A 51-year-old man presents to his dermatologist because of severe stomatitis and superficial skin erosions over his trunk. His condition started 2 months ago and was unresponsive to oral antibiotics and antiherpetic medications. He has no history of a similar rash. His medical history is remarkable for type 2 diabetes mellitus and essential hypertension. The physical examination reveals numerous flaccid blisters and bullae which rupture easily. Nikolsky's sign is positive. Which of the following best represents the etiology of this patient’s condition?
Q342
A 7-month old boy, born to immigrant parents from Greece, presents to the hospital with pallor and abdominal distention. His parents note that they recently moved into an old apartment building and have been concerned about their son's exposure to chipped paint from the walls. On physical exam, the patient is found to have hepatosplenomegaly and frontal skull bossing. Hemoglobin electrophoresis reveals markedly increased HbF and HbA2 levels. What would be the most likely findings on a peripheral blood smear?
Q343
A 27-year-old woman with sickle cell disease and at 39-weeks' gestation is brought to the emergency department in active labor. She has had multiple episodes of acute chest syndrome and has required several transfusions in the past. She has a prolonged vaginal delivery complicated by postpartum bleeding, and she receives a transfusion of 1 unit of packed red blood cells. One hour later, the patient experiences acute flank pain. Her temperature is 38.7°C (101.6°F), pulse is 115/min, respirations are 24/min, and blood pressure is 95/55 mm Hg. Foley catheter shows dark brown urine. Further evaluation of this patient is most likely to show which of the following?
Q344
A 71-year-old man presents to his primary care physician because he is increasingly troubled by a tremor in his hands. He says that the tremor is worse when he is resting and gets better when he reaches for objects. His wife reports that he has been slowing in his movements and also has difficulty starting to walk. His steps have been short and unsteady even when he is able to initiate movement. Physical exam reveals rigidity in his muscles when tested for active range of motion. Histology in this patient would most likely reveal which of the following findings?
Q345
A 28-year-old man presents for severe abdominal pain and is diagnosed with appendicitis. He is taken for emergent appendectomy. During the procedure, the patient has massive and persistent bleeding requiring a blood transfusion. The preoperative laboratory studies showed a normal bleeding time, normal prothrombin time (PT), an INR of 1.0, and a normal platelet count. Postoperatively, when the patient is told about the complications during the surgery, he recalls that he forgot to mention that he has a family history of an unknown bleeding disorder. The postoperative laboratory tests reveal a prolonged partial thromboplastin time (PTT). Which of the following is the most likely diagnosis in this patient?
Q346
A previously healthy 40-year-old woman comes to the physician because of a 3-day history of fever, headaches, and fatigue. She also reports a persistent tingling sensation in her right hand and numbness in her right arm that started this morning. Physical examination shows pallor, mild scleral icterus, and petechiae on her forearms and legs. On mental status examination, she appears confused and is only oriented to person. Laboratory studies show:
Hemoglobin 11.1 g/dL
Platelet count 39,500/mm3
Bleeding time 9 minutes
Prothrombin time 14 seconds
Partial thromboplastin time 35 seconds
Serum
Creatinine 1.7 mg/dL
Total bilirubin 2.1 mg/dL
A peripheral blood smear shows fragmented erythrocytes. Which of the following is the most likely underlying cause of this patient's condition?
Q347
A 12-year-old boy presents to your office with facial swelling and dark urine. He has no other complaints other than a sore throat 3 weeks ago that resolved after 6 days. He is otherwise healthy, lives at home with his mother and 2 cats, has no recent history of travel, and no sick contacts. On physical examination his temperature is 99°F (37.2°C), blood pressure is 130/85 mmHg, pulse is 80/min, respirations are 19/min, and pulse oximetry is 99% on room air. Cardiopulmonary and abdominal examinations are unremarkable. There is mild periorbital and pedal edema. Urinalysis shows 12-15 RBC/hpf, 2-5 WBC/hpf, and 30 mg/dL protein. Which additional finding would you expect to see on urinalysis?
