Based on NIH | In a patient with endometrial cancer who develops low blood pressure, which laboratory and imaging test results are most useful to identify causes such as hemorrhage, sepsis, or dehydration?

Low blood pressure (hypotension) in someone with endometrial cancer can arise from several urgent causes most commonly hemorrhage (bleeding), sepsis (severe infection), or dehydration with overlapping signs. The most useful approach combines targeted laboratory panels and imaging to quickly narrow the diagnosis and guide treatment. Below is a practical, evidence‑informed checklist of what to order and how to interpret results for each suspected cause.

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Initial Priorities

• Assess vitals and perfusion: Blood pressure, heart rate, respiratory rate, oxygen saturation, temperature, mental status, and urine output. Low blood pressure with fast heart rate and reduced urine can occur in hemorrhage, sepsis, and dehydration, and signals shock risk. ^{[1] [2]}
• Draw broad labs early: CBC, basic metabolic panel (electrolytes, BUN/creatinine), lactate, blood cultures (before antibiotics if infection suspected), coagulation panel, and type & crossmatch if bleeding is possible. These help triage to hemorrhage vs infection vs dehydration. ^{[3] [4] [5]}
• Start rapid imaging based on context: Focused ultrasound (including FAST exam) for intra‑abdominal/pelvic fluid, pelvic ultrasound, and CT abdomen/pelvis for suspected internal bleeding or complications; chest imaging if respiratory source or metastasis is suspected. Ultrasound can also support hypovolemia assessment. ^{[6] [7] [8]}

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Key Lab Markers by Suspected Cause

Hemorrhage (bleeding)

• CBC (hemoglobin/hematocrit, platelets): Falling hemoglobin/hematocrit over serial checks suggests active or recent blood loss; platelet count informs coagulopathy and bleeding risk. ^[2]
• Coagulation panel (PT/INR, aPTT, fibrinogen): Coagulopathy may accompany severe bleeding or consumptive states. ^[9]
• Type & screen/crossmatch: Prepare for transfusion when hemorrhage is likely. ^[9]
• Serum lactate: Elevated lactate indicates tissue hypoperfusion from shock; increased levels warrant urgent resuscitation and reassessment. ^[5]

Sepsis (severe infection)

• Blood cultures (ideally before antibiotics): Identify bloodstream infection and guide targeted therapy. ^[5]
• Serum lactate (initial and repeat): Elevated lactate correlates with severity and guides resuscitation; remeasurement within hours is recommended to track response. ^[5]
• Procalcitonin (PCT): Higher levels can support a bacterial source and sepsis severity assessment; useful for antibiotic decision‑making and monitoring. ^{[10] [11]}
• CBC with differential: Leukocytosis or leukopenia can occur in sepsis, and platelet changes may suggest disseminated intravascular coagulation. ^[1]
• Basic metabolic panel and kidney function: Acute kidney injury and electrolyte disturbances are common in sepsis and influence fluid/vasopressor decisions. ^[12]
• Urinalysis and urine culture: Check for urinary sources of infection, especially with decreased urine output. ^[12]

Dehydration (volume depletion)

• Basic metabolic panel (sodium, potassium, chloride, bicarbonate), BUN/creatinine: Elevated BUN/creatinine ratio and hypernatremia may point to dehydration; potassium can be abnormal with GI losses. ^{[12] [4]}
• Urine tests (specific gravity, ketones): Concentrated urine (high specific gravity) supports dehydration and prerenal state. ^[12]
• Vital signs and physical exam correlation: Tachycardia, dry mucous membranes, poor skin turgor, and reduced urine output are common in dehydration‑related hypotension. ^[13]

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Imaging to Pinpoint the Source

When bleeding is suspected

• FAST (Focused Assessment with Sonography in Trauma) or point‑of‑care ultrasound: Rapidly checks for free fluid (blood) in the abdomen/pelvis; helps differentiate hypovolemic shock from other types in the emergency setting. ^{[6] [2]}
• Pelvic ultrasound: Evaluates the uterus, adnexa, and pelvis for masses, hematomas, or fluid collections; essential in gynecologic contexts. ^{[7] [8]}
• CT abdomen/pelvis with contrast (as tolerated): Defines bleeding source, extent, and associated complications; useful to plan interventional radiology or surgery. ^{[9] [8]}

When infection/sepsis is suspected

• Chest x‑ray or chest CT: Screens for pneumonia or pulmonary sources if respiratory symptoms are present. ^[3]
• CT abdomen/pelvis: Looks for abscesses, bowel perforation, urinary obstruction, or infected collections after cancer surgery or treatment. ^[7]
• Targeted ultrasound: Identifies fluid collections amenable to drainage and helps guide procedures. ^[6]

When dehydration is suspected

• Ultrasound for IVC (inferior vena cava) collapsibility: Can help estimate volume status; supportive data alongside clinical judgment since no single test perfectly predicts fluid responsiveness. ^[14]
• Limited imaging: Often not required if labs and clinical picture clearly show dehydration; use selectively to rule out other causes or complications. ^[13]

