Postmortem Changes — MCQs
First sign of putrefaction in a dead body:
Greenish discoloration of the body first seen in the right iliac fossa after death is due to formation of -
Color of postmortem lividity in hypothermic deaths: NEET 2012
A dead fetus retained in utero characteristically shows
A dead body is having cadaveric lividity of bluish green color. The most likely cause of death is by poisoning due to:
What is the cooling curve of the body post-mortem?
Post-mortem caloricity is not seen in which of the following conditions?
Vitreous humor is preserved in suspected poisoning with:
Which is the best fluid for postmortem investigation?
What is the histopathological finding 12 hours after ischemic injury to heart?
Postmortem Changes Indian Medical PG Practice Questions and MCQs
Question 1: First sign of putrefaction in a dead body:
- A. Putrefaction
- B. Mummification
- C. Greenish discoloration of right iliac fossa (Correct Answer)
- D. Maggot formation
Explanation: ***Greenish discoloration of right iliac fossa*** - The **greenish discoloration** in the **right iliac fossa** is a recognized and reliable early sign of **putrefaction**, resulting from the action of **bacteria** on **hemoglobin** producing **sulfhemoglobin**. - The large intestine, particularly the **cecum** and **ascending colon** located in the right iliac fossa, is rich in bacteria that initiate the breakdown of tissues soon after death. *Putrefaction* - **Putrefaction** refers to the overall process of **decomposition** of organic matter by microorganisms, which includes many signs, but not a single initial sign. - It is a broad term encompassing the entire process rather than a specific initial manifestation. *Mummification* - **Mummification** is a form of decomposition where the body dries out, often in **hot, dry environments**, preserving the tissues rather than causing active putrefaction. - It is a **desiccative process**, not a initial sign of bacterial putrefaction. *Maggot formation* - **Maggot formation** (larvae of flies) is an indication of **insect activity** and relies on the presence of flies to lay eggs. - While common in decomposition, it typically occurs **later in the process** and is dependent on external environmental factors like access by insects, not the first internal biological change.
Question 2: Greenish discoloration of the body first seen in the right iliac fossa after death is due to formation of -
- A. Sulfhemoglobin (Correct Answer)
- B. Sulfmethemoglobin
- C. Methemoglobin
- D. None of the options
Explanation: ***Sulfhemoglobin*** - This greenish discoloration, often starting in the **right iliac fossa**, is a classic sign of **putrefaction** due to the action of **anaerobic bacteria** in the cecum. - **Hydrogen sulfide (H₂S)** produced by these bacteria (especially *Clostridium* species) reacts with the **hemoglobin** in red blood cells to form **sulfhemoglobin**, which is responsible for the characteristic **green hue**. - The right iliac fossa is affected first because of its proximity to the **cecum**, which contains abundant bacteria that begin post-mortem activity early. *Sulfmethemoglobin* - This term is **not a recognized compound** in forensic pathology or biochemistry. - While sulfhemoglobin exists, adding "meth-" creates a non-existent hybrid term with no biological basis in post-mortem changes. *Methemoglobin* - **Methemoglobin** is formed when the **ferrous iron (Fe²⁺)** in hemoglobin is oxidized to **ferric iron (Fe³⁺)**, reducing its oxygen-carrying capacity. - It typically causes a **chocolate-brown or grayish discoloration** of blood and tissues, not the **greenish hue** seen in post-mortem putrefaction. - Methemoglobin formation is more relevant to **carbon monoxide poisoning, cyanide toxicity**, or certain drug exposures in living individuals. *None of the options* - This option is incorrect because **sulfhemoglobin** is the direct and well-established cause of the greenish discoloration observed during the putrefaction process. - The formation of sulfhemoglobin is a **characteristic forensic finding** in decomposition, particularly in the early stages of putrefaction.
Question 3: Color of postmortem lividity in hypothermic deaths: NEET 2012
- A. Purple
- B. Deep red
- C. Cherry red
- D. Bright pink (Correct Answer)
Explanation: ***Bright pink*** - In **hypothermic deaths**, postmortem lividity characteristically appears **bright pink** due to **increased oxygen affinity of hemoglobin at lower temperatures**. - At cold temperatures, hemoglobin retains oxygen more tightly, resulting in well-oxygenated blood that produces a pinkish hue in dependent areas. - This is considered a **characteristic finding** in deaths due to cold exposure and hypothermia. *Purple* - **Purple lividity** is the **typical/classical color** seen in most deaths due to pooling of deoxygenated blood (reduced hemoglobin). - While this is the general appearance of livor mortis, it is **not specific** to hypothermic deaths. - Purple represents the baseline color, whereas bright pink is the distinguishing feature in hypothermia. *Deep red* - Deep red lividity may occur with well-oxygenated blood but is not specifically characteristic of hypothermia. - This color variation depends on general oxygenation status rather than cold-specific mechanisms. *Cherry red* - **Cherry red livor mortis** is a classic sign of **carbon monoxide poisoning** or **cyanide poisoning**. - Carboxyhemoglobin (in CO poisoning) produces a characteristic bright cherry red color. - This is unrelated to hypothermic deaths.
