What is a thyroid storm?
A thyroid storm, also known as thyroid crisis or thyrotoxicosis crisis, is a rare but life-threatening condition caused by an exacerbation of hyperthyroidism or overactive thyroid. It is a medical emergency that requires prompt treatment. Some key signs and symptoms of a thyroid storm include high fever, rapid heartbeat, nausea, vomiting, diarrhea, dehydration, agitation, delirium, seizures, and coma.
What causes a thyroid storm?
A thyroid storm can occur in people who already have underlying hyperthyroidism or Graves’ disease. It is usually triggered by a stressor such as an infection, trauma, a surgical procedure, labor and delivery, medications, or not taking anti-thyroid medications properly. The exact mechanisms are not fully understood but it is thought to involve a sudden surge of thyroid hormones in the body.
Who is at risk for a thyroid storm?
Factors that can increase the risk of a thyroid storm include:
– Untreated or poorly controlled hyperthyroidism
– Graves’ disease – an autoimmune disorder that causes overproduction of thyroid hormones
– Patients who have stopped taking their anti-thyroid medications
– Underlying infection or recent surgery/trauma
– Diabetic ketoacidosis
– Heart problems such as atrial fibrillation
– Recent administration of iodine through medications or contrast dye
How do you diagnose a thyroid storm?
There is no single diagnostic test for a thyroid storm. The diagnosis is made clinically based on signs, symptoms, and laboratory findings. Tests that may be done to help confirm the diagnosis include:
– Blood tests to check thyroid hormone levels – T4 and T3 levels will typically be elevated but not always
– Markers of increased metabolism such as low potassium, high liver enzymes, and high lactate
– Elevated inflammatory markers like CRP and white blood cell count
– Liver and kidney function tests as organs can be affected
– Cardiac markers like troponin if heart is involved
– Blood cultures to check for infection
– Blood glucose – high blood sugar is common
Scoring systems like the Burch-Wartofsky Point Scale can also be used. It assigns points based on clinical criteria, with a score above 45 suggesting thyroid storm.
How do you stabilize a patient with suspected thyroid storm?
The priority in a patient with suspected thyroid storm is to stabilize them as soon as possible. Steps include:
– Admit to intensive care unit for close monitoring
– Monitor vital signs frequently – blood pressure, heart rate, respiratory rate, oxygen saturation
– Start IV fluids to maintain hydration
– Treat hyperthermia with cooling blankets/ice packs if temp >103 F (39.4 C)
– Treat agitation or delirium with sedatives if needed
– Treat high blood sugar with insulin if needed
– Administer beta blockers like propranolol to lower heart rate
– Give thionamides like methimazole or propylthiouracil to block new hormone synthesis
– Give iodine solutions to block thyroid hormone release
– Treat infections with antibiotics if present
– Avoid medications that stimulate thyroid hormone release
Once the patient is stabilized, underlying triggers like infections should be treated. Ongoing management of hyperthyroidism is also necessary to prevent recurrence.
What is involved in ruling out a thyroid storm?
Ruling out a thyroid storm involves both diagnostic evaluation and response to treatment:
– Taking a thorough history and physical exam to look for typical signs and symptoms
– Checking thyroid hormone levels, though levels do not always correlate with severity
– Evaluating for other causes of similar presentations like infection, sepsis, neuropsychiatric disorders
– Assessing response to treatment – if a suspected thyroid storm does not improve with aggressive treatment, it may be another condition
– Monitoring vital signs – if fever, tachycardia, hypertension do not improve with treatment of a thyroid storm, consider other diagnoses
– Repeating thyroid function tests after recovery – normal hormone levels help rule out a thyroid storm retrospectively
– Considering other test results – normal glucose, electrolytes, liver enzymes make thyroid storm less likely
– Reviewing medication history for potential triggers
– Consulting endocrinology to help rule in or out thyroid storm
The diagnostic uncertainty and protean manifestations make ruling out a thyroid storm challenging. But ultimately lack of a clear response to treatment would point to an alternative diagnosis.
