Thalidomide teratogenicity most commonly causes a congenital anomaly?

JIPMER Nursing Officer-2024

Pharmacology

Easy

Appeared in: JIPMER Nursing Officer-2024

Explanation

Thalidomide is a potent teratogen, a substance that can cause birth defects.
Its most characteristic and notorious congenital anomaly is phocomelia, a severe type of limb-reduction defect.
In phocomelia, the long bones of the arms and/or legs are absent or severely underdeveloped.
This results in the hands and feet being attached very close to the trunk, sometimes by a small, rudimentary bone, resembling the flippers of a seal.
The critical period for this teratogenic effect is very specific, occurring with exposure between 34 and 50 days of menstrual age.

Option B: Hydrocephalus is the buildup of fluid in the ventricles deep within the brain. While it can be a congenital defect, it is not the primary or characteristic anomaly associated with thalidomide exposure.
Option C: Spina bifida is a neural tube defect where there is incomplete closing of the spine and membranes around the spinal cord. It is not caused by thalidomide.
Option D: Cleft lip and/or palate are openings or splits in the upper lip or roof of the mouth. These are not the hallmark defects of thalidomide.

Visual 1: Image - A historical photograph or medical illustration of an infant with phocomelia, showing the characteristic shortened or absent limbs. This provides a powerful visual anchor for the concept.
Visual 2: Diagram - A timeline of embryonic development highlighting the critical periods when different organs are most susceptible to teratogens. This would show the specific window (4-8 weeks) when thalidomide affects limb development.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Teratogenic effects of thalidomide as background academic context rather than a clinical decision trigger.
This question underscores the critical importance of medication reconciliation and safety counseling for all women of childbearing potential.
Nurses must educate patients about the risks of taking certain medications during pregnancy and the importance of consulting a healthcare provider before starting or stopping any drug.
The thalidomide tragedy of the late 1950s and early 1960s led to major reforms in drug testing and regulation, including the development of pregnancy risk categories (now replaced by the Pregnancy and Lactation Labeling Rule - PLLR) to prevent similar disasters.

How to Approach the Question

This is a factual recall question from pharmacology and teratology.
First, identify the core concept being tested: the specific congenital anomaly caused by the drug thalidomide.
Recall the classic, infamous association. Thalidomide is one of the most notorious teratogens in medical history.
Mentally link the keyword "thalidomide" with its hallmark defect: "phocomelia" or severe limb deformities often described as "seal-like limbs."
Scan the options to find the one that matches this knowledge. Option A, "Phocomelia (limb reduction)," is a direct match.
Briefly review the other options to confirm they are incorrect. Hydrocephalus, spina bifida, and cleft palate are all significant congenital anomalies, but they are classically associated with different causes (e.g., folic acid deficiency for spina bifida).

Concept Tested & Keywords

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