Fever of unknown origin US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Fever of unknown origin. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Fever of unknown origin US Medical PG Question 1: A 23-year-old woman presents with progressively worsening headache, photophobia, and intermittent fever that have lasted for 6 days. She says her headache is mostly frontal and radiates down her neck. She denies any recent history of blood transfusions, recent travel, or contact with animals. Her past medical history is unremarkable. She is sexually active with a single partner for the past 3 years. Her temperature is 38.5°C (101.3°F). On physical examination, she appears pale and diaphoretic. A fine erythematous rash is noted on the neck and forearms. A lumbar puncture is performed and CSF analysis reveals:
Opening pressure: 300 mm H2O
Erythrocytes: None
Leukocytes: 72/mm3
Neutrophils: 10%
Lymphocytes: 75%
Mononuclear: 15%
Protein: 100 mg/dL
Glucose: 70 mg/dL
Which of the following is the most likely diagnosis in this patient?
- A. Lymphocytic choriomeningitis virus
- B. Ehrlichiosis
- C. Enterovirus meningitis (Correct Answer)
- D. Brucellosis
- E. Mumps meningitis
Fever of unknown origin Explanation: ***Enterovirus meningitis***
- The patient's symptoms of **headache**, **photophobia**, **fever**, and a **fine erythematous rash**, combined with CSF findings of **lymphocytic pleocytosis (75%)**, **elevated protein**, and **normal glucose**, are classic for **viral (aseptic) meningitis**.
- Enteroviruses (including coxsackievirus and echovirus) are the **most common cause** of viral meningitis in immunocompetent adults, particularly in summer and fall.
- The **normal glucose level** (70 mg/dL) effectively rules out bacterial meningitis, while the **lymphocytic predominance** with mildly elevated protein is pathognomonic for viral etiology.
- The fine erythematous rash is consistent with enteroviral exanthem.
*Lymphocytic choriomeningitis virus*
- While LCMV can cause aseptic meningitis with similar CSF findings (lymphocytic pleocytosis, normal glucose), it is typically acquired through contact with **rodent urine or feces**, particularly from pet hamsters or mice.
- The patient **denies animal contact**, making this diagnosis less likely than the more prevalent enterovirus infection.
*Ehrlichiosis*
- Ehrlichiosis is a **tick-borne illness** (from *Ehrlichia* species) that can cause fever, headache, and rash, but typically presents with **leukopenia**, **thrombocytopenia**, and elevated liver enzymes.
- The rash in ehrlichiosis is often petechial or absent entirely. CNS involvement is uncommon and would more likely present as meningoencephalitis rather than isolated meningitis.
- The CSF profile with prominent lymphocytic pleocytosis and normal glucose fits viral meningitis better than ehrlichiosis.
*Brucellosis*
- Brucellosis is a **zoonotic infection** acquired through contact with **unpasteurized dairy products** or infected livestock (cattle, goats, pigs), which the patient denies.
- While *Brucella* can cause chronic meningitis with lymphocytic pleocytosis, it classically presents with **undulating fever**, hepatosplenomegaly, and a more protracted course (weeks to months).
- The acute 6-day presentation without exposure history makes this unlikely.
*Mumps meningitis*
- Mumps virus can cause aseptic meningitis with a similar CSF profile (lymphocytic pleocytosis, normal glucose).
- However, mumps meningitis typically occurs in association with or following **parotitis (parotid gland swelling)**, which is not mentioned in this case.
- With widespread MMR vaccination, mumps is now rare in immunized populations, making enterovirus a more likely diagnosis.
