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Practice review

How to care for patients undergoing surgery for primary hyperparathyroidism

Hyperparathyroidism is often seen as a silent disease. Nurses need to be able to link pathophysiology to nursing practice to provide safe and effective care

Author

Elaine Hughes, RGN, BSc, Med, is a senior lecturer, Edge Hill University, Ormskirk.

Abstract

Hughes E (2010) How to care for patients undergoing surgery for primary hyperparathyroidism. Nursing Times; 106: 44, early online publication.

Primary hyperparathyroidism is the third most common endocrine condition. Initial symptoms can be vague, leading to problems in other body systems before diagnosis, and ifit remains undiagnosed it can lead to life threatening parathyroid crisis. This in itself provides challenges to nurses working within surgical and endocrine specialties, where a thorough understanding of physiology is essential to ensure safe practice and promote good patient outcomes. This article discusses the pathophysiology of primary hyperparathyroidism and the care of patients with the condition.

Keywords Primary hyperparathyroidism, Homeostasis, Hypercalcaemia

  • This article has been double blind peer reviewed

Practice points

  • Care of patients with primary hyperparathyroidism should be based around a holistic viewpoint.
  • Knowledge of pathophysiology is essential to ensure its specific complications can be identified and treated quickly.
  • Monitoring patients using traditional skills, such as taking manual pulses and blood pressures (where the cuff can be left on for a determined period) can quickly help to establish emerging complications.
  • Discharge advice is essential to ensure patients keep contact details up to date and return for bone mineral density scans in the following years.

 

Introduction

Hyperparathyroidism is a condition affecting the parathyroid glands. Because these glands have a primary role in the body’s regulation of calcium in the blood any changes to these glands can cause wide ranging issues for patients with this condition.

There are three classifications of hyperparathyroidism: primary, secondary and tertiary (; Merck, 2010; Fraser, 2009; Inabet et al, 2006). This article focuses on primary hyperparathyroidism, which is the third most common endocrine condition (Fraser, 2009).

The incidence of primary hyperparathyroidism varies internationally, with reports of a higher incidence in countries in the northern hemisphere (Fraser, 2009; Inabet et al, 2006). A recent study in Scotland showed the incidence to be as high as 6.72 per 1,000 population (Donnan et al, 2009). However, what all studies have in common is that incidence of increases with age, and is 2-3 times greater in women than men (Fraser, 2009; Donnan et al, 2009).

Anatomy and physiology

The parathyroid glands are part of the endocrine system and secrete parathyroid hormone (PTH). The parathyroid gland consists of four small glands which sit behind the thyroid gland in the neck and are responsible for the regulation of plasma calcium levels. Although the function of the thyroid gland is often associated with metabolism, it also has a role in calcium regulation and produces the hormone calcitonin. This hormone is responsible for the uptake of calcium by the bones when plasma calcium levels are high (Tortora and Derrickson, 2009).

Regulation of calcium is the only role of the parathyroid gland, which constantly measures the body’s plasma calcium concentration through the parathyroid calcium sensing receptors. When the levels fall below the normal range, PTH is released from the chief cells in the parathyroid tissue.

Because the parathyroid gland is highly vascular the PTH is quickly released into the circulation, stimulating the bones to release calcium. This works in conjunction with calcitrol, the active form of vitamin D, to increase calcium absorption from the gastrointestinal tract. PTH also works on the renal tubules to increase the reabsorption of filtered calcium and the excretion of phosphate via the urine. This rapidly returns plasma calcium levels to normal. When this biofeedback mechanism occurs, the release of PTH is inhibited ensuring homeostasis (Tortora and Derrickson, 2009) (Fig 1).

In hyperparathyroidism, normal homeostatic mechanisms are affected. In around 87% of cases this is caused by an adenoma in one of the glands (Moe, 2008; Inabnet et al, 2006). The adenoma secrets an excess of PTH independent of the calcium levels, which leads to depletion of the calcium stores from bones and over time can lead to osteoporosis. This is because high levels of PTH not only inhibit the release of calcitonin from the thyroid gland - which would normally help to decrease calcium loss - but continues to move calcium from the bones, intestines and kidneys into the circulation. This results in bone mineral density loss and can also result in hypercalcaemia (Inabnet et al, 2006).

Signs, symptoms and diagnosis

The symptoms for primary hyperparathyroidism, which are often referred to as “stones, bones, abdominal groans and psychic moans” relate to the skeletal, cardiac, renal, gastrointestinal and central nervous systems (Box 1). Fatigue is also a common symptom and is experienced by over 80% of people who present with this condition (Inabnet et al, 2006).

