Hypotension case 2

Hypotension case 2


A 32-year-old woman goes to the local emergency department because she has been feeling increasingly ilI. When she tries to stand to go
into the examining room, she loses consciousness and falls to the floor. Her blood pressure is 70/40 mm Hg. Her temperature is 40.1 C (104
F), and her skin shows a diffuse, sunburn-Iike, erythema. IV fluids are started, and the woman's husband is questioned. He reports that her
symptoms began approximately 24 hours previously and that she has been experiencing headache, sore throat, profound lethargy, vomiting,
profuse diarrhea, muscle pain, and the rash. Examination of the patient's vagina demonstrates a blood-filled tampon. Gram's stain of a vaginal
smear shows nearly complete replacement of the normal vaginal flora by gram-positive cocci.


Q 1
Which of the following is the most likely diagnosis?
/ A. Kawasaki syndrome
/ B. Meningococcemia
/ C. Reye syndrome
/ D. Rocky Mountain spotted fever
/ E. Toxic shock syndrome


Q 2
This condition is most closely associated with which of the following organisms?

Moraxella catarrhalis.
Neisseria gonorrhoeae
Staphylococcus aureus
Streptococcus agalactiae
Streptococcus pyogenes

Q 3
The exotoxin implicated in this patient's disease is unusual in that it is a superantigen. This means which of the following?
/ A. It can bind to the inside surfaces of the normal peptide grooves of both lgA and the TCR molecule
/ B. It can bind to the inside surfaces of the normal peptide grooves of both lgE and the TCR molecule
/ C. It can bind to the inside surfaces of the normal peptide grooves of both the MHC class l molecule and the TCR molecule
/ D. It can bind to the outside surfaces of the normal peptide grooves of both lgG and the TCR molecule
/ E. It can bind to the outside surfaces of the normal peptide grooves of both the MHC class ll molecule and the TCR molecule


Q 4
One of the compounds that has been implicated in the severe hypotension seen in this patient's disease is tumor necrosis factor (TNF)-alpha.
This molecule is produced by which of the following cell types?
/ A. B Iymphocytes
/ B. Eosinophils
/ C. Macrophages
/ D. Neutrophils
/ E. T Iymphocytes

Q 5
Which of the following is the most appropriate pharmacotherapy?
/ A. Chloramphenicol
/ B. Gentamicin
/ C. Nafcillin
/ D. Penicillin
/ E. Tetracycline


Q 6
The mortality in this patient's condition is high, in large part because multi-organ failure may develop. Which of the following serum laboratory
results would suggest developing renal failure?
/ A. AIanine aminotransferase (ALT) 105 U/L
/ B. Aspartate aminotransferase (AST) 100 U/L
/ C. Creatinine 2.5 mg/dL
/ D. Serum sodium 141 mEq/L
/ E. Total creatine kinase 550 U/L


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Hypotension case 2 answers

A1
The correct answer is E. This woman's presentation is typical for toxic shock syndrome. In patients who survive, the rash eventually becomes desquamating. Toxic shock syndrome is a rare, but very dangerous disease with a 5% mortality rate, primarily related to the complications of shock. Many cases have been related to the use of super absorbent tampons, which favor bacterial overgrowth. Since removal of some of the more strongly implicated tampons from the market, the incidence of toxic shock syndrome has dropped and now appears to be about 3 cases/100,000 menstruating women. Cases can also be seen complicating postpartum or postoperative infections. Gram-positive cocci would not cause any of the other conditions listed.
Kawasaki syndrome (choice A) usually occurs in children, and while it causes severe rash, it does not usually cause shock.
Meningococcemia (choice B) and Rocky Mountain spotted fever (choice D) both usually cause macular rashes.
Reye syndrome (choice C) can cause rash, but it is almost always seen in individuals less than 18 years of age.


