1. Cabot ring
2. Seen in:
   • Lead poisoning
   • Pernicious anemia (vitamin B12 deficiency)
   • Hemolytic anemias

1. Basophilic stippling (*can be asked along with X-ray knee of lead poisoning).
2. Differential diagnoses:
   • Lead poisoning
   • Thalassemia
   • Vitamin B12 deficiency

Note: The Desferal therapeutic index or Porter index is defined as mean daily dose of desferrioxamine in mg/kg, divided by serum ferritin (useful in thalassemia patients; calculated every 6 months in patients receiving desferrioxamine; should not exceed 0.025 to minimize sensorineural hearing loss).

1. Platelet satellitism: Platelet clustering around neutrophils (and rarely monocytes) in the presence of EDTA.
2. Clinical significance: Causes pseudothrombocytopenia (spurious thrombocytopenia because cellular aggregates are counted as leukocytes rather than platelets).
3. Next step: Repeat platelet count in a heparinized or citrate blood sample.

1. Two macrophages are shown which have a fibrillar, crumpled tissue paper-appearing cytoplasm and eccentric nuclei, consistent with Gaucher cells. Diagnosis: Gaucher disease.
2. Differential diagnoses: Niemann-Pick disease, Mucopolysaccharidosis (MPS).
3. Management: Enzyme replacement therapy (ERT) with Cerezyme (imiglucerase for injection) at $60\text{ U/kg}$.

1. Blast cell: L3 type lymphoblast — Burkitt lymphoma / B-cell ALL.
2. Favorable prognostic factors:
   • Age between 1 and 10 years
   • Hyperdiploidy (>50 chromosomes)
   • Presence of t(12;21) [TEL-AML1] translocation
   • Low TLC / WBC count at diagnosis (<50,000/μL)
   • Rapid early response to therapy

1. Leishman-Donovan (LD) bodies (amastigotes) in bone marrow macrophage — Kala-azar (Visceral Leishmaniasis).
2. Diagnostic tests:
   • Bone marrow / splenic aspirate smear (LD bodies)
   • NNN media culture (Novy-MacNeal-Nicolle medium)
   • rK39 immunochromatographic rapid dipstick test
   • Direct Agglutination Test (DAT) / PCR
3. Treatment:
   • Standard: Sodium stibogluconate (20 mg/kg/day for 28–30 days) or Amphotericin B (1 mg/kg/day alternate days for 14–20 days) / Liposomal Amphotericin B.
   • Newer oral/parenteral drugs: Miltefosine, Paromomycin, Pentamidine.

1. Diagnosis: Niemann-Pick disease (Type A) showing foamy histiocytes / lipid-laden macrophages ("foam cells").
2. Inheritance: Autosomal Recessive (AR).
3. Enzyme defect: Acid sphingomyelinase deficiency.

1. Identification:
   • Slide A: Plasmodium vivax (trophozoite / ring form with Schüffner dots / enlarged RBC).
   • Slide B: Plasmodium falciparum (multiple delicate ring forms / crescent-shaped gametocyte, high parasitemia >80% RBCs infected).
2. Treatment:
   • A (P. vivax): Chloroquine for 3 days followed by Primaquine (0.25–0.5 mg/kg/day) for 14 days (after ruling out G6PD deficiency).
   • B (P. falciparum): Artemisinin-based combination therapy (ACT, e.g., Artesunate + Sulfadoxine-Pyrimethamine or Artemether-Lumefantrine) for 3 days plus single dose Primaquine on day 2.

1. Identification:

   • A: Gram-negative bacilli / cocci
   • B: Acid-Fast Bacilli (AFB)
   • C: Gram-positive cocci
   • D: Gram-negative bacilli

2. Staining Procedures:

   • Steps of Gram Staining:

     1. Heat fixation of smear
     2. Primary stain: Apply Crystal Violet for 1 minute
     3. Mordant: Flood with Gram's Iodine for 1 minute (or 10–30 sec)
     4. Decolorization: Decolorize with 95% ethyl alcohol / acetone-alcohol rapidly (10–15 sec) and wash with water immediately
     5. Counterstain: Apply Safranin / Basic Fuchsin for 30–60 seconds, wash with water and dry

   • Steps of Acid-Fast (Ziehl-Neelsen) Staining:

     1. Heat and dry-fix the smear
     2. Primary stain: Add Strong Carbol Fuchsin and heat gently until steaming (do not boil) for 5 minutes
     3. Decolorization: Decolorize with 20% sulfuric acid (or acid-alcohol) and wash with water
     4. Counterstain: Apply Methylene Blue for 1–2 minutes, wash with water, air dry and examine

• 1 – F: Spur cell (Acanthocyte) $\to$ Liver disease / Abetalipoproteinemia
• 2 – A: Burr cell (Echinocyte) $\to$ Renal disease (Uremia)
• 3 – B: Target cell (Codocyte) $\to$ Thalassemia / Hemoglobinopathies
• 4 – C: Cabot ring $\to$ Pernicious anemia (Megablastic anemia / Lead poisoning)
• 5 – D: Bite cell $\to$ G6PD deficiency
• 6 – E: Teardrop cell (Dacrocyte) $\to$ Myelofibrosis