Fever of unknown origin US Medical PG Question 2: A 34-year-old man comes to the physician because of fatigue and shortness of breath with moderate exertion for the past 2 months. Over the past 10 days, he has had low-grade fevers and night sweats. He has no history of serious illness except for a bicuspid aortic valve diagnosed 5 years ago. He has smoked one pack of cigarettes daily for 10 years and drinks 3–5 beers on social occasions. He does not use illicit drugs. The patient takes no medications. He appears weak. His temperature is 37.7°C (99.9°F), pulse is 70/min, and blood pressure is 128/64 mm Hg. The lungs are clear to auscultation. A grade 2/6 systolic murmur is heard best at the right sternal border and second intercostal space. There are several hemorrhages underneath his fingernails on both hands and multiple tender, red nodules on his fingers. Which of the following is the most likely causal organism?
- A. Candida albicans
- B. Streptococcus sanguinis (Correct Answer)
- C. Streptococcus pneumoniae
- D. Staphylococcus epidermidis
Fever of unknown origin Explanation: ***Streptococcus sanguinis***
- The patient's history of **bicuspid aortic valve** represents a predisposing cardiac lesion for **infective endocarditis**.
- **S. sanguinis** is part of the **viridans group streptococci**, common inhabitants of the oral flora, and is a frequent cause of subacute bacterial endocarditis, especially in individuals with damaged heart valves.
- The clinical presentation of **splinter hemorrhages** and **Osler nodes** (tender nodules on fingers) along with low-grade fever and constitutional symptoms is classic for subacute bacterial endocarditis.
*Candida albicans*
- While *Candida* can cause endocarditis, it is typically seen in specific risk groups such as **intravenous drug users**, immunocompromised patients, or after prosthetic valve surgery, none of which apply here.
- Fungal endocarditis often presents with larger **vegetations** and a more subacute course, but bacterial causes (especially viridans streptococci) are far more common in this clinical setting.
*Streptococcus pneumoniae*
- *S. pneumoniae* (pneumococcus) is a known cause of **pneumonia**, **meningitis**, and **otitis media**, but it is an uncommon cause of endocarditis.
- Pneumococcal endocarditis, when it occurs, typically presents with a more fulminant course and may be associated with other sites of pneumococcal infection.
*Staphylococcus epidermidis*
- *S. epidermidis* is a common cause of **prosthetic valve endocarditis** and infections related to foreign bodies or catheters.
- Given the patient's **native valve** issue and absence of prosthetic material or recent invasive procedures, it is less likely than **viridans streptococci**.
Fever of unknown origin US Medical PG Question 3: A 33-year-old man presents to the emergency department with a fever and fatigue. He states that he has not felt well since he returned from a hiking trip in Alabama. He is generally healthy and has no other medical conditions. His temperature is 101°F (38.3°C), blood pressure is 127/85 mmHg, pulse is 108/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam including a full dermatologic inspection is unremarkable. Laboratory studies are ordered as seen below.
Hemoglobin: 13 g/dL
Hematocrit: 39%
Leukocyte count: 2,200/mm^3 with normal differential
Platelet count: 77,000/mm^3
Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 4.3 mEq/L
HCO3-: 24 mEq/L
BUN: 19 mg/dL
Glucose: 98 mg/dL
Creatinine: 1.3 mg/dL
Ca2+: 10.2 mg/dL
AST: 92 U/L
ALT: 100 U/L
Which of the following is the most likely diagnosis?
- A. Lyme disease
- B. Babesiosis
- C. Influenza
- D. Ehrlichiosis (Correct Answer)
- E. Rocky Mountain spotted fever
Fever of unknown origin Explanation: ***Ehrlichiosis***
- This patient's symptoms (fever, fatigue), recent travel to an **endemic area** (Alabama), **leukopenia** (WBC 2,200/mm^3), **thrombocytopenia** (platelet 77,000/mm^3), and **elevated liver enzymes** (AST 92, ALT 100) are highly characteristic of ehrlichiosis, a **tick-borne disease**.
- The absence of a rash helps differentiate it from some other tick-borne illnesses.
*Lyme disease*
- While Lyme disease is also tick-borne, it typically presents with an **erythema migrans rash**, which is absent in this case.
