Patho: Chapter 34 (Renal Disorders)

What happens when the kidneys fail?

• Less waste is removed

• Blood urea nitrogen (BUN) and creatinine accumulate in the blood

• Fluid, electrolyte, and pH balance cannot be properly regulated.

What are the three major types of acute kidney injury (acute renal failure)?

• Prerenal acute kidney injury

• Intrarenal (intrinsic) acute kidney injury

• Postrenal acute kidney injury

What is a prerenal acute kidney injury?

An acute kidney injury caused by markedly reduced renal blood flow and blood supply.

What causes a prerenal acute kidney injury?

• Hemorrhage

• Dehydration

• Vasoconstriction

• Heart failure

• Shock

What is an intrarenal (intrinsic) acute kidney injury?

An acute kidney injury caused by damage to structures within the kidney that decreases kidney tubule function.

What causes an intrarenal (intrinsic) acute kidney injury?

• Ischemia

• Toxins

• Intratubular obstruction

• Acute tubular necrosis (ATN)

What is a postrenal acute kidney injury?

An acute kidney injury caused by obstruction of urine outflow from the kidney.

What causes a postrenal acute kidney injury?

• Kidney stones

• Tumors

• Enlarged prostate

What is Acute Tubular Necrosis (ATN)?

Destruction of tubular epithelial cells with acute suppression of renal function

What causes Acute Tubular Necrosis (ATN)?

• Prolonged renal ischemia

• Exposure to nephrotoxic drugs

• Exposure to metals

• Exposure to organic solvents

• Intratubular obstruction from Hemoglobinuria, Myoglobinuria, Myeloma light chains, and Uric acid casts

• Acute renal disease

• Sepsis

What is Chronic Kidney Disease (CKD)?

A progrressive decline in kidney function caused by the permanent loss of npehrons, or a GFR less than 50 mL/min/1.73m² for 3 months or longer.

What causes Chronic Kidney Disease (CKD)?

• Diabetes mellitus

• Hypertension

• Glomeruonephritis

• Polycystic kidney disease'

• Urinary tract obstructions

• Cancers

• Autoimmune disorders

• Diseases of the heart or lungs

• Chronic use of pain medications

The lower the number of functioning nephrons, the _____ the GFR.

Lower

The higher the number of functioning nephrons, the _____ the GFR.

Higher

What are some manifestations of Chronic Kidney Disease?

• Uremia/azotemia

• Altered fluid, electrolyte, and pH balance

• Hypertension/heart disease

• Anorexia/nausea/vomiting

• Bone disease

• Anemia

• Peripheral neuropathy

• Restless leg syndrome

• Sexual dysfunction

• Decreased immunity

What causes hypertension in patients with Chronic Kidney Disease (CKD)?

• Increased vascular volume

• Increased peripheral vascular resistance

• Decreased levels of renal vasodilator prostaglandins

• Increased activity of the renin-angiotensin-aldosterone system (RAAS)

What is salt wasting?

Loss of sodium due to impaired tubular reabsorption of sodium, resulting in abnormal serum sodium levels.

What specifically causes salt wasting?

Impaired tubular reabsorption of sodium in advanced kidney failure

What is uremia?

The clinical manifestations of kidney failure caused by the buildup of waste products (toxins) in the blood due tp the kidney’s inability to filter them.

What is azotemia?

An abnormally high level of nitrogen-containing waste products in the blood.

What causes anemia to occur in Chronic Kidney Disease (CKD)?

• Chronic blood loss

• Hemolysis

• Bone marrow suppression

• Decreased erythropoiten production

• Iron deficiency

What happens when a patient develops anemia in Chronic Kidney Disease (CKD)?

• Weakness

• Fatigue

• Depression

• Insomnia

• Decreased cognitive function

• Peripheral vasodilation

What happens to platelets in Chronic Kidney Disease (CKD)?

Platelet function becomes impaired, leading to an increased risk of bleeding

Why do patients with Chronic Kidney Disease (CKD) have an increased risk of bleeding?

Their platelet function is impaired leading to less effective clotting

What is metastatic calcification?

Deposition of calcium in normal tissues due to disturbances in mineral metabolism.

Why is there bone loss in Chronic Kidney Disease (CKD)?

• Hyperphosphatemia causes hypocalcemia

• Hypocalcemia increases parathyroid hormone (PTH) secretion

• Increased PTH causes calcium resorption from bone

• Bone loss occurs as calcium is removed from bone tissue

What happens to active vitamin D (calcitrol) levels in Chronic Kidney Disease (CKD)?

Calcitrol levels decrease because vitamin D activation is impaired

What are the consequences of decreased calcitrol levels in Chronic Kidney Disease (CKD)?

• Increased parathyroid hormone (PTH) levels

• Impaired osteoblast function

• Contributes to bone loss

What causes mineral metabolism disorders in Chronic Kidney Disease (CKD)?

• Hyperphosphatemia

• Hypocalcemia

• Increased PTH

• Decreased calcitrol (active vitamin D) levels

What is peripheral neuropathy?

Damage to peripheral nerves that can occur as a complication of Chronic Kidney Disease

What is restless leg syndrome?

A neurologic complication of Chronic Kidney Disease characterized by an uncontrollable urge to move the legs

What is uremic enecephalopathy?

Brain dysfunction caused by the accumulation of toxins in the blood during kidney failure

What is sexual dysfunction in Chronic Kidney Disease (CKD)?

Impaired sexual function that may occur as a complication of Chronic Kidney Disease (CKD)?

What are the characteristics/manifestations of sexual dysfunction in Chronic Kidney Disease (CKD)?

• Impotence (erectile dysfunction)

• Hypofertility

• Dysmenorrhea (frequent menstrual cramps)

What skin disorders can occur in Chronic Kidney Disease (CKD)?

• Dry skin

• Pruritus (severe itching)

• Brusing

• Brittle nails

Why do people with Chronic Kidney Disease (CKD) have dry skin?

A reduction in sweat glands decreases skin moisture, causing dry skin

Why do people with Chronic Kidney Disease (CKD) have pruritus (severe itching)?

High serum phosphate levels and the development of phosphate crystals associated with hyperparathyroidism cause severe itching

What is diaylsis?

A renal displacement therapy that removes waste products and excess fluid from the blood when the kidneys can no longer perform these function adequately

What are the two types of dialysis?

• Hemodialysis

• Peritoneal dialysis

What is hemodialysis?

A type of dialysis that filters blood through a machine to remove wastes, excess fluids, and electrolytes.

What is peritoneal dialysis?

A type of dialysis that uses the peritoneal membrane as a semipermeable membrane to remove wastes and excess fluid from the blood.

When is dialysis indicated?

When advanced uremia or serious electrolyte imbalances are present

The GFR is considered to be the best measure of renal function. What is used to estimate the GFR?

Serum creatinine

A client in renal failure has marked decrease in renal blood flow caused by hypovolemia, the result of gastrointestinal bleeding. The nurse is aware that this form of renal failure can be reversed if the bleeding in under control. Which form of acute renal injury does this client have?

Prerenal failure