When reviewing these symptoms in isolation they could appear to be the result of other, more minor, conditions that people often self medicate for at home, such as constipation or indigestion, while everyday, hectic lifestyles often lead to fatigue. Small wonder then, that hyperparathyroidism is often seen as a silent disease with subtle symptoms until homeostasis becomes so disturbed that patients either present in crisis - which accounts for 1-2% of new cases - or are diagnosed coincidentally and have no apparent symptoms, which accounts for up to 80% of cases (Fraser, 2009).

Diagnosis of primary hyperparathyroidism is related to clinical symptoms and blood tests. Raised inonised serum calcium levels and elevated intact PTH levels are classic indicators of the disease (Fraser, 2009; Inabnet et al, 2006). When using blood results for diagnostic purposes, a single blood test should not be relied on as an indicator of primary hyperparathyroidism. Blood tests for calcium, magnesium, PTH and phosphate should be repeated to ensure correct diagnosis (endocrinesurgeon, 2010a).

Routine management in mild hypercalcaemia

For patients with mild hypercalcaemia who do not meet the criteria for parathyroid surgery or are unfit for surgery, treatment with oestrogens or biophosphates can be useful if their bone mineral density has been affected. The focus is on preventing bone loss and normalising calcium levels. Where all these methods are contraindicated the calcimimetic cinacelcet can be useful, but Fraser (2009) suggests further research should be undertaken to establish the long term benefits of this approach. However, regular monitoring of renal function, calcium levels and bone mineral density is required to ensure the patient’s condition does not deteriorate. If this does occur parathyroidectomy can be offered and can often be undertaken as a day case, depending on the patient’s condition.

Presentation and management in crisis

Although primary hyperparathyroidism can be difficult to detect as initial symptoms can be vague a small percentage of those who are diagnosed with the disease can have life threatening symptoms which are related to hypercalcaemia (Inabnet et al, 2006). Patients who present in crisis often are acutely confused or psychotic and in rare cases this can initially be attributed to mental health problems.

Acute arrhythmias are often seen due to high calcium levels. However, other symptoms such as dehydration, abdominal pain, vomiting and poor urine output may also be present. These symptoms can be easily attributed to other, more common conditions, which is why it is easy to overlook the possibility that the patient might have primary hyperparathyroidism.

Initial management of hyperparathyroid crisis involves correcting plasma calcium levels to safe limits. Depending on the patient’s presentation, this can take different forms. Merck, (2010) suggests there are four approaches to lowering calcium levels, which relate to lowering intestinal absorption, decreasing bone resorption, increasing urinary excretion of calcium and in excessive hypercalcaemia, dialysis may be necessary to restore normal levels.

High levels of plasma calcium can be addressed in several ways. Fluid management with intravenous (IV) saline to correct dehydration and stimulate the kidneys to excrete calcium is often first line management (Fraser, 2009; Inabnet, 2006). In the non dehydrated patient, IV frusemide can be given as this increases urine production and assists the kidneys to excrete excess calcium (Merck, 2010; Inabnet et al, 2006). However, regular biochemical assessment is required due to the risk of overhydrating the patient. If calcium levels are extremely high, further medical management may be required with biophosphonates – such as pamidronate - to reduce the calcium level further and reduce bone turnover, thus improving bone mineral density.

It should be noted that for patients who have undergone treatment for parathyroid crisis, surgery should be planned carefully because treatment with biophosphonates has a maximum effect in around five days. This can have a negative effect in the post operative period, where they can become hypocalcaemic as a result of preoperative treatment for hypercalcaemia (Fraser, 2009)

Surgical treatment

Once diagnosis is made surgery is curative in 97% of patients who undergo the procedure (Adamek, 2007). The surgical approach is decided by criteria set by the National Institute of Health in 2002 [please provide this reference]]; the criteria, which are currently being updated,include:

  • Serum albumin adjusted calcium levels more than 0.25mmol/l above local laboratory ranges;
  • Urine calcium levels more than 10mmol in 24 hours;
  • Younger than 50 years of age;
  • A “T” score of ≤ -2.5 at any site on a bone mineral density scan;
  • A reduction of 30% or more in creatinine clearance;
  • Patient request, especially if follow up may prove to be challenging.