Q348
A 61-year-old man with a history of stage IIIa lung adenocarcinoma that has been treated with wedge resection and chemotherapy presents to the primary care clinic. He is largely asymptomatic, but he demonstrates a persistent microcytic anemia despite iron supplementation. Colonoscopy performed 3 years earlier was unremarkable. His past medical history is significant for diabetes mellitus type II, hypertension, acute lymphoblastic leukemia as a child, and hypercholesterolemia. He currently smokes 1 pack of cigarettes per day, drinks a glass of pinot grigio per day, and currently denies any illicit drug use. His vital signs include: temperature, 36.7°C (98.0°F); blood pressure, 126/74 mm Hg; heart rate, 87/min; and respiratory rate, 17/min. On physical examination, his pulses are bounding, complexion is pale, but breath sounds remain clear. Oxygen saturation was initially 91% on room air, with a new oxygen requirement of 2 L by nasal cannula. Which of the following lab values would suggest anemia of chronic disease as the underlying etiology?
Systemic Pathology US Medical PG Practice Questions and MCQs
Question 341: A 51-year-old man presents to his dermatologist because of severe stomatitis and superficial skin erosions over his trunk. His condition started 2 months ago and was unresponsive to oral antibiotics and antiherpetic medications. He has no history of a similar rash. His medical history is remarkable for type 2 diabetes mellitus and essential hypertension. The physical examination reveals numerous flaccid blisters and bullae which rupture easily. Nikolsky's sign is positive. Which of the following best represents the etiology of this patient’s condition?
A. Dermatophyte infection
B. Cutaneous T cell lymphoma
C. Increased mitotic activity of basal and suprabasal cells
D. Anti-hemidesmosome antibodies
E. Anti-desmoglein-3 antibodies (Correct Answer)
Explanation: ***Anti-desmoglein-3 antibodies***
- The patient's presentation with **flaccid blisters**, widespread **erosions** (including oral mucosa), **positive Nikolsky's sign**, and **unresponsiveness to antibiotics/antivirals** is highly suggestive of **Pemphigus Vulgaris**.
- **Pemphigus Vulgaris** is an autoimmune blistering disease characterized by the production of **autoantibodies against desmoglein 3** (and sometimes desmoglein 1), which are components of desmosomes responsible for keratinocyte adhesion.
*Dermatophyte infection*
- **Dermatophyte infections** (tinea) typically present as **erythematous, scaly, pruritic plaques** with peripheral spreading, often without blistering, and are usually responsive to antifungal treatments.
- They do not cause flaccid blisters, extensive erosions, or a positive Nikolsky's sign.
*Cutaneous T cell lymphoma*
- **Cutaneous T-cell lymphoma (CTCL)**, such as Mycosis Fungoides, typically manifests as **patches, plaques, or tumors** in the skin, often with a chronic, relapsing course, and is not characterized by the acute onset of flaccid blisters and erosions.
- It involves proliferation of malignant T-cells in the skin and does not present with positive Nikolsky's sign or widespread bullae.
*Increased mitotic activity of basal and suprabasal cells*
- **Increased mitotic activity** is a general feature of various proliferative conditions, including hyperplastic states or malignancies like squamous cell carcinoma, but it does not directly explain the formation of **flaccid blisters and erosions** due to loss of keratinocyte adhesion.
- This finding would be a histological observation, not the primary immunological etiology of blister formation in pemphigus.
*Anti-hemidesmosome antibodies*
- **Anti-hemidesmosome antibodies** are characteristic of **Bullous Pemphigoid**, another autoimmune blistering disease.
- Unlike **Pemphigus Vulgaris**, **Bullous Pemphigoid** typically presents with **tense bullae** that are less prone to rupture, usually spares the oral mucosa, and a negative Nikolsky's sign.