Question 4: A dead fetus retained in utero characteristically shows
- A. mummification
- B. Rigor mortis
- C. Adipocere formation
- D. Maceration (Correct Answer)
Explanation: ***Maceration*** - This is the characteristic post-mortem change observed in a **fetus that dies in utero** and remains within the amniotic fluid for an extended period. - The skin becomes soft, wrinkled, and eventually peels, often referred to as "**washerwoman's hands**" or "glove-and-stocking" appearance. *Mummification* - This occurs when a body dries out quickly in very **dry and hot environments**, preventing putrefaction and bacterial decay. - It's rarely seen in a fetus inside the uterus due to the presence of amniotic fluid. *Rigor mortis* - This is the **stiffening of muscles** after death due to the depletion of adenosine triphosphate (ATP), typically occurring several hours post-mortem. - While it can occur in a neonate after birth, it is not consistently observed in a fetus that dies and remains in utero. *Adipocere formation* - This is the transformation of fatty tissues into a **waxy, soap-like substance** (grave wax), occurring in damp, anaerobic environments. - It usually takes weeks to months and is not the typical immediate post-mortem change seen in a fetus within the uterus.
Question 5: A dead body is having cadaveric lividity of bluish green color. The most likely cause of death is by poisoning due to:
- A. Hydrogen sulfide (Correct Answer)
- B. Hydrocyanic acid
- C. Oleander
- D. Sodium nitrite
Explanation: ***Hydrogen sulfide*** - **Hydrogen sulfide poisoning** classically causes a **bluish-green cadaveric lividity** due to the formation of sulfhemoglobin. - This distinct discoloration is a key indicator often noted during post-mortem examination in cases of hydrogen sulfide exposure. *Hydrocyanic acid* - **Hydrocyanic acid poisoning** typically leads to a **cherry-red lividity** due to the inhibition of cytochrome oxidase, preventing tissue oxygen utilization, which is different from the bluish-green color described. - The bright red color results from the persistence of oxygenated hemoglobin in the venous blood. *Oleander* - **Oleander poisoning** affects the heart, causing **cardiac arrhythmias** and bradycardia, but does not typically produce a characteristic or distinct cadaveric discoloration like the bluish-green hue. - Lividity would generally be a more typical reddish-purple, consistent with simple hypostasis. *Sodium nitrite* - **Sodium nitrite poisoning** causes **methemoglobinemia**, leading to a characteristic **chocolate-brown or grayish-blue lividity** due to the oxidation of hemoglobin, which differs from the specific bluish-green described. - This change is due to the formation of methemoglobin, which cannot carry oxygen effectively.
Question 6: What is the cooling curve of the body post-mortem?
- A. Linear
- B. Hyperbola
- C. Sigmoid (Correct Answer)
- D. Parabola
Explanation: ***Sigmoid*** - The **cooling curve of the body post-mortem** is typically described as a **sigmoid (S-shaped) curve**, reflecting different phases of cooling. - This curve initially shows a slow drop in temperature, followed by a more rapid decline, and then a gradual tapering as the body approaches ambient temperature. *Linear* - A **linear cooling curve** would imply a constant rate of temperature loss, which is not accurate for post-mortem cooling. - The rate of heat loss changes as the temperature difference between the body and its environment changes, making a linear model inappropriate. *Hyperbola* - A **hyperbolic curve** does not accurately represent the distinct phases of post-mortem cooling, which include initial slow cooling, rapid cooling, and eventual plateau. - Hyperbolic functions are generally used to describe inverse relationships or specific growth patterns not observed in body cooling. *Parabola* - A **parabolic curve** typically describes processes that accelerate or decelerate symmetrically around a central point, which does not match the observed pattern of post-mortem temperature decline. - The cooling process is more complex, influenced by factors like initial body temperature, ambient temperature, and insulation.
Question 7: Post-mortem caloricity is not seen in which of the following conditions?
- A. Pontine haemorrhage
- B. Bacteremia
- C. Status epilepticus
- D. Post-mortem glycogenolysis (Correct Answer)
Explanation: ***Post-mortem glycogenolysis*** - **Post-mortem glycogenolysis** is a **normal biochemical process** that occurs after death, involving the breakdown of glycogen in tissues. - It is **NOT a pre-death pathological condition** and does not cause the body temperature to rise after death. - **Post-mortem caloricity** occurs due to ante-mortem conditions with intense metabolic activity or thermoregulatory dysfunction, not from normal post-mortem biochemical changes. - This is the **correct answer** as it does NOT cause post-mortem caloricity. *Pontine haemorrhage* - **Pontine haemorrhage** causes damage to the **thermoregulatory centers** in the brainstem. - This leads to dysregulation and **uncontrolled heat generation**, resulting in hyperthermia. - The elevated metabolic state can persist briefly after death, causing **post-mortem caloricity**. *Bacteremia* - **Bacteremia** and **sepsis** trigger a massive **inflammatory response** with increased metabolic activity. - The heightened metabolic state generates significant heat before and immediately after death. - This contributes to elevated body temperature observed as **post-mortem caloricity**. *Status epilepticus* - **Status epilepticus** involves **prolonged, intense muscle contractions** and widespread neuronal activity. - This extreme metabolic demand generates substantial heat through continuous muscle activity. - The heat generation can persist briefly post-mortem, leading to **post-mortem caloricity**.