1. Diagnosis: Sickle Cell Anemia (showing sickle cells / drepanocytes and target cells).
2. Drug of choice for prevention of painful episodes: Hydroxyurea.
3. Primary prevention of stroke:
   • Screening with Transcranial Doppler (TCD) ultrasonography annually (evaluating time-averaged mean maximum velocity of internal carotid/middle cerebral artery; if velocity $>200\text{ cm/sec}$, high risk).
   • Chronic transfusion therapy (to maintain $\text{HbS}<30\mathrm{\%}$).
4. Antibiotics of choice in acute chest syndrome: Third-generation cephalosporin (e.g., Cefotaxime/Ceftriaxone) plus a Macrolide (e.g., Azithromycin) to cover atypical pathogens (Mycoplasma, Chlamydia).
5. Renal malignancy: Renal medullary carcinoma.

1. Smear finding: Howell-Jolly bodies (small, round, purple nuclear remnants of condensed DNA in RBCs).
2. Clinical association: Asplenia / Functional asplenia (or post-splenectomy).
3. Likely cause of symptoms: Overwhelming post-splenectomy infection (OPSI) / Bacterial meningitis / Sepsis.
4. Responsible organism: Streptococcus pneumoniae (encapsulated organisms).
5. Prevention:
   • Immunization: Pneumococcal conjugate/polysaccharide vaccine, Meningococcal vaccine, Haemophilus influenzae type b (Hib) vaccine.
   • Prophylactic oral penicillin.

1. Description: Acanthocytes (spur cells) — RBCs lacking central pallor with multiple thorn-like, spiked projections of variable length located at irregular intervals.
2. Conditions:
   • Neurological: Neuroacanthocytosis (e.g., Chorea-acanthocytosis, McLeod syndrome)
   • Metabolic: Abetalipoproteinemia (Bassen-Kornzweig syndrome)
   • Hepatic: Severe liver dysfunction / Cirrhosis (spur cell anemia)
   • Endocrinal: Hypothyroidism

1. Description: Macro-ovalocytes (large oval RBCs) and hypersegmented neutrophils.
2. Diagnosis: Megaloblastic anemia (Vitamin B12 / Folate deficiency).
   • Differential diagnoses of Macrocytosis:
     1. Vitamin B12 deficiency
     2. Folate deficiency
     3. Chronic liver disease
     4. Hypothyroidism
     5. Aplastic anemia
     6. Diamond-Blackfan anemia
     7. Orotic aciduria / Drugs (hydroxyurea, methotrexate, AZT)
3. Hypersegmented neutrophil:
   • Definition: Presence of $\ge 5\mathrm{\%}$ neutrophils with 5 lobes or $\ge 1\mathrm{\%}$ neutrophil with 6 or more lobes on a 100-neutrophil differential count.
   • Causes:
     1. Vitamin B12 deficiency
     2. Folate deficiency
     3. Iron deficiency anemia (rare/mixed)
     4. Uremia
     5. Hydroxyurea / Chemotherapeutic drug therapy

1. Identification: Giant lysosomal granule within leukocyte (granulocyte/neutrophil), seen in Chédiak-Higashi syndrome.
2. Clinical features:
   • Partial oculocutaneous albinism (silvery hair, photophobia, nystagmus)
   • Recurrent severe pyogenic infections
   • Peripheral neuropathy
   • Bleeding diathesis (platelet dense granule defect)
   • Accelerated phase (hemophagocytic lymphohistiocytosis / pancytopenia)

1. Complications (of Diphtheria):
   • Toxic myocarditis / Arrhythmias / Heart failure
   • Neurological complications / Cranial neuropathies (palatal weakness, ciliary paralysis) and peripheral neuropathy
   • Airway obstruction due to pseudomembrane
2. Stain: Albert stain (shows metachromatic granules of Corynebacterium diphtheriae).
3. Differential diagnoses of white patch / membrane on tonsil:
   • Streptococcal tonsillitis / pharyngitis
   • Infectious mononucleosis (EBV)
   • Candidiasis (Oral thrush)
   • Vincent angina (acute necrotizing ulcerative gingivostomatitis)
   • Agranulocytosis

1. Spot: Improved Neubauer hemocytometer counting chamber.
2. Chambers used:
   • A (Large 4 corner squares): Used for White Blood Cell (WBC) counting.
   • B (Central large square / 5 smaller squares within): Used for Red Blood Cell (RBC) and Platelet counting.
3. CSF cytology for WBCs: All 9 large squares (including 4 corners and central squares) are counted.

1. Abnormality: Acanthocytes (spur cells).
2. Diagnosis: Abetalipoproteinemia (Bassen-Kornzweig syndrome).
3. Vitamin deficiency: Vitamin E deficiency (causing ataxia, neuropathy, loss of proprioception).
4. Lipid abnormalities:
   • Markedly decreased / absent Serum triglycerides
   • Markedly decreased Serum cholesterol
   • Absence of ApoB-containing lipoproteins (chylomicrons, VLDL, LDL).
5. Fundus finding: Retinitis pigmentosa (atypical).
6. Mode of inheritance: Autosomal recessive.