What are the differential diagnoses for a thyroid storm?
Some key conditions that should be considered in the differential diagnosis when a thyroid storm is being ruled out include:
– Sepsis – can cause fever, tachycardia, mental status changes
– Meningitis or encephalitis – may see fever, neurological symptoms
– Sympathomimetic toxicity – look for drug or medication use
– Anticholinergic toxidrome – delirium, tachycardia, fever
– Malignant hyperthermia – hypermetabolism, high fever, muscle rigidity after anesthesia
– Heat stroke – extremely high temperature, CNS abnormalities
– Pheochromocytoma – adrenal tumor causing catecholamine excess
– Thyrotoxic psychosis – thyroid hormone excess causing just mental status changes
– Medication effect – many drugs can precipitate thyroid storm or mimic symptoms
– Neuroleptic malignant syndrome – due to antipsychotic medications
A detailed history examining for other exposures, tests like blood cultures, spinal tap, EEG, and response to treatment can help distinguish these possibilities from a true thyroid storm.
Ruling out a thyroid storm involves a stepwise approach, starting with stabilizing a patient with supportive care and specific treatment like beta blockers and thionamides. Lack of clear improvement suggests an alternative diagnosis. Differential diagnoses like infection, sepsis, encephalopathy, drug toxicity and others should be considered. Repeating thyroid function testing after recovery, evaluating medication history, and consulting endocrinology can help confirm or exclude a thyroid storm retrospectively. While challenging, establishing the correct diagnosis is crucial given a thyroid storm’s potentially high mortality without prompt treatment.
Key Points to Remember
- A thyroid storm presents with exaggerated hyperthyroidism and systemic organ dysfunction, requiring hospitalization in intensive care.
- There is no single confirmatory test – the diagnosis is made clinically based on symptoms, exam, thyroid function tests and other labs.
- Stabilizing with aggressive treatment including beta blockers, thionamides, cooling and IV fluids is first priority.
- Lack of clear improvement with targeted treatment suggests an alternative diagnosis should be considered.
- Differential diagnoses include sepsis, drug toxicity, heat stroke, malignant hyperthermia among others.
- Normal thyroid function testing after recovery argues against a thyroid storm.
- Reviewing medication and imaging history along with consulting endocrinology can help confirm or exclude thyroid storm.
When to Suspect Thyroid Storm
|Clinical Features||Common or Concerning Findings|
|Symptoms||Fever, heat intolerance, sweating, palpitations, diarrhea, vomiting, agitation, psychosis|
|Vital signs||Tachycardia, hypertension, hyperthermia, tachypnea|
|Physical exam||Warm, flushed skin, tremor, delirium, heart murmurs, lung crackles|
|Labs||Elevated T3/T4, low potassium, high lactate, abnormal LFTs, leukocytosis|
Diagnosing Thyroid Storm
|Findings Supporting Diagnosis||Findings Argue Against Diagnosis|
|Marked tachycardia, agitation, delirium out of proportion to thyroid levels||Relatively normal vital signs and mental status|
|Extremely elevated thyroid hormones (T3/T4)||Only mildly elevated or normal thyroid hormones|
|Failure to respond to aggressive treatment||Rapid stabilization with beta blockers, thionamides, cooling|
|No other identifiable cause for symptoms||Evidence pointing to alternate diagnosis like infection|
|Normal thyroid function after recovery||Ongoing hyperthyroidism after clinical improvement|
Differential Diagnoses for Thyroid Storm
|Sepsis||Positive blood cultures, leukocytosis, low BP|
|Sympathomimetic toxicity||Drug screen, history of cocaine/methamphetamine use|
|Anticholinergic toxidrome||Dilated pupils, dry skin, urinary retention|
|Malignant hyperthermia||Previous anesthesia exposure, muscle rigidity, elevated CK|
|Heat stroke||Extremely high temperature, hot environment|
|Meningitis/encephalitis||Stiff neck, CSF pleocytosis|