Medical Quiz: Clots and Deficiencies

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Questions and Answers

What is the primary purpose of an Inferior Vena Cava (IVC) Filter?

To enhance anticoagulation effects

To increase blood flow to the lower body

To replace anticoagulation therapy

To catch clots traveling to the lungs (correct)

Which of the following is a common cause of Vitamin B12 deficiency?

Increased vitamin C consumption

Pernicious anaemia (correct)

Low iron intake

Dehydration

What type of anaemia is primarily associated with Vitamin B12 deficiency?

Iron-deficiency anaemia

Hemolytic anaemia

Microcytic anaemia

Macrocytic anaemia (correct)

Which test is considered the first-line investigation for pernicious anaemia?

Intrinsic factor antibodies testing Signup and view all the answers

Which of the following neurological symptoms is specifically associated with Vitamin B12 deficiency?

Loss of vibration sense Signup and view all the answers

What condition involves an autoimmune attack on intrinsic factor, impairing Vitamin B12 absorption?

Pernicious anaemia Signup and view all the answers

Which dietary group is particularly at risk for Vitamin B12 deficiency?

Vegans Signup and view all the answers

Which of the following is a common indicator for cancer screening in unexplained VTE cases?

Review of malignancy indicators Signup and view all the answers

What is a management strategy for Haemolytic disease of the newborn?

Anti-D prophylaxis Signup and view all the answers

Which blood film finding is characteristic of Microangiopathic Haemolytic Anaemia (MAHA)?

Schistocytes Signup and view all the answers

What is a potential consequence of untreated Beta-thalassaemia?

Iron overload Signup and view all the answers

Which feature is NOT commonly associated with Thalassaemia?

High blood pressure Signup and view all the answers

Which management option is essential for Prosthetic Valve-Related Haemolysis?

Monitoring and blood transfusions if severe Signup and view all the answers

What is the primary hemoglobin defect in Thalassaemia?

Insufficient production of hemoglobin chains Signup and view all the answers

Which condition is NOT associated with Microangiopathic Haemolytic Anaemia (MAHA)?

Sickle cell disease Signup and view all the answers

Which of the following symptoms is NOT typically seen in Thalassaemia?

Hypertension Signup and view all the answers

What is the primary management step for a tension pneumothorax?

Insertion of a large bore cannula Signup and view all the answers

Which type of pleurodesis uses a physical irritation method?

Abrasive Pleurodesis Signup and view all the answers

What causes the life-threatening condition known as tension pneumothorax?

Inability of trapped air to exit the pleural space Signup and view all the answers

How is Mycobacterium tuberculosis identified microscopically?

Ziehl-Neelsen stain Signup and view all the answers

What is a common sign of a tension pneumothorax when assessed clinically?

Tracheal deviation away from the affected side Signup and view all the answers

Which characteristic is NOT associated with Mycobacterium tuberculosis?

Rapid division rate Signup and view all the answers

Which of the following is a definitive treatment for tension pneumothorax after decompression?

Chest drain insertion Signup and view all the answers

What outcome may result immediately after exposure to Mycobacterium tuberculosis?

Clearance of the bacteria by the immune system Signup and view all the answers

What is the primary purpose of a D-dimer test in the context of venous thromboembolism (VTE)?

To rule out VTE in low-suspicion cases Signup and view all the answers

Which imaging method is considered the first-line choice for detecting pulmonary embolism?

CT Pulmonary Angiogram (CTPA) Signup and view all the answers

What is a common false positive cause for an elevated D-dimer result?

Pneumonia Signup and view all the answers

In patients unsuitable for CTPA, which type of V/Q scan produces more accurate 3D images?

V/Q SPECT Signup and view all the answers

What finding is typical in an arterial blood gas (ABG) analysis for pulmonary embolism?

Respiratory alkalosis with low pCO₂ Signup and view all the answers

Which anticoagulant is recommended as the first-line agent for managing VTE?

Apixaban Signup and view all the answers

What duration of anticoagulation is typically recommended if a reversible cause of pulmonary embolism is identified?

