General Pathology Practice Questions

Q: Which of the following is not teratogenic for fetal development?

Herpes. **Explanation:** The correct answer is **Herpes (HSV-2)**. In the context of teratogenicity—which refers to agents causing structural malformations during organogenesis (typically the first trimester)—Herpes Simplex Virus is generally not considered a classic teratogen. While HSV can cause devastating neonatal infection, it is usually transmitted **perinatally** (during passage through the birth canal) rather than transplacentally during early development. **Why the other options are incorrect:** * **Rubella:** A classic member of the TORCH complex. Infection in the first trimester leads to **Congenital Rubella Syndrome**, characterized by the triad of cataracts, sensorineural deafness, and cardiac defects (PDA). * **Alcohol:** The most common preventable cause of teratogenicity. It leads to **Fetal Alcohol Syndrome (FAS)**, presenting with microcephaly, smooth philtrum, thin upper lip, and intellectual disability. * **Tetracycline:** A well-known pharmacological teratogen. It crosses the placenta and chelates calcium, leading to **permanent yellow-brown discoloration of deciduous teeth** and inhibition of bone growth. **High-Yield Clinical Pearls for NEET-PG:** * **TORCH Agents:** Remember that while Rubella, CMV, and Toxoplasmosis are classic teratogens, **HSV and HIV** are primarily transmitted during delivery (vertical transmission). * **Rule of Thumb:** Teratogens act most severely during the **3rd to 8th week** of gestation (organogenesis). * **Tetracycline Timing:** It affects teeth if taken after the 14th week of gestation when deciduous teeth begin to calcify. * **Safe Antibiotics in Pregnancy:** Penicillins, Cephalosporins, and Erythromycin are generally preferred over Tetracyclines or Fluoroquinolones.

Q: The mother of a newborn boy is alarmed that her baby regurgitates at every feeding. An endoscopic examination reveals that the child's esophagus is almost completely occluded. This finding represents an example of which of the following errors of morphogenesis?

Atresia. **Explanation:** The clinical presentation of a newborn with immediate regurgitation and an occluded esophagus is a classic description of **Esophageal Atresia** [1]. **1. Why Atresia is Correct:** In embryology, **Atresia** refers to the congenital absence or closure of a normal body orifice or tubular organ. During the 4th to 6th weeks of development, the esophagus undergoes a period of rapid epithelial proliferation that temporarily occluded the lumen. This is followed by **recanalization**. Failure of this recanalization process results in atresia. In the esophagus, this is often associated with a Tracheoesophageal Fistula (TEF). **2. Analysis of Incorrect Options:** * **Aplasia:** Refers to the complete failure of an organ or tissue to develop, despite the presence of its primordial precursor. In this case, the esophagus exists but is not patent. * **Dysplasia:** Refers to abnormal organization of cells within tissues, resulting in altered morphology (e.g., fibrous dysplasia of bone or precancerous epithelial changes). It is a qualitative defect, not a structural occlusion. * **Dysraphic Anomaly:** Refers to a failure of fusion of homologous structures along the midline. The most common examples are neural tube defects like Spina Bifida or Craniorachischisis. **3. NEET-PG High-Yield Pearls:** * **Most Common Type:** The most common variant of TEF is **Type C** (Esophageal atresia with a distal fistula), occurring in ~85% of cases [1]. * **Clinical Sign:** Look for "Maternal Polyhydramnios" in the history, as the fetus cannot swallow amniotic fluid [1]. * **Associated Syndrome:** Often part of the **VACTERL** association (Vertebral, Anal atresia, Cardiac, TEF, Renal, Limb defects). * **Diagnosis:** Inability to pass a nasogastric tube into the stomach; confirmed by an X-ray showing the tube coiled in the upper esophageal pouch [1].

Q: Two siblings have osteogenesis imperfecta, but their parents are normal. What is the most likely mechanism of inheritance?

