Case Presentation: Acute Compartment Syndrome (ACS) develops when the tissue pressure within a closed compartment exceeds its perfusion pressure, leading to myoneural ischemia. If sustained, this ischemia can result in irreversible muscle necrosis and nerve damage.We present a case of hypothyroid myxedema leading to recurrent nontraumatic ACS of the lower extremity. A 42-year-old male with a medical history of iatrogenic hypothyroidism following radioiodine ablation for Graves’ disease was hospitalized seven years ago with hypothyroid myxedema due to medication noncompliance, resulting in a right leg ACS treated with fasciotomy. Two months prior to the current admission, a prolonged grief disorder led to his repeated self-discontinuation of thyroid supplementation. He presented with a 3-day history of worsening left leg pain and swelling below the knee, associated with pretibial paresthesia. On physical examination, the left leg showed non-pitting edema, hypertrophic skin, and severe tenderness and tension in the left anterior compartment. There was decreased pinprick sensation below the left knee, minimally diminished plantar and dorsiflexion of the left foot, and intact circulation.Biochemical workup was diagnostic for hypothyroidism and rhabdomyolysis, showing: TSH: 61.9 µU/mL ( 0.465–4.680), Free T4: 0.38 ng/dL ( 0.78–2.19), CPK: 24,823 U/L (25–170), AST: 182 U/L (17–59), ALT: 90 U/L ( < 50)Compartment pressure measurement revealed severe elevation in the left anterior compartment at 195 mmHg and delta pressure (Diastolic Blood Pressure - Compartment Pressure) of -95 mmHg. Limb-saving intervention was promptly implemented, with a left leg four-compartment fasciotomy, which was diagnostic for anterior and lateral compartment muscle ischemia and minimal contractility. He subsequently underwent five incisions and debridement of the fasciotomy wounds. Intravenous then oral thyroid supplementation was initiated. Ultimately he was released home with a wound VAC, viable left leg muscles and referral for interval skin grafting.
Discussion: Causal correlation between hypothyroidism and ACS has been suggested by few case reports. Our case is the first documented recurrent ACS repeatedly linked to hypothyroidism. The pathogenesis of ACS in hypothyroidism is not well understood. Contributing factors may include a combination of hypothyroidism-induced muscular, vascular, and connective tissue abnormalities, such as muscle hypertrophy, increased vascular permeability, impaired lymphatic flow, and elevated interstitial glycosaminoglycan content. ACS-induced muscle breakdown can lead to rhabdomyolysis. While slight to moderate elevations in creatine kinase are commonly seen in hypothyroidism, in rare cases, hypothyroidism-related inhibition of glycogen catabolism and mitochondrial dysfunction may cause a cascade of metabolic abnormalities leading to rhabdomyolysis. In our case, rhabdomyolysis was directly attributed to ACS.
Conclusions: Hypothyroidism may provoke ACS. A high index of suspicion is required to diagnose ACS in hypothyroid myxedema-related extremity swelling and to identify hypothyroidism in idiopathic ACS. Diagnostic testing includes TSH, Free T4, CPK along with compartment pressure measurement in suspected cases. Early surgical compartment decompression is crucial to prevent permanent neuromuscular damage and associated disability.