Question 342: A 7-month old boy, born to immigrant parents from Greece, presents to the hospital with pallor and abdominal distention. His parents note that they recently moved into an old apartment building and have been concerned about their son's exposure to chipped paint from the walls. On physical exam, the patient is found to have hepatosplenomegaly and frontal skull bossing. Hemoglobin electrophoresis reveals markedly increased HbF and HbA2 levels. What would be the most likely findings on a peripheral blood smear?
A. Microcytosis and hypochromasia of erythrocytes (Correct Answer)
B. Sickling of erythrocytes
C. Basophilic stippling of erythrocytes
D. Macrocytosis of erythrocytes with hypersegmented neutrophils
E. Schistocytes and normocytic erythrocytes
Explanation: ### ***Microcytosis and hypochromasia of erythrocytes***
- This patient presents with **β-thalassemia major**, as evidenced by **Greek ancestry** (Mediterranean population at high risk), **markedly elevated HbF and HbA2 levels** on hemoglobin electrophoresis, **frontal skull bossing** from bone marrow expansion, and **hepatosplenomegaly** from extramedullary hematopoiesis.
- The peripheral blood smear in β-thalassemia major characteristically shows **severe microcytic, hypochromic anemia** with target cells, nucleated RBCs, and marked anisocytosis and poikilocytosis.
- The inadequate β-globin chain production leads to ineffective erythropoiesis and severe hemolysis, resulting in the microcytic, hypochromic pattern.
### *Basophilic stippling of erythrocytes*
- While **basophilic stippling** can be seen in β-thalassemia, it is not the **most characteristic** finding and is more commonly associated with **lead poisoning**.
- The chipped paint exposure in this case is a distractor; **lead poisoning does NOT cause elevated HbF/HbA2, frontal bossing, or this degree of organomegaly** in a 7-month-old.
- The hemoglobin electrophoresis findings definitively point to thalassemia, not lead toxicity.
### *Sickling of erythrocytes*
- **Sickling** is pathognomonic for **sickle cell disease**, which presents with elevated HbS (not HbF and HbA2) on electrophoresis.
- While both are hemoglobinopathies affecting Mediterranean populations, the electrophoresis pattern and clinical features clearly indicate thalassemia, not sickle cell disease.
### *Schistocytes and normocytic erythrocytes*
- **Schistocytes** indicate **microangiopathic hemolytic anemia** (e.g., TTP, HUS, DIC), which involves mechanical RBC fragmentation in damaged microvasculature.
- The patient's chronic presentation, organomegaly, skeletal changes, and hemoglobin electrophoresis findings are inconsistent with microangiopathic hemolysis.
### *Macrocytosis of erythrocytes with hypersegmented neutrophils*
- **Macrocytic anemia with hypersegmented neutrophils** is characteristic of **megaloblastic anemia** from vitamin B12 or folate deficiency.
- β-thalassemia causes **microcytic** anemia due to deficient hemoglobin synthesis, not macrocytic anemia from impaired DNA synthesis.
Question 343: A 27-year-old woman with sickle cell disease and at 39-weeks' gestation is brought to the emergency department in active labor. She has had multiple episodes of acute chest syndrome and has required several transfusions in the past. She has a prolonged vaginal delivery complicated by postpartum bleeding, and she receives a transfusion of 1 unit of packed red blood cells. One hour later, the patient experiences acute flank pain. Her temperature is 38.7°C (101.6°F), pulse is 115/min, respirations are 24/min, and blood pressure is 95/55 mm Hg. Foley catheter shows dark brown urine. Further evaluation of this patient is most likely to show which of the following?
A. Positive blood cultures
B. Serum antibodies against class I HLA antigens
C. Low levels of serum IgA immunoglobulins
D. Positive direct Coombs test (Correct Answer)
E. Bilateral pulmonary infiltrates on chest x-ray
Explanation: ***Positive direct Coombs test***
- The patient's symptoms (flank pain, fever, tachycardia, hypotension, dark brown urine) following a blood transfusion are highly suggestive of an acute hemolytic transfusion reaction (AHTR).
