Article, Surgery

Acute compartment syndrome caused by uncontrolled hypothyroidism

a b s t r a c t

Acute compartment syndrome is increased tissue pressure exceeding perfusion pressure in a closed compart- ment resulting in nerve and muscle ischemia. Common precipitating causes are Crush injuries, burns, substance abuse, osseous or vascular limb trauma. This is a case of 42 year old female with history of hypothyroidism who presented to emergency room with acute onset of severe pain and swelling in right lower extremity. Physical ex- amination was concerning for acute compartment syndrome of right leg which was confirmed by demonstration of elevated compartmental pressures. No precipitating causes were readily identified. Further laboratory testing revealed uncontrolled hypothyroidism. Management included emergent fasciotomy and initiating thyroid hor- mone replacement. This case represents a rare association between acute compartment syndrome and uncon- trolled hypothyroidism. We also discuss the pathogenesis of compartment syndrome in hypothyroid patients and emphasize the importance of evaluating for less common causes, particularly in setting of non-traumatic compartment syndrome.

Introduction

Acute compartment syndrome (CS) is defined as increased tissue pressure which exceeds perfusion pressure in a closed compartment resulting in nerve and muscle ischemia. Common causes of CS include crush injuries, burns, vigorous exercise, substance abuse, or osseous and vascular limb trauma [1]. Less frequent causes of CS such as vascu- litis, leukemic infiltration and drugs (statins and anticoagulants) have been reported. We present an unusual case of CS as a result of severe hypothyroidism.

Case report

A 42 year old female presented to the emergency department with a chief complaint of right Lower extremity pain and swelling which she noticed upon waking two days prior to arrival. She described severe burning pain, unrelieved by rest, resulting in inability to move her right lower extremity. Patient denied any history of recent trauma or similar symptoms previously. A review of systems was positive for on- going myalgias, fatigue and poor appetite, which started several months ago. All other systems were negative. Review of her medical history was significant for Hashimoto’s hypothyroidism with levothyroxine non-

? Authors have nothing to disclose.

* Corresponding author at: Endocrinology Fellow, Cooper University Hospital, Camden, NJ, USA.

E-mail address: [email protected] (A. Modi).

adherence. She denied taking anticoagulants, anti-platelet agents or statins. Social history was significant for a one-half pack daily smoking history but no recent alcohol or illicit drug use. She admitted to a seden- tary lifestyle and denied any recent excessive physical activity. Physical examination showed normal vital signs with a blood pressure of 126/ 82 mm Hg, pulse 73 beats/min, temperature 97.3 F, and oxygen satura- tion of 98% on room air. No neck masses were noted. Cardiovascular and pulmonary examinations were normal. Her right lower extremity distal to her knee was tense, edematous and she had pain with passive flexion of great toe. She had intact sensation to light touch and symmetric patel- lar reflexes. Femoral, popliteal, dorsalis pedis and posterior tibial pulses were palpable. Laboratory values revealed hemoglobin 13.5 g/dl (12- 14), WBC 9.86 (4.5-11), Serum glucose 141 mg/dl (70-110), serum so- dium 134 mmol/l (135-145), potassium 4.0 mmol/l (3.5-5), calcium 9.3 mg/dl (8.5-10.5), Creatinine kinase 1854 U/l (0-200), creatinine 1.06

mg/dl (0.6-1.2), BUN 17 mg/dl (9-23), Thyroid stimulating hormone 147.29 U/Ml (0.27-4.20), and negative urine toxicology. Electro- cardiogram showed normal sinus rhythm with no evidence of acute is- chemia. X-ray of the right tibia and fibula showed no acute osseous abnormalities and normal Soft tissues without effusion in the right knee or ankle. Venous Doppler ultrasound of the right lower extremity was negative for deep venous thrombosis. A Stryker needle used to measure the compartmental pressures in the right leg, showed elevated pressures of 142 and 96 mm/hg (0-8) in lateral and anterior compart- ments respectively. Patient underwent an emergent lateral compart- ment fasciotomy. Upon release of pressure, underlying muscles were noted to immediately protrude and appeared viable and pink.

http://dx.doi.org/10.1016/j.ajem.2016.12.054

Levothyroxine 125 mcg daily was restarted. Thyroid levels normalized over a course of 2 months.

Discussion

The diagnosis of CS was made in this patient on the basis of elevated compartmental pressures though no etiology was readily apparent until labs revealed a very elevated TSH; thus suggesting an association be- tween uncontrolled hypothyroidism and CS. Bilateral anterior tibial compartment syndrome (ATCS) in association with hypothyroidism was first described in 1993 wherein the patient presented with myx- edema [2]. Another case report by Hsu SL et al. reported a similar asso- ciation between ATCS and hypothyroidism [3].

A combination of muscular, vascular and connective tissue abnor- malities can precipitate CS in a patient with hypothyroidism.

The pathogenesis contributing to CS can be broadly categorized into conditions which (a) decrease the size of compartment and (b) increase the content of the compartment [4]. TSH is hypothesized to stimulate fi- broblast to produce excess of hyaluronic acid. On the other hand, defi- ciency of thyroxine inhibits degradation of hyaluronic acid [5,6]. This causes increased deposition of glycosaminoglycans in skin, muscles and other connective tissues; leading to muscle enlargement and de- crease in compartment size [6]. Increase in the vascular permeability and impaired lymph flow noted in hypothyroidism can further lead to extravasation of protein rich fluid in the interstitium [7]. Deposition of glycosaminoglycan in the walls of compartmental vessels of hypothy- roid patients can lead to decreased perfusion as has been previously demonstrated in ATCS [8,9].

It remains unclear what triggers CS in hypothyroid patients. An in- crease in energy demand during mild exercise has been associated with increased risk of rhabdomyolysis in patients with uncontrolled hy- pothyroidism [10]. Since CS is a known complication of rhabdomyolysis, similar mechanisms triggering CS in hypothyroid patients could be questioned [11]. Tissue trauma, which occurs with mild exercise in these patients, when followed by extracellular fluid accumulation and

impaired vascular and lymphatic drainage might increase the compart- mental pressures, precipitating CS.

Conclusion

This case represents a rare association between uncontrolled hypo- thyroidism and CS. Since diagnosis is based on a suspicion of disease and measuring compartmental pressures, patients who present with CS without traumatic injury need to be evaluated for less common causes, including hypothyroidism.

Conflict of interest

Authors have no conflict of interest.

References

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