A 57-year-old man comes to the physician for a follow-up visit. Serum studies show:
AST 134 U/L
ALT 152 U/L
Hepatitis B surface antigen Positive
A photomicrograph of the microscopic findings of a liver biopsy is shown. These biopsy findings are most characteristic of which of the following types of inflammatory reactions?
Q12
A 37-year-old man presents to his primary care physician because he has had constipation for the last several weeks. He has also been feeling lethargic and complains that this winter has been particularly cold. He also complains that he has been gaining weight despite no change in his normal activities. He reveals that two months prior to presentation he had what felt like the flu for which he took Tylenol and did not seek medical attention. Several days after this he developed anterior neck pain. Which of the following findings would most likely be seen on biopsy of this patient's abnormality?
Q13
A 23-year-old woman comes to the physician for evaluation of two masses on her right auricle for several months. The masses appeared a few weeks after she had her ear pierced and have increased in size since then. A photograph of her right ear is shown. Which of the following is the most likely cause of these findings?
Q14
A 4-year-old male is accompanied by his mother to the pediatrician. His mother reports that over the past two weeks, the child has had intermittent low grade fevers and has been more lethargic than usual. The child’s past medical history is notable for myelomeningocele complicated by lower extremity weakness as well as bowel and bladder dysfunction. He has been hospitalized multiple times at an outside facility for recurrent urinary tract infections. The child is in the 15th percentile for both height and weight. His temperature is 100.7°F (38.2°C), blood pressure is 115/70 mmHg, pulse is 115/min, and respirations are 20/min. Physical examination is notable for costovertebral angle tenderness that is worse on the right. Which of the following would most likely be found on biopsy of this patient’s kidney?
Q15
A 68-year-old man is admitted to the emergency department after 2 days of difficulty breathing and fever. His past medical history is significant for hypertension and benign prostate hypertrophy. He takes hydrochlorothiazide and tamsulosin. He also admits to drinking alcohol on the weekends and a half pack a day smoking habit. Upon admission, he is found to have blood pressure of 125/83 mm Hg, pulse of 88/min, a respiratory rate of 28/min, and a temperature of 38.9°C (102°F). On physical exam breath sounds are decreased at the left pulmonary base. A chest x-ray reveals consolidation in the left lower lobe. Additional laboratory tests demonstrate leukocytosis, elevated C-reactive protein, a serum creatinine (Cr) of 8.0 mg/dL, and a blood urea nitrogen (BUN) of 32 mg/dL. The patient is admitted to the hospital and started on cefepime and clarithromycin. His dyspnea slowly improves after 48 hours, however, his body temperature remains at 39°C (102.2°F). Recent laboratory tests show reduced C-reactive protein levels, a Cr of 1.8 mg/dL and a BUN of 35 mg/dL. A urinalysis is ordered. Which of the following would you expect to find in this patient’s urine?
Q16
A 69-year-old diabetic woman comes to the emergency department due to right flank pain for 10 days. Her right flank pain is radiating towards her groin and is associated with fever and chills. The pain is exacerbated with hip extension. She feels fatigued and is lying on her left side with her right hip flexed. The CT guided percutaneous drainage reveals 900 ml of greenish pus. The vital signs include blood pressure 145/75 mm Hg, pulse rate 96/min, temperature 36.9°C (98.4°F), respiratory rate 16/min, and the oxygen saturation is 95%. The complete blood count shows the following results upon admission:
CBC results
Leukocytes 16,600/mm3
Neutrophils 80%
Lymphocytes 16%
Eosinophils 1%
Basophils 1%
Monocyte 2%
Hemoglobin 7.6 g/dL
Creatinine 0.8 mg/dL
BUN 15 mg/dL
Which of the following processes most likely could have occurred?
