Case A1 & A2 Flashcards
This 6-year-old female presented with a 1-week history of a febrile illness with a sore throat and headache. She was given oral ampicillin by her local physician. One day prior to hospital admission, the patient awakened with pain and swelling in the right ankle. She has had repeated episodes of Strep throat in past. She was evaluated on the day of admission, and in addition to a warm, swollen right ankle, she was noted to have a new grade II diastolic heart murmur thought to be consistent with mitral stenosis. She was admitted for work-up of Acute Rheumatic Fever.
List the clinical differentials and identify the most probable diagnosis.
Clinical differentials:
o Kawasaki Disease
o Sepsis, Bacterial
o Septic arthritis
o Systemic Lupus Erythematosus
o Acute Rheumatic Fever
Most probable diagnosis:
o Acute Rheumatic Fever secondary to Group A Streptococcal infection
*Group A Streptococcus – Streptococcus pyogenes
This 6-year-old female presented with a 1-week history of a febrile illness with a sore throat and headache. She was given oral ampicillin by her local physician. One day prior to hospital admission, the patient awakened with pain and swelling in the right ankle. She has had repeated episodes of Strep throat in past. She was evaluated on the day of admission, and in addition to a warm, swollen right ankle, she was noted to have a new grade II diastolic heart murmur thought to be consistent with mitral stenosis. She was admitted for work-up of Acute Rheumatic Fever.
Characterize the morphologic and antigenic structure of the bacteria.
The bacteria is Streptococcus pyogenes
Morphology
o Gram positive cocci arranged in chains
o When in chains, may sometimes present with a diplococcal appearance
o Produces capsules with hyaluronic acid
o Hair-like fimbriae that project through the capsule
o Grow in white discoid having a 1-2mm diameter and typically produce large zones of β-hemolysis
Antigenic structure
o M Protein – major virulence factor, Can be found in the pili
o T Substance – no relationship to virulence of streptococci
Acid and heat labile
o Nucleoproteins
o Fimbriae
Hair-like structures in the bacterial surface that serves as attachment to the different mucus membranes of the body
Makes it harder to dislodge the bacteria from the mucus membranes of the body
o Hyaluronidase
Spreading factors
Can cleave or desroy the hyaluronic acid matrix that makes up the connective tissue
The reason for deep seated skin infections
o Lipoteichoic acid
Major component of Gram positive bacterial cell wall
This 6-year-old female presented with a 1-week history of a febrile illness with a sore throat and headache. She was given oral ampicillin by her local physician. One day prior to hospital admission, the patient awakened with pain and swelling in the right ankle. She has had repeated episodes of Strep throat in past. She was evaluated on the day of admission, and in addition to a warm, swollen right ankle, she was noted to have a new grade II diastolic heart murmur thought to be consistent with mitral stenosis. She was admitted for work-up of Acute Rheumatic Fever.
Formulate a diagnostic plan for the case.
i. Get a throat swab
ii. Gram stain
iii. Culture in Blood Agar plate – look for β-hemolytic colonies
iv. Catalase test – if S. pyogenes, it would be catalase negative (no effervescence after coming into contact with Hydrogen Peroxide)
v. Bacitracin Susceptibility test – Bacitracin sensitive, growth inhibition by Bacitracin if S. pyogenes
Serologic test – Antistreptolysin O (ASO) Test
o Positive ASO test, presence of Group A Strep
o Faster than Gram stain and culture
This 6-year-old female presented with a 1-week history of a febrile illness with a sore throat and headache. She was given oral ampicillin by her local physician. One day prior to hospital admission, the patient awakened with pain and swelling in the right ankle. She has had repeated episodes of Strep throat in past. She was evaluated on the day of admission, and in addition to a warm, swollen right ankle, she was noted to have a new grade II diastolic heart murmur thought to be consistent with mitral stenosis. She was admitted for work-up of Acute Rheumatic Fever.
Formulate a therapeutic plan for the case.
A 10 day drug therapy of the following is preferred:
o Peniciliin G
o Erythromycin (or other macrolides) for penicillin allergic patients
For skin infections: intramuscular or intravenous injections
For mitral stenosis, mitral valve replacement may be needed
This 6-year-old female presented with a 1-week history of a febrile illness with a sore throat and headache. She was given oral ampicillin by her local physician. One day prior to hospital admission, the patient awakened with pain and swelling in the right ankle. She has had repeated episodes of Strep throat in past. She was evaluated on the day of admission, and in addition to a warm, swollen right ankle, she was noted to have a new grade II diastolic heart murmur thought to be consistent with mitral stenosis. She was admitted for work-up of Acute Rheumatic Fever.
List down the preventive measures pertinent to prevent further recurrence and long term cardiac complications
Detection and early anti-microbial therapy of respiratory and skin infections of Group A Streptococci
Anti-streptococcal chemoprophylaxis of people who have suffered an attack of Rheumatic disease
A medical technologist accidentally pricks his finger with a used needle from a blood extraction in a jaundiced female patient in the hospital. The patient is positive for HbsAg. The health worker is seronegative for Hepatitis B Serology (no previous vaccination for Hepatitis B).
Characterize the genome, morphologic and antigenic structure of Hepatitis B Virus.
Hepatitis B Virus (HBV)
o Member of the hepadnaviridae family
o Circular double stranded DNA virus
o Double shelled virus structure
Hepatitis B Surface Antigen (HBsAg) – outer surface, the presence of HBsAg indicates active HBV infection, whether acute or
chronic.
Hepatitis B Core Antigen (HBcAg) – inner core
S : Surface :: C : Core
A medical technologist accidentally pricks his finger with a used needle from a blood extraction in a jaundiced female patient in the hospital. The patient is positive for HbsAg. The health worker is seronegative for Hepatitis B Serology (no previous vaccination for Hepatitis B).
Compare the clinical picture, structure and diagnostic test of the different hepatitis viruses.
A medical technologist accidentally pricks his finger with a used needle from a blood extraction in a jaundiced female patient in the hospital. The patient is positive for HbsAg. The health worker is seronegative for Hepatitis B Serology (no previous vaccination for Hepatitis B).
Predict the risks of long term complications of Hepatitis B and C Viruses.
Chronic Hepatitis B infection may lead to:
o Hepatocellular carcinoma
o Hepatocellular necrosis from host reaction to the virus
Chronic Hepatitis C infection may lead to:
o Liver cirrhosis
o End-stage liver disease
A medical technologist accidentally pricks his finger with a used needle from a blood extraction in a jaundiced female patient in the hospital. The patient is positive for HbsAg. The health worker is seronegative for Hepatitis B Serology (no previous vaccination for Hepatitis B).
State the caveat in the interpretation of serologic tests in Acute Viral Hepatitis.
**Caveat – an explanation or warning that should be remembered when you are doing or thinking about something
HBsAg – detect present infection
o If present and reactive for more than 6 months – the patient is a carrier
HBeAg – envelope form of HBcAg
o Marker of high infectivity. E for Enfectious.
HBcAg can’t be tested for since it is in the core of the virus
Anti-HBc is the only detectable marker during the “window phase” of HBV infections
Anti-HBs is the serologic marker for recovery and immunity.It’s the major protective antibody in this disease hence;
- To better visualize the window period:
o Area between: - After the fall of HBsAg levels
- Before the Anti-HBs levels rise
- High titer of Anti-HBc, Lower titer of Anti-HBe
Different Serologic Titers in a Hepatitis Infection
Serologic tests in acute viral hepatitis and its interpretation
Course of a Hepatitis B Infection Focusing on the Window Period