- Lyme disease is less commonly associated with the **pronounced leukopenia** and **thrombocytopenia** seen here.
*Rocky Mountain spotted fever*
- Rocky Mountain Spotted Fever (RMSF) is characterized by a **maculopapular rash** that often starts on the ankles and wrists and spreads centrally, involving the palms and soles. This rash is absent in the patient.
- While RMSF can cause thrombocytopenia and elevated liver enzymes, the **lack of rash is a key differentiator**.
*Babesiosis*
- Babesiosis is a tick-borne parasitic infection that causes **hemolytic anemia**, which is not clearly indicated by the patient's hemoglobin and hematocrit, and typically results in severe fatigue and sometimes splenomegaly.
- This condition is often seen in immunocompromised individuals or those without a spleen, and the labs here are more consistent with ehrlichiosis than babesiosis.
*Influenza*
- Influenza presents with fever, fatigue, myalgia, and respiratory symptoms, but it does not cause **thrombocytopenia**, **leukopenia**, or **elevated liver enzymes** to the extent seen in this patient.
- The symptoms are more indicative of a **tick-borne illness** given the travel history and specific lab abnormalities.
Fever of unknown origin US Medical PG Question 4: A 32-year-old man presents to the physician with a history of fever, malaise, and arthralgia in the large joints for the last 2 months. He also mentions that his appetite has been significantly decreased during this period, and he has lost considerable weight. He also informs the physician that he often experiences tingling and numbness in his right upper limb, and his urine is also dark in color. The past medical records show that he was diagnosed with an infection 7 months before and recovered well. On physical examination, the temperature is 37.7°C (99.8°F), the pulse rate is 86/min, the respiratory rate is 14/min, and the blood pressure is 130/94 mm Hg. Which of the following infections has most likely caused the condition the patient is suffering from?
- A. Mycoplasma pneumoniae
- B. Epstein-Barr virus infection
- C. Yersinia enterocolitica
- D. Hepatitis B virus (Correct Answer)
- E. Chlamydophila pneumoniae
Fever of unknown origin Explanation: ***Hepatitis B virus***
- The patient's symptoms of **fever**, **malaise**, **arthralgia** in large joints, **dark urine**, and **weight loss** are classic signs of **hepatitis B virus (HBV)** infection with **extrahepatic manifestations**.
- **Dark urine** indicates **bilirubinuria** from hepatic involvement, confirming liver pathology.
- **Arthralgia in large joints** is a well-recognized extrahepatic manifestation of HBV caused by **immune complex deposition** (Type III hypersensitivity).
- The **neurological symptoms** (tingling and numbness) strongly suggest **polyarteritis nodosa (PAN)**, a necrotizing vasculitis associated with HBV that commonly causes **mononeuritis multiplex** and peripheral neuropathy.
- The history of infection **7 months ago** with ongoing symptoms suggests progression to **chronic HBV infection** with systemic complications.
*Mycoplasma pneumoniae*
- This infection primarily causes **respiratory symptoms**, such as **atypical pneumonia** ("walking pneumonia"), and is less likely to lead to persistent arthralgia, significant weight loss, or dark urine.
- While post-infectious arthralgia can rarely occur, it is not a prominent feature and does not explain the hepatic (dark urine) or neurological manifestations.
*Epstein-Barr virus infection*
- **Epstein-Barr virus (EBV)** typically causes **infectious mononucleosis**, characterized by **fever**, **fatigue**, **pharyngitis**, **lymphadenopathy**, and **splenomegaly**.
- While mild arthralgia can occur, it is not a dominant feature, and **dark urine** (bilirubinuria), **significant weight loss**, and **peripheral neuropathy** are not characteristic of EBV infection.
*Yersinia enterocolitica*
- Infections with **Yersinia enterocolitica** typically cause **acute gastroenteritis** with **diarrhea**, **abdominal pain**, and sometimes **reactive arthritis** (Reiter syndrome).