- A **positive direct Coombs test** (direct antiglobulin test) confirms AHTR by detecting antibodies or complement components bound to the surface of the patient's red blood cells, indicating immune-mediated destruction.
*Positive blood cultures*
- While fever is present, the constellation of symptoms, especially **flank pain** and **dark brown urine** immediately post-transfusion, points away from a primary bacterial infection.
- Blood cultures would be relevant for a **septic transfusion reaction**, but the rapid onset and hematologic signs are more consistent with immune hemolysis.
*Serum antibodies against class I HLA antigens*
- **HLA antibodies** are primarily associated with **febrile nonhemolytic transfusion reactions** or **transfusion-related acute lung injury (TRALI)**.
- While fever is present, the severe **hemolytic signs** (flank pain, dark urine) are not typical for these reactions.
*Low levels of serum IgA immunoglobulins*
- **IgA deficiency** can lead to severe **anaphylactic transfusion reactions** in patients who receive IgA-containing blood products and have anti-IgA antibodies.
- Anaphylactic reactions typically present with sudden **hypotension**, **bronchospasm**, and **angioedema**, not primarily with flank pain and dark urine from hemolysis.
*Bilateral pulmonary infiltrates on chest X-ray*
- **Bilateral pulmonary infiltrates** on chest X-ray are characteristic of **transfusion-related acute lung injury (TRALI)**.
- While TRALI can cause acute respiratory distress and hypoxemia, the patient's predominant symptoms of flank pain and dark brown urine point specifically to **hemolysis**, not primarily lung injury.
Question 344: A 71-year-old man presents to his primary care physician because he is increasingly troubled by a tremor in his hands. He says that the tremor is worse when he is resting and gets better when he reaches for objects. His wife reports that he has been slowing in his movements and also has difficulty starting to walk. His steps have been short and unsteady even when he is able to initiate movement. Physical exam reveals rigidity in his muscles when tested for active range of motion. Histology in this patient would most likely reveal which of the following findings?
A. Intracellular hyperphosphorylated tau
B. Large intracellular vacuoles
C. Amyloid beta plaques
D. Perivascular inflammation
E. Alpha-synuclein (Correct Answer)
Explanation: ***Alpha-synuclein***
- The patient's symptoms of a **resting tremor** that improves with action, **bradykinesia** (slowed movements, difficulty initiating walking, short steps), and **rigidity** are classic for **Parkinson's disease**.
- Histologically, Parkinson's disease is characterized by the presence of **Lewy bodies**, which are intracellular inclusions comprised primarily of aggregated **alpha-synuclein** protein, particularly in the substantia nigra.
*Intracellular hyperphosphorylated tau*
- **Hyperphosphorylated tau protein** forms **neurofibrillary tangles** and is characteristic of **Alzheimer's disease** and other tauopathies (e.g., frontotemporal dementia), which typically present with cognitive decline rather than primarily motor symptoms as seen here.
- While Parkinson's disease can have co-existing tau pathology, it is not the primary histological hallmark for the motor symptoms described.
*Large intracellular vacuoles*
- The presence of **large intracellular vacuoles** within neurons is characteristic of **spongiform encephalopathies** (e.g., Creutzfeldt-Jakob disease), which present with rapidly progressive dementia, myoclonus, and ataxia.
- This finding is not associated with the classic motor symptoms of Parkinson's disease.
*Amyloid beta plaques*
- **Amyloid beta plaques** (extracellular deposits of amyloid-beta protein) are a hallmark of **Alzheimer's disease**, which primarily manifests with progressive cognitive impairment and memory loss.
- These plaques are not the primary histological feature of Parkinson's disease.
*Perivascular inflammation*
- **Perivascular inflammation** is typically seen in **inflammatory or demyelinating diseases** of the central nervous system, such as **multiple sclerosis** or **encephalitis**.
- This finding is not characteristic of neurodegenerative disorders like Parkinson's disease, which are instead marked by protein aggregation and neuronal loss.
