Differential Diagnosis Consider white blood cell (WBC) proliferation in patients with infections and other inflammatory states, such as autoimmune disorders. An increase in neutrophils commonly occurs during a bacterial infection. Continue Reading Lymphocytosis can be found in tuberculosis (TB), acute bowel infections, and infectious mononucleosis. Monocyte count is usually increased along with an elevated lymphocyte…
Differential Diagnosis Hashimoto thyroiditis Ablative hypothyroidism Continue Reading Infantile hypothyroidism Euthyroid sick syndrome Dangerous Situations Early diagnosis and treatment of infantile hypothyroidism with thyroid hormone prevents irreversible mental retardation and growth impairment. Commonly Encountered Situations Hashimoto thyroiditis accounts for about 90% of all hypothyroidism cases. Suggested Additional Lab Testing Hashimoto thyroiditis T4 is normal and…
Differential Diagnosis An artifactually high value can occur with hemolysis of red blood cells (RBCs) during venipuncture, especially if there is prolonged tourniquet use and fist clenching during the drawing of the blood or at any time prior to potassium measurement. An artifactually high potassium value can also occur when there are greater than 1,000,000…
Differential Diagnosis Excessive parenteral sodium administration in an unconscious patient whose thirst mechanism is absent. Excessive use of diuretics or other drugs leading to water loss in the patient who cannot compensate by intake of water. Continue Reading Diabetes insipidus may be central (neurogenic), acquired nephrogenic, or congenital nephrogenic. Mineralocorticoid or glucocorticoid excess from primary…
Differential Diagnosis Primary hyperparathyroidism Excess parathyroid hormone (PTH) secretion from a single parathyroid adenoma, hyperplasia of the parathyroids, parathyroid carcinoma Malignant tumorsContinue Reading Especially tumors of the breast, lung, and kidney in which hypercalcemia may occur from direct bony metastasis Multiple myeloma that directly degrades bone Other cancers that produce hypercalcemia by inducing PTH secretion…
Differential Diagnosis Acute pancreatitis Chronic pancreatitis Continue Reading Pancreatic carcinoma Dangerous Situations Pancreatic carcinoma is associated with a very short life span following diagnosis. Commonly Encountered Situations Acute pancreatitis is the most common of the disorders listed. Suggested Additional Lab Testing Acute pancreatitis Tests to assess alcohol intake and triglyceride levels are useful. Most common…
Differential Diagnosis Essential thrombocythemia with platelet count typically greater than 600,000/µL Reactive thrombocytosis from: Continue Reading inflammation infection malignancy iron deficiency anemia acute blood loss rebound from marrow suppression or immune thrombocytopenia post-splenectomy Dangerous Situations Platelet counts greater than 1,000,000/µL are worrisome for acute thrombotic events. Elevated platelet count with poorly functioning platelets does not…
Differential Diagnosis Pt has slightly, moderately, or extremely elevated level of blood lead. The three levels have different clinical outcomes and recommended treatment. Dangerous Situations Blood lead levels greater than 70 µg/dL: treat as a medical emergency Continue Reading Levels 45-69 µg/dL: give immediate treatment with chelation therapy.
Differential Diagnosis Pituitary cause for Cushing syndrome Adrenal cause for Cushing syndrome Continue Reading Ectopic ACTH secretion as a cause for Cushing syndrome One of many conditions that produce a high cortisol level wtihout manifestations of Cushing syndrome Suggested Additional Lab Testing Pituitary Cushing syndrome No ACTH suppression and, therefore, no cortisol suppression in the…
Differential Diagnosis Loss of renal tubular concentrating ability Overhydration Continue Reading Diabetes insipidus Unsatisfactory collection of specimen producing low specific gravity Suggested Additional Lab Testing Serum or plasma BUN and/or creatinine as initial assessment for renal disease Repeat urinalysis to assess whether unsatisfactory collection (most likely dilution with water) produced the low specific gravity Tests…