- **Reactive arthritis** more commonly affects **lower extremity joints** in an **asymmetric pattern** and occurs post-infection, not during active infection.
- The **dark urine**, **neuropathy**, and **chronic constitutional symptoms** are not characteristic of Yersinia infection.
*Chlamydophila pneumoniae*
- This pathogen primarily causes **respiratory tract infections**, similar to Mycoplasma pneumoniae, leading to **atypical pneumonia** or **bronchitis**.
- It is not typically associated with chronic arthralgia, significant weight loss, dark urine (hepatic involvement), or neurological symptoms as described in this case.
Fever of unknown origin US Medical PG Question 5: A 26-year-old woman seeks evaluation at an urgent care clinic with complaints of fever and generalized muscle and joint pain for the past 3 days. She also complains of nausea, but denies vomiting. She does not mention any past similar episodes. Her past medical history is unremarkable, but she returned to the United States 1 week ago after spending 2 weeks in southeast Asia doing charity work. She received all the recommended vaccines prior to traveling. The temperature is 40.0°C (104.0°F), the respirations are 15/min, the pulse is 107/min, and the blood pressure is 98/78 mm Hg. Physical examination shows mild gingival bleeding and a petechial rash over the trunk. Laboratory studies show the following:
Laboratory test
Leukocyte count 4,000/mm³
Platelet count 100,000/mm³
Partial thromboplastin time (activated) 45 seconds
Which of the following is the most likely cause of this patient’s condition?
- A. Dengue fever (Correct Answer)
- B. Leptospirosis
- C. Typhoid fever
- D. Yellow fever
- E. Ebola virus
Fever of unknown origin Explanation: ***Dengue fever***
- This patient presents with a classic constellation of symptoms including **high fever**, **myalgia**, **arthralgia** (break-bone fever), **nausea**, and **petechial rash**, along with **thrombocytopenia** and evidence of **hemorrhagic manifestations** (mild gingival bleeding, petechiae, and prolonged PTT due to thrombocytopenia). Recent travel to Southeast Asia, an endemic region, further supports this diagnosis.
- The combination of **fever**, **leukopenia**, **thrombocytopenia**, and **hemorrhagic signs** in a patient returning from an endemic area is highly suggestive of dengue fever.
*Leptospirosis*
- While leptospirosis can cause **fever**, **myalgia**, and **nausea**, it is typically associated with contact with **contaminated water** or animal urine and often presents with **conjunctival suffusion** and sometimes **renal or hepatic involvement**, which are not prominent here.
- **Thrombocytopenia** and **hemorrhagic manifestations** are less common or severe in typical leptospirosis compared to dengue.
*Typhoid fever*
- Typhoid fever is characterized by a **gradually escalating fever**, **relative bradycardia**, and often a **"rose spot" rash**, along with **gastrointestinal symptoms** like constipation or diarrhea.
- While leukopenia can occur, **thrombocytopenia** and **hemorrhagic signs** like petechiae and gingival bleeding are not typical features.
*Yellow fever*
- Yellow fever, though mosquito-borne and endemic in some tropical regions, typically presents with **jaundice** (hence "yellow" fever), **renal failure**, and more severe **hemorrhage** (black vomitus) in its toxic phase.
- The patient's symptoms are more consistent with dengue's milder hemorrhagic picture and lack the prominent liver and kidney involvement seen in yellow fever.
*Ebola virus*
- Ebola virus disease causes a severe **hemorrhagic fever** with rapid onset and high mortality, characterized by profound **multi-organ failure**, widespread **hemorrhage** (internal and external), and severe **gastrointestinal symptoms** (vomiting, diarrhea).
- The clinical presentation, while including fever and some hemorrhagic signs, is not as severe or rapidly progressing as typical Ebola, nor does it fit the travel epidemiology for this patient (Ebola is endemic to Central and West Africa, not Southeast Asia).