Q17
A 33-year-old woman presents to the emergency department with a 3-day history of backache, progressive bilateral lower limb weakness, and a pins-and-needles sensation in both of her legs. She has not passed urine for the past 24 hours. Her medical history is unremarkable. Her blood pressure is 112/74 mm Hg, heart rate is 82/min, and temperature is 37°C (98.6°F). She is alert and oriented to person, place, and time. Higher mental functions are intact. Muscle strength is 5/5 in the upper limbs and 3/5 in the lower limbs. The lower limb weakness is accompanied by increased muscle tone, brisk deep tendon reflexes, and a bilateral upgoing plantar reflex. Pinprick sensations are decreased at and below the level of the umbilicus. The bladder is palpable on abdominal examination. What is the most likely pathophysiology involved in the development of this patient’s condition?
Q18
A 31-year-old woman scrapes her finger on an exposed nail and sustains a minor laceration. Five minutes later, her finger is red, swollen, and painful. She has no past medical history and does not take any medications. She drinks socially with her friends and does not smoke. The inflammatory cell type most likely to be prominent in this patient's finger has which of the following characteristics?
Q19
A 14-year-old boy is brought to the physician by his parents for the evaluation of a skin rash for one day. The patient reports intense itching. He was born at 39 weeks' gestation and has a history of atopic dermatitis. He attends junior high school and went on a camping trip with his school the day before yesterday. His older brother has celiac disease. Examination shows erythematous papules and vesicles that are arranged in a linear pattern on the right forearm. Laboratory studies are within normal limits. Which of the following is the most likely underlying cause of this patient's symptoms?
Q20
A 62-year-old woman with type 2 diabetes mellitus is brought to the emergency room because of a 3-day history of fever and shaking chills. Her temperature is 39.4°C (103°F). Examination of the back shows right costovertebral angle tenderness. Analysis of the urine shows WBCs, WBC casts, and gram-negative rods. Ultrasound examination of the kidneys shows no signs of obstruction. Biopsy of the patient's kidney is most likely to show which of the following?
Inflammation US Medical PG Practice Questions and MCQs
Question 11: A 57-year-old man comes to the physician for a follow-up visit. Serum studies show:
AST 134 U/L
ALT 152 U/L
Hepatitis B surface antigen Positive
A photomicrograph of the microscopic findings of a liver biopsy is shown. These biopsy findings are most characteristic of which of the following types of inflammatory reactions?
A. Malignant transformation
B. Granulomatous inflammation
C. Chronic inflammation (Correct Answer)
D. Acute inflammation
E. Ischemic necrosis
Explanation: ***Chronic inflammation***
- The combination of **elevated AST/ALT** and **positive Hepatitis B surface antigen** indicates persistent liver damage due to a chronic viral infection.
- Liver **biopsy findings** in such cases typically reveal **lymphocytic infiltrates**, fibrosis, and ongoing hepatocellular injury, which are hallmarks of chronic inflammation.
*Malignant transformation*
- While chronic viral hepatitis can lead to **hepatocellular carcinoma**, the question describes inflammatory findings, not **neoplastic changes** like cellular atypia or uncontrolled proliferation.
- **Malignant transformation** would present with disorganized architectural patterns and significant cellular pleomorphism.
*Granulomatous inflammation*
- **Granulomatous inflammation** is characterized by aggregates of activated macrophages (epithelioid cells), often with giant cells, which are not the primary feature described in chronic viral hepatitis.
- This type of inflammation is typically seen in diseases like **tuberculosis**, sarcoidosis, or fungal infections, not usually in viral hepatitis.
*Acute inflammation*
- **Acute inflammation** would present with a predominance of **neutrophils**, pronounced edema, and rapid onset of symptoms.
- The elevated liver enzymes and positive HBsAg suggest ongoing, long-term inflammation, which is characteristic of a chronic process.
*Ischemic necrosis*
- **Ischemic necrosis** is caused by a lack of blood supply, leading to cell death, and would typically present with **coagulative necrosis** of hepatocytes with minimal inflammatory infiltrate in the early stages.
- The clinical picture of chronic hepatitis B infection does not primarily involve an acute ischemic event affecting the liver.
