Cruising for a bruising? An asymptomatic patient with low platelets

Clinical pearls for frontline PCPs

A 65-year-old male presented for his annual exam.

The medical assistant (MA) checking the patient in remarked that he is asymptomatic except for reporting being a little bit more fatigued than usual. Lab work included a thyroid-stimulating hormone test, which was normal, and a complete blood count that showed a white blood cell count (WBC) of 6.5 with a normal differential, a hemoglobin of 14 and a platelet count of 95,000.

The patient denies any bleeding history or a family history of bleeding disorders. He has not had any recent illnesses, recent hospitalizations or exposure to heparin. A complete medical history shows no history of liver disease, autoimmune disorders, immune deficiency disorders, malignancies, organ transplant or heart valve surgery. He also denies any history of hematochezia, epistaxis or bruising, in addition to no weight loss, fevers or pain.

The patient is a nonsmoker and drinks two glasses of wine per week or less, with no other alcohol use. His medications include lisinopril 10 mg daily and venlafaxine 150 mg twice daily. He denies taking any aspirin, NSAIDs or other over-the-counter medication. He received COVID-19 and influenza vaccines about 1 month before this visit. His hobbies include water skiing and mountain biking.

A review of the patient’s chart shows that he had a CBC that was normal — including a platelet count of 180,000 — about 5 years ago before a hernia surgery. He received treatment at an urgent care facility about a year ago, where he had a normal CBC, except for a platelet count of 110,000.

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A physical examination showed a normal, healthy-appearing 65-year-old man. No evidence of bleeding, ecchymosis, petechiae, lymphadenopathy or heart murmurs were noted.

A liver exam did not show evidence of an enlarged liver. A repeat CBC showed a hemoglobin of 14.2, a WBC of 6.8 with a normal differential and a platelet count was 95,000.

A call to the pathologist asking her to review the slide showed no evidence of large or clumped platelets.

The physician decided to repeat the CBC in about 6 weeks, and it returned showing hemoglobin of 13.8, a WBC of 6.5 with a normal differential and a platelet count of 90,000.

Philip A. Bain

The physician told the patient he was unsure about the cause of the persistently low platelets and recommended that he be seen by a hematologist to sort out the cause. The hematologist believed that the patient was in no immediate danger and that he should have his platelets rechecked every 3 to 6 months.

The primary care physician continued to check the CBC every 3 months. It showed a gradual decline in his platelet count with the other two cell lines remaining normal over the course of the next 12 to 15 months. The patient was scheduled for a total hip replacement, and his preoperative labs showed a platelet count of 55,000. The patient was seen again by the hematologist who believed that he likely could tolerate the surgery but that the platelet count had become an emerging concern. The hematologist made the diagnosis of immune-mediated thrombocytopenia and recommended treatment of the disorder with steroids prior to any consideration of his elective surgery. The patient completed an 8-week course of steroids, and his platelet count improved to 130,000. At that point, the hematologist believed that the patient could go ahead with the elective surgery.

Lessons learned

1. Thrombocytopenia is a relatively common finding in primary care. A normal platelet count is 150,000 to 450,000. Thrombocytopenia is diagnosed when the platelet count is less than 150,000. Platelet counts 100,000 to 150,000 are called mild thrombocytopenia. Counts of 50,000 to 90,000 are termed moderate thrombocytopenia, and a platelet count of less than 50,000 is generally referred to as severe thrombocytopenia.
2. Patients with platelet counts in the mild range (100,000 to 150,000) are usually asymptomatic without evidence of bleeding, petechiae, purpura or ecchymosis. Patients with platelet counts in the 20,000-to-50,000 range often will show signs of ecchymosis, petechiae or purpura. When the platelet count drops below 50,000, it is usually advised that the patient postpone elective surgery, if possible, until the cause and treatment options of the low platelet count are considered. Patients with platelet counts of less than 10,000 are at high risk for serious bleeding complications, including internal bleeding.
3. The main causes of a low platelets include decreased production of platelets, increased destruction of platelets, splenic sequestration of platelets, dilutional thrombocytopenia and clumping (usually termed pseudothrombocytopenia).
4. In general, low platelets can be associated with bleeding or bruising, but certain causes of low platelets are associated with bleeding and thrombosis. Examples include antiphospholipid syndrome, heparin-induced thrombocytopenia and the thrombotic microangiopathies like thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS).
5. Patients with isolated low platelets (ie, have normal WBC and hemoglobin) without significant systemic illness usually have immune thrombocytopenia or medication-related thrombocytopenia.
6. Immune thrombocytopenia is a diagnosis of exclusion.
7. An important first step in evaluating stable outpatients with mild to moderate thrombocytopenia is to rule out pseudothrombocytopenia due to clumping of platelets. This can be done by asking the lab to collect blood in a heparin sodium citrate tube to rule out clumping effect.
8. It is important for PCPs to always repeat a CBC if mild to moderate thrombocytopenia is found before pursuing a hematology consultation to confirm that it is persistent.
9. The next step is to sort out if the low platelet condition is acute or chronic by reviewing old CBCs.
10. Common emergency causes generally require hospitalization to prevent further complications and hasten diagnosis. These include heparin-induced thrombocytopenia, one of the thrombotic microangiopathies (TTP, HUS), hemolysis, significantly abnormal liver function tests and hemolysis, elevated liver enzymes, low platelet count in pregnant patients. Common nonemergency causes include immune thrombocytopenia, medication-associated thrombocytopenia and liver disease.

References :

• Gauer RL, et al. Am Fam Physician. 2022;106(3):288-298.
• Platelet disorders: Thrombocytopenia. Available at: https://www.nhlbi.nih.gov/health/thrombocytopenia. Accessed March 18, 2025.
• Jinna S, et al. Stat pearls: Thrombocytopenia. Available at: https://www.ncbi.nlm.nih.gov/books/NBK542208/. Updated July 4, 2023. Accessed March 3, 2025.
• Watto M. #167 Common CBC abnormalities with Mary Kwok MD: The curbsiders internal medicine podcast. Available at: https://thecurbsiders.com/curbsiders-podcast/167-cbc. Published Aug. 19, 2019.