Fever of unknown origin US Medical PG Question 6: A 25-year-old woman is admitted to the intensive care unit (ICU) with hematemesis and shock. Five days ago she had a severe fever 40.0℃ (104.0℉), retro-orbital pain, nausea, and myalgias. The high temperatures decreased over a few days, but she developed severe abdominal pain and bleeding gums. A single episode of hematemesis occurred prior to ICU admission. She travels to Latin America every winter. Two weeks ago, she traveled to Brazil and spent most of her time outdoors. She is restless. The temperature is 38.0℃ (100.4℉), the pulse is 110/min, the respiration rate is 33/min, and the blood pressure is 90/70 mm Hg. Conjunctival suffusion is seen. The extremities are cold. A maculopapular rash covers the trunk and extremities. Ecchymoses are observed on the lower extremities. The lung bases reveal absent sounds with dullness to percussion. The abdomen is distended. The liver edge is palpable and liver span is 15 cm. Shifting dullness is present. The laboratory studies show the following:
Laboratory test
Hemoglobin 16.5 g/dL
Leukocyte count 3500/mm3
Segmented neutrophils 55%
Lymphocytes 30%
Platelet count 90,000/mm3
Serum
Alanine aminotransferase (ALT) 75 U/L
Aspartate aminotransferase (AST) 70 U/L
Total bilirubin 0.8 mg/dL
Direct bilirubin 0.2 mg/dL
Which of the following is the most likely diagnosis?
- A. Yellow fever
- B. Dengue fever (Correct Answer)
- C. Chikungunya virus infection
- D. Zika virus infection
- E. Chagas disease
Fever of unknown origin Explanation: ***Correct: Dengue fever***
- The patient's presentation with **biphasic fever**, retro-orbital pain, severe abdominal pain, bleeding gums, **hematemesis**, maculopapular rash, **thrombocytopenia** (platelet count 90,000/mm3), hemoconcentration (hemoglobin 16.5 g/dL), leukopenia, and travel history to **Latin America** (Brazil) highly correlates with severe dengue fever.
- The **signs of plasma leakage** (absent lung sounds with dullness at bases, distended abdomen with shifting dullness indicating ascites, cold extremities, and hypotension) and shock are characteristic of **dengue hemorrhagic fever/dengue shock syndrome**.
*Incorrect: Yellow fever*
- While yellow fever can present with fever, myalgia, and hemorrhage, **jaundice (yellow skin)** is a prominent feature, often leading to the name "yellow fever," which is absent here (total bilirubin 0.8 mg/dL).
- Liver enzyme elevations in yellow fever are typically much higher, often in the thousands, compared to the modest elevations seen in this patient.
*Incorrect: Chikungunya virus infection*
- Characterized primarily by **severe arthralgia** (joint pain) that is often debilitating and can be prolonged, which is not the main presenting complaint in this case.
- While fever and rash can occur, severe hemorrhagic manifestations and shock leading to ICU admission are **less common** compared to dengue.
*Incorrect: Zika virus infection*
- Often presents with a **milder illness** involving maculopapular rash, fever, arthralgia, and **conjunctivitis**, but severe manifestations like hemorrhage, shock, and significant organ involvement are rare.
- The severe constitutional symptoms, profound thrombocytopenia, and signs of plasma leakage seen in this patient are **not typical** for Zika.
*Incorrect: Chagas disease*
- Chagas disease (caused by *Trypanosoma cruzi*) is typically a chronic infection that can lead to **cardiomyopathy** or **gastrointestinal mega-syndromes** years after the initial infection.
- The acute phase may involve fever and local swelling (chagoma or Romaña's sign), but it does not typically present with the acute, severe hemorrhagic and shock syndrome observed here.