Germline mosaicism. **Explanation:** The correct answer is **Germline mosaicism** (also known as gonadal mosaicism). **1. Why Germline Mosaicism is correct:** Osteogenesis Imperfecta (OI) is typically an **Autosomal Dominant (AD)** disorder. When two siblings are affected but both parents are phenotypically normal (and test negative for the mutation in their blood/somatic cells), the most likely explanation is that one parent carries the mutation specifically in a subset of their **germ cells** (sperm or eggs). Since the mutation is absent in the parent's somatic cells, they remain healthy, but they can pass the mutation to multiple offspring. This explains the recurrence in siblings without a family history. **2. Why the other options are incorrect:** * **Anticipation:** Refers to the increasing severity or earlier onset of a disease in successive generations (e.g., Huntington’s disease, Fragile X). It does not explain how normal parents have two affected children. * **Genomic Imprinting:** Involves differential expression of a gene depending on which parent it is inherited from (e.g., Prader-Willi/Angelman syndromes). It does not typically result in the recurrence of an AD condition from normal parents. * **New Mutation (De novo):** While a new mutation can cause OI in a child of normal parents, the probability of a *de novo* mutation occurring twice in the same family (affecting two siblings) is statistically negligible. **Clinical Pearls for NEET-PG:** * **Germline Mosaicism** is a classic "trap" for AD conditions like **Osteogenesis Imperfecta** and **Duchenne Muscular Dystrophy (DMD)**. * Always suspect germline mosaicism when **two or more siblings** are affected by an AD or X-linked disorder, but the parents are clinically and genetically normal. * **OI Type II** (the lethal perinatal form) is the most common subtype associated with germline mosaicism in board exams.

Question 1

Which of the following is false regarding Gaucher's disease?

Accepted Answer

Tartrate-resistant acid phosphatase is negative

Answer

Beta-glucocerebrosidase is defective

Answer

Cherry red spots are seen on fundoscopy

Answer

Erlenmeyer's flask deformity is present

Question 2

Coagulative necrosis is commonly seen in all except:

Accepted Answer

Encephalitis

Answer

Tuberculosis

Answer

Sarcoidosis

Answer

Wet gangrene

Question 3

A patient is a known case of polyarteritis nodosa. On examination of a biopsy, accumulation of amorphous, eosinophilic, proteinaceous material in the vessel wall was seen. This finding is suggestive of:

Accepted Answer

Fibrinoid necrosis

Answer

Leukocytoclastic vasculitis

Answer

Hyaline arteriosclerosis

Answer

Caseous necrosis

Question 4

Pathologic calcification is seen in which of the following conditions?

Accepted Answer

Scleroderma

Answer

Lichen planus

Answer

Dystrophic epidermolysis bullosa

Answer

Lupus erythematosus

Question 5

Which of the following is not teratogenic for fetal development?

Accepted Answer

Herpes

Answer

Rubella

Answer

Alcohol

Answer

Tetracycline

Question 6

Which of the following statements is NOT true concerning amyloidosis?

Accepted Answer

Amyloidosis of the spleen is associated with severe anemia.

Answer

Amyloidosis associated with multiple myeloma has the poorest prognosis.

Answer

Fine-needle biopsy of subcutaneous abdominal fat is a simple and reliable method for diagnosing secondary systemic amyloidosis.

Answer

Hepatic amyloid disease produces hepatomegaly but rarely jaundice.

Question 7

Which enzyme converts hydrogen peroxide to water and oxygen?

Accepted Answer

Catalase

Answer

Superoxide dismutase

Answer

Glutathione peroxidase

Answer

Myeloperoxidase

Question 8

The mother of a newborn boy is alarmed that her baby regurgitates at every feeding. An endoscopic examination reveals that the child's esophagus is almost completely occluded. This finding represents an example of which of the following errors of morphogenesis?

Accepted Answer

Atresia

Answer

Aplasia

Answer

Dysplasia

Answer

Dysraphic anomaly

Question 9

Two siblings have osteogenesis imperfecta, but their parents are normal. What is the most likely mechanism of inheritance?

Accepted Answer

Germline mosaicism

Answer

Anticipation

Answer

Genomic imprinting

Answer

New mutation

Question 10

Metastatic calcification is commonly seen in all of the following, except:

Accepted Answer

Cardiac valves

Answer

Lungs

Answer

Kidneys

Answer

Gastric mucosa

General Pathology — MCQs

General Pathology — MCQs

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