Written before any result for NU610 Unit 4, this memo estimates how likely a calf vein clot is in a composite traveler, picks a matching first test, and plans each outcome. Searches like "nu 610 unit 4 assignment example", "nu610 unit 4 sample" and "nu610 unit 4 example" land here.
Diagnostic Reasoning Memo: Does This Left Calf Hold a Deep Vein Clot? Pretest Probability Committed Before Any Result
[Student Name]
Purdue University Global
NU610: NP III Clinical - Primary Care Focus
Unit 4 Diagnostic Reasoning Memo
[Instructor Name]
[Date]
The patient is composite; dates, times and measurements are bracketed, and treatment choices are left as bracketed composites.
To: [Supervising clinician], clinical file From: [Writer], nurse practitioner student Date: [date], [time] Subject: Does she have a deep vein thrombosis of the left calf or thigh?
Case Summary
[39]-year-old woman, [three] days of left calf pain and swelling, starting the day after a [nine-hour] flight. Left calf circumference [3 cm] greater than right at [10 cm] below the tibial tuberosity; pitting edema of the left ankle and calf; tenderness along the deep veins of the calf. Takes [an estrogen-containing contraceptive]; no prior clot, no cancer, no recent surgery, no immobilization, no family history of clotting disorders known. No chest pain, no shortness of breath, heart rate [82], oxygen saturation [98 percent] on room air. No trauma; she did not exercise unusually before or after the flight.
Pretest Probability
Wells criteria for deep vein thrombosis, scored one item at a time:
1. Active cancer: no, 0.
2. Paralysis, paresis or recent cast of the leg: no, 0.
3. Recently bedridden three days or more, or major surgery within twelve weeks: no, 0.
4. Localized tenderness along the deep venous system: yes, 1.
5. Entire leg swollen: no, calf and ankle only, 0.
6. Calf swelling at least 3 cm greater than the other side: yes, 1.
7. Pitting edema confined to the symptomatic leg: yes, 1.
8. Collateral superficial veins, not varicose: no, 0.
9. Previously documented deep vein thrombosis: no, 0.
10. Alternative diagnosis at least as likely: no, subtract 0.
Total: [3]. In the two-level version of the rule, a score of two or more places her in the likely category (Wells et al., 2003).
The score does not capture the two facts that worry me most, the estrogen-containing contraceptive and the long flight, neither of which appears among its items. Both raise my concern above what the number alone suggests. They do not change her category, which is already likely, but they reinforce it.
Choosing the First Test
Pretest probability decides the first test. For patients with a low pretest probability, a sensitive D-dimer is a reasonable first step, because a negative result can rule out a clot without imaging. For patients in a likely or high category, the American Society of Hematology guideline suggests starting with ultrasound rather than a D-dimer, because a negative D-dimer in this group does not lower the probability enough to stop, and a positive one adds nothing, since imaging will be needed anyway (Lim et al., 2018).
I am therefore ordering compression ultrasound of the left leg, requesting whole-leg imaging if available so the calf veins are examined as well as the proximal veins. I am not ordering a D-dimer first.
Differential
Ruptured popliteal (Baker's) cyst: could cause calf pain and swelling; favored by a history of knee arthritis or a sudden onset with knee swelling, neither present. Ultrasound would show it. Calf muscle strain or tear: favored by a clear moment of onset during exertion and focal tenderness in the muscle rather than along the veins; she reports no exertion. Superficial thrombophlebitis: favored by a tender, palpable cord in a superficial vein; none is felt, but ultrasound would show it and look for extension into the deep system. Cellulitis: favored by warmth, redness and fever; she has none.
Plan by Result
If the ultrasound shows a deep vein thrombosis: begin anticoagulation with [a bracketed composite regimen] after checking kidney function and bleeding risk, discuss stopping the estrogen-containing contraceptive and alternatives, and assess for symptoms of pulmonary embolism at every contact.