Question 12: A 37-year-old man presents to his primary care physician because he has had constipation for the last several weeks. He has also been feeling lethargic and complains that this winter has been particularly cold. He also complains that he has been gaining weight despite no change in his normal activities. He reveals that two months prior to presentation he had what felt like the flu for which he took Tylenol and did not seek medical attention. Several days after this he developed anterior neck pain. Which of the following findings would most likely be seen on biopsy of this patient's abnormality?
A. Focal hyperplasia
B. Germinal follicles
C. Scalloped clear areas
D. Fibrous tissue
E. Granulomatous inflammation (Correct Answer)
Explanation: ***Granulomatous inflammation***
- The patient's presentation with **constipation**, **lethargy**, **cold intolerance**, and **weight gain** after a flu-like illness followed by **anterior neck pain** is highly suggestive of **subacute granulomatous thyroiditis (de Quervain thyroiditis)**.
- A biopsy of the thyroid in cases of de Quervain thyroiditis typically reveals **granulomatous inflammation** with scattered **giant cells** and lymphocytes, reflecting the destructive inflammatory process.
*Focal hyperplasia*
- **Focal hyperplasia** is characterized by an increase in the number of thyroid follicular cells and is seen in conditions like **Graves' disease** or **multinodular goiter**, particularly when the gland is overstimulated.
- This finding would not be expected in subacute granulomatous thyroiditis, where the primary pathology is destruction rather than proliferation.
*Germinal follicles*
- **Germinal follicles** are characteristic of chronic lymphocytic thyroiditis (**Hashimoto's thyroiditis**), an autoimmune condition where the thyroid gland is infiltrated by lymphocytes, plasma cells, and macrophages.
- While Hashimoto's can cause hypothyroidism, the preceding flu-like illness and acute neck pain make de Quervain thyroiditis a more likely diagnosis.
*Scalloped clear areas*
- **Scalloped clear areas** at the colloid-epithelial interface, also known as **colloid resorption vacuoles**, are a histological feature of **hyperactive thyroid follicles**, typically seen in conditions causing hyperthyroidism like **Graves' disease**.
- The patient's symptoms of lethargy, cold intolerance, and weight gain indicate hypothyroidism, which can follow the initial hyperthyroid phase of de Quervain thyroiditis but are not indicative of active hyperfunction on biopsy at this stage.
*Fibrous tissue*
- An increased amount of **fibrous tissue** is characteristic of **Riedel's thyroiditis**, a rare condition characterized by dense fibrosis that replaces normal thyroid parenchyma and can extend into surrounding neck structures.
- This patient's presentation with a preceding febrile illness and neck pain is not typical for Riedel's thyroiditis, which usually presents as a hard, fixed mass without an antecedent viral infection.
Question 13: A 23-year-old woman comes to the physician for evaluation of two masses on her right auricle for several months. The masses appeared a few weeks after she had her ear pierced and have increased in size since then. A photograph of her right ear is shown. Which of the following is the most likely cause of these findings?
A. Implantation of epidermis into the dermis
B. Malignant transformation of keratinocytes
C. Increased production of hyalinized collagen (Correct Answer)
D. Excess formation of organized extracellular matrix
E. Infection with human papilloma virus
Explanation: ***Increased production of hyalinized collagen***
- The image shows **keloids**, which are characterized by the overgrowth of **dense, hyalinized collagen** that extends beyond the original wound boundaries.
- Keloids often develop after skin trauma like ear piercing, and they tend to grow and persist, consistent with the patient's presentation.
*Implantation of epidermis into the dermis*
- This process typically leads to the formation of an **epidermoid cyst** or **inclusion cyst**, which is usually a smooth, mobile, subcutaneous nodule filled with keratinous debris.
- While it can occur after trauma like piercing, the resulting lesion does not typically have the exophytic, firm, and irregular appearance of the masses shown.
*Malignant transformation of keratinocytes*
- Malignant transformation of keratinocytes would suggest a skin cancer like **squamous cell carcinoma**, which can appear as an ulcerated, nodular, or scaly lesion.
- These lesions are typically not a result of ear piercing and do not present as uniform, firm, shiny masses extending beyond the wound boundary as seen in the image.
