2025 – PAGE 116 – ALLERGY & IMMUNOLOGY

CHEDIAK-HIGASHI SYNDROME

In Chediak-Higashi Syndrome, there is NEUTROPENIA, poor neutrophil chemotaxis, and platelet dysfunction. Neutrophils containing giant lysosomal granules are seen on microscopy. Patients have OCULOCUTANEOUS ALBINISM and frequent SKIN and LUNG INFECTIONS with Staphylococcus and Streptococcus. (They can have recurrent pneumonias.)  There may also be neurologic dysfunction.

PEARL: Don’t get confused with Hyper-IgM, which has Neutropenia + LYMPHOCYTOSIS.

MNEMONIC: Imagine a pair of All-American WHITE BOYS. They’re brothers, and their names are “CHAD and ZACH, the ASHY white boys” with BLOND HAIR, PINK EYES, and WHITE SKIN that’s so ASHY that they get INFECTIONS all over. They like to play with NEUTROglycerine sticks shaped like MAGNETS and blow things up in their backyard (like jars filled with PENNIES).

• KEY: WHITE BOYS = Cutaneous Albinism, CHAD & ZACH the ASHY white boys = Sounds like the name of the disease, BLOND HAIR = Blond hair, PINK EYES = Ocular albinism, ASHY = Can also refer to white skin, INFECTIONS = Recurrent infections, NEUTROglycerine = A reference to neutrophils, NEUTRO + MAGNETS = Neutrophils that have trouble with chemotaxis, NEUTRO + PENNIES = NEUTROPENIA.

(DOUBLE TAKE) SHWACHMAN-DIAMOND SYNDROME

SHWACHMAN-DIAMOND SYNDROME is a rare, autosomal recessive (AR) disorder associated with bone marrow failure (pancytopenia/neutropenia), pancreatic insufficiency, bone/skeletal abnormalities, and possible neutrophil defects (migration and chemotaxis). Recurrent bacterial infections are common, including recurrent pneumonias, skin infections, otitis media, and sinusitis. Patients may also have aphthous stomatitis.

• PEARL: Due to some overlapping symptoms with Cystic Fibrosis (CF), such as pancreatic insufficiency, you may have to choose between this disorder and CF. Remember, this one has cell line issues, and the electrolytes and lungs are NORMAL.
• MNEMONIC: Imagine a DIAMOND in a SHWACH WATCH being used to make a CREASE in a black PAN with a white handle made of HOLLOW BONE.”
  • KEY: PAN/HOLLOW = PANCYTOPENIA/NEUTROPENIA!!! CREASE = panCREASE, PAN = PANcytopenia, HOLLOW BONE = Aplasia resulting in PANcytopenia and neutropenia.
• NAME ALERT: The name alert is for DIAMOND-BLACKFAN ANEMIA.

(DOUBLE TAKE) DIAMOND-BLACKFAN ANEMIA

DIAMOND-BLACKFAN ANEMIA is an anemia due to pure red cell aplasia. That means that unlike “aplastic anemias” which affect all cell lines (ie, pancytopenia), ONLY THE RED CELL LINE IS AFFECTED. Red cells are MACROCYTIC, anemia is typically severe, patients present around 3 months of age, and they may have TRIPHALANGEAL THUMBS and craniofacial anomalies. Look for low reticulocyte counts. If asked about treatment, use steroids chronically and transfuse for severe anemia.

• MNEMONIC: Imagine looking at a standing BLACK FAN with THREE GIANT PLASTIC BLADES. The blades are BLACK but are SHAPED LIKE RED CELLS.
  • KEY: BLACK FAN = Name, THREE = TRIphalangeal thumbs and 3 months old at presentation, GIANT = MACROCYTOSIS, PLASTIC = aPLASTIC because of the APLASIA, SHAPE = Reminder that this is a pure RED CELL aplasia. Remember that while there is “aplasia,” this is not a true “aplastic anemia” because those include pancytopenia.

• PEARL: If you see a patient with anemia and icterus or hyperbilirubinemia suggesting hemolysis, it is NOT Diamond-Blackfan Anemia. Since there is a red cell aplasia, the anemia is from a lack of production, NOT from hemolysis.
• NAME ALERT: The name alert is for SHWACHMAN-DIAMOND SYNDROME and Fanconi Anemia.