Hematologic and Renal Emergencies

Blood clotting & coagulopathies

The body stops bleeding with two systems working together. The first is platelet aggregation, the fastest and initial response, in which platelets gather at the site of the injury. The second is the clotting factors, proteins made in the liver that form the more stable, lasting clot. A coagulopathy is any abnormality of clotting. The form most relevant to the EMT is blood that clots too slowly, which produces uncontrolled bleeding, and its most common cause is a prescribed blood-thinning medication.

Blood thinner medications

Blood thinners fall into two groups according to which part of the clotting process they interfere with. The table below sets out the two types, their mechanisms and common examples.

Table 28.1Blood thinner medications

Always ask trauma patients specifically whether they take a blood thinner. In a patient on one of these medications, even a seemingly minor injury, such as a minor bump to the head, carries a genuinely elevated risk of bleeding; significant intracranial bleeding can follow a mechanism that looks trivial. Notify the hospital early when a trauma patient takes a blood thinner.

Anemia & sickle cell disease

Anemia is a deficiency in the number of red blood cells (RBCs), and how it presents depends on how quickly it developed. Acute anemia, from trauma or a sudden GI bleed, produces the signs of shock rapidly. Chronic anemia, from heavy menstrual periods or slow GI blood loss, produces pallor, fatigue and pale conjunctiva, and the signs of shock appear only late.

Sickle cell disease (SCD) is an inherited defect of hemoglobin that gives the red blood cells an abnormal shape; it is most common in patients of African descent. The abnormally shaped cells clump together and block small vessels, a process called sludging, and sludging produces the complications of the disease. A sickle cell crisis, or pain crisis, causes severe pain in the arms, legs, chest or abdomen. Acute chest syndrome causes shortness of breath (SOB), chest pain and hypoxia. Sludging can also cause priapism, stroke and jaundice.

Sickle cell trait is not the same as sickle cell disease. Trait carriers usually have no complications and have a normal lifespan. In a patient with the disease, never assume that a presentation is "just another pain crisis," because the risk of infection, stroke and a chest crisis is high at the same time.

UTIs, kidney stones & catheters

Urinary tract infections (UTIs) are the most common disease of the renal and urinary system. They are bacterial and are usually limited to the bladder. Left untreated, the infection can ascend to the kidney, where it is called pyelonephritis; the patient then has unilateral flank pain and is sicker overall. Untreated pyelonephritis can become life-threatening by progressing to sepsis, especially in the elderly. Kidney stones cause severe unilateral flank pain that radiates to the groin as the stone descends the ureter.

Renal failure & dialysis

Renal failure may be acute or chronic. Acute renal failure, from causes such as shock or a toxic ingestion, is sometimes recoverable if the cause is corrected quickly. Chronic renal failure, from causes such as diabetes and hypertension, is progressive and often irreversible. End-stage renal disease (ESRD) requires dialysis, which takes one of the two forms set out in the table below.

Table 28.2Renal failure & dialysis

Never take a blood pressure on the arm with a fistula. A properly functioning A-V fistula has a palpable vibration, called a thrill.

ESRD emergencies

The patient with ESRD who misses dialysis presents much like a patient in congestive heart failure (CHF), because fluid the kidneys cannot remove overloads the circulation; the signs are shortness of breath and peripheral edema. The more dangerous consequence is elevated potassium, which can cause fatal dysrhythmias. Cardiac arrest in an ESRD patient may not respond to standard defibrillation.

Dialysis itself produces complications. A fistula may bleed or clot; for bleeding, use direct pressure, and avoid a tourniquet unless the bleeding is life-threatening — the fistula is the patient's lifeline for dialysis and is worth preserving where it safely can be. Peritoneal dialysis can lead to peritonitis, which presents with abdominal pain, fever and cloudy dialysis fluid that resembles chicken broth. Transport the drained bag with the patient so that the fluid can be tested.

Kidney transplant patients

The kidney is the most commonly transplanted organ. A transplant patient must take immunosuppressant medications for life to prevent rejection of the new kidney, and those same drugs make the patient more susceptible to serious infections, including sepsis.