*Excess formation of organized extracellular matrix*
- While keloids do involve excess extracellular matrix (ECM) production, the term "organized extracellular matrix" is too broad and does not specifically describe the characteristic pathological feature seen in keloids.
- The key specific feature of keloids is the overabundance of **thick, hyalinized collagen bundles**, which is a more precise histological description than generally "organized extracellular matrix."
*Infection with human papilloma virus*
- **Human Papillomavirus (HPV)** causes **warts**, which are typically rough, papillomatous, and often have a "cauliflower-like" appearance.
- Warts are not typically smooth, firm, and well-demarcated masses, nor do they usually grow to this size on the ear after a piercing, and their histology involves epidermal hyperplasia rather than collagen overgrowth.
Question 14: A 4-year-old male is accompanied by his mother to the pediatrician. His mother reports that over the past two weeks, the child has had intermittent low grade fevers and has been more lethargic than usual. The child’s past medical history is notable for myelomeningocele complicated by lower extremity weakness as well as bowel and bladder dysfunction. He has been hospitalized multiple times at an outside facility for recurrent urinary tract infections. The child is in the 15th percentile for both height and weight. His temperature is 100.7°F (38.2°C), blood pressure is 115/70 mmHg, pulse is 115/min, and respirations are 20/min. Physical examination is notable for costovertebral angle tenderness that is worse on the right. Which of the following would most likely be found on biopsy of this patient’s kidney?
A. Replacement of renal parenchyma with foamy histiocytes
B. Tubular colloid casts with diffuse lymphoplasmacytic infiltrate (Correct Answer)
C. Diffusely necrotic papillae with dystrophic calcification
D. Mononuclear and eosinophilic infiltrate
E. Destruction of the proximal tubule and medullary thick ascending limb
Explanation: ***Tubular colloid casts with diffuse lymphoplasmacytic infiltrate***
- The patient's history of **myelomeningocele**, recurrent **urinary tract infections (UTIs)**, and current symptoms (fever, lethargy, CVA tenderness) strongly suggest **chronic pyelonephritis**.
- **Chronic pyelonephritis** is characterized histologically by **tubular atrophy**, interstitial fibrosis, and a **lymphoplasmacytic infiltrate**, often with "thyroidization" of the tubules where they are dilated and filled with colloid casts.
*Replacement of renal parenchyma with foamy histiocytes*
- This description is characteristic of **xanthogranulomatous pyelonephritis**, a severe and rare form of chronic pyelonephritis.
- While possible given chronic UTIs, the more general and common finding in chronic pyelonephritis is a diffuse lymphoplasmacytic infiltrate, not necessarily dominant foamy histiocytes.
*Diffusely necrotic papillae with dystrophic calcification*
- This finding is most consistent with **renal papillary necrosis**.
- Renal papillary necrosis is typically associated with conditions like **analgesic nephropathy**, **sickle cell disease**, or severe acute pyelonephritis, but not the primary histological change in chronic pyelonephritis as described.
*Mononuclear and eosinophilic infiltrate*
- A prominent **eosinophilic infiltrate** in the kidney is often seen in **acute interstitial nephritis**, which can be drug-induced.
- While chronic inflammation involves mononuclear cells, the specific mention of eosinophils makes this less likely to be the primary finding in chronic pyelonephritis from recurrent UTIs.
*Destruction of the proximal tubule and medullary thick ascending limb*
- Destruction of specific tubular segments, particularly the **proximal tubule**, is characteristic of acute tubular necrosis (ATN).
- While chronic pyelonephritis leads to tubular atrophy and damage, the primary description here points to an acute injury rather than the chronic inflammatory changes expected.
