Medical Emergencies Study Guide for the CEN

Immunodeficiencies

Primary immunodeficiency diseases are genetic disorders that cause dysfunction in the body’s immune system. Effects include defective antibodies, low levels of antibodies, and defects in immune cells such as T-cells and B-cells. Examples of primary immunodeficiencies include common variable immunodeficiency, congenital agammaglobulinemia, selective IgA deficiency, and Wiskott-Aldrich syndrome. Primary immunodeficiencies greatly increase the patient’s risk of both minor and life-threatening infections.

Assessment

The primary symptoms of immunodeficiencies are repeated and severe infections. Areas of the body most commonly infected include the ears, sinuses, lungs, and bronchi. The patient may experience widespread lymphadenopathy. Splenomegaly is sometimes also present. Many patients develop granulomas, with the most common sites being their skin, lungs, lymph nodes, and liver. Gastrointestinal symptoms of immunodeficiencies include nausea, vomiting, diarrhea, abdominal pain, and weight loss. Some patients experience polyarthritis (arthritis in at least five different joints) due to widespread inflammation.

Diagnosis is primarily guided by a physical exam, family history (since they are genetic conditions), and various lab tests, which include:

complete blood count
serum antibodies
serum immunoglobulin

Treatment

The primary treatment is the replacement of immunoglobulins that are missing due to the specific disorder. This helps the immune system to function more normally but is not a cure—the immunoglobulins need to be infused regularly, either intravenously or subcutaneously. The patient may be prescribed long-term antibiotics for severe or repeated infections. Lifestyle changes include washing hands thoroughly, wiping down high-touch surfaces, cooking food thoroughly, wearing a medical-grade mask in public (especially indoors and in the winter), and avoiding large crowds.

Renal Failure

Renal failure can be considered acute, chronic, or acute on chronic—an exacerbation of underlying kidney disease. Chronic kidney disease is graded in five stages: I, II, III, IV and V (end stage kidney failure). The kidneys lose their ability to remove fluids, toxins, and metabolic waste products from the body. Acute renal injury or failure is caused by excessive use of NSAIDs or other medications such as lithium, sepsis, kidney infection, kidney stones, or trauma to the kidneys. Chronic renal failure is caused by uncontrolled diabetes, uncontrolled hypertension, autoimmune conditions such as lupus that attack the kidneys, polycystic kidney disease, and glomerulonephritis.

Assessment

The early stages of kidney disease are usually asymptomatic. As the renal disease progresses, the patient may notice decreased urine output, fatigue, and mild swelling in their extremities or face. In the moderate stages of kidney failure, patients may notice nausea and vomiting, muscle cramps, decreased appetite, paleness, and increased thirst. In end stage kidney disease or acute renal failure, the patient can experience shortness of breath, become anuric, develop bone pain, become confused, develop severe systemic swelling, have seizures, and develop cardiac arrhythmias due to electrolyte abnormalities.

Lab work will include a serum creatinine w/ GFR to assess kidney function, a comprehensive metabolic panel, and complete blood count. An ECG will be obtained to evaluate the patient’s cardiac rhythm. The severity of a patient’s chronic kidney disease is evaluated based on their estimated GFR:

Stage 1—eGFR 90 or more
Stage 2—eGFR 60 to 89
Stage 3a—eGFR 45 to 59
Stage 3b—eGFR 30 to 44
Stage 4—eGFR 15 to 29
Stage 5/end stage renal disease—eGFR <15

Treatment

In the case of an acute kidney injury, the patient will receive IV fluid boluses and be maintained on IV fluids. Any nephrotoxic agents such as NSAIDs, ACE inhibitors, ARBS, rifampin, cyclosporins, and tacrolimus will be stopped immediately. The patient’s blood pressure will be tightly controlled to reduce stress on the kidneys. Any underlying cause will be addressed as well. For instance, the patient will receive antibiotics if they have a kidney infection. An obstructing kidney stone can be broken up using extracorporeal shock wave lithotripsy, laser lithotripsy and a stone basket extraction via ureteroscopy or a percutaneous nephrolithotomy if the stone is too large to remove through the ureter. The patient’s electrolytes will be closely monitored and managed to reduce stress on the kidneys.

