Infectious Disease Cases Flashcards
A 66 year old patient had been well until age 13 when she developed a heart murmur and rheumatic fever. She developed an abscess on her heel after a periodontal surgery in her mouth. A culture from the abscess on her foot revealed an alpha-hemolytic Gram (+) coccus in long chains. What is the suspected microbe and diagnosis for the cardiac symptoms?
Streptococcus viridans (Group C) resulting in infective endocarditis.
A 35 year old male comes into the clinic with GI symptoms and peeling of the skin. A few days prior he had a serosanguineous wound ooze out its contents. A culture from the wound contained an organism that was not found in the blood. What is the microbe and the diagnosis?
Staphylococcus aureus associated with Toxic Shock Syndrome
A 39 year-old woman is admitted with a fever/cough. She has a history of bronchiectasis. A culture from her sputum grows a Gram (+) aerobic colony. What is the cause of this patient’s infection?
Nocardial infection caused by aerobic bacteria in the dust. This was probably brought upon by a T-cell deficiency from the long-standing pulmonary issues.
Name at least 3 factors predisposing a person to an anaerobic infection.
- Compromised vascular supply
- Trauma
- Tissue destruction
For a patient with Clostridium perfringens infection in the leg,why would healthcare staff be concerned with the stability of the patient’s hemoglobin?
Clostridium makes an alpha toxin which lyses RBCs, which would be indicated by a drop in Hemoglobin levels.
A woman comes into the clinic with purpura on her lower leg and small bubbles within them. Culture of the purpura revealed Gram (-) rods. What could the microbe be?
E. Coli leading to the small CO2 bubbles within the purpura. The fact that the culture shows Gram (-) rods eliminates Clostridium genus.
What is the microorganism that causes “Cat-scratch Disease”? Describe a few features.
Bartonella Henselae can be transmitted by cat scratches. It presents as stellate macula in the eyeball and swollen lymph nodes
What microbe is a Gram-negative coccobaccilli that causes upper respiratory tract infection?
Haemophilus influenzae
What is one way in which a persistent sore throat can spread the infection to the thorax without involving the lungs?
The infectious agent can spread through the retropharyngeal space.
What Gram-negative diploccocus ferments only glucose? Provide at least 3 examples of clinical presentations.
Niesseria Gonorrhea.
- Conjunctivitis
- Urethritis in males
- Cervicitis in females
What microbe is responsible for “rice-water”, secretory stool and can be contracted from contaminated water/ shellfish? Briefly describe how it works
Vibrio cholerae - elevates cAMP and Cl-/ water secretion
A 30-year old man is admitted to the hospital with abdominal pain made worse by eating. Gastroscope revealed unusual peptic ulcers that were biopsies and Silver stained via Rapid Plasma Reagin test. What microbe was stained?
Treponema pallidum which is the cause of Syphillis. Helicobacter pylori (associated with ordinary peptic ulcers) does not stain with RPR.
Describe the Jalisco-Herxheimer reaction.
This is a reaction marked by fever and chills, described in spirochetal diseases (syphilis, relapsing fever and Lyme disease). It occurs hours after treatment is started, since sudden killing of these spirochetes releases toxins that makes them sick.
Describe the bouts of chills and temperature changes in relapsing fever.
Bouts of chills and headaches appeare periodically in Relapsing fever. This is due to borrelia seen in peripheral blood smears (Wright Stain). These are spread by soft ticks.
A young patient from South America emigrates to the US with fine crackles in the upper lobe and weight loss experienced over the past 2 weeks. What is the diagnosis? What lab test is needed to confirm?
Mycoplasma tuberculosis infection. This is confirmed by culture and acid-fast stain.
