Overview
Definition:
Asplenia refers to the congenital or acquired absence of splenic tissue, leading to impaired immune function, particularly against encapsulated bacteria
Children with asplenia are at a significantly increased risk of severe, rapidly progressing infections, known as overwhelming postsplenectomy infection (OPSI).
Epidemiology:
Congenital asplenia is rare, often associated with other congenital anomalies (e.g., complex cardiac defects in Ivemark syndrome)
Acquired asplenia is more common, resulting from splenectomy (due to trauma, malignancy, or hemolytic anemias like thalassemia or sickle cell disease) or splenic infarction in conditions like sickle cell disease where splenic function is progressively lost.
Clinical Significance:
Children with functional or anatomical asplenia are highly vulnerable to life-threatening infections
Prompt recognition, appropriate prophylaxis, and a well-defined fever management plan are critical to reduce morbidity and mortality
This topic is of paramount importance for pediatricians preparing for DNB and NEET SS examinations, as managing these high-risk patients is a core competency.
Clinical Presentation
Symptoms:
Fever, often sudden onset and high grade
Lethargy and irritability
Poor feeding
Vomiting and diarrhea
Rash (petechiae, purpura, or cellulitis)
Respiratory distress
Signs of sepsis, including hypotension and altered mental status.
Signs:
Fever
Tachycardia and hypotension
Pallor
Jaundice (if underlying condition)
Splenomegaly may be absent or difficult to palpate in functional asplenia
Signs of localized infection (e.g., pneumonia, meningitis, cellulitis).
Diagnostic Criteria:
There are no specific diagnostic criteria for asplenia itself, as the diagnosis is usually made based on history (splenectomy, splenic infarction) or congenital anomalies
The critical aspect is recognizing the *risk* of infection in a child with documented or suspected asplenia
Functional asplenia can be inferred from recurrent severe infections, although specific tests like Howell-Jolly bodies in peripheral blood smear can be indicative but are not routinely used for clinical management decisions.
Diagnostic Approach
History Taking:
Detailed history of previous splenectomy or splenic surgery
History of trauma to the abdomen
History of conditions causing splenic infarction (e.g., sickle cell disease, thalassemia, lupus)
History of recurrent infections, especially bacterial
Vaccination history, particularly pneumococcal, meningococcal, and Haemophilus influenzae type b (Hib)
Travel history
Family history of asplenia or related conditions.
Physical Examination:
Complete physical examination, focusing on vital signs (temperature, heart rate, blood pressure, respiratory rate)
Assessment for signs of sepsis
Thorough examination of the abdomen for tenderness, organomegaly, or signs of trauma
Examination for skin lesions, joint swelling, or neurological deficits
Evaluation of the vaccination scar (if any).
Investigations:
Complete Blood Count (CBC) with differential: may show anemia, leukocytosis, or presence of Howell-Jolly bodies (indicative of absent splenic function)
Blood cultures: crucial for identifying causative pathogens
Other cultures as clinically indicated (e.g., urine, cerebrospinal fluid)
Imaging: Ultrasound of the abdomen to confirm absence of spleen (if congenital or post-surgical)
Chest X-ray if respiratory symptoms
Lumbar puncture for CSF analysis if meningitis suspected.
Differential Diagnosis:
Sepsis from other causes in immunocompromised children
Viral exanthems
Meningitis from other causes
Pneumonia from other causes
Cellulitis from other causes
Other causes of fever in children
It is crucial to remember that these are *not* differentials for asplenia, but for the presenting symptoms, while keeping the high-risk status of the asplenic child central.
Management
Prophylaxis:
Vaccination: Administer conjugate pneumococcal vaccines (PCV13, PPSV23), meningococcal vaccines (MenACWY, MenB), and Hib vaccine as per schedule, with booster doses recommended
Influenza vaccination annually
Early referral for prophylactic antibiotic therapy if vaccination is delayed or incomplete
Penicillin prophylaxis: Daily oral penicillin V (e.g., 125mg BID for <5 years, 250mg BID for >5 years) is recommended for children with functional or anatomical asplenia, especially those with sickle cell disease, until at least 5 years of age and for 1 year post-splenectomy
Consider continuation indefinitely in high-risk individuals
Prophylactic antibiotics may be started while awaiting vaccination series completion.