Fever of unknown origin US Medical PG Question 7: A 42-year-old woman presents to a medical office with complaints of fatigue, weight loss, and low-grade fever for 1 week. She noticed bleeding spots on her feet this morning. The past medical history is significant for a recent dental appointment. She is a non-smoker and does not drink alcohol. She does not currently take any medications. On examination, the vital signs include temperature 37.8°C (100.0°F), blood pressure 138/90 mm Hg, respirations 21/min, and pulse 87/min. Cardiac auscultation reveals a pansystolic murmur in the mitral area with radiation to the left axilla. Laboratory studies show hemoglobin levels of 17.2 g/dL, erythrocyte sedimentation rate (ESR) of 25 mm/h, and a white blood cell (WBC) count of 12,000 cells/mm3. An echocardiogram reveals valvular vegetations on the mitral valve with mild regurgitation. Blood samples are sent for bacterial culture. Empiric antibiotic therapy is initiated with ceftriaxone and vancomycin. The blood cultures most likely will yield the growth of which of the following organisms?
- A. Actinomyces israelii
- B. Coxiella burnetii
- C. Group B Streptococcus
- D. Staphylococcus aureus
- E. Streptococcus viridans (Correct Answer)
Fever of unknown origin Explanation: ***Streptococcus viridans***
- The patient's recent **dental appointment**, the presence of an **oral organism**, and symptoms consistent with **subacute bacterial endocarditis** (fatigue, fever, weight loss, petechiae) strongly suggest *S. viridans* as the causative agent.
- *Streptococcus viridans* species are common inhabitants of the **oral flora** and are a leading cause of endocarditis following dental procedures, especially in individuals with pre-existing valvular abnormalities.
*Actinomyces israelii*
- While *Actinomyces israelii* is an oral commensal, it typically causes **actinomycosis**, a chronic, suppurative infection characterized by abscess formation and sinus tracts, often following dental procedures.
- It less commonly presents as acute or subacute endocarditis and would not typically cause the rapid progression of symptoms described.
*Coxiella burnetii*
- *Coxiella burnetii* causes **Q fever**, which can manifest as endocarditis, often associated with exposure to **farm animals** or their products.
- The patient's history lacks any such exposure, and the clinical presentation is more aligned with standard bacterial endocarditis from oral flora.
*Group B Streptococcus*
- **Group B Streptococcus** (*Streptococcus agalactiae*) is primarily known as a cause of **neonatal sepsis** and meningitis, and infections in immunocompromised adults or those with underlying conditions like diabetes.
- It is not typically associated with endocarditis following a dental procedure in an otherwise healthy adult.
*Staphylococcus aureus*
- **Staphylococcus aureus** can cause endocarditis, particularly in **intravenous drug users** or patients with prosthetic valves/indwelling lines, and often presents as a more **acute and aggressive disease**.
- While possible, the association with a recent dental procedure and the subacute course makes *Streptococcus viridans* a more likely culprit in this specific scenario.
Fever of unknown origin US Medical PG Question 8: A 55-year-old man is brought to the emergency department by ambulance after being found disoriented. He has limited ability to communicate in English but indicates that he has left flank pain and a fever. Chart review reveals that he has diabetes and sleep apnea but both are well controlled. He also has a 30-pack-year smoking history and has lost about 20 pounds since his last presentation. Physical exam reveals a bulge in his left scrotum and ultrasound reveals bilateral kidney stones. Which of the following findings is also associated with the most likely cause of this patient's symptoms?
- A. Gynecomastia
- B. Cavitary lung lesion
- C. Jaundice
- D. Increased hematocrit (Correct Answer)
- E. Aniridia
Fever of unknown origin Explanation: ***Increased hematocrit***
- This patient's symptoms (disorientation, left flank pain, fever, weight loss, smoking history, and **left scrotal bulge suggesting varicocele**) are highly suggestive of **renal cell carcinoma (RCC)**.
- The **left-sided varicocele** in an adult male is particularly significant, as it may indicate **left renal vein obstruction** by the tumor (the left testicular vein drains into the left renal vein).