Fraser (2009) suggests that 85% of all presenting cases have one adenomatous gland, while up to 15% have multiple adenomas. For this reason, surgical procedures differ according to the patient’s diagnosis. The two common surgical approaches can consist of the following methods:

  • A total parathyroidectomy - a traditional approach consisting of a bilateral exploration of all four glands, where the surgeon can visualise the glands and remove them. In some cases one or more glands may be retained if the affected glands can be identified.
  • A subtotal parathyroidectomy - minimally invasive targeted surgery that can be done under a local anaesthetic for single localised enlarged glands.
  • A total parathyroidectomy with auto transplant. This is used is some cases where all four glands are removed and a small amount of parathyroid tissue is transplanted into the forearm. Placement here has the benefits of being readily accessible should the transplanted tissue begin to enlarge and require further surgery to reduce its size.

Imaging of enlarged glands can facilitate selective minimally invasive surgery, enabling a targeted approach. Obviously this has the advantage of requiring less anaesthetic time, which can be particularly useful when treating older patients; it also has the benefits of decreased admission time and improved recovery.

Several imaging methods can be used such as:

  • Ultrasound;
  • CT;
  • MRI; 
  • Sestamibi scans. (endocrinesurgeon, 2010b)

Intraoperative assays of intact PTH can be useful to determine the removal of all affected glands. Because PTH levels fall rapidly, testing while the patient is still under anaesthetic can be a reliable method of determining whether the problematic gland has been removed (Fraser, 2009).

Some specific complications can arise as a result of parathyroidectomy. In less than 1% of cases, paralysis of the vocal cords or damage to the laryngeal nerve can occur, while postoperative bleeding can occur in one in 750 cases. However, a more common complication is severe hypocalcaemia, known as hungry bone syndrome (HBS), which is present in 42% of cases (Mittendorf et al, 2004).  This is more common in patients who have large parathyroid adenomas, are over 60 years of age and with high preoperative levels for calcium, PTH and phosphatase.  With HBS, removal of the enlarged parathyroid gland reduces the amount of PTH released into the vascular system. This subsequently increases the uptake of calcium into the bones causing hypocalcaemia, and often requires calcium supplementation (Mittendorf et al, 2004).

Preoperative nursing care in elective surgery

For many patients who require parathyroidectomy the procedure can be done as an elective day case, depending on the patient’s co-existing problems. Most patients need only a pre-operative assessment before their surgery. This assessment involves taking routine nursing observations, which provide a postoperative baseline, and preparing the patient for theatre, offering psychological support and information about what to expect.

Preoperative care for patients in crisis

Taking into consideration the medical management and physiological changes to patients, it is important to be able to plan and implement nursing care for those in crisis. This should be based not only on a holistic assessment, but should also take into account the specific challenges that this acute problem can bring. It is here that knowledge of pathophysiology is vital. This can be an extremely frightening time not only for the patient, but for family members as well, and nurses need to be empathetic and provide psychological support to all concerned.

Nurses have an essential role in haemodynamic monitoring and fluid balance measurement to ensure patient safety. The extended role of the nurse in some acute areas may involve ordering blood tests, where daily bloods should be taken for calcium, urea and electrolytes,  and phosphates in the preoperative period.

Using a track and trigger monitoring system such as a Modified Early Warning System (MEWS) is an essential part of the nursing role. NICE (2007) suggests that patients in acute care settings should have the frequency of their physiological observations prescribed by medical staff, which is tailored to the individual patient’s condition. The recording and reporting of observations outside of normal parameters is essential, as high calcium levels can affect cardiac rhythm. It is therefore essential to feel for a pulse manually, rather than rely on electronic equipment that only provides rate measurement (Boulanger and Toghill, 2009). 

Because patients can be very dehydrated, the monitoring of observations can help to determine levels of hydration. While low blood pressure can be an indication of dehydration, nurses should also observe for fast pulse rates because the body tries to compensate for the reduction in circulating fluid by increasing the heart rate (Scales and Pilsworth, 2008). The pulse may also be weak and this vital information would be missed if only electronic equipment is used (Boulanger and Toghill, 2009).

Fluid balance is an essential part of the specific care of patients with primary hyperparathyroidism, especially when they present in crisis. While documenting all input and output is important observing the colour of urine can also be useful as dark urine is a sign of dehydration, as the body releases antidiuretic hormone to prevent further loss of fluid from the renal tract (Tortora and Derrickson, 2009). It is also important to ensure that patients do not retain too much fluid, as this can lead to cause cardiac problems and fluid overload.

