Nursing Care Plan (NCP) for Phenylketonuria (PKU)

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Phenylketonuria (PKU) is an inherited disorder in which the body cannot metabolize phenylalanine (Phe), which is an amino acid found in many foods. When phenylalanine levels get too high, it can cause intellectual disability, brain damage or death. Classic PKU is the most severe form of the disorder and doesn’t usually show symptoms until the infant is a few months old but can lead to severe brain damage if not treated. Milder forms of the disorder may be controlled with diet.  All babies born in hospitals in the United States receive testing for this disorder when they are born through a heel stick blood test. Early diagnosis and treatment can relieve symptoms and prevent the development of brain damage and intellectual disabilities.


Phenylalanine (Phe) is an amino acid that is the building block of proteins. This substance is found in most foods, especially protein rich foods like milk, meat and pasta. In PKU, there is a genetic mutation that causes a deficiency in the enzyme that is needed to process phenylalanine causing extremely high Phe levels that affect the brain. As an autosomal recessive trait, a person may be a carrier, but not actually have the disease. Both parents must carry the trait in order to have a child with the disease.

Desired Outcome

Patient will have optimal cognitive functioning; patient and family/caregiver will be educated on diet and prevention of symptoms; patient will maintain optimal learning ability; patient will be free from injury

Phenylketonuria (PKU) Nursing Care Plan

Subjective Data:

  • Hyperactivity
  • Behavioral or emotional problems

Objective Data:

  • Fair skin and hair, blue eyes
  • Slow growth
  • Musty odor of the urine, skin or breath
  • Seizures
  • Skin rash (eczema)
  • Microcephaly

Nursing Interventions and Rationales

  • Assess skin for rash


Patients with PKU often have eczema that is difficult to control.


  • Perform heel stick diagnostic test after birth as ordered


Heel sticks are done on newborns to diagnose PKU. This should be done in a timely fashion, as certain infant formulas contain phenylalanine.


  • Monitor serum lab results


PKU is usually diagnosed within a few weeks of life. Make sure parents are aware if their newborn has received a positive test result.

Monitor patient for elevated levels of phenylalanine routinely and if symptoms appear


  • Inform parents/caregivers of appropriate foods and formulas to give


Special formulas will be required that are phenylalanine free. Refer to dietitian for guidance.

Foods to avoid:

High protein foods, such as milk, dairy products, meat, fish, chicken, eggs, beans, and nuts.


  • Provide safety for patient with seizures (seizure precautions)


Patients with high levels of phenylalanine may have convulsions or seizures. Safety is important to prevent injury. Provide cribs and make sure rails are up.


  • Monitor growth and development


Children with PKU often have slow growth and development. Monitor for changes in growth or signs that developmental milestones are not being met.


  • Administer medications as necessary


Sapropterin is an approved medication that has been found to lower phenylalanine levels in combination with special diet.  It is important, however, that families recognize that dietary changes should be adhered to, regardless of medication use.


  • Provide patient and family education regarding diet, safety and disease process


Maintaining low phenylalanine diet will be a lifelong requirement. Make sure patients’ families understand how to read labels, make healthy diet choices and provide support as necessary

Safety should be stressed, especially in situations where patient may have convulsions or seizures

Writing a Nursing Care Plan (NCP) for Phenylketonuria (PKU)

A Nursing Care Plan (NCP) for Phenylketonuria (PKU) starts when at patient admission and documents all activities and changes in the patient’s condition. The goal of an NCP is to create a treatment plan that is specific to the patient. They should be anchored in evidence-based practices and accurately record existing data and identify potential needs or risks.


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Let’s work on the care plan for phenylketonuria or PKU. PKU is an inherited disorder in which the body cannot metabolize alanine. You know, the amino acids with peanut alanine levels get too high. It can cause intellectual disability, brain damage or death. So the nursing considerations that we want to think of. So we want to make sure that we do a lab draw. That’s what is called a heel stick test. We also want to do some diet education. Remember, that our outcome is for the patient to have optimal cognitive functioning, the patient and the family caregiver should be educated on the diet. In the prevention of symptoms. The patient is going to maintain optimal learning ability, and we want the patient to be free from injury. Remember, most cases can be managed with diet. We want to avoid foods high in alanine. 

So some symptoms, these are some subjective data of how the patient is going to present to us. This is another one of those conditions that is diagnosed pretty early on because the test is one of those first blood tests that’s performed when a newborn is brought into the world. So there’s going to be complaints of hyperactivity and behavioral or emotional problems. These patients tend to be very impulsive. Okay. So some objective things that we’re going to notice when we assess these patients Okay, we are going to notice that they have very fair skin, blue eyes. 

They are going to have slow growth, and a musty odor. That odor may also be in their skin or in their breath. These patients are prone to seizures. They’re going to have skin rash or eczema. And finally, we may notice a microcephaly or small head with these patients. So nursing consideration, what are some things that we want to intervene? How are we going to intervene with these patients? Well, let’s first assess. Let’s assess their skin because of that eczema. We’re going to assess for rash, okay? These patients with PKU oftentimes will have eczema, and it’s very difficult to control. 

We’re going to perform a heel stick diagnostic test after birth. Remember, that’s one of the first blood test. So that is called a heel stick. And pretty much the heel sticks are done on the newborn; it’s done with every newborn and it’s for the diagnosis of PKU. And usually it’s done in a timely fashion because certain formulas, like supplemental infant formulas, contain phenylalanine. So we want to make sure we get that diagnosed early on. We want to monitor the labs, their results. So, we want to monitor labs. The reason why we want to do a good monitoring of their labs is because PKU is diagnosed. The first few weeks of life, parents are to be aware as soon as the diagnosis of PKU is made. So that way they can make certain adjustments with either breast milk or certain formulas that contain phenylalanine and make sure we inform the parents and caregivers, appropriate foods and formulas to give special formulas are required. So they need special formulas. 

We want to refer to our dietician for guidance. These are some foods to avoid: we want to avoid foods with high protein that are going to be milk, dairy, meat, fish, chicken, eggs, beans, nuts. We want to avoid these in these patients with PKU. Here’s the complete care plan. And these are the key points. PKU is inherited. The body cannot metabolize phenylalanine. The result of this is either brain damage or death. Okay? Some subjective things that the patient will present with, they are going to be hyperactive. So hyperactivity also, they’re going to have some behavior or emotional problems. And we’re going to observe when we assess some objective things: the patient is going to exhibit slow growth. They’re going to be prone to seizures, eczema, and microcephaly. Remember these patients can also have fair skin, blue eyes. The heel stick test is how we diagnose phenylalanine. This is drawn early on in the first 24 hours or so after the patient has taken some protein into their diet in the form of breast milk or formula diet education is very important. Most cases of PKU can be easily managed with diet control. Remember that we want to avoid a lot of foods that contain protein, cheese, eggs, soy beans, chicken, beef, pork and fish. These things are things that we want to avoid with these patients. 

We love you guys; go out and be your best self today. And, as always, happy nursing.


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