- Approximately 3-10% of patients with RCC develop **erythrocytosis** due to **ectopic erythropoietin (EPO) production** by the tumor, leading to **increased hematocrit** as a paraneoplastic syndrome.
- Other paraneoplastic manifestations of RCC include hypercalcemia (PTHrP production), hypertension (renin production), and Stauffer syndrome (hepatic dysfunction).
*Gynecomastia*
- While paraneoplastic syndromes can occur with RCC, **gynecomastia** is not a common associated finding.
- Gynecomastia is more often associated with **testicular tumors** (hCG-secreting), liver disease, or certain medications.
*Cavitary lung lesion*
- While RCC can metastasize to the lungs, presenting as **nodules or masses** (cannonball metastases), a **cavitary lesion** is more characteristic of infections (e.g., tuberculosis, fungal infections) or **squamous cell carcinoma** of the lung.
- The primary presentation here points to renal pathology with paraneoplastic manifestations.
*Jaundice*
- **Jaundice** indicates **hyperbilirubinemia** and is not a direct paraneoplastic syndrome of RCC.
- It may occur with extensive metastatic disease to the liver causing biliary obstruction or in Stauffer syndrome (non-metastatic hepatic dysfunction), but this is less common than erythrocytosis.
*Aniridia*
- **Aniridia** (absence of the iris) is a rare congenital condition strongly associated with **Wilms' tumor** (nephroblastoma), a pediatric kidney cancer, as part of the **WAGR syndrome** (Wilms tumor, Aniridia, Genitourinary abnormalities, intellectual disability/Range of developmental delays).
- It is not associated with adult renal cell carcinoma.
Fever of unknown origin US Medical PG Question 9: A 34-year-old woman comes to the emergency department because of right flank pain and vomiting for 5 hours. She has had fever and chills for the past 2 days. She attended a barbecue 3 days ago, where she ate egg salad. She underwent surgery for left ovarian torsion a year ago. Menses occur at regular 28-day intervals and last 5 days. She is sexually active with 2 male partners and uses condoms inconsistently. Her only medication is an oral contraceptive pill. She is 163 cm (5 ft 4 in) tall and weighs 72.5 kg (160 lb); BMI is 27.5 kg/m2. She appears uncomfortable. Her temperature is 38.9°C (102°F), pulse is 101/min, and blood pressure is 118/76 mm Hg. The lungs are clear to auscultation. The right lower quadrant and right flank show severe tenderness to palpation. Pelvic examination shows no abnormalities. Laboratory studies show:
Hemoglobin 12.8 g/dL
Leukocyte count 14,200/mm3
Platelet count 230,000/mm3
Serum
Na+ 136 mEq/L
K+ 3.8 mEq/L
Cl- 103 mEq/L
Urea nitrogen 23 mg/dL
Creatinine 1.2 mg/dL
Urine
Blood 1+
Protein 1+
Glucose negative
Leukocyte esterase positive
Nitrites negative
RBC 6–8/hpf
WBC 80–85/hpf
Which of the following is the most likely diagnosis?
- A. Ovarian torsion
- B. Pelvic inflammatory disease
- C. Urethritis
- D. Pyelonephritis (Correct Answer)
- E. Gastroenteritis
Fever of unknown origin Explanation: ***Pyelonephritis***
- The patient presents with **fever, chills, right flank pain**, and **vomiting**, with **costovertebral angle tenderness** on examination, all characteristic of pyelonephritis.
- Urinalysis shows significant **leukocyturia (WBC 80-85/hpf)**, **leukocyte esterase positivity**, and low-grade **hematuria**, further supporting a urinary tract infection that has ascended to the kidneys.
*Ovarian torsion*
- While ovarian torsion can cause acute, severe unilateral abdominal pain and vomiting, the patient's **fever and chills**, severe **flank tenderness**, and **urinalysis findings (leukocyturia)** are inconsistent with ovarian torsion.
- A pelvic exam showing **no abnormalities** also makes ovarian pathology less likely.