Question 15: A 68-year-old man is admitted to the emergency department after 2 days of difficulty breathing and fever. His past medical history is significant for hypertension and benign prostate hypertrophy. He takes hydrochlorothiazide and tamsulosin. He also admits to drinking alcohol on the weekends and a half pack a day smoking habit. Upon admission, he is found to have blood pressure of 125/83 mm Hg, pulse of 88/min, a respiratory rate of 28/min, and a temperature of 38.9°C (102°F). On physical exam breath sounds are decreased at the left pulmonary base. A chest x-ray reveals consolidation in the left lower lobe. Additional laboratory tests demonstrate leukocytosis, elevated C-reactive protein, a serum creatinine (Cr) of 8.0 mg/dL, and a blood urea nitrogen (BUN) of 32 mg/dL. The patient is admitted to the hospital and started on cefepime and clarithromycin. His dyspnea slowly improves after 48 hours, however, his body temperature remains at 39°C (102.2°F). Recent laboratory tests show reduced C-reactive protein levels, a Cr of 1.8 mg/dL and a BUN of 35 mg/dL. A urinalysis is ordered. Which of the following would you expect to find in this patient’s urine?
A. Hyaline casts
B. Urate crystals
C. Acanthocytes
D. White blood cell casts (Correct Answer)
E. Calcium oxalate crystals
Explanation: ***White blood cell casts***
- This patient's **persistent fever** despite improving pneumonia symptoms and **acute kidney injury** (Cr 8.0 → 1.8 mg/dL) after starting antibiotics strongly suggests **drug-induced acute interstitial nephritis (AIN)**.
- **WBC casts** are the hallmark urinary finding in **acute interstitial nephritis**, indicating inflammatory infiltration of the renal tubules and interstitium.
- **Classic triad of AIN**: fever, rash (not always present), and AKI after drug exposure (cefepime and clarithromycin are known culprits).
- The persistence of fever while other inflammatory markers improve points to an **allergic/hypersensitivity reaction** in the kidneys rather than worsening infection.
*Hyaline casts*
- **Hyaline casts** are composed of **Tamm-Horsfall protein** and are the most common type of cast, seen in concentrated urine, after exercise, or with dehydration.
- They are **non-specific** and can occur in healthy individuals; they do not indicate acute inflammation or explain the persistent fever and AKI pattern.
*Urate crystals*
- **Urate crystals** are seen in acidic urine and associated with **hyperuricemia, gout**, or **tumor lysis syndrome**.
- They do not explain the inflammatory process causing persistent fever or the temporal relationship with antibiotic initiation.
*Acanthocytes*
- **Acanthocytes** (dysmorphic RBCs) indicate **glomerular bleeding** and are characteristic of **glomerulonephritis**.
- There is **no hematuria** mentioned in this case, and the clinical picture (fever, drug exposure, AKI) points to **tubular-interstitial disease** (AIN) rather than glomerular pathology.
*Calcium oxalate crystals*
- **Calcium oxalate crystals** are common urinary findings that may be associated with **nephrolithiasis, ethylene glycol toxicity**, or dietary factors.
- Their presence is **non-specific** and does not explain the acute inflammatory renal process with persistent fever following antibiotic exposure.
Question 16: A 69-year-old diabetic woman comes to the emergency department due to right flank pain for 10 days. Her right flank pain is radiating towards her groin and is associated with fever and chills. The pain is exacerbated with hip extension. She feels fatigued and is lying on her left side with her right hip flexed. The CT guided percutaneous drainage reveals 900 ml of greenish pus. The vital signs include blood pressure 145/75 mm Hg, pulse rate 96/min, temperature 36.9°C (98.4°F), respiratory rate 16/min, and the oxygen saturation is 95%. The complete blood count shows the following results upon admission:
CBC results
Leukocytes 16,600/mm3
Neutrophils 80%
Lymphocytes 16%
Eosinophils 1%
Basophils 1%
Monocyte 2%
Hemoglobin 7.6 g/dL
Creatinine 0.8 mg/dL
BUN 15 mg/dL
Which of the following processes most likely could have occurred?
A. Neutrophil diapedesis and release of chemotactic agents (Correct Answer)
B. Decreased expression of selectin in the endothelium
C. Vasoconstriction
D. Activation of cytosolic caspases
E. Downregulation of cellular adhesion molecules in the endothelium
Explanation: ***Neutrophil diapedesis and release of chemotactic agents***
- The patient presents with symptoms and signs of a **psoas abscess**, including **flank pain radiating to the groin**, fever, chills, a **positive psoas sign** (pain with hip extension, lying with hip flexed), leukocytosis with neutrophilia, and the drainage of **greenish pus**.