Question 345: A 28-year-old man presents for severe abdominal pain and is diagnosed with appendicitis. He is taken for emergent appendectomy. During the procedure, the patient has massive and persistent bleeding requiring a blood transfusion. The preoperative laboratory studies showed a normal bleeding time, normal prothrombin time (PT), an INR of 1.0, and a normal platelet count. Postoperatively, when the patient is told about the complications during the surgery, he recalls that he forgot to mention that he has a family history of an unknown bleeding disorder. The postoperative laboratory tests reveal a prolonged partial thromboplastin time (PTT). Which of the following is the most likely diagnosis in this patient?
A. von Willebrand disease
B. Bernard-Soulier syndrome
C. Thrombotic thrombocytopenic purpura
D. Hemophilia A (Correct Answer)
E. Glanzmann thrombasthenia
Explanation: ***Hemophilia A***
- The patient's presentation with **severe, persistent bleeding** during surgery despite normal preoperative coagulation studies (PT, INR, platelet count) and a subsequent **prolonged PTT** strongly indicates a **factor deficiency in the intrinsic pathway**.
- **Hemophilia A**, an X-linked recessive disorder, is caused by a deficiency of **Factor VIII**, leading to a prolonged PTT and deep tissue bleeding, which fits the clinical picture and family history.
*von Willebrand disease*
- This condition typically presents with **mucocutaneous bleeding** (e.g., nosebleeds, menorrhagia) and can have a prolonged bleeding time, but the primary defect is in **platelet adhesion**, not usually massive operative bleeding with normal platelet count.
- While **von Willebrand factor (vWF)** carries Factor VIII, a primary deficiency of vWF would affect factor VIII levels but the presentation and normal bleeding time here make it less likely than direct factor VIII deficiency.
*Bernard-Soulier syndrome*
- This is a **platelet disorder** characterized by defective **glycoprotein Ib/IX/V complex**, leading to impaired platelet adhesion and often **thrombocytopenia** with unusually large platelets.
- The patient had a **normal platelet count** and a subsequent prolonged PTT, which points away from a primary platelet adhesion defect.
*Thrombotic thrombocytopenic purpura*
- This is a microangiopathic hemolytic anemia characterized by a **pentad of symptoms**: fever, neurologic symptoms, renal dysfunction, thrombocytopenia, and microangiopathic hemolytic anemia.
- It involves widespread **thrombosis** and **low platelet count**, which does not align with the patient's presentation of massive bleeding with normal platelet counts.
*Glanzmann thrombasthenia*
- This is a rare **platelet aggregation disorder** caused by a defect in **glycoprotein IIb/IIIa**, leading to impaired fibrinogen binding and platelet aggregation.
- While it causes severe bleeding, it would be associated with a **prolonged bleeding time** and normal PTT, which contradicts the patient's normal bleeding time and prolonged PTT.
Question 346: A previously healthy 40-year-old woman comes to the physician because of a 3-day history of fever, headaches, and fatigue. She also reports a persistent tingling sensation in her right hand and numbness in her right arm that started this morning. Physical examination shows pallor, mild scleral icterus, and petechiae on her forearms and legs. On mental status examination, she appears confused and is only oriented to person. Laboratory studies show:
Hemoglobin 11.1 g/dL
Platelet count 39,500/mm3
Bleeding time 9 minutes
Prothrombin time 14 seconds
Partial thromboplastin time 35 seconds
Serum
Creatinine 1.7 mg/dL
Total bilirubin 2.1 mg/dL
A peripheral blood smear shows fragmented erythrocytes. Which of the following is the most likely underlying cause of this patient's condition?