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Practical Decision Pathway

1. Immediate labs for any hypotensive episode: CBC, BMP (electrolytes, BUN/Cr), lactate, coagulation panel; add blood cultures if infection is possible; type & crossmatch if bleeding is likely. Elevated lactate and abnormal vitals signal shock risk and the need for aggressive resuscitation. ^{[5] [4] [2] [1]}
2. Imaging choice guided by suspicion: FAST/pelvic ultrasound and CT for bleeding; chest imaging and CT abdomen/pelvis for suspected sepsis or intra‑abdominal infection; point‑of‑care ultrasound for volume status. ^{[6] [9] [7] [8]}
3. Serial reassessment: Repeat hemoglobin/hematocrit to track bleeding, remeasure lactate within hours in suspected sepsis, and monitor kidney function and electrolytes in dehydration; adjust therapy accordingly. ^{[5] [2] [12]}

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Quick‑Reference Tables

Table 1. Lab Patterns Suggesting Hemorrhage, Sepsis, or Dehydration

Test	Hemorrhage	Sepsis	Dehydration
Hemoglobin/Hematocrit (CBC)	Falling Hgb/Hct over time suggests blood loss	Variable; may be normal or low	Often normal unless concurrent bleeding
Platelets	May be low with consumptive coagulopathy	Can drop with DIC	Typically normal
PT/INR, aPTT, Fibrinogen	Coagulopathy can be present	Coagulopathy/DIC possible	Usually normal
Lactate	Elevated in shock from hypoperfusion	Elevated; track serially	Mildly elevated if severe hypoperfusion
WBC (CBC with differential)	Stress leukocytosis possible	High or low WBC; left shift	Often normal
Procalcitonin	Not characteristic	Elevated supports bacterial sepsis	Not elevated due to dehydration
BUN/Creatinine	Rise if prerenal from blood loss	Rise with AKI from sepsis	Elevated BUN/Cr ratio common
Electrolytes (Na, K)	Variable	Disturbances common	Hypernatremia and K abnormalities possible
Urinalysis		Check for infection	High specific gravity suggests dehydration

References: CBC/coagulation for hemorrhage and shock evaluation. ^[2] Lactate trending in sepsis care. ^[5] Procalcitonin utility for bacterial sepsis. ^{[10] [11]} Dehydration workup with electrolytes, kidney function, urine tests. ^[12] Basic metabolic panel components. ^[4]

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Table 2. Imaging Choices by Clinical Question

Clinical question	Preferred imaging	What it shows
Is there internal bleeding?	FAST/POCUS; CT abdomen/pelvis	Free fluid, hematoma, bleeding source
Is there a pelvic source?	Pelvic ultrasound; CT	Uterine/adnexal masses, collections
Is infection causing hypotension?	CT abdomen/pelvis; chest x‑ray/CT	Abscesses, pneumonia, perforation
Is the patient volume depleted?	Ultrasound IVC assessment	Supports hypovolemia when combined with exam

References: Ultrasound to differentiate shock types. ^[6] CT and ultrasound roles in gynecologic and abdominal evaluation. ^{[7] [8]} FAST and imaging in hypovolemic shock. ^[2]

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Putting It All Together for Endometrial Cancer

• Endometrial cancer care often involves surgery and oncologic treatments, which can predispose to post‑operative bleeding, infected collections (abscess), and treatment‑related dehydration; use imaging and labs tailored to these risks. ^[7]
• Transvaginal/pelvic ultrasound remains central in gynecologic evaluation and can quickly detect pelvic fluid or masses; MRI/CT are complementary for staging or detecting complications and may be crucial if hypotension raises concern for internal bleeding or infection. ^[7]
• In hypotension with suspected sepsis, obtain blood cultures early, measure lactate and repeat within hours, and consider procalcitonin to support bacterial infection decisions; immediate antibiotics and fluids are typically warranted while diagnostic confirmation proceeds. ^{[5] [10] [11]}

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Key Takeaways

• Hemorrhage: Serial CBC (falling hemoglobin), coagulation panel, type & crossmatch, elevated lactate; confirm with FAST/pelvic ultrasound and CT to locate bleeding. ^{[2] [5]}
• Sepsis: Blood cultures before antibiotics, elevated lactate with remeasurement, possible high procalcitonin, CBC changes; CT/ultrasound to find abscess or infected source; chest imaging for pulmonary causes. ^{[5] [10] [11] [1]}
• Dehydration: Electrolytes and kidney function abnormalities (BUN/Cr), concentrated urine; ultrasound can support hypovolemia assessment; treat with fluids and correct electrolytes while ruling out other causes. ^{[12] [4] [13]}

Early, goal‑directed testing and imaging paired with prompt resuscitation are essential because no single test perfectly distinguishes these causes, and patients can have more than one at the same time. ^{[14] [9]}