SICKLE CELL ANEMIA - Nursing Case Study

Pathophysiology

• Primary mechanism: Sickle cell anemia is caused by a genetic mutation in the HBB gene, leading to the production of abnormal hemoglobin S (HbS). When deoxygenated, HbS polymerizes, causing red blood cells to become rigid and sickle-shaped, impairing their ability to flow through small blood vessels.

• Secondary mechanism: The sickled red blood cells have a reduced lifespan, typically lasting only 10-20 days compared to the normal 120 days. This leads to chronic hemolytic anemia as the body cannot produce new red blood cells quickly enough to replace the destroyed ones.

• Key complication: The sickle-shaped cells can occlude microvasculature, causing vaso-occlusive crises characterized by severe pain and potential organ damage. Repeated episodes contribute to cumulative organ damage, notably affecting the spleen, lungs, and brain, increasing the risk for infections and acute chest syndrome.

Patient Profile

Demographics:

32-year-old female, school teacher

History:

• Key past medical history: Diagnosed with sickle cell anemia at age 4, history of acute chest syndrome, and splenic sequestration

• Current medications: Hydroxyurea, folic acid, and occasional use of pain medications (acetaminophen)

• Allergies: Penicillin

Current Presentation:

• Chief complaint: Increasing episodes of fatigue and joint pain

• Key symptoms: Shortness of breath, intermittent joint pain (especially in knees and elbows), mild jaundice, and abdominal pain

• Vital signs: Temperature 100.2°F, Heart rate 112 bpm, Blood pressure 108/64 mmHg, Respiratory rate 22 breaths per minute, Oxygen saturation 93% on room air

Section 1

New Complications:

Over the next 24 hours, the patient's condition begins to deteriorate, indicating the development of new complications. Her joint pain becomes increasingly severe and persistent, unresponsive to acetaminophen, suggesting a more intense vaso-occlusive crisis. The abdominal pain intensifies, raising concerns about potential splenic infarction or liver involvement. Her jaundice deepens, hinting at an escalation in hemolytic activity. Clinically, she presents with scleral icterus and mild hepatomegaly upon palpation.

Laboratory results reveal a marked drop in hemoglobin levels to 6.8 g/dL, down from her baseline of around 8 g/dL, indicating acute exacerbation of anemia. The reticulocyte count is elevated at 15%, reflecting a compensatory response to increased hemolysis. Additionally, a peripheral blood smear shows increased sickling and polychromasia. Her lactate dehydrogenase (LDH) levels are elevated, and liver function tests show a slight increase in transaminases, supporting the evidence of acute hemolysis and possible liver involvement. The combination of these findings suggests that the patient may be experiencing a hemolytic crisis alongside the vaso-occlusive event.

Clinicians now face the challenge of managing these overlapping complications. The priority is to provide adequate pain control, hydration, and oxygen therapy to improve her oxygen saturation, which remains concerning at 90% on room air. Considering her history of acute chest syndrome, her respiratory status is closely monitored for any worsening signs. The healthcare team initiates discussions about potential red blood cell transfusion to address the acute anemia, while carefully balancing the risks of alloimmunization. These developments necessitate a multidisciplinary approach to prevent further organ damage and manage the evolving complications effectively.

Section 2

As the healthcare team closely monitors the patient, a change in her status becomes evident. Overnight, her oxygen saturation drops to 85% despite supplemental oxygen via nasal cannula at 2 L/min, prompting an escalation to 4 L/min. Her respiratory rate increases to 28 breaths per minute, and she exhibits intercostal retractions, suggesting the onset of acute chest syndrome. Auscultation reveals diminished breath sounds at the lung bases and inspiratory crackles, raising concerns about potential pulmonary involvement. Her temperature spikes to 101.8°F (38.8°C), and she appears diaphoretic and tachycardic, with a heart rate of 130 beats per minute, indicating a possible infectious process or further exacerbation of her sickle cell crisis.

In light of these developments, the healthcare team orders a chest X-ray and arterial blood gas analysis to further evaluate her respiratory status. The chest X-ray reveals bilateral infiltrates, confirming the suspicion of acute chest syndrome. Arterial blood gas results show a pH of 7.32, PaCO2 of 48 mmHg, and PaO2 of 58 mmHg, indicating respiratory acidosis and significant hypoxemia. These findings necessitate more aggressive respiratory support and the initiation of broad-spectrum antibiotics to cover potential underlying infections, while also considering corticosteroids to reduce lung inflammation.

The patient is transferred to a higher level of care for continuous monitoring and potential interventions, such as non-invasive ventilation or exchange transfusion, to manage her acute chest syndrome effectively. The multidisciplinary team, including hematologists, pulmonologists, and critical care specialists, collaborates to refine her treatment plan, focusing on stabilizing her oxygenation, controlling her pain, and addressing her acute anemia. These efforts aim to prevent further deterioration and support her recovery from this complex interplay of sickle cell-related complications.