Question 8: Vitreous humor is preserved in suspected poisoning with:
- A. Cyanide
- B. Morphine
- C. Alcohol (Correct Answer)
- D. Carbon monoxide
Explanation: ***Alcohol*** - **Vitreous humor** is an ideal sample for postmortem alcohol analysis due to its **sequestration** from other body fluids, which minimizes postmortem production or degradation of alcohol. - Its **avascular nature** and **slow diffusion** rates ensure that the alcohol concentration in the vitreous humor closely reflects the ante-mortem blood alcohol concentration. *Cyanide* - Sampling **vitreous humor** is generally not the primary choice for detecting cyanide because cyanide is rapidly absorbed and metabolized, making its detection more reliable in other tissues. - Cyanide can degrade in biological samples, and its concentration in the vitreous humor may not accurately reflect the lethal dose or recent exposure. *Morphine* - While **vitreous humor** can be used for opiate detection, **blood and urine** are generally preferred for initial screening and quantitative analysis of morphine. - Morphine undergoes metabolism during its elimination, and its distribution into the vitreous humor might not always accurately reflect the **pharmacodynamics** or precise time of exposure compared to blood. *Carbon monoxide* - **Carbon monoxide (CO) poisoning** is primarily diagnosed by measuring **carboxyhemoglobin levels** in blood, as CO binds avidly to hemoglobin. - The vitreous humor is not a suitable sample for detecting carbon monoxide or carboxyhemoglobin as it lacks red blood cells and hemoglobin, which are the targets of CO toxicity.
Question 9: Which is the best fluid for postmortem investigation?
- A. CSF
- B. Serum
- C. Synovial fluid
- D. Vitreous (Correct Answer)
Explanation: ***Vitreous humor*** is the **best fluid for postmortem investigation** due to its relative isolation and slow decomposition compared to other body fluids. It offers a **stable matrix** for analyzing electrolytes (especially potassium for estimating postmortem interval), drugs, and alcohol, providing a clearer picture of antemortem levels. *CSF (Cerebrospinal fluid)* is more susceptible to rapid postmortem changes and bacterial contamination. While useful in some cases, its instability makes it less reliable for general postmortem analysis compared to vitreous humor. *Serum* undergoes rapid and significant degradation after death, leading to hemolysis and the release of cellular contents. This makes postmortem serum analysis challenging as its composition quickly deviates from antemortem levels, potentially causing misleading results. *Synovial fluid* is found in joints and is prone to putrefaction and contamination soon after death. Its limited volume and rapid decomposition make it less suitable for comprehensive postmortem analysis.
Question 10: What is the histopathological finding 12 hours after ischemic injury to heart?
- A. Neocapillary invasion of myocytes
- B. Hyper-eosinophilia of myocytes (Correct Answer)
- C. Karyorrhexis of myocytes
- D. Coagulation necrosis of myocytes
Explanation: ***Hyper-eosinophilia of myocytes*** - Within **4-12 hours** of myocardial ischemia, the most characteristic histological finding is the development of **hypereosinophilia** in the sarcoplasm of myocardial cells [1]. - This is due to the loss of **glycogen** and an increase in **cytoplasmic protein binding** to eosin, indicating early irreversible cell injury [1], [2]. *Neocapillary invasion of myocytes* - **Neocapillary invasion** is a feature of **healing** and **repair** processes, usually observed much later, typically days to weeks after the initial injury, to facilitate scar formation [1]. - This process involves the growth of **new blood vessels** into the damaged tissue. *Karyorrhexis of myocytes* - **Karyorrhexis**, the fragmentation of the cell nucleus, is a later stage of necrosis, usually becoming apparent **12-24 hours post-infarction** [1]. - In the initial 12 hours, nuclear changes like **pyknosis** (nuclear shrinkage and increased basophilia) might be observed, but karyorrhexis is not prominent [1]. *Coagulation necrosis of myocytes* - While myocardial infarction is characterized by **coagulation necrosis**, the classic histological signs of full-blown coagulation necrosis, such as loss of striations and nuclear changes, become prominent at **12-24 hours and beyond** [1]. - In the first 12 hours, **hypereosinophilia** is the primary early indicator of this necrotic process, preceding the more overt classical features [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 552. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 548-550.
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