A. Antibodies against double-stranded DNA
B. Mutation of the PIGA gene
C. Antibodies against GpIIb/IIIa
D. Antibodies against ADAMTS13 (Correct Answer)
E. Absence of platelet GpIIb/IIIa receptors
Explanation: ***Antibodies against ADAMTS13***
- This patient presents with a classic pentad of symptoms: **fever**, **neurologic symptoms** (confusion, tingling, numbness), **renal failure** (creatinine 1.7 mg/dL), **thrombocytopenia** (platelet count 39,500/mm3), and **microangiopathic hemolytic anemia** (pallor, scleral icterus, fragmented erythrocytes on smear). This constellation of findings is highly suggestive of **Thrombotic Thrombocytopenic Purpura (TTP)**.
- TTP is primarily caused by a deficiency of the **ADAMTS13 enzyme**, often due to **autoantibodies** that inhibit its activity. ADAMTS13 is responsible for cleaving large **von Willebrand factor (vWF) multimers**, and its deficiency leads to the accumulation of these large multimers, promoting platelet aggregation and microthrombi formation.
*Antibodies against double-stranded DNA*
- Antibodies against double-stranded DNA (**anti-dsDNA antibodies**) are characteristic of **Systemic Lupus Erythematosus (SLE)**, which can present with various systemic symptoms.
- While SLE can cause thrombocytopenia and renal involvement, it typically does not cause the severe **microangiopathic hemolytic anemia** with schistocytes or the combination of symptoms seen in this patient to the extent of TTP.
*Mutation of the PIGA gene*
- A **mutation of the *PIGA* gene** is responsible for **Paroxysmal Nocturnal Hemoglobinuria (PNH)**, a clonal stem cell disorder characterized by hemolytic anemia, thrombosis, and bone marrow failure.
- While PNH involves hemolysis, it typically lacks the prominent neurological symptoms, severe thrombocytopenia with microangiopathic features, and renal failure seen in TTP.
*Antibodies against GpIIb/IIIa*
- **Antibodies against GpIIb/IIIa** (glycoprotein IIb/IIIa) receptors are the hallmark of **Immune Thrombocytopenic Purpura (ITP)**, causing accelerated platelet destruction.
- ITP primarily causes **isolated thrombocytopenia** and mucocutaneous bleeding, but it does not cause microangiopathic hemolytic anemia, renal failure, or neurological symptoms that are prominent in this patient.
*Absence of platelet GpIIb/IIIa receptors*
- The **absence of platelet GpIIb/IIIa receptors** is characteristic of **Glanzmann's thrombasthenia**, a rare inherited disorder of platelet function.
- Glanzmann's thrombasthenia leads to **mucocutaneous bleeding** due to impaired platelet aggregation, but it does not cause thrombocytopenia, hemolytic anemia, renal failure, or neurological symptoms.
Question 347: A 12-year-old boy presents to your office with facial swelling and dark urine. He has no other complaints other than a sore throat 3 weeks ago that resolved after 6 days. He is otherwise healthy, lives at home with his mother and 2 cats, has no recent history of travel, and no sick contacts. On physical examination his temperature is 99°F (37.2°C), blood pressure is 130/85 mmHg, pulse is 80/min, respirations are 19/min, and pulse oximetry is 99% on room air. Cardiopulmonary and abdominal examinations are unremarkable. There is mild periorbital and pedal edema. Urinalysis shows 12-15 RBC/hpf, 2-5 WBC/hpf, and 30 mg/dL protein. Which additional finding would you expect to see on urinalysis?
A. Fatty casts
B. RBC casts (Correct Answer)
C. WBC casts
D. Granular casts
E. Hyaline casts
Explanation: ***RBC casts***
- The patient's presentation with **facial swelling**, **dark urine**, and a history of a recent **sore throat** points toward **post-streptococcal glomerulonephritis (PSGN)**.
- **RBC casts** are a hallmark microscopic finding in **glomerulonephritis**, indicating **glomerular inflammation** and bleeding.
*Fatty casts*
- **Fatty casts** are characteristic of **nephrotic syndrome**, which primarily involves heavy proteinuria and generalized edema.
- While there is some proteinuria and edema, the dark urine and history of recent infection are more consistent with nephritic syndrome.