Section 3

As the patient is closely monitored in the higher level of care, the healthcare team observes her response to the interventions initiated for acute chest syndrome. Over the next 12 hours, her oxygen saturation improves to 92% with the assistance of non-invasive ventilation, allowing the supplemental oxygen to be gradually reduced. Her respiratory rate decreases to 22 breaths per minute, and she continues to receive broad-spectrum antibiotics and corticosteroids. Despite these improvements, her pain remains a significant concern, requiring consistent administration of intravenous opioids and careful monitoring for potential side effects.

A follow-up chest X-ray is performed to assess her pulmonary status, revealing a slight reduction in bilateral infiltrates, suggesting some resolution of the acute chest syndrome. However, her laboratory results show a hemoglobin level of 6.8 g/dL, indicating a severe drop compared to previous readings. This acute anemia prompts the team to consider an urgent exchange transfusion to reduce the sickle cell load and improve oxygen-carrying capacity, especially given her ongoing respiratory challenges. Her reticulocyte count is notably elevated, reflecting increased erythropoietic activity in response to hemolysis.

As the patient continues to stabilize, there is a new development: her renal function tests, including serum creatinine and blood urea nitrogen (BUN), reveal a rising trend, suggesting potential acute kidney injury (AKI) secondary to the sickle cell crisis and recent hypotensive episodes. This necessitates close collaboration with nephrology to optimize fluid management and monitor for further renal impairment. The team remains vigilant, understanding that managing her renal function is crucial to prevent additional complications and ensure a holistic approach to her recovery.

Section 4

As the healthcare team continues to closely monitor the patient's condition, a significant change in her status is noted. Her urine output has decreased markedly over the past eight hours, with less than 20 mL/hour, prompting concerns about worsening renal function. Concurrently, her blood pressure readings have become labile, fluctuating between hypotensive episodes of 85/55 mmHg and more stable periods at 100/70 mmHg. Her heart rate remains elevated at a consistent 110-120 beats per minute, reflecting a compensatory response to both anemia and possible fluid shifts.

In light of these developments, a comprehensive reassessment is conducted to evaluate the potential causes of her oliguria and hemodynamic instability. The team considers the cumulative impact of sickle cell-related vascular occlusions, recent hypotensive episodes, and the potential nephrotoxic effects of medications used during her acute chest syndrome management. Repeat laboratory tests reveal a further increase in serum creatinine to 2.1 mg/dL, up from 1.4 mg/dL, and a BUN level rising to 35 mg/dL, confirming a progression towards acute kidney injury. Urinalysis shows the presence of hematuria and proteinuria, suggesting renal parenchymal involvement.

These findings necessitate a multidisciplinary discussion to adjust her treatment plan, emphasizing the need for careful fluid management to prevent further renal compromise while avoiding fluid overload that could exacerbate her respiratory status. The nephrology team recommends initiating renal protective strategies, including possible diuretic therapy or renal replacement options if oliguria persists. The patient's pain management regimen is also reviewed to minimize nephrotoxicity while ensuring adequate analgesia. This change in patient status underscores the complexity of managing sickle cell disease with multi-organ involvement, necessitating a dynamic and coordinated approach to support her recovery trajectory.

Section 5

As the interdisciplinary team reconvenes, the nephrology consultant suggests a cautious trial of diuretic therapy to manage the patient's fluid status, given her decreasing urine output and fluctuating blood pressure. Furosemide is administered intravenously, with careful monitoring planned to assess her renal response and hemodynamic stability. Within two hours of administration, there is a modest increase in urine output to 25 mL/hour, providing a slight indication of renal responsiveness. However, her blood pressure remains erratic, with readings ranging from 88/58 mmHg to 95/65 mmHg, necessitating close vigilance.

Amid these adjustments, a further complication emerges. The patient begins exhibiting mild confusion and disorientation, suggesting possible cerebral involvement. Neurological assessment reveals brisk deep tendon reflexes and a positive Babinski sign, raising suspicion for a cerebrovascular complication secondary to sickle cell disease. The hematology team raises concerns regarding the potential for a silent cerebral infarct, a known complication, particularly given her fluctuating blood pressure and elevated heart rate.

To confirm this suspicion and guide further management, an urgent MRI of the brain is ordered. The imaging reveals small areas of ischemia in the frontal lobe, consistent with silent infarcts. This development prompts a reevaluation of her anticoagulation strategy and highlights the need for enhanced cerebral protection measures. The team discusses the potential benefits of exchange transfusion to decrease the proportion of sickled cells and improve overall cerebral perfusion, aiming to stabilize her neurological status and prevent further ischemic episodes. This complex new layer to her condition emphasizes the intricate interplay between sickle cell pathology and multi-system complications, requiring a nuanced and proactive treatment plan.