to maintain the proportion of sickle haemoglobin below 30% and correct the severe anaemia is currently considered the mainstay [8,27,28]. This approach has also been employed in the few reported patients with ACS and COVID-19, who subsequently had good clinical outcomes [12,13,16]. Although there has been a report of case [29] in a resource-limited setting where manual exchange transfusion was implemented with limited blood supply with good clinical results, this could not be reproduced in our case as we had no means of testing baseline HbS levels. We, therefore, had to rely on simple topup transfusion.
Even though the use of systemic corticosteroids is known to trigger rebound vaso-occlusive painful episodes in SCD patients, we nevertheless elected to administer dexamethasone in our patient after weighing the benefits of giving dexamethasone in the context of severe COVID-19 infection versus the risk of rebound VOC [30]. The use of dexamethasone in SCD patients with severe respiratory disease due to COVID-19 is still recommended to date and has been shown to limit severe lung injury. Rebound vaso-occlusive events, if they occur, are in turn managed symptomatically [7,31]. We monitored our patient closely, and he did not develop a rebound vaso-occlusive event.
Likewise, hydroxyurea, a crucial drug in SCD, is known to decrease the incidence of acute painful events and ACS and prolongs survival [32]. Our patient, having never used hydroxyurea, was, therefore, more vulnerable to ACS. Rather than managing the current event, hydroxyurea was initiated in our patient to reduce the risk of future vasoocclusive events. Whether hydroxyurea has any role in preventing any additional complications of COVID-19 in SCD patients is yet to be determined.

CONSENT TO PUBLICATION
Written informed consent for publication of clinical details and clinical images was obtained from the patient. A copy of the consent form is available for review by the editor.

CONFLICT OF INTEREST
The authors have no conflict of interest to disclose.

AUTHOR CONTRIBUTIONS
William Frank Mawalla gathered the patient's history and clinical findings, interpreted the laboratory results and wrote the report.
Ahlam Nasser managed the patient and wrote the report. James