- This indicates an acute bacterial infection, which would involve the recruitment of **neutrophils** to the site of infection via **diapedesis** (migration through the vessel wall), guided by **chemotactic agents** (such as IL-8, C5a, and bacterial products) released during inflammation.
*Downregulation of cellular adhesion molecules in the endothelium*
- **Downregulation of adhesion molecules** would hinder the migration of leukocytes into the infected tissue, which contradicts the presence of a large pus collection and **neutrophilic leukocytosis**.
- Effective leukocyte extravasation into inflamed tissues relies on the **upregulation** and appropriate function of these adhesion molecules.
*Decreased expression of selectin in the endothelium*
- **Selectins** are crucial for the initial rolling of leukocytes along the endothelial surface, a necessary step before firm adhesion and diapedesis.
- **Decreased expression** would impair leukocyte recruitment, which is inconsistent with the patient's robust inflammatory response and pus formation.
*Vasoconstriction*
- In an inflammatory process like an abscess, the initial response generally involves **vasodilation** in the affected area, leading to increased blood flow and facilitating the delivery of immune cells and mediators.
- While some localized constriction might occur in later stages or distal to the site, overall **vasodilation** is characteristic of acute inflammation.
*Activation of cytosolic caspases*
- **Activation of cytosolic caspases** is a hallmark of **apoptosis** (programmed cell death), which is a controlled process and not the primary mechanism behind the massive accumulation of pus and acute inflammation seen in a bacterial abscess.
- While some host cells might undergo apoptosis during infection, the significant pus indicates a predominant **necrotic** and inflammatory process driven by bacterial toxins and immune cell activity.
Question 17: A 33-year-old woman presents to the emergency department with a 3-day history of backache, progressive bilateral lower limb weakness, and a pins-and-needles sensation in both of her legs. She has not passed urine for the past 24 hours. Her medical history is unremarkable. Her blood pressure is 112/74 mm Hg, heart rate is 82/min, and temperature is 37°C (98.6°F). She is alert and oriented to person, place, and time. Higher mental functions are intact. Muscle strength is 5/5 in the upper limbs and 3/5 in the lower limbs. The lower limb weakness is accompanied by increased muscle tone, brisk deep tendon reflexes, and a bilateral upgoing plantar reflex. Pinprick sensations are decreased at and below the level of the umbilicus. The bladder is palpable on abdominal examination. What is the most likely pathophysiology involved in the development of this patient’s condition?
A. Nutritional deficiency
B. Low serum potassium levels
C. Demyelination of peripheral nerves
D. Inflammation of the spinal cord (Correct Answer)
E. Enlargement of a central fluid-filled cavity within spinal cord
Explanation: ***Inflammation of the spinal cord***
- The patient presents with **rapidly progressive bilateral lower limb weakness**, **sensory deficits below the umbilicus**, and **urinary retention**, along with **upper motor neuron signs** (increased tone, brisk reflexes, upgoing plantars). This clinical picture is highly suggestive of **acute transverse myelitis**, which involves inflammation of the spinal cord.
- **Acute transverse myelitis** typically involves focal inflammation that damages the myelin and/or axons of the spinal cord, leading to neurological dysfunction at and below the level of the lesion.
*Nutritional deficiency*
- Nutritional deficiencies, such as **Vitamin B12 deficiency**, can cause neurological symptoms, including weakness and sensory issues, but they typically develop more gradually and often present with a **peripheral neuropathy** or **subacute combined degeneration** (demyelination of posterior columns and corticospinal tracts), usually affecting vibration and proprioception more prominently.
- The acute onset, prominent upper motor neuron signs, and discrete sensory level are less typical for isolated nutritional deficiencies.
*Low serum potassium levels*
- **Hypokalemia** can cause **muscle weakness** and paralysis, but it typically presents with **flaccid paralysis** and **decreased deep tendon reflexes**, characteristic of a lower motor neuron disorder.
