3 Hemogramas Que (deberían) Preocupar a Cualquier Médico

Understanding Hemogram Findings and Cancer Risk

Introduction to Hemogram Findings

• The expression of a doctor when viewing a hemogram can indicate various findings, some of which should raise concerns about cancer.

• This discussion will focus on specific hemogram abnormalities that suggest malignancy while also covering fundamental aspects of the hemogram.

Key Abnormalities in Hemograms

Leukocytosis

• Defined as a white blood cell count greater than 11,000 cells per cubic millimeter; it is one of the most common findings in clinical practice.

• Differentiating causes requires a thorough patient history and physical examination, focusing on signs of infection, inflammation, and medication use.

Cellular Lineages in Leukocytosis

• White blood cells are categorized into three main families: granulocytes (neutrophils, eosinophils, basophils), lymphocytes (B and T cells), and monocytes. Each lineage suggests different differential diagnoses when elevated.

Common Misinterpretations

• A frequent error is relying on percentages rather than absolute counts for diagnosing conditions like neutrophilia or neutropenia; absolute counts provide more accurate insights into the patient's condition.

Differential Diagnoses Based on Cell Type Elevation

Neutrophils

• Elevated neutrophil levels typically indicate bacterial infections but may also relate to chronic inflammatory processes or medications such as glucocorticoids.

Lymphocytes

• Increased lymphocyte counts often point to viral infections or stress responses (e.g., postoperative states) rather than bacterial issues.

Eosinophils and Monocytes/Basophils

• Eosinophilia usually indicates parasitic infections or allergies; monocytosis/basophilia may suggest underlying hematological neoplasia if markedly elevated alone.

Critical Hemogram Findings Suggesting Cancer

Urgent Clinical Indicators

1. Bone Marrow Failure: Multiple cytopenias alongside leukocytosis signal significant clinical concern requiring immediate evaluation. Example: leukocyte count at 30,000 with low platelets and hemoglobin levels suggests serious pathology.

2. Hyperleukocytosis: A white blood cell count exceeding 100,000 cells per cubic millimeter is almost exclusively seen in neoplastic conditions and poses various risks necessitating urgent referral to emergency services.

3. Presence of Blasts: Identifying blasts either in differential counts or peripheral blood smears raises immediate suspicion for acute leukemia or other malignancies requiring prompt action from healthcare providers.

Acute Leukemia Diagnosis and Considerations

Key Findings Indicative of Acute Leukemia

• The discovery of findings suggestive of acute leukemia necessitates immediate referral to emergency services, particularly in cases of bone marrow failure, hyperleukocytosis, and the presence of blasts.

• A white blood cell count exceeding 50,000 can indicate potential malignancy; however, it may also represent a leukemoid reaction not linked to cancer.

• Elevated immature forms other than blasts or accompanying symptoms like unexplained weight loss or night sweats should raise suspicion for neoplasia.

Additional Suspicious Hematological Findings

• Other concerning findings include elevated levels of erythrocytes or platelets and marked basophilia. A leukoerythroblastic pattern in the hemogram is particularly alarming.

• Understanding leukocyte maturation is crucial; significant increases in immature precursors are worrisome as they may indicate a high likelihood of medullary neoplasia.

Specific Indicators for Neoplasia

• Basophilia (greater than 100 cells per microliter), especially values over 400, has a sensitivity close to 70% and specificity near 99% for myeloid neoplasms.

• Isolated or marked monocytosis can be misleading due to automated counts potentially misclassifying circulating blasts as monocytes.

Identifying Symptoms and Physical Exam Findings

Clinical Symptoms Suggestive of Hematological Neoplasia

• Constitutional symptoms such as unexplained weight loss, night sweats, and non-infectious fever should heighten suspicion during patient history taking.

• Signs of cytopenias like bleeding tendencies or recurrent infections are critical indicators that warrant further investigation.

Physical Examination Insights

• On physical examination, key findings include splenomegaly, lymphadenopathy, and bleeding stigmata such as petechiae which could suggest hematological malignancies.

Approach to Suspected Hematological Neoplasia

Initial Diagnostic Steps

• If a hematological neoplasm is suspected based on previous findings, general practitioners should order a complete blood count (CBC), peripheral blood smear, electrolytes panel, renal function tests, liver profile, LDH levels and refer the patient to hematology for specialized testing including bone marrow aspiration.

Understanding Polycythemia: Causes and Implications

Definition and Measurement Challenges

• Polycythemia refers to an increase in red cell mass typically defined by hemoglobin levels above 16.5 g/dL in men or above 16 g/dL in women; however measuring red cell mass directly is often impractical.

Types of Polycythemia

• There are three main causes: relative polycythemia due to hypovolemia without increased cellular mass; primary polycythemia from autonomous production (e.g., polycythemia vera); secondary polycythemia resulting from systemic stimulation leading to increased erythropoiesis.

Understanding Secondary Polycythemia and Thrombocytopenia

Causes of Secondary Polycythemia

• The discussion begins with the identification of conditions leading to systemic oxygenation issues, such as chronic obstructive pulmonary disease (COPD) and renal hypoperfusion due to bilateral renal stenosis.

• Other causes include smoking, medications like SGLT2 inhibitors, and tumors that produce erythropoietin (EPO), all contributing to secondary polycythemia.