In end stage chronic renal disease, dialysis or renal transplants are the only treatment options. The patient will need to limit their fluid intake and follow a renal-friendly diet that limits potassium. Dialysis can be performed as hemodialysis at a facility several days per week or peritoneal dialysis can be managed at home on a nightly basis by the patient. Kidneys can sometimes recover in cases of acute renal failure and dialysis will only be needed for a period of weeks or months, instead of for the rest of the patient’s life or until they receive a kidney transplant if eligible.

Sepsis

Sepsis is a life-threatening systemic immune response to an infection—usually bacterial or fungal. The immune response is known as SIRS—short for systemic inflammatory response syndrome. When SIRS combines with a localized or systemic infection, it becomes sepsis. Left unchecked, sepsis can progress into severe sepsis, septic shock, and eventually multi-symptom organ failure, which can lead to death. Sepsis can become life-threatening in a matter of hours. Early identification and treatment is key to saving lives. Many hospitals have a system-wide sepsis alert, which notifies the healthcare provider/nursing staff when the patient begins exhibiting symptoms that are consistent with SIRS.

Assessment

The patient must experience at least two of the following symptoms to be diagnosed with SIRS:

tachypnea or PaCO2 <32 mmHg
temperature >38 degrees Celsius or rectal temperature <36 degrees Celsius
tachycardia (HR >100)
leukocytosis (WBC >12,000) or leukopenia (WBC <4,000)

To be diagnosed with sepsis, the patient must have SIRS and at least one of the following indicators:

changes in mental status (e.g., confusion or drowsiness)
hypoxemia (without underlying lung disease)
elevated lactic acid
decreased urinary output: less than 30 mL/hour or 5 mL/kg/hr for at least one hour

Severe sepsis is the next step in the progression of sepsis. The patient must demonstrate signs of both SIRS and sepsis as well as hypotension (SBP <100 or MAP <65) or signs of increasing organ dysfunction (such as increased creatinine) due to poor perfusion.

If the treatment for septic shock is ineffective or insufficient, the patient will become more hypotensive and develop symptoms of lactic acidosis (confusion, fatigue, abdominal pain, hypotension, hypothermia, diarrhea, nausea, and vomiting).

As perfusion to the organs worsens, the patient can eventually develop multi-organ dysfunction syndrome (MODS). The patient’s cardiac output decreases, ARDS (acute respiratory distress syndrome) begins, and renal injury or failure can occur after tubular or cortical necrosis. The liver and bowel are also negatively impacted and can become ischemic. Around 30% of patients develop thrombocytopenia and have clotting difficulties.

Lab work and diagnostic imaging used to diagnose sepsis include:

blood cultures (must be drawn before initiating antibiotics)
CBC with differential
CMP
lactic acid
procalcitonin level
coagulation studies
urinalysis
chest X-ray (to rule out pneumonia)

Treatment

The treatment involves treating the underlying cause of the septic shock. The patient will receive strong intravenous antibiotics or antifungal medications based on the results of their blood culture. Until the blood cultures result, the patient will generally be started on a broad-spectrum IV antibiotic such as piperacillin-tazobactam (Zosyn). If there is a physical cause, such as an abscess or perforated bowel, the cause must be addressed surgically.

At least two large-bore (18 gauge or bigger) IV access sites should be obtained. Inotropic or vasoconstrictive agents (dobutamine, dopamine, norepinephrine) are used to maintain blood pressure to vital organs but have the downside of restricting blood flow to the extremities. The long-term use of vasopressors requires the insertion of a central line and runs the risk of IV extravasation. IV fluid resuscitation and boluses using isotonic crystalloids (4-6 liters) will also be used to maintain blood pressure.

Supplemental oxygen will be provided to assist with oxygenation. Some patients with septic shock will need to be intubated and temporarily placed on a ventilator. If kidney failure occurs, the patient will be placed on dialysis, which can be administered several times per week, or, if the patient’s condition is especially tenuous, on continuous renal replacement therapy (CRRT). The patient’s vitals signs should be monitored closely. In many cases, the patient will need to be admitted to the intensive care unit. Some sepsis survivors end up needing amputations and suffer permanent organ damage.