If whole-leg ultrasound is negative: deep vein thrombosis is effectively excluded, and I will return to the differential, with a focus on a muscle cause or a cyst the report may mention. If only the proximal veins were imaged and they are negative, I will follow the guideline's approach of either a D-dimer or a repeat proximal ultrasound in about [one] week, rather than stopping at a single negative proximal scan in a likely patient (Bates et al., 2012).
If the scan is technically limited, for example by swelling or body habitus: repeat ultrasound within [24 to 48] hours or consider alternative imaging, and discuss interim anticoagulation with the supervising clinician given her likely category.
In every branch, she knows to seek emergency care at once for chest pain, shortness of breath or coughing blood.
Time Stamp
This memo was completed at [14:10], [twenty] minutes after the ultrasound was requested and before any result was available.
References
Bates, S. M., Jaeschke, R., Stevens, S. M., Goodacre, S., Wells, P. S., Stevenson, M. D., Kearon, C., Schunemann, H. J., Crowther, M., Pauker, S. G., Makdissi, R., & Guyatt, G. H. (2012). Diagnosis of DVT: Antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest, 141(2 Suppl.), e351S-e418S. https://doi.org/10.1378/chest.11-2299
Lim, W., Le Gal, G., Bates, S. M., Righini, M., Haramati, L. B., Lang, E., Kline, J. A., Chasteen, S., Snyder, M., Patel, P., Bhatt, M., Patel, P., Braun, C., Begum, H., Wiercioch, W., Schünemann, H. J., & Mustafa, R. A. (2018). American Society of Hematology 2018 guidelines for management of venous thromboembolism: Diagnosis of venous thromboembolism. Blood Advances, 2(22), 3226-3256. https://doi.org/10.1182/bloodadvances.2018024828
Wells, P. S., Anderson, D. R., Rodger, M., Forgie, M., Kearon, C., Dreyer, J., Kovacs, G., Mitchell, M., Lewandowski, B., & Kovacs, M. J. (2003). Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. New England Journal of Medicine, 349(13), 1227-1235. https://doi.org/10.1056/NEJMoa023153
How this NU610 Unit 4 example is structured
The subject line poses the question as a yes-or-no clinical proposition. The case summary follows, trimmed to the findings the probability rule and the differential need. Next comes the pretest section, the heart of the memo: the Wells items scored one by one, the total, the category it implies, and a sentence on what the score cannot capture, here the contraceptive and the flight, which raise concern without appearing among the items. The test-selection section explains why this category rules out starting with a D-dimer. The differential section keeps a ruptured popliteal cyst and a calf muscle strain alive, with the findings that would favor each. The three-branch plan is written as conditional statements, each ending in an action. The memo's last line gives the time it was completed relative to the scan request, so its reader can confirm it preceded any result.
Get an NU610 Unit 4 example written to your instructions
Upload your NU610 Unit 4 case along with the memo instructions and rubric. On a first request at no charge, the memo is returned within 24-48h, committing to a probability category before any result, showing the scoring item by item, and planning an action for every outcome, whether the result comes back positive, negative or inconclusive. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
NU610 Unit 4 questions, answered
Which clinical decision rule should the memo use?
The one validated for the question your case raises: Wells for deep vein thrombosis, Wells or the PERC rule for pulmonary embolism, the Canadian CT head rule for minor head injury, and so on. Name the rule, show every item, and state its limits for this patient. If no validated rule fits, estimate probability from the history and say so.
Can I state pretest probability as a number?
A category is usually safer than a precise percentage unless the rule you used publishes one. Low, intermediate or high, or unlikely versus likely, with the source of the category named, lets a grader follow your reasoning without asking where an exact figure came from. Where you do give a number, cite the study behind it.
Why does the memo end before the result?
Because that is the point of the exercise: showing that the test choice and the response to each outcome were settled in advance. Some sections release results afterward and ask for an addendum. If yours does, keep the original memo unchanged and add a dated section comparing the result with what each branch predicted.