Many of these patients are unable to supplement their oral intake with enough fluids to promote adequate diuresis, so will require intravenous infusions. Observing the site of the cannula is essential to ensure the fluids are running to prevent dehydration. All cannula sites should be monitored and changed regularly; national guidelines  advocate changing the cannula every 72 hours (RCN, 2010;  Department of Health, 2007), but a recent Cochrane review (Webster et al, 2010) suggests the evidence to support this is weak and recommends that cannulas be changed on clinical indication.

Postoperative nursing care

Haemodynamic monitoring, including fluid balance is essential in the postoperative period. However, it is important to remember that pain control and wound care also require consideration as well as the specific challenges of this particular patient group. For patients undergoing elective surgery, discharge the same day with strong analgesia is possible, while those who have undergone surgery following crisis - especially if thoracic surgery was required - can be provided with patient controlled analgesia (PCA). The importance of physiological monitoring for patients on PCA cannot be understated, because of the risk of respiratory depression. This must be recorded on MEWS charts and using pain scoring systems to ensure the adequacy of the method of pain control (McArthur-Rouse and Prosser, 2007).

Although wound management is relatively straightforward in such cases, nurses play an extremely important role, particularly supporting patients who are dealing with altered body image issues following surgery. Initially scars can be quite visible and can cause distress, so strong communication skills and empathy are essential. Scars at the neck and the mediastinum can cause a sense of loss, and counselling can be beneficial in these cases. It must be remembered that scarring is not only a biological issue, but also impinges on psychological and social wellbeing, which can lead to depression and social isolation (Rumsey and Harcourt, 2005). There is also a risk of laryngeal nerve damage and paralysis of the vocal cords, which will also mean patients need good psychological care.

As mentioned earlier, patients can develop HBS postoperatively, so nurses should observe for signs of hypocalcaemia. Classic observable signs are those of tetany, where patients exhibit neuromuscular excitability. Here a positive Trousseau’s sign - where carpopedal spasm occurs after the inflation of a blood pressure cuff on the arm above systolic pressure for three minutes - or Chvostek’s sign - where tapping the facial nerve causes the facial muscles to spasm - can indicate the beginning of tetany (Merck, 2010).

The reduction of bone mineral density often caused by the pathophysiological changes associated with primary hyperparathyroidism means these patients may need long term care. Those with low bone density should have bone mineral density scans every two years to ensure there is improvement in bone mass; studies have shown that bone density can begin to recover within the first postoperative year (Suliburk and Perrier, 2007).

Conclusion

Primary hyperparathyroidism can be a challenging condition for both patients and nurses, and can even be life threatening. The treatment options that are available in crisis enable patients to be managed successfully in order to prepare them for surgery. This brings with it challenges for nurses who need to be able to link pathophysiology to nursing practice to provide safe and effective nursing care.

Not only is it important to be able to care for patients in the acute phases of the primary hyperparathyroidism, it is also vital that nurses care for them holistically. This condition not only affects the biological domain, but in many cases also impacts on the psychological, social and economic areas of a person’s life.

Box 1. Case study: ‘The thoracic approach is esssential’

Karen Parker, aged 18, presents with longstanding fatigue, polydipsia, polyuria constipation and worsening depression. Her initial presentation is at A&E following an overdose of paracetamol. She is treated for the overdose and discharged the following day. At this early point it is easy to miss the diagnosis and to only treat the presenting problem. Her depressed state is linked to rising calcium levels which, if remain untreated, can lead to a psychotic episode.

Several months later Ms Parker is readmitted to A&E following a psychotic episode where she attempted to severely injure herself. Here, the worsening mental state is clearly linked to increasing hypercalcaemia.

After three days of discussions between the mental health crisis team and medical team, hypercalcaemia is noted with high PTH levels, and appropriate referrals are made. The length of time taken to make a diagnosis is linked to Ms Parker being outside the “normal” presenting picture in terms of age, and the fact that PTH levels are not a routine investigation.

Two weeks of drug and fluid therapy ensue to normalise her calcium levels. This is essential in order to improve safety, not only in the preoperative period, but also during surgery. A subtotal parathyroidectomy is performed, only for the calcium levels to rise again on the third postoperative day.

Further investigations confirm the presence of a further parathyroid gland in the mediastinum and more surgery is required to remove this.

Although Palazzo and Saddler (2004) suggest that multiple imaging using both ultrasound and sestamibi scans can have up to a 98% success rate of identifying a single adenoma, in up to 16% of cases an extra gland is situated in the mediastinum and a small number of these patients require a thoracic approach to remove the gland (Fraser, 2009).

The thoracic approach is essential for Ms Parker. Even if preoperative scanning had been performed, without a thoracic MRI it is unlikely this gland would have been located.

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