Spleen pathology Notes

NOTES NOTES SPLEEN PATHOLOGY GENERALLY, WHAT IS IT? PATHOLOGY & CAUSES ▪ Injuries/medical procedures/illnesses ▫ Impair splenic function/lead to spleen removal SIGNS & SYMPTOMS ▪ Asplenia → frequent infections ▪ Traumatic rupture → shock, referred pain to left shoulder DIAGNOSIS OTHER DIAGNOSTICS Enlarged spleen ▪ Palpable (increased risk of rupture) TREATMENT MEDICATIONS Asplenia ▪ Immunization/antibiotic prophylaxis SURGERY DIAGNOSTIC IMAGING Splenic rupture ▪ Splenectomy ▫ If hemodynamically unstable Ultrasound/CT scan ▪ Splenic rupture, asplenia OTHER INTERVENTIONS LAB RESULTS Splenic rupture ▪ Strict bed rest, 1–3 days ▫ Conservative; if hemodynamically stable ▪ Impaired blood filtration OSMOSIS.ORG 451

ASPLENIA osms.it/asplenia PATHOLOGY & CAUSES ▪ Absence of normal spleen → immunodeficiency ▪ Splenic macrophages loss → inability to clear opsonized bacteria from blood ▪ T-cell independent antibodies deficiency ▪ Increased infection risk, severity from polysaccharide encapsulated bacteria ▫ Haemophilus influenzae type b, Streptococcus pneumoniae, Neisseria meningitidis, Group B streptococcus, Klebsiella pneumoniae, Salmonella typhi TYPES Acquired asplenia ▪ Splenectomy ▫ Surgical procedure, spleen partially/ completely removed (following trauma, cancer, hemoglobinopathies, massive enlargement) ▪ Auto-splenectomy ▫ Underlying disease → focal venous occlusion → repeated infarction → gradual perivascular fibrosis → loss of function (e.g. sickle-cell disease, pneumococcal septicaemia, systemic lupus erythematosus) Congenital asplenia (rare) ▪ Heterotaxy syndrome (situs ambiguus) → disruption to splenic development during embryogenesis → no spleen/formation of multiple ineffective spleens → functional asplenia ▪ Isolated congenital asplenia → ribosomal mutation → failure of spleen development Functional asplenia ▪ Splenic tissue present, functionally impaired (e.g. sickle-cell disease, isolated congenital asplenia) Hyposplenism 452 OSMOSIS.ORG ▪ Reduced splenic function, less severe SIGNS & SYMPTOMS ▪ Recurrent infection ▪ Sickle cell disease ▫ Enlarged palpable spleen DIAGNOSIS DIAGNOSTIC IMAGING ▪ Abdominal ultrasound, CT scan/MRI ▪ Radionuclide scan ▫ Assess for function LAB RESULTS ▪ Thrombocytosis (elevated platelet count), leukocytosis (elevated white cell count) ▪ Howell–Jolly bodies ▫ Erythrocytes containing basophilic DNA fragments ▪ Target cells ▫ Erythrocytes with increased ratio of surface membrane area to volume TREATMENT MEDICATIONS Antibiotics ▪ Antibiotic prophylaxis (penicillins) ▪ Early antibiotic prescription at first sign of infection (common/otherwise) Vaccination ▪ Pneumococcal polysaccharide vaccine ▪ Haemophilus influenzae type b vaccine ▪ Meningococcal conjugate vaccine ▪ Influenza vaccine

Chapter 58 Spleen Pathology Figure 58.1 A peripheral blood smear with erythrocytes containing Howell–Jolly bodies. Howell-Jolly bodies represent a damaged or absent spleen which has failed to filter these red blood cells. Figure 58.2 A peripheral blood smear containing target cells; erythrocytes that have become derformed and damaged, yet have not been cleared by an absent spleen. RUPTURED SPLEEN osms.it/ruptured-spleen PATHOLOGY & CAUSES ▪ Splenic rupture → break in splenic structural integrity → large amount of blood leaks into abdomen → shock → death CAUSES Traumatic ▪ Significant force to spleen → rupture ▪ Blunt trauma to abdomen ▪ Penetrating trauma (e.g. gunshots/ stabwounds) Non-traumatic ▪ Splenomegaly → capsule thins, decreases structural integrity ▪ Infectious diseases ▫ Malaria, infectious mononucleosis ▪ Medical procedures ▫ Colonoscopy ▪ Hematological disease ▫ Non-Hodgkin’s lymphoma, acute lymphoblastic leukemia ▪ Malignancy ▫ Angiosarcoma ▪ Medications ▫ Anticoagulants ▪ Pregnancy ▪ Enlarged spleens more vulnerable to traumatic rupture SIGNS & SYMPTOMS ▪ Abdominal pain, epigastric tenderness, pain in left flank ▪ Kehr’s sign ▫ Blood in peritoneal cavity → irritation of surrounding tissues → pain referred to tip of left shoulder ▪ Hypovolemic shock ▫ Tachycardia, hypotension, tachypnea, pallor, anxiety DIAGNOSIS DIAGNOSTIC IMAGING Emergency ultrasound ▪ Free blood in peritoneum OSMOSIS.ORG 453

CT scan with contrast ▪ Free blood in peritoneum ▪ Spleen → inhomogeneous hypodense regions OTHER DIAGNOSTICS Procedural ▪ Peritoneal lavage → free blood drawn from peritoneum Figure 58.3 An abdominal CT scan in the axial plane demonstrating a large perisplenic hematoma. This hematoma has formed as a result of splenic rupture, most likely as a result of trauma. 454 OSMOSIS.ORG TREATMENT SURGERY Splenectomy ▪ Hemodynamically unstable/emergency/ grade IV, V injury OTHER INTERVENTIONS Strict bed rest, 1–3 days ▪ Conservative (hemodynamically stable) ▪ Follow-up CT scan in seven days Figure 58.4 The gross pathology of a spleen ruptured by trauma. The capsule is torn, revealing the dark red splenic parenchyma.