Fever Plan:
Immediate medical attention for any fever >38.0°C (100.4°F)
Rapid assessment for signs of sepsis
Empiric broad-spectrum antibiotics (IV) should be administered *promptly*, ideally within 1 hour of presentation, even before cultures are drawn
Common choices include third-generation cephalosporins (e.g., ceftriaxone 50-100 mg/kg/day IV in single or divided doses) or piperacillin-tazobactam, covering common encapsulated pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis)
Prompt investigations including CBC and blood cultures are mandatory
Close monitoring for hemodynamic instability and organ dysfunction is essential
Parental education on recognizing early signs of infection and the importance of prompt medical consultation is paramount.
Supportive Care:
Intravenous fluid resuscitation for dehydration or hypotension
Oxygen therapy if hypoxic
Antipyretics (paracetamol, ibuprofen) for fever control
Close monitoring of vital signs, urine output, and neurological status
Management of underlying conditions contributing to asplenia (e.g., blood transfusions for sickle cell disease).
Complications
Early Complications:
Overwhelming Postsplenectomy Infection (OPSI): rapid, fulminant sepsis caused by encapsulated bacteria, with high mortality
Meningococcemia
Pneumococcal sepsis
Haemophilus influenzae sepsis
Septic shock
Disseminated intravascular coagulation (DIC).
Late Complications:
Recurrent infections
Chronic pain related to underlying conditions
Complications of chronic illness (e.g., vaso-occlusive crises in sickle cell disease).
Prevention Strategies:
Strict adherence to vaccination schedules
Regular antibiotic prophylaxis (especially for young children and those with sickle cell disease)
Educating parents and caregivers about the risks and the importance of prompt medical attention for fever
Avoiding travel to areas with high endemic rates of certain infections if possible, or ensuring appropriate prophylaxis
Prompt management of any splenic injury to prevent or minimize damage.
Prognosis
Factors Affecting Prognosis:
Timeliness of antibiotic administration upon fever onset
Virulence of the causative organism
Degree of immune compromise
Presence of underlying comorbidities
Promptness of diagnosis and initiation of supportive care.
Outcomes:
With prompt and appropriate management, many children can survive severe infections
However, OPSI can be rapidly fatal
Long-term prognosis is generally good for survival with vigilant prophylaxis and rapid response to fever, but the risk of recurrent infections remains
Congenital asplenia, especially when part of complex syndromes, carries a more guarded prognosis.
Follow Up:
Regular follow-up with a pediatrician or hematologist is essential
Monitoring vaccination status and administering booster doses as required
Re-evaluation of the need for continued antibiotic prophylaxis based on age, risk factors, and infection history
Education on ongoing vigilance and prompt reporting of any febrile illness.
Key Points
Exam Focus:
OPSI is the major life-threatening complication of asplenia
Encapsulated bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis) are the primary pathogens
Prophylactic antibiotics (e.g., Penicillin V) and prompt vaccination are cornerstones of prevention
Any fever in an asplenic child is a medical emergency requiring immediate IV antibiotics.
Clinical Pearls:
Always ask about splenectomy or splenic issues in children presenting with severe infections
Educate parents thoroughly: "Fever equals ER" for asplenic children
Don't delay antibiotics for fever, even before blood cultures result
Review vaccination records meticulously
Consider indefinite antibiotic prophylaxis for high-risk asplenic individuals.
Common Mistakes:
Underestimating the severity of fever in an asplenic child
Delaying antibiotic administration
Relying solely on vaccination without considering prophylactic antibiotics in high-risk groups
Inadequate parent education regarding fever management
Failing to consider asplenia in the differential diagnosis of severe sepsis in children.