3 months Signup and view all the answers

What is the recommended INR target for patients with antiphospholipid syndrome on Warfarin?

2 to 3 Signup and view all the answers

What is the method used in the Mantoux Test to detect immune response?

Intradermal injection of tuberculin Signup and view all the answers

What indicates a positive result in the Mantoux Test?

Induration of ≥5mm Signup and view all the answers

What feature is characteristic of Miliary TB on a chest X-ray?

Small, uniformly distributed nodules (1-3mm) Signup and view all the answers

Which test is specifically used to confirm the presence of TB bacteria?

Sputum Cultures Signup and view all the answers

What is one of the recommended treatments for latent TB?

Isoniazid and Rifampicin for 3 months Signup and view all the answers

What is the primary advantage of Nucleic Acid Amplification Tests (NAAT) over traditional cultures?

Faster diagnosis by detecting TB DNA Signup and view all the answers

What might be inferred from a positive result from an Interferon-Gamma Release Assay (IGRA)?

Prior contact with M. tuberculosis Signup and view all the answers

What is a limitation of Sputum Cultures in diagnosing TB?

Takes several weeks for growth Signup and view all the answers

Study Notes

Inferior Vena Cava (IVC) Filter

Used for patients who cannot tolerate anticoagulation, or have recurrent pulmonary embolism despite anticoagulation
Acts as a filter in the Inferior Vena Cava to catch clots traveling from lower body veins toward the lungs

Investigating Unprovoked Deep Vein Thrombosis (DVT)

Cancer screening: Review history, baseline blood tests, and physical examination for malignancy indicators
Thrombophilia testing: Check for antiphospholipid syndrome if DVT is unprovoked and anticoagulation is not continuing beyond 3-6 months; hereditary thrombophilias can be tested if a first-degree relative also has a DVT history

Vitamin B12 Deficiency and Pernicious Anaemia

Vitamin B12 deficiency is often considered in patients presenting with peripheral neuropathy, especially those reporting pins and needles
Vitamin B12 deficiency primarily leads to macrocytic anemia and can cause neurological symptoms due to its role in nerve function and red blood cell formation
Common causes of vitamin B12 deficiency include: pernicious anemia, insufficient dietary intake of B12 (especially in vegans, as B12 is primarily found in animal products), medications (e.g., proton pump inhibitors and metformin), which reduce B12 absorption

Pernicious Anaemia Pathophysiology

Pernicious anemia is an autoimmune condition
Autoantibodies target either the stomach's parietal cells or intrinsic factor
Intrinsic factor, produced by parietal cells, is crucial for vitamin B12 absorption in the distal ileum
Antibodies against intrinsic factor or parietal cells lead to a lack of intrinsic factor, impairing B12 absorption and resulting in deficiency

Symptoms of Vitamin B12 Deficiency

Anemia: Macrocytic anemia with fatigue, weakness, and pallor
Neurological symptoms (specific to B12 deficiency):
- Peripheral neuropathy: Numbness and paraesthesia (pins and needles)
- Loss of vibration sense and proprioception
- Visual changes
- Mood and cognitive changes (e.g., memory loss, mood swings)

Diagnostic Autoantibodies for Pernicious Anaemia

First-line investigation: Intrinsic factor antibodies

Alloimmune Haemolytic Anaemia

Types:
- Haemolytic transfusion reaction: reaction to transfused red blood cells
- Haemolytic disease of the newborn: maternal antibodies attack fetal red blood cells in Rh-incompatible pregnancies
Management: Anti-D prophylaxis to prevent sensitisation in Rh-negative mothers

Paroxysmal Nocturnal Haemoglobinuria

Features: Red morning urine, anemia, thrombosis, smooth muscle dystonia
Management: Eculizumab (monoclonal antibody against C5) or bone marrow transplant if needed

Microangiopathic Haemolytic Anaemia (MAHA)

Associated conditions: Haemolytic uraemic syndrome (HUS), disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), cancer, systemic lupus erythematosus (SLE)
Blood film finding: Schistocytes
Management: Treat underlying cause, supportive care

Features: Anemia due to red blood cell damage from turbulent blood flow around the valve
Management: Monitoring, iron and folic acid supplements, blood transfusions if severe, and potential valve revision surgery if necessary

General Management of Haemolytic Anaemia

Identify and manage underlying cause
Supportive care:
- Folate supplementation: To aid red blood cell production
- Blood transfusions: If severe anemia
- Splenectomy: In cases of significant splenic sequestration or inherited conditions like hereditary spherocytosis

Thalassaemia

Thalassaemia is an inherited blood disorder caused by genetic defects in hemoglobin production
The defect can affect either the alpha or beta chains of hemoglobin, resulting in alpha-thalassaemia or beta-thalassaemia
Both types are autosomal recessive
The primary consequence is haemolytic anaemia, as fragile red blood cells (RBCs) break down easily, leading to various symptoms

Common Features of Thalassaemia

Microcytic anaemia
Fatigue and pallor
Jaundice due to haemolysis
Gallstones due to increased bilirubin from red blood cell breakdown
Splenomegaly (enlarged spleen as it filters out destroyed red blood cells)
Poor growth and development in severe cases

Investigations for Thalassaemia

Full Blood Count (FBC): Microcytic anaemia (low MCV)
Ferritin: Raised ferritin levels may indicate iron overload
Haemoglobin Electrophoresis: Diagnostic tool to identify abnormal haemoglobin chains
Chest X-ray (CXR): Typically normal but necessary to exclude other causes

Pulmonary Embolism (PE)

High sensitivity for venous thromboembolism (VTE) but low specificity
Used to rule out VTE in low-suspicion cases
False positives: Other causes of raised D-dimer include pneumonia, malignancy, heart failure, recent surgery, and pregnancy

Imaging for PE

CT Pulmonary Angiogram (CTPA): First-line imaging choice for PE, uses contrast to visualize clots in pulmonary arteries
Ventilation-Perfusion (V/Q) Scans: Used in patients unsuitable for CTPA (e.g., with renal impairment, contrast allergy, or radiation risk)
- Planar V/Q scan: Produces 2D images
- V/Q SPECT: Produces more accurate 3D images

Arterial Blood Gas (ABG)

Typical finding: Respiratory alkalosis with low CO₂ due to increased respiratory rate from hypoxia
Respiratory alkalosis can also result from hyperventilation syndrome, but PE usually presents with low pO₂

Management of PE

Supportive care: Hospital admission if needed, supplemental oxygen as required, analgesia for pain management, continuous monitoring for potential deterioration
Anticoagulation:
- First-line agents: Apixaban or rivaroxaban (per NICE 2020)
- Alternative: LMWH, especially if delay in confirmatory scan
Massive PE with Haemodynamic Compromise: Treated with continuous unfractionated heparin infusion
- Thrombolysis: Used when benefits outweigh bleeding risks
  - Agents: Streptokinase, alteplase, tenecteplase
  - Methods:
    - Intravenous: Through peripheral cannula
    - Catheter-directed: Delivered directly into pulmonary arteries using a central catheter

Long-Term Anticoagulation

Options:
- DOACs: Apixaban, rivaroxaban, edoxaban, dabigatran (no monitoring required)
- Warfarin: For patients with antiphospholipid syndrome; INR target between 2 and 3
- LMWH: Preferred for pregnancy
Duration:
- 3 months: If a reversible cause is identified, with a review afterward
- Beyond 3 months: For unprovoked PE, recurrent VTE, or irreversible causes (e.g., thrombophilia)
- 3-6 months: For patients with active cancer, with a review afterward

Pneumothorax

Indications: Persistent pneumothorax, chest drain failure, or recurrent pneumothorax
Surgical options:
- Video-Assisted Thoracoscopic Surgery (VATS):
  - Pleurodesis: Causes pleural irritation to seal the space
  - Pleurectomy: Removal of pleura
- Types of Pleurodesis:
  - Abrasive Pleurodesis: Physical irritation
  - Chemical Pleurodesis: Use of chemicals (e.g., talc powder)