- The patient's presentation of **spasticity**, **brisk reflexes**, and an **upgoing plantar reflex** contradicts the hallmarks of hypokalemic paralysis.
*Demyelination of peripheral nerves*
- **Demyelination of peripheral nerves**, as seen in conditions like **Guillain-Barré Syndrome**, typically causes **ascending paralysis** with **areflexia** or **hyporeflexia** and sensory loss in a "stocking-glove" distribution.
- The findings of **increased muscle tone**, **brisk reflexes**, and a **distinct sensory level at the umbilicus** point towards a central nervous system lesion rather than a peripheral neuropathy.
*Enlargement of a central fluid-filled cavity within spinal cord*
- An **enlarged central fluid-filled cavity within the spinal cord**, known as a **syrinx** or **syringomyelia**, typically causes symptoms that are more chronic and progressive.
- Its classic presentation often involves **cape-like loss of pain and temperature sensation** due to damage to the spinothalamic tracts, often with dissociated sensory loss, and typically **lower motor neuron signs** at the level of the syrinx (weakness, atrophy, fasciculations) and **upper motor neuron signs** below the level of the syrinx. The acute, rapid onset and sensory level are more consistent with an acute inflammatory process.
Question 18: A 31-year-old woman scrapes her finger on an exposed nail and sustains a minor laceration. Five minutes later, her finger is red, swollen, and painful. She has no past medical history and does not take any medications. She drinks socially with her friends and does not smoke. The inflammatory cell type most likely to be prominent in this patient's finger has which of the following characteristics?
A. Segmented nuclei (Correct Answer)
B. Dramatically expanded endoplasmic reticulum
C. Large cell with amoeboid movement
D. Multiple peripheral processes
E. Dark histamine containing granules
Explanation: ***Segmented nuclei***
- This scenario describes **acute inflammation** following a minor injury, with classic signs of **redness, swelling, and pain** within minutes.
- **Neutrophils** are the primary inflammatory cells in acute inflammation and are characterized by their **segmented (multi-lobed) nuclei.**
*Dramatically expanded endoplasmic reticulum*
- An expanded endoplasmic reticulum is characteristic of cells highly active in protein synthesis and secretion, such as **plasma cells** producing antibodies.
- Plasma cells are typically involved in **chronic inflammation** and adaptive immune responses, not rapid acute inflammation.
*Large cell with amoeboid movement*
- This describes **macrophages**, which are phagocytic cells important in both acute and chronic inflammation, and in cleaning up debris.
- While macrophages are present, **neutrophils** are the predominant early responders in acute bacterial infections and tissue injury.
*Multiple peripheral processes*
- This description is characteristic of **dendritic cells**, which are antigen-presenting cells that initiate adaptive immune responses.
- Dendritic cells play a role in linking innate and adaptive immunity but are not the primary inflammatory cell type in the immediate acute response.
*Dark histamine containing granules*
- This description applies to **mast cells** and **basophils**, which release histamine and other mediators in allergic reactions and acute inflammation.
- While mast cells are involved in the immediate response by releasing mediators, **neutrophils** are the main cellular players migrating to the site of injury.
Question 19: A 14-year-old boy is brought to the physician by his parents for the evaluation of a skin rash for one day. The patient reports intense itching. He was born at 39 weeks' gestation and has a history of atopic dermatitis. He attends junior high school and went on a camping trip with his school the day before yesterday. His older brother has celiac disease. Examination shows erythematous papules and vesicles that are arranged in a linear pattern on the right forearm. Laboratory studies are within normal limits. Which of the following is the most likely underlying cause of this patient's symptoms?
A. Preformed IgE antibodies
B. Immune complex formation
C. IgG antibodies against desmoglein
D. Presensitized T cells (Correct Answer)
E. IgG antibodies against hemidesmosomes
Explanation: ***Presensitized T cells***
- The patient's rash, characterized by **erythematous papules and vesicles in a linear pattern**, after a camping trip, is highly suggestive of **allergic contact dermatitis** caused by exposure to poison ivy or similar plants.
