Hereditary Spherocytosis (HS)

Get the baseline hematologic picture - CBC with reticulocyte count, MCHC, bilirubin, and a blood smear. Coombs-negative hemolysis with an elevated MCHC plus spherocytes on microscopy makes the diagnosis; osmotic fragility, eosin-5-maleimide binding, or the acidified glycerol lysis test confirms it.

Know the severity band - Hemoglobin under 8 g/dL is severe disease, 8 to 10 g/dL moderate, and 10 to 11.5 g/dL in women or 10 to 13.5 g/dL in men mild. That single number tells you how much reserve the patient has before surgical blood loss becomes a problem.

Use isotonic fluids - Spherocytes cannot buffer a fall in osmolarity the way a normal biconcave cell can. Hypotonic solutions are an avoidable stress on an already fragile membrane.

Defer elective surgery during a crisis - Hemolytic crisis presents with fever and is often triggered by viral infection. Aplastic crisis, classically parvovirus B19, is worse and can cause acute heart failure, with hemoglobin and reticulocytes falling before the marrow recovers. Megaloblastic crisis follows folate depletion — these patients consume folate rapidly because erythropoiesis is running hard, and need supplementation.

The two operations you will see - Cholelithiasis is one of the most common complications, typically presenting between ages 10 and 30, so cholecystectomy is common. Splenectomy (total or partial) is the definitive therapy because the spleen is where the destruction occurs; clinical response correlates with the degree of spectrin deficiency.

Asplenia and infection - Post-splenectomy patients are at risk of overwhelming sepsis from encapsulated organisms — Streptococcus pneumoniae most often, then Neisseria meningitidis and Haemophilus influenzae. Confirm vaccination status against encapsulated organisms before an elective splenectomy. Howell-Jolly bodies on the postoperative smear are expected; their absence suggests residual splenic tissue.

Neonates and infants - The classic triad of jaundice, anemia, and splenomegaly is rare in neonates; jaundice alone is the usual finding. Untreated hyperbilirubinemia risks kernicterus, and the decision to exchange transfuse weighs gestational and chronological age against the indirect bilirubin level and its rate of rise.

Hereditary spherocytosis (HS) is the most common congenital hemolytic anemia caused by an abnormal red cell membrane, diagnosed in roughly 1 in 2,000 people. Deficient or defective spectrin, ankyrin, band 3, or band 4.2 uncouples the cytoskeleton from the lipid bilayer. The cell progressively sheds membrane in the microvasculature, adopts a sphere shape with a poor surface-to-volume ratio, and loses deformability. Abnormal ionic permeability lets sodium in, raising Na/K pump work and ATP demand.

Rigid spherocytes cannot squeeze through the spleen, so they are trapped and destroyed there — extravascular hemolysis with a low MCV, a high MCHC, and increased osmotic fragility. The high membrane tension also means these cells cannot buffer a drop in plasma osmolarity, which is the detail that matters when you choose fluids.