MDS PREP
Gas Gangrene is caused by -
1. Clostridium tetani
2. Clostridium perfringens
3. Clostridium difficile
4. Peptostreptococci
Pathology
Answer: 2
Gas Gangrene, also known as clostridial myonecrosis or anaerobic cellulitis,
is a severe and rapidly progressing form of necrotizing soft tissue infection
caused by the bacterial genus Clostridium. The condition is characterized by the
production of gas within the tissues due to the fermentation of carbohydrates by
the bacteria. The most common species implicated in gas gangrene is Clostridium
perfringens.
1. Clostridium tetani: This bacterium is the causative agent of tetanus, which
is a neurotoxic disease that leads to muscle spasms and rigidity. It is not
directly associated with gas gangrene, although both are anaerobic infections
that can occur in deep puncture wounds and both produce exotoxins. However, the
primary symptom of tetanus is muscular rigidity and spasms due to the production
of tetanospasmin, not the tissue destruction and gas production seen in gas
gangrene.
2. Clostridium perfringens: This is the most common cause of gas gangrene. C.
perfringens produces alpha toxin, which is a powerful enzyme that can break down
tissue and release gas as a byproduct. The infection typically occurs in the
deep layers of the skin and muscles following a severe trauma, surgery, or
burns, where there is a lack of oxygen, allowing the anaerobic bacteria to
thrive. The rapid spread of infection is due to the bacteria's ability to
produce multiple exotoxins that cause tissue necrosis and vasoconstriction,
leading to ischemia and further tissue damage.
3. Clostridium difficile: Although a member of the Clostridium genus, C.
difficile is mainly associated with antibiotic-associated diarrhea and
pseudomembranous colitis. It is a hospital-acquired infection that affects the
intestinal tract and is not typically involved in causing gas gangrene. While it
is an anaerobic bacterium, its pathogenicity is primarily due to the production
of toxins that damage the colon's mucosal lining rather than invading tissues
outside the gut.
4. Peptostreptococci: These are anaerobic bacteria that can be part of the
normal skin and mucosal flora. They are involved in various infections,
particularly in immunocompromised individuals or those with underlying medical
conditions. Peptostreptococci are more commonly associated with mixed anaerobic
infections such as abscesses, osteomyelitis, and other soft tissue infections,
but they are not typically the sole cause of gas gangrene.
Oral lesions on the tongue and other mucosal surfaces of the oral cavity is commonly caused by the deficiency of
1. Vit B
2. Niacin
3. Vit C
4. Vit K
Oral Pathology
Answer: 2
Oral lesions on the tongue are commonly caused by a deficiency of Niacin (Vitamin B3).
A patient who has geen given tumoricidal dose of radiotherapy recently reports to dental clinic with painful carious exposed mandibular first molar with periapical abscess. The treatment of choice should be
1. Extraction of the offending tooth
2. Root canal treatment if possible
3. No treatment should be given
4. Incision and drainage of abscess
Oral Pathology
Answer: 2
Root canal treatment is the treatment of choice for a patient with a painful carious exposed mandibular first molar with periapical abscess.
Paroxymal noctural hemoglobinuria is due to -
1) Acquired red cell defect
2) Congential red cell defect
3) Auto immune defect
4) Lead poisoning
General Pathology
Answer: 1
Paroxysmal nocturnal hemoglobinuria is due to an acquired red cell defect, specifically a defect in the cell membrane that makes red blood cells susceptible to lysis.
Immune surveillance is an effective host defence against tumours because:
1. Tumour cells are of different shapes and sizes
2. Tumour cells have lost growth control
3. Tumour cells have genetic alterations which result in expression of nonself proteins
4. Immune surveillance is a hypothetical concept
Pathology
Answer: 3
Tumour cells have genetic alterations which result in expression of nonself proteins: This is the most accurate statement regarding immune surveillance. Tumor cells often undergo genetic mutations that lead to the expression of abnormal proteins (neoantigens) that are not present in normal cells. These nonself proteins can be recognized by the immune system as foreign, triggering an immune response. This recognition is a key aspect of how immune surveillance functions effectively against tumors.
Extensive cellulitis is known as:
1. Phlegm
2. Phlegmon
3. Cellulitis majora
4. Cellulitis prima
Pathology Answer: 2
Extensive cellulitis is most accurately described by the term "phlegmon
Phlegm is a thick, viscous substance produced by the respiratory tract,
especially during a respiratory infection, which can be coughed up from the
lungs or expelled from the nose. It is primarily composed of mucus, dead cells,
and other substances.
Phlegmon is a term that is closely related to extensive cellulitis. It refers
to a severe form of cellulitis where the infection has spread deeply into the
subcutaneous tissues and is accompanied by significant inflammation, including
the presence of pus and necrosis. Phlegmon is characterized by intense pain,
swelling, redness, and warmth in the affected area. This condition often
requires aggressive medical management, including intravenous antibiotics and
surgical drainage if an abscess forms. It is an advanced and severe stage of
cellulitis that can lead to systemic infection if not treated properly.
True about Sickle cell anemia except -
1) Commonly seen in black
2) R.B.C. size is altered
3) Valine for Glutamic acid in ?-chain globin
4) Deletion of gene
General Pathology
Answer: 4
Deletion of a gene is not true about sickle cell anemia; it is caused by a point mutation, not a deletion.
Which of the following additional clinical findings would MOST be associated with a woman who has oral mucosal swelling, xerostomia, and intense salivary gland destructive inflammation?
1) Conjunctivitis
2) Goiter
3) Hemolytic anemia
4) Proximal muscle weakness
Conjunctivitis is often associated with Sjögren's syndrome, which can cause oral mucosal swelling and xerostomia.