Clinical Approach to Diagnosis

• A thorough clinical history and physical examination are essential for identifying the underlying cause of polycythemia in patients.

• Symptoms indicating dehydration, such as high-output diarrhea, may lead to polycythemia being a secondary finding; rehydration could resolve the issue.

• Key findings during history-taking include signs of chronic lung disease, smoking history, or abdominal masses that might indicate secondary causes.

Identifying Primary Etiologies

• The presence of symptoms like erythromelalgia (painful redness in palms/soles), aquagenic pruritus (itching after water contact), or retinal vein dilation can suggest primary causes like polycythemia vera.

Diagnostic Testing

• If a potential secondary cause is identified but hemoglobin levels are excessively high, initial tests should include urinalysis, renal function tests, liver profile, electrolytes, and EPO levels.

• Ideally, JAK2 mutation testing should be performed since it is commonly associated with hematological neoplasms causing polycythemia. If not feasible initially, it can be done later if suspicion persists.

Referral Considerations

• Patients suspected of having primary etiologies or those without identifiable secondary causes should be referred to a hematologist.

• Urgent referrals are necessary for patients exhibiting life-threatening symptoms related to hyperviscosity syndrome.

Exploring Thrombocytopenia: Causes and Management

Definition and Prevalence

• Thrombocytopenia is defined as a platelet count below 150,000. Notably, counts at this threshold can occur in up to 2.5% of healthy individuals.

Understanding Causes: The 5D Framework

• Five main reasons for thrombocytopenia are summarized using the mnemonic "5D": dilution, destruction, demand, detention, and deficit.

Dilution

• Often results from aggressive fluid resuscitation in hospitalized patients leading to lower platelet concentrations.

Destruction

• Immune-mediated destruction is common; conditions like immune thrombocytopenic purpura (ITP), antiphospholipid syndrome, lupus erythematosus must also be considered.

Demand

• Conditions requiring increased platelet usage for thrombus formation can lead to decreased counts; examples include thrombotic microangiopathies or disseminated intravascular coagulation (DIC).

Detention

• Situations causing platelets to sequester in an enlarged spleen result in reduced circulating numbers; portal hypertension can exacerbate this condition.

Deficit

• Nutritional deficiencies affecting platelet production or bone marrow disorders may lead to thrombocytopenia; these include vitamin B12 deficiency or various hematological malignancies.

Clinical Approach to Thrombocytopenia

Initial Assessment Steps

• The first step involves a thorough clinical history and physical examination aimed at identifying findings suggestive of various etiologies, including recent travel, alcohol consumption, medication use, dietary habits, sexual behaviors, neurological symptoms, autoimmune symptoms, and signs of malignancy such as constitutional symptoms or splenomegaly.

• During the physical exam, special attention should be given to detecting visceromegaly, lymphadenopathy, and chronic liver disease signs. It's also crucial to inquire about bleeding tendencies in skin and mucous membranes.

Identifying Urgent Cases

• The next step is identifying patients who need urgent referral. This includes those with platelet counts below 50,000 or suspected hemolytic anemia indicating underlying thrombotic microangiopathy.

• Patients with blasts in peripheral blood smears or signs of bone marrow failure should also be referred urgently. Pregnant women with platelet counts under 100,000 and those suspected of heparin-induced thrombocytopenia or vaccine-related thrombocytopenia require immediate attention.

Evaluating Peripheral Blood Smear

• If no urgent scenarios are identified, the next appropriate step is a careful evaluation of the peripheral blood smear for clues regarding the etiology of thrombocytopenia.

• Key findings include schistocytes suggesting thrombotic microangiopathy; microspherocytes or agglutinated erythrocytes indicating immune hemolysis; abnormal-sized platelets hinting at congenital conditions; atypical lymphocytes or toxic granulations suggesting infection; and leukoerythroblastosis raising suspicion for an underlying malignancy.

Differentiating True vs Pseudothrombocytopenia

• The blood smear is essential for distinguishing true thrombocytopenia from pseudothrombocytopenia—where platelet counts appear falsely low due to EDTA-dependent antibody reactions causing clumping that misleads automated counters.

• This phenomenon occurs in approximately 0.1% of the population and can lead to unnecessary treatments if not recognized correctly.

Further Laboratory Investigations

• Following the blood smear analysis, specific laboratory tests should be requested based on clinical suspicion: vitamin B9/B12 levels for megaloblastic anemia; ultrasound and liver profile for chronic liver disease; ANA antibodies for autoimmune conditions; bone marrow biopsy if malignancy is suspected.

• In cases without clear causes, essential studies include a complete blood count with peripheral smear again along with HIV serology, hepatitis C serology, liver function tests (LFT), renal function tests (RFT), TSH levels, LDH levels, and possibly Helicobacter pylori studies in endemic areas.

Indicators for Hematology Referral

• Key findings warranting hematology referral in thrombocytopenic patients include constitutional symptoms presence; leukoerythroblastic findings; unexplained organomegaly; unusual cytotoxic thrombus presence; significant elevation in myeloid cell lines or other unexplained cytopenias.

• Additionally mentioned was a course available on myeloproliferative syndromes for further learning about hematological neoplasms.