*Pelvic inflammatory disease*
- PID typically presents with **lower abdominal pain**, fever, and vaginal discharge, often associated with a **positive cervical motion tenderness** or adnexal tenderness on pelvic exam.
- The patient's primary complaint of **flank pain** and the absence of pelvic exam findings or discharge make PID less likely.
*Urethritis*
- Urethritis primarily causes **dysuria, urinary frequency, and urgency** with little to no fever or flank pain unless it progresses to cystitis or pyelonephritis.
- The patient's systemic symptoms (fever, chills) and significant flank pain indicate a more severe, upper urinary tract infection.
*Gastroenteritis*
- Gastroenteritis typically presents with **nausea, vomiting, diarrhea**, and abdominal cramping, often preceded by exposure to contaminated food.
- While vomiting is present, the **lack of diarrhea**, prominent **flank pain**, fever, and especially the **pathologic urinalysis findings** (high WBCs) rule out uncomplicated gastroenteritis.
Fever of unknown origin US Medical PG Question 10: A 65-year-old man presents to the emergency department with a fever and weakness. He states his symptoms started yesterday and have been gradually worsening. The patient has a past medical history of obesity, diabetes, alcohol abuse, as well as a 30 pack-year smoking history. He lives in a nursing home and has presented multiple times in the past for ulcers and delirium. His temperature is 103°F (39.4°C), blood pressure is 122/88 mmHg, pulse is 129/min, respirations are 24/min, and oxygen saturation is 99% on room air. Physical exam is notable for a murmur. The patient is started on vancomycin and piperacillin-tazobactam and is admitted to the medicine floor. During his hospital stay, blood cultures grow Streptococcus bovis and his antibiotics are appropriately altered. A transesophageal echocardiograph is within normal limits. The patient’s fever decreases and his symptoms improve. Which of the following is also necessary in this patient?
- A. Addiction medicine referral
- B. Colonoscopy (Correct Answer)
- C. Social work consult for elder abuse
- D. Repeat blood cultures for contamination concern
- E. Replace the patient’s central line and repeat echocardiography
Fever of unknown origin Explanation: ***Colonoscopy***
- The isolation of **_Streptococcus bovis_** (now often referred to as _Streptococcus gallolyticus_) from blood cultures is highly associated with **colorectal neoplasms** or other gastrointestinal pathologies.
- A comprehensive workup, including a **colonoscopy**, is crucial to identify the underlying source of bacteremia and screen for malignancy.
*Addiction medicine referral*
- While the patient has a history of **alcohol abuse**, there is no indication that his current presentation or the discovery of _Streptococcus bovis_ necessitates an immediate addiction medicine referral as the primary next step from an acute management perspective.
- Addiction management is an important long-term consideration but not the most pressing diagnostic need.
*Social work consult for elder abuse*
- The patient lives in a **nursing home** and has a history of delirium and frequent hospitalizations for ulcers, which can be concerning. However, there are no specific signs or symptoms presented in this vignette that directly suggest elder abuse as the reason for his current _S. bovis_ bacteremia, making it a less immediate priority compared to diagnosing the source of infection.
- While a general social work assessment might be beneficial for a vulnerable patient in a nursing home, it is not the most necessary intervention based on the microbiological finding.
*Repeat blood cultures for contamination concern*
- The question states that **_Streptococcus bovis_** blood cultures "grew" and antibiotics were "appropriately altered," suggesting a confirmed infection rather than contamination.
- Furthermore, _S. bovis_ is a known pathogen with specific associations and is not typically considered a common contaminant in the same vein as coagulase-negative staphylococci.
*Replace the patient’s central line and repeat echocardiography*
- The patient's **transesophageal echocardiogram (TEE) was normal**, ruling out endocarditis as the source of bacteremia in this case.
- There is no mention of a central line, and even if there were, the normal TEE and the specific pathogen (_S. bovis_) point towards a gastrointestinal source.
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