Hypolipidemia in a Special Operations Candidate: Case Report and Review of the Literature.

BACKGROUND: A 19-year-old male military recruit who presented for a screening physical for US Naval Special Warfare Duty was found to have hypolipidemia. Medical history revealed mildly increased frequency of bowel movements, but was otherwise unremarkable. His presentation was most consistent with heterozygous familial hypobetalipoproteinemia (FHBL), and the patient was cleared for Special Operations duty. METHODS: A literature search was conducted using PubMed/MEDLINE. Keywords included familial hypobetalipoproteinemia, heterozygous familial hypobetalipoproteinemia, abetalipoproteinemia, hypolipidemia, diving, special operations, and military. Results that included cases of familial hypobetalipoproteinemia were included. RESULTS: Review of the literature reveals that FHBL is a genetic disorder frequently, but not always, due to a mutation in the apolipoprotein B (apoB) gene. Those with the condition should be screened for ophthalmologic, neurologic, and gastrointestinal complications. Analysis of the disease, as well as the absence of reported cases of FHBL in diving and Special Operations, suggest there is minimal increased risk in diving and Special Operations for patients who are likely heterozygous, are asymptomatic, and have a negative workup for potential complications from the disease. CONCLUSION: Individuals with presumed or proven heterozygous FHBL seeking clearance for Special Operations duty should be given precautions, undergo careful questioning for history of disease-specific complications, and should have a baseline evaluation. If negative, it seems reasonable to clear the patient for Special Operations and diving.

Recurrent, pruritic papules on the legs.

We present a patient with recurrent, pruritic, erythematous papules to the legs.

Erythema nodosum.

An active duty female Sailor reports to your clinic complaining of tender nodules to her legs beginning 1.5 weeks ago. She is diagnosed with erythema nodosum (EN), a painful disorder of the subcutaneous fat that is usually self-limited but may be a clue to an additional underlying medical diagnosis. This article reviews the pathophysiology, causes, course, diagnosis, and management of EN.

Ketogenic diet for high partial pressure oxygen diving.

INTRODUCTION: A ketogenic diet (KD) may decrease central nervous system oxygen toxicity symptoms in divers, and in view of this implication a feasibility/ toxicity pilot study was performed to demonstrate tolerance of KD while performing normal diving profiles. The exact mechanism of neuroprotection from the KD remains unknown; however, evidence to support the efficacy of the KD in reducing seizures is present in epilepsy and oxygen toxicity studies, and may provide valuable insight in diving activities. METHODS: Three divers (two males and one female ages 32-45 with a history of deep diving and high pO2 exposure) on the KD made dives to varying depths in Hawaii using fully closed-circuit MK-15 and Inspiration rebreathers. These rebreathers have an electronically controlled set point, allowing the divers to monitor and control the oxygen level in the breathing loop, which can be varied manually by the divers. Oxygen level was varied during descent, bottom depth and ascent (decompression). Divers fasted for 12-18 hours before diet initiation. The ketosis level was verified by urinating on a Ketostix (reagent strips for urinalysis). RESULTS/SUMMARY: Ketosis was achieved and was easily monitored with Ketostix in the simulated operational environment. The KD did not interfere with the diving mission; no seizure activity or signs or symptoms of CNS toxicity were observed, and there were no adverse effects noted by the divers while on the KD.

Sickle cell trait and diving: review and recommendations.

INTRODUCTION: Sickle cell trait, once thought to be a benign condition, has been associated with complications which may be of concern to the diver, such as splenic infarction and exercise-related sudden death. Medical clearance to dive for those with this common hemoglobinopathy has been a source of debate, with differing recommendations for both civilian and military candidates. To assess this disparity, a review was conducted of published findings and opinions regarding sickle cell trait and fitness to dive. METHODS: Literature search was conducted using PubMed/Medline. Keywords included sickle cell trait, hemoglobinopathy, exercise-related sudden death, decompression sickness, diving, special operations, military. Results that included cases of sickle cell trait were included. Further, current guidelines were ascertained from public institutions, prominent diving texts, and the U.S. Military. RESULTS: Review of the literature reveals that complications of sickle cell trait are rare, with no reports of corresponding dive-related injury. Analysis of the physiology of diving as it pertains to the condition, as well as the absence of reported cases, suggest there is minimal increased risk in sport and technical civilian diving. Opinion for military fitness to dive is varied. CONCLUSIONS: As specific circumstances thought to predispose to sickle cell trait complication may be unavoidable in the completion of military duties, diving is not recommended for these individuals. However, recreational and commercial diving using typical precautions seems reasonable.

Fitness for duty: two cases of rare hemoglobin variants in U.S. Navy recruits.

OBJECTIVE: There are many hemoglobin (Hb) variants that vary in prevalence as well as in clinical significance. Two young male military recruits were incidentally found to have two uncommon Hb variants. This led to an investigation of Hb Lepore-Boston and G-Waimanalo to determine if these U.S. Navy recruits were healthy enough to perform their designated duties. METHODS: Literature search was conducted using PubMed/Medline. Keywords included "hemoglobinopathy," "hemoglobin variant," "Lepore-Boston," "G-Waimanalo." Results that included cases of Hb Lepore-Boston and G-Waimanalo literature were included. RESULTS: There are few reported cases of these Hb variants that have geographical patterns. It was discovered that Hb Lepore is a group of three variants, characterized by hybrid 뫧 chains, which expresses features of ß-thalassemia trait in heterozygotes. Hb G-Waimanalo or α64(E13) Aspartic acid (Asp) → Asparagine (Asn) is a slow-moving α chain variant, which often results in a mild microcytic hypochromic anemia. CONCLUSION: Hb Lepore-Boston and G-Waimanalo are benign Hb variants that typically produce mild and asymptomatic anemia. With no clinical relevance in either of these rare Hb variants, the recruits were found qualified for both general duty and their specialty rates.

Case report: clearance to dive for a naval candidate with family history of malignant hyperthermia.

INTRODUCTION: A 20-year-old male military recruit who presented for a screening physical for U.S.Naval Diving Duty was found to have family history significant for malignant hyperthermia. He had never been exposed to anesthesia, a trigger for the condition, and had not undergone testing. Medical history was otherwise unremarkable, and the patient was cleared for diving. METHODS: Literature search was conducted using PubMed/Medline. Keywords included malignant hyperthermia, exertional heat illness, exertional rhabdomyolysis, diving, special operations, military. Results that included cases of malignant hyperthermia were included. RESULTS: Review of the literature reveals that malignant hyperthermia is primary a pharmacogenetic disorder limited to specific anesthetics, with rare reports of environmental triggers. Analysis of the disease, as well as the absence of reported cases of malignant hyperthermia in diving, suggest there is minimal increased risk in diving for subjects without history of exercise intolerance. CONCLUSION: Individuals with presumed or proven malignant hyperthermia susceptibility seeking activity clearance should be given precautions and undergo careful questioning for history of heat- or exercise-related illness. If negative, it seems reasonable to allow the patient participation in recreational or technical diving.