Tension Pneumothorax

Life-threatening pneumothorax with a one-way valve effect, causing trapped air and rising intrathoracic pressure
Pathophysiology: Air enters the pleural space on inspiration but cannot exit, increasing intrathoracic pressure, leading to mediastinal shift, vessel kinking, and cardiorespiratory arrest

Signs of Tension Pneumothorax

Tracheal deviation: Away from the affected side
Reduced air entry: On the affected side
Percussion resonance: Increased on the affected side
Vital signs: Tachycardia, hypotension

Management of Tension Pneumothorax

Immediate action: Insert a large-bore cannula:
- Traditional location: 2nd intercostal space, midclavicular line
- Alternative (ATLS 2018): 4th or 5th intercostal space, anterior to midaxillary line for adults (chest wall thickness considerations)
Definitive treatment: Chest drain once decompression has been achieved with a cannula

Overview of Tuberculosis (TB)

Caused by Mycobacterium tuberculosis (M.tuberculosis), a slow-dividing bacillus (rod-shaped bacteria) with high oxygen needs
Characteristics:
- Acid-Fast Bacilli: M.tuberculosis has a waxy cell wall, making it resistant to gram staining. It is identified as an “acid-fast” bacterium
- Ziehl-Neelsen Stain: This special stain turns TB bacteria bright red against a blue background, essential for identification
Multidrug-Resistant TB (MDR-TB): Some TB strains resist multiple drugs, such as isoniazid and rifampicin, complicating treatment

Course of TB

Primarily spread through inhaling respiratory droplets from an infected individual
Possible outcomes after exposure:
- Immediate clearance: The immune system clears the bacteria without illness
- Primary active TB: Initial active infection soon after exposure
Tests for Immune Response (to detect exposure, latent or active TB):
- Mantoux Test: Skin test using purified protein derivative (PPD) to detect immune response.
- Interferon-Gamma Release Assay (IGRA): Blood test to detect immune response to TB antigens, used in cases where Mantoux results are unclear
Tests for Active Disease:
- Chest X-ray: Identifies characteristic lung changes
- Sputum Cultures: Confirms presence of TB bacteria, though growth is slow and can take several weeks

Diagnostic Testing for Tuberculosis

Mantoux Test:
- Procedure: Involves intradermal injection of tuberculin (TB proteins) on the forearm, creating a small raised bleb.
- Reading the Test: After 72 hours, measure the induration (firm swelling) at the injection site
- Positive Result: An induration of ≥5mm is considered positive, indicating TB exposure or infection
Interferon-Gamma Release Assays (IGRA):
- Mechanism: Mixes blood with TB antigens; sensitized white blood cells from prior TB exposure release interferon-gamma.
- Interpretation: A positive result indicates prior contact with M.tuberculosis
Chest X-Ray Findings:
- Primary TB: May show patchy consolidation, pleural effusions, and hilar lymphadenopathy.
- Reactivated TB: Displays patchy or nodular consolidation with cavitation, usually in the upper lung zones.
- Miliary TB: Characterized by “millet seed” appearance—small, uniformly distributed nodules (1-3mm) across lung fields
Cultures: Ideally collected before initiating treatment to assess drug resistance
- Collection Methods:
  - Sputum Cultures: Requires three separate samples
  - Blood Cultures: Special bottles for Mycobacterium blood cultures
  - Lymph Node Biopsy or Aspiration
- Special Techniques: Sputum induction (nebulized saline) or bronchoscopy with lavage if sputum production is low
Nucleic Acid Amplification Tests (NAAT): Detects TB DNA for quicker diagnosis than traditional culture.
- Use Cases: Employed in high-risk patients (e.g., HIV positive, children under 16) and suspected drug-resistant cases

Treatment of Tuberculosis

Latent TB:
- Options include:
  - Isoniazid and Rifampicin: Taken for 3 months
  - Isoniazid: Taken alone for 6 months

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Description

Test your knowledge on critical medical topics including Inferior Vena Cava filters, unprovoked deep vein thrombosis investigations, and vitamin B12 deficiency. This quiz covers aspects of patient care, diagnostics, and associated conditions. Perfect for medical students and healthcare professionals!