A2
The correct answer is C. Almost all cases of classic toxic shock syndrome have been associated with exotoxin-producing strains of phage group 1 Staphylococcus aureus. Streptococcus pyogenes can also, less commonly, produce a toxic shock-like syndrome. The toxin implicated in staphylococcal toxic shock syndrome has been called toxic shock syndrome toxin-1 (TSST-1). It is thought that women who develop toxic shock syndrome following tampon use have vaginas that were previously colonized by small numbers of the toxin-producing bacteria, and that then as the vaginal conditions change, bacterial overgrowth with the staphylococci occurs. Toxic shock syndrome is unusual, in that sepsis-like systemic effects are seen even though true bacteremia does not occur, just absorption of a very potent toxin. Antibiotic therapy is usually included in treatment of toxic shock, but the intent is to eradicate the colonization and prevent recurrence, rather than treat an active, true infection.
Moraxella catarrhalis(choice A) is a gram-negative coccus that forms part of the normal nasal flora, and has been occasionally implicated as a cause of otitis media, bronchitis, and bronchopneumonia.
Neisseria gonorrhoeae(choice B) is a gram-negative coccus that causes gonorrhea.
Streptococcus agalactiae(choice D) is a group B, beta-hemolytic streptococcus that colonizes the vagina (with no harm to the mother) and causes neonatal septicemia and meningitis.
Streptococcus pyogenes(choice E) is a group A, beta-hemolytic streptococcus that also produces potent toxins, and has been implicated in pharyngitis, scarlet fever, impetigo, rheumatic fever, and acute glomerulonephritis.


A3
The correct answer is E. Both the staphylococcal toxic shock syndrome toxin-1 (TSST-1) and the streptococcal super antigen (SSA) are unusual in that they tend to trigger a massive release of cytokines in response to relatively small amounts of toxin. The reason is that, unlike normal antigens that bind inside the normal peptide grooves of the MHC class II molecule on the antigen presenting cell and the T cell receptor (TCR) molecule of the T lymphocyte, these antigens recognize sites outside the grooves on these two molecules. The result is that they can, in effect, "turn on" almost every T cell they find, thereby producing the massive release of cytokines.
IgA (choice A), IgE (choice B), MHC class I molecules (choice C), and IgG (choice D) are not involved in these processes.


A4
The correct answer is E. Tumor necrosis factor alpha is produced by T lymphocytes, and it acts by increasing the fluid leakage out of the vasculature as part of its more generalized stimulation of inflammatory processes. It is also thought the TSST-1 may directly alter capillary permeability. Macrophages (choice C) produce IL-1, which is also important in triggering the severe hypotension by a similar mechanism to that of TNF-alpha.
B lymphocytes (choice A), eosinophils (choice B), and neutrophils (choice D) do not produce TNF-alpha and are not as important in triggering the hypotension of toxic shock.


A5
The correct answer is C. Treatment measures for TSS include rehydration, management of cardiac and renal failure (if present), administration of antistaphylococcal agents (e.g., nafcillin), as well as removal of the source of the toxin, such as removal of the tampon or drainage of an abscess.
Chloramphenicol (choice A) is an older antibacterial agent used in the treatment of severe infections only when less toxic agents cannot be used. Examples of such infections include Salmonella infections, H. influenzae infections, and various types of meningitis.
Gentamicin (choice B) is a bactericidal aminoglycoside antibiotic used primarily in the treatment of serious gram-negative infections. This agent requires active transport across the cell membrane to exhibit activity. In an acidic environment, the drug becomes ionized and less is transported to the interior of the cell. Gentamicin is a concentration-dependent killer: the drug only needs to be in contact with the bacteria for a short period of time to exert a killing effect (a property that may help minimize toxicity). It also exerts a postantibiotic effect in which the antimicrobial action is "seen" after drug concentration falls below minimum inhibitory concentration.
Penicillin (choice D) is a bactericidal antibiotic with broad gram-negative and gram-positive coverage as well as moderate anaerobic coverage. It inhibits the biosynthesis of cell wall mucopeptides. Most hospital isolates of Staph aureus are resistant to penicillin.
Tetracycline (choice E) has mild-to-moderate gram-negative and gram-positive coverage. It provides coverage for many rickettsial, spirochetal, and chlamydial infections. Tetracycline acts by inhibiting protein synthesis by binding to the 30S ribosome. It is primarily used for uncomplicated gonococcal infections and acne.


A 6
The correct answer is C. The multi-organ failure seen in toxic shock syndrome is, in large part, due to the very difficult-to-manage hypotension as fluid shifts out of the vascular space and into the tissues. This produces the paradox that you can get a markedly edematous patient who is actually hypotensive secondary to fluid losses within the body. Patients may require 10 liters or more of IV fluids per day in order to prevent multiorgan failure. Impending renal failure is indicated by dropping urine output and rising BUN and serum creatinine levels.
The liver is also very vulnerable, and damage is indicated by rising ALT (choice A) and AST (choice B) levels.
Serum sodium (choice D) is usually not affected, since the fluid replacement is usually with normal saline or similar isotonic fluids.
Muscle damage may be a prominent feature and cause leakage of creatine kinase (choice E).