- Allergic contact dermatitis is a **Type IV hypersensitivity reaction** mediated by **presensitized T cells** that recognize antigens presented by Langerhans cells in the skin upon re-exposure.
*Preformed IgE antibodies*
- This mechanism is characteristic of **Type I hypersensitivity reactions**, such as **anaphylaxis** or **atopic dermatitis flares** triggered by allergens binding to **IgE on mast cells**.
- While the patient has a history of atopic dermatitis, the linear pattern of the rash after contact with an environmental trigger points away from an immediate IgE-mediated response.
*Immune complex formation*
- This describes a **Type III hypersensitivity reaction**, where **antigen-antibody complexes** deposit in tissues, leading to inflammation, as seen in conditions like **serum sickness** or **lupus nephritis**.
- The clinical presentation of a linear, vesicular rash is not consistent with immune complex deposition.
*IgG antibodies against desmoglein*
- This mechanism is central to **pemphigus vulgaris**, an **autoimmune blistering disease** where IgG antibodies disrupt cell-cell adhesion in the epidermis.
- Pemphigus vulgaris typically presents with **flaccid bullae** and erosions, usually without a clear linear pattern or acute environmental trigger.
*IgG antibodies against hemidesmosomes*
- This mechanism is characteristic of **bullous pemphigoid**, another **autoimmune blistering disorder** where IgG antibodies target components of the **dermal-epidermal junction**.
- Bullous pemphigoid exhibits **tense bullae** and often affects older individuals, which does not match the patient's age or rash characteristics.
Question 20: A 62-year-old woman with type 2 diabetes mellitus is brought to the emergency room because of a 3-day history of fever and shaking chills. Her temperature is 39.4°C (103°F). Examination of the back shows right costovertebral angle tenderness. Analysis of the urine shows WBCs, WBC casts, and gram-negative rods. Ultrasound examination of the kidneys shows no signs of obstruction. Biopsy of the patient's kidney is most likely to show which of the following?
A. Polygonal clear cells filled with lipids and carbohydrates
B. Polymorphonuclear leukocytes in tubules (Correct Answer)
C. Tubular eosinophilic casts
D. Widespread granulomatous tissue and foamy macrophages
E. Cystic dilation of the renal medulla
Explanation: ***Polymorphonuclear leukocytes in tubules***
- The patient presents with classic signs and symptoms of **acute pyelonephritis**, including fever, chills, **costovertebral angle tenderness**, **WBCs and WBC casts** in the urine, and **gram-negative rods**, indicating a bacterial infection of the kidney parenchyma.
- A kidney biopsy in acute pyelonephritis would reveal an intense **inflammatory infiltrate** primarily composed of **polymorphonuclear leukocytes (neutrophils)** within the renal tubules and interstitium, responding to the bacterial invasion.
*Polygonal clear cells filled with lipids and carbohydrates*
- This description is characteristic of **renal cell carcinoma**, specifically the **clear cell subtype**.
- While this is a possible renal pathology, it does not align with the acute infectious presentation of fever, chills, CVA tenderness, and urinary findings of infection.
*Tubular eosinophilic casts*
- **Eosinophilic casts** in renal tubules are typical of **acute tubular necrosis (ATN)**, often resulting from ischemic or nephrotoxic injury.
- Although ATN can cause acute renal failure, the presence of **fever, shaking chills, and gram-negative rods** points more directly to an active bacterial infection.
*Widespread granulomatous tissue and foamy macrophages*
- This finding is suggestive of a granulomatous disease like **tuberculosis** or **xanthogranulomatous pyelonephritis**.
- While **xanthogranulomatous pyelonephritis** is a severe chronic form of pyelonephritis, it typically involves a destructive mass and often presents with a more subacute or chronic course rather than acute onset with shaking chills and evidence of uncomplicated bacterial infection.
*Cystic dilation of the renal medulla*
- This points to conditions such as **medullary sponge kidney** or **polycystic kidney disease**.
- These are primarily congenital or developmental anomalies and do not explain the acute signs of infection and inflammation seen in this patient.