*Hyaline casts*
- **Hyaline casts** are composed of Tamm-Horsfall proteins and can be found in healthy individuals, or in conditions like **dehydration** or **fever**.
- They are a non-specific finding and do not indicate specific renal pathology like glomerulonephritis.
*WBC casts*
- **WBC casts** are typically seen in **pyelonephritis** (kidney infection) or **interstitial nephritis**, indicating inflammation within the renal tubules.
- The patient's primary symptoms and lab findings are more consistent with glomerular disease rather than an infection of the renal parenchyma.
*Granular casts*
- **Granular casts** are formed from degenerated cellular casts or protein aggregates and are often seen in **acute tubular necrosis (ATN)** or **chronic kidney disease**.
- While they suggest renal parenchymal injury, they are not as specific for glomerulonephritis as RBC casts, especially in a subacute presentation like this.
Question 348: A 61-year-old man with a history of stage IIIa lung adenocarcinoma that has been treated with wedge resection and chemotherapy presents to the primary care clinic. He is largely asymptomatic, but he demonstrates a persistent microcytic anemia despite iron supplementation. Colonoscopy performed 3 years earlier was unremarkable. His past medical history is significant for diabetes mellitus type II, hypertension, acute lymphoblastic leukemia as a child, and hypercholesterolemia. He currently smokes 1 pack of cigarettes per day, drinks a glass of pinot grigio per day, and currently denies any illicit drug use. His vital signs include: temperature, 36.7°C (98.0°F); blood pressure, 126/74 mm Hg; heart rate, 87/min; and respiratory rate, 17/min. On physical examination, his pulses are bounding, complexion is pale, but breath sounds remain clear. Oxygen saturation was initially 91% on room air, with a new oxygen requirement of 2 L by nasal cannula. Which of the following lab values would suggest anemia of chronic disease as the underlying etiology?
A. Decreased serum iron and transferrin, decreased ferritin, normal serum transferrin receptor
B. Increased serum iron and transferrin, increased ferritin, normal serum transferrin receptor
Explanation: ***Decreased serum iron and transferrin, increased ferritin, normal serum transferrin receptor***
- In **anemia of chronic disease (ACD)**, inflammation leads to increased **hepcidin** levels, which blocks iron release from stores and reduces iron absorption, resulting in **decreased serum iron and transferrin** (which reflects transferrin saturation).
- The inflammatory state also causes **ferritin** (an acute phase reactant and iron storage protein) to be **increased** or normal, as iron is sequestered. **Serum transferrin receptor** levels are typically normal, differentiating it from iron deficiency anemia.
*Decreased serum iron and transferrin, decreased ferritin, normal serum transferrin receptor*
- This pattern, particularly the **decreased ferritin**, is more indicative of **iron deficiency anemia**, where the body's iron stores are depleted.
- In iron deficiency, the body attempts to increase iron absorption and mobilization, thus ferritin would be low.
*Increased serum iron and transferrin, increased ferritin, normal serum transferrin receptor*
- This combination is not typical for any common anemia. **Increased serum iron and transferrin** might suggest iron overload conditions, but not iron-restricted erythropoiesis.
- While ferritin can be increased in chronic disease, the increased serum iron and transferrin are contradictory to ACD.
*Decreased serum iron, increased transferrin, decreased ferritin, increased serum transferrin receptor*
- This constellation, especially the **increased transferrin** and **decreased ferritin**, is characteristic of **iron deficiency anemia**.
- **Increased serum transferrin receptor** is a hallmark of iron deficiency, as cells upregulate receptors to capture more iron when deficient.
*Decreased serum iron, decreased transferrin, increased ferritin, increased serum transferrin receptor*
- While **decreased serum iron, decreased transferrin** (low transferrin saturation), and **increased ferritin** can be seen in ACD, the presence of an **increased serum transferrin receptor** is inconsistent.
- An increased serum transferrin receptor is usually a marker for increased erythropoietic activity or iron deficiency